Appendix_6__PWG_Guidelines.pdf

NTP Guidelines for the conduct of a

Pathology Working Group (PWG) review

1. GENERAL

As part of the National Toxicology Program, nominated compounds are selected for toxicology studies to further assess toxicity and carcinogenicity. Chronic (2 year), subchronic (90-day) and other studies are conducted by private contract laboratories generally called study laboratories. Initial gross and microscopic pathology evaluation is conducted by a pathologist for the study laboratory (referred to as the study pathologist or SP). The pathology findings generated at the study laboratory are then subjected to two independent pathology reviews. The first level is the Pathology Quality Assessment (Pathology QA or PQA) review conducted by a second pathology contractor. Following this the findings of the pathology QA contractor are reviewed by a third pathology contractor, called a Pathology Working Group Coordinator (PWGC), and the selected findings are reviewed at a Pathology Working Group (PWG), which represents the final stage of review. The NTP pathologist assigned to the study oversees the entire process.

Pathology Working Groups (PWGs) are typically convened at NIEHS in RTP, North Carolina for all chronic studies and selected subchronic studies. For many subchronic studies a Pathology Peer Review (PPR) is conducted and consists of the PWGC, NTP pathologist and possibly one or two other expert pathologists to review the pathology findings and achieve consensus. These guidelines generally apply to the conduct and reporting of PWG findings as well as to PPRs. Reviewed study data are ultimately incorporated into government issued Technical Reports, which represent the evidence as to a compound’s potential toxicity and carcinogenicity in rodents.

PWG responsibilities are assigned by the NTP Pathology Support contract’s Contracting Officer’s Technical Representative (COTR) based on schedules, resource availability and PWGC’s previous experience with a compound or group of related compounds. The process is initiated by way of a contract Work Assignment (WA) request.

August, 2010

2. GLOSSARY

Pathology working group (PWG): Group of pathologists invited by the NTP to achieve consensus diagnoses for NTP studies.

NTP staff pathologist: The staff pathologist assigned to the NTP study to oversee all aspects of interpretation, reporting, peer review, and defense of the pathology findings.

Study pathologist (SP): The contractor pathologist at the laboratory where the study was originally conducted.

Quality assessment pathologist (QAP): Sometimes also referred to as the reviewing pathologist (RP). These designate the contractor pathologist who performs the quality assessment review of pathology findings reported by the SP.

PWG Coordinator (PWGC): Contractor pathologist who performs the second peer review of the selected lesions, identifies areas of significant disagreement between the SP and QAP, and under the direction of the NTP pathologist, coordinates and reports the conduct of the PWG meeting and application of consensus opinions in the NTP study results.

PWG module: The software application for managing data entry and worksheets for the PWG

Pathology Peer Review (PPR): Conducted instead of a PWG, with fewer pathologists and usually used for the review of minor issues

SRWS = Slide review worksheet

DCU = NTP Data Coordination Unit

QC = Quality control

PDR = Pathology Data Review

PQA = Pathology Quality Assessment

TDMSE = Toxicology Data Management System Enterprise

COTR = Contracting Officer’s Technical Representative

IANR = Individual Animal Necropsy Record

3. PURPOSE

The main purpose of the PWG review is to achieve consensus on pathology diagnoses of all neoplasms, unusual lesions, and treatment-related neoplastic and non-neoplastic lesions. This is accomplished by resolving diagnostic discrepancies that arise during the pathology review of NTP studies. The PWG review represents the culmination of the NTP pathology review process. The findings of the PWG are considered to be the final pathology results and are used by the NTP to generate publicly available data and reports that subsequently are used for the preparation of the Technical Report.

The purpose of this document is to provide instruction and guidance in the conduct of Pathology Working Group reviews. All pathologists coordinating their first NTP PWG [i.e., it is their first time being a PWG Coordinator (PWGC)] should be mentored closely through the process by a pathologist with repetitive experience as an NTP PWGC for NTP studies.

4. OBJECTIVES

In general, the objectives are to:

- Establish validity of diagnoses

- Resolve discrepancies, if any, either with the NTP pathologist or at the

PWG

- Identify new discrepancies/issues if present for tissues under review

- Indicate whether the PWG-reviewed data might affect the conclusions

- Conduct a PWG

- Report the conduct and findings of the PWG including histological criteria for diagnoses and severity grades of potentially treatment-related lesions (with references if applicable), and description of post- PWG action items and results if applicable

5. MATERIALS

Required materials are included in a PWG Package received from the NTP Quality Assessment pathology contractor. The package contains the set of glass slides for histological evaluation, the study report from the laboratory conducting the study which includes the Study Pathologist’s

(SP) pathology narrative, the Pathology Data Review, the Pathology Quality Assessment (PQA) report, disk of the PWG module with QA findings, the pertinent Toxicology Data Management System Enterprise (TDMSE) computer data tables, copies of the Individual Animal Necropsy Records (IANRs), and, for chronic study PWGs, a copy of the subchronic study pathology reports and a copy of the SP’s report for the companion species. The slide set contains slides of all tissues containing potential treatment-related lesions and all diagnosed neoplasms (except in some circumstances such as high incidences of testicular interstitial tumors in male F344 rats). The set may also contain other slides of lesions reviewed for terminology issues, duplicate diagnoses, unusual incidences, or unusual lesions. In addition, for subchronic studies all slides of all tissues are included from six animals per sex from the control groups and from the highest dose groups with at least 60% survival at study termination, as well as from all early death animals. Tissues are selected for review of all or selected findings based upon the Pathology Quality Assessment (PQA) Review. The Quality Assessment (QA) report consists of one or more volumes which contain the Quality Assessment Pathologist’s (QAP) narrative and the Slide Review Worksheets. The Worksheets list all of the tissues and diagnoses that were reviewed during the pathology QA review, give the SP’s and QAP’s findings for each of these tissues, and provide space to record the PWGC’s and subsequent PWG findings as comments and the action to be taken e.g. add a diagnosis, change a diagnosis, etc. The TDMSE tables received include Incidence Rates of Neoplasms by Anatomic Site (PEIRPT02), Incidence Rates of Non-euplastic Lesions by Anatomic Site (PEIRPT03), Neoplasms by Individual Animal (PEIRPT04 and PEIRPT17), Statistical Analysis of Primary Tumors (PEIRPT08), Non-neoplastic Lesions by Individual Animal (PEIRPT09), Statistical Analysis of Survival Data (PEIRPT11), and Individual Animal Pathology Data (PEIRPT14).

In addition to being recorded in the volumes containing the Slide Review Worksheets, the pathology findings from the QA review are entered into a computer program known as the “PWG Module”. The information is provided electronically in the PWG set so that the PWGC’s and the PWG’s findings can be entered into the PWG Module.

6. PREPARATION FOR THE PWG

6.1 Review data. The PWGC reviews the laboratory report including the pathology narrative, pathology summary tables, gross lesions, clinical pathology data (for subchronic studies), mortality data, clinical signs, body and organ weights, and food consumption (where appropriate) and any other relevant data (i.e., thyroid hormone or Cytochrome P450 levels). The Pathology Data Review

(PDR) is reviewed and identifies dose-related positive and negative trends in lesion incidence (neoplastic and non-neoplastic), unusual lesions, lesions with unusual incidences, tumor incidences that fall below or exceed the historical incidence range, potential duplications in topography/morphology, inappropriate morphology for a given topography, or incorrect terminology for description of a lesion. The Quality Assessment (QA) report is reviewed for treatment-related lesions, areas of disagreement between the findings of the Study Pathologist (SP) and Quality Assessment Pathologist (QAP), quality of histopathology evaluation, tissue accountability, and histology technique quality. The PWGC becomes completely familiar with all potential treatment-related lesions and the diagnostic criteria used by the SP and the QAP.

Next the PWGC examines the TDMSE tables of incidence rates and the statistical analysis results to identify potential treatment-related effects, and ensures that the SP and QAP have identified these effects. The survival data are examined to determine whether there are differences in survival among groups that could influence lesion incidence. For chronic studies the subchronic PWGC’s report, if available, is reviewed to determine whether any lesions similar to those seen in the chronic study were also seen in the subchronic study. It is generally expected that lesions occurring in the subchronic study will also be present in the chronic study and if the lesions are not present, their absence may require some investigation and comment by the PWGC. Narrative comments are received from the NTP pathologist and discussion of particular diagnostic or nomenclature issues can occur with the NTP Pathologist at this time if needed.

6.2 Examine slides. Once the paper data have been reviewed and comments have been received from the NTP pathologist, the PWGC examines the slides in the PWG set and compares the findings in each slide with those listed in the QA report in Slide Review Worksheets. These worksheets list the tissue examined, the SP’s and QAP’s findings in that tissue. They also provide columns for the PWGC’s findings and the PWG’s findings as comments, and the action to be taken in the case of disagreements. Findings may be entered either directly by the PWGC into the PWG Module, or the PWGC may enter their findings by hand on the Worksheets in which case findings are entered into the PWG Module by a data entry specialist. If the QAP agrees with the SP, and the PWGC also agrees with the SP, the PWGC simply enters “Agree” or makes a checkmark in the PWGC’s comment column. If the QAP disagrees with the SP and the PWGC agrees with the QAP they enter “Agree with QAP", and if they agree with the SP they enter “Agree with SP".

If at any time the PWGC disagrees with both the SP and QAP they must enter their own diagnosis on the Worksheets and the slide in question is set aside for initial review by the NTP pathologist responsible for this particular study, and for possible review by the PWG. The PWGC reviews all slides in the slide set, even if the SP and QAP agree on the diagnosis, unless directed by the NTP pathologist that a full slide review is unnecessary.

While reviewing the slides the PWGC checks to see that the findings of the SP and QAP are in agreement and to ensure that all chemical/dose-related effects are accurately identified and evaluated. In subchronic studies, the PWGC examines all slides from six male and six female animals from the control groups as well as from the highest dose groups with at least 60% survival at study termination. This is done in order to ensure no potential treatment-related effects were missed during prior evaluations. In subchronic studies all slides are also examined from all early death animals in order to determine the cause of death and determine whether or not death was related to the test compound. The PWGC also maintains vigilance for consistency in lesion identification and terminology between mouse and rat studies, and between subchronic and chronic studies.

6.3 Severity grades. Grades should generally be applied according to the threshold and criteria of the SP, unless there is some compelling reason to do otherwise (e.g. to better characterize non-neoplastic lesions or confirm potential treatment-related effects not discerned with SP or QAP grading results).

The QAP and PWGC should review severity grades for lesions identified in the PDR (i.e. – lesions with treatment-related increases in severity and/or incidence). Occasionally discrepancies might be noticed by the QAP or PWGC during review and if so, should be brought to the attention of the NTP pathologist to discuss.

The QAP and PWGC should grade lesion severity independently of the SP findings. If the vast majority of occurrences are within one severity grade of the SP’s grade and the QAPs findings generally supports the SP’s conclusion(s) (effect or not) then the SP diagnoses are accepted. If the QAP’s severity scores for a particular lesion is frequently more than 1 severity grade different from the SP; or if the QAP identifies a treatment-related effect not found by the SP, or finds no effect where the SP did, then the

PWGC should bring this to the attention of the NTP pathologist.

The PWG may be used to resolve grading discrepancies.

The PWG outcomes could be:

1. accept all SP grades

2. accept all QAP grades

3. accept all PWGC grades

The PWG is not designed to confirm individual grades but rather to give an overall assessment of whether the SP grading system is adequate or not based on analyzing discrepancies presented at the PWG. Grading is subjective and relative to other animals in the study; therefore, the grading scheme of one pathologist is globally accepted and applied rather than grades for individual lesions being determined by a 2 out of 3 consensus (i.e. SP, QAP, and PWGC).

6.4 IANRs. The IANRs occasionally must be consulted during the slide review to resolve questions such as which slide contains the section of a gross lesion or to resolve discrepancies concerning tumor multiplicity (e.g., whether one or more tumors were seen grossly).

6.5 Selection of slides. The PWGC makes a list of slides to be potentially shown to the PWG and about which they will consult with the NTP pathologist assigned to that chemical. This list will include 1.) representative or all slides to resolve discrepancies between the SP and QAP, 2.) slides of representative toxicologically significant lesions in which there is agreement among the SP, QAP, and PWGC, 3.) all slides in which the PWGC disagrees with both the SP and QAP, 4.) slides of borderline lesions (e.g., very small neoplasms), which the PWGC feels should be reviewed by the PWG in order to obtain a solid definitive diagnosis and 5.) unusual lesions, even if not treatment-related, in order to confirm the diagnosis. In the case of a subchronic PWG in which the “no effect” level is to be identified, the PWGC selects representative slides from the dose levels at which there is agreement that treatment-related lesions are present and not present, as well as slides in which there are disagreements as to the presence of a treatment-related lesion.

6.6 As soon as possible after the slide review is completed, the PWGC should contact the NTP pathologist. The PWGC and NTP pathologist should microscopically examine representative sections of lesions. (If remotely located the PWGC should send images to the NTP pathologist.) The PWGC discusses the findings, including disagreements and discrepancies in diagnoses, with the NTP pathologist, recommends tissues and lesions to be shown to the PWG; and gives an estimate of the number of slides that must be shown in order to provide the PWG with an accurate representation of the lesions. Disagreements in background or minor treatment-related lesions may be resolved at this time at the NTP pathologist’s discretion, without presentation to the PWG.

Disagreements in appropriate terminology or lesion characterization may be reviewed with the NTP pathologist but are generally always presented to the PWG for discussion and consensus agreement.

Tumors with three disparate opinions or in which the PWGC disagrees with the SP and QAP are generally presented for PWG review but may also be reviewed by the NTP pathologist at this time. The PWGC and the NTP pathologist make the final decisions concerning what tissues and slides will be shown to the PWG. In the event of a missed target tissue (most likely with subchronic studies), the PWGC informs the NTP pathologist who may then request that the PWGC review that tissue for all study animals prior to the PWG.

6.7 All chronic studies will have a full PWG unless as directed by the

Head of the NTP Pathology Group to do otherwise.

6.8 Pathology Peer Review (PPR). For most subchronic studies, including 90-day or immunotoxicity studies, in which there are no significant findings, or only minimal findings, a Pathology Peer Review (PPR) is conducted instead of a full PWG. The PWGC meets with the responsible NTP pathologist (and perhaps one or more other NTP pathologists) to review selected slides and resolve disagreements. The report of the Pathology Peer Review is the same as for the subchronic PWG except the term Pathology Peer Review is used instead of Pathology Working Group for the final Coordinator’s written report.

6.9 The PWGC prepares a slide set and completes the Pathology Working Group Participants Worksheets, which lists the slides to be examined by the PWG. The slides are clearly labeled with worksheet-assigned numbers on brightly colored dots that are affixed to the slides. They are arranged in such a manner that treatment-related lesions in different organs are each presented as separate groups which are listed in order on the Participants Worksheets (also called “handwritten worksheets”). Unless instructed otherwise, all slides for the PWG shall be scanned. A PowerPoint presentation generated by the PWGC should be sent to DCU and made available for review by the PWG participants prior to the PWG. Slides should be submitted to DCU no later than 2 weeks prior to the PWG. Once scanned images are uploaded to the Spectrum website, the PWGC adds questions or comments for the PWG participants to view, and annotates scanned slides to identify/locate the lesion(s) or area(s) of interest as needed.

The Participants Worksheets list the dot color and slide number, the animal identification number, the number of slides shown per dot/animal number, and the organ or tissue. The Participants Worksheets contain space in which the PWG participants can write their diagnoses after reviewing a slide. In order to focus the PWG’s attention on the particular question/lesion of concern, it is best on the worksheets to provide clear alternatives to the PWG (Adenoma Yes or No? Adenoma or Hyperplasia?) In most instances the PWGC should use a marker pen to direct the participants' attention to a particular part of the slide being reviewed. Areas for focused examination of tissue can also be marked on the digital PWG images. Copies of standardized Participants’ Worksheets are distributed to the participants at the beginning of the PWG. The PWG participant’s votes are entered onto the PWGC’s Master Worksheet and this document is retained as an official record of the PWG. Votes for global changes on diagnoses and terminologies are also indicated on this document. (Note: worksheets are also created for a Pathology Peer Review.)

Following completion of the PWG slide review, a data entry specialist or the PWGC enters the PWG’s diagnoses into the computerized PWG Module. In addition, entries are made into the Action Taken column of the Slide Review Worksheets on the PWG module. Entries made in this column include no change required (if no change is to be made to the findings), change diagnosis, delete diagnosis, or add diagnosis, and may additionally contain comments and tissue notes.

7 CONDUCT OF THE PWG

7.1 Organizing and set up. The contractor is responsible for

organizing and inviting PWG participants in consultation with the designated NTP pathologist in the NTP Pathology Group. This designee is generally one of the Contracting Officer’s Technical Representatives from one of the NTP pathology contracts.

Prior to the PWG the DCU staff will make available (via email or website) the complete QA narrative in pdf format to all PWG participants.

The PWGC conducts PWG reviews for NTP toxicity studies

(subchronic, chronic, immunotox, etc) under the direction of the NTP pathologist assigned to that chemical.

7.2 The big day. The PWGC should arrive at least 30 minutes prior to the PWG, assist with setting up the room and projector, and be ready to begin the PWG promptly. At the end of the PWG, the PWGC should help put microscopes, projector, and telecommunication equipment away.

At the beginning of the PWG, the PWGC and/or the NTP study scientist, if available, gives the PWG participants a general introduction and provides an overview of the study, which includes a basic description of the test compound; review of the study design; dose groups; mortality; body weight and organ weight data;

significant clinical signs; pathology findings; clinical pathology data for subchronic studies; and for chronic study PWGs, results of the subchronic study. PowerPoint presentations shall be used for presenting this data and can illustrate specific lesions and observations under consideration. The PWGC shall present 1.) the major issues for resolution, 2.) the plan to resolve and 3.) any relevant diagnostic and/or grading terminology issues and criteria.

A handout containing the presented information may be given to each PWG participant at the beginning of the PWG. All PWG participants are asked to sign a PWG signature sheet which becomes part of the PWG report. This is obtained from the DCU the day of the PWG by the NTP pathologist.

The PWGC distributes slides in groups for review by the PWG members. After all PWG members have viewed all of the slides from a group, the PWG members are asked to look at their worksheets and give their diagnoses for each slide examined (generally by raised-hand voting). The diagnosis favored by a majority of the members is considered to represent the consensus diagnosis of the PWG and is recorded by the PWGC on the PWGC’s Master Worksheet. In a few instances a clear consensus is not reached. The PWGC may reserve their vote to break any ties in the lack of a clear consensus or the diagnosis may revert to the SP diagnosis. Digital images of the slides may be projected during the PWG voting for discussion purposes. Occasionally a re-vote is warranted after discussion.

7.3 In PWGs for subchronic studies, the PWG may be asked to

comment on the "no effect" dose level (if one was reached).

7.4 Any problems related to the pathology evaluation and quality of histology technique (disproportionate sampling of tissues, labeling discrepancies, etc.) are discussed and the consensus opinion of the PWG regarding their effect, if any, on the pathology findings is recorded by the PWGC and included in the PWGC’s report. The PWG is in a unique position to comment on the biological significance of treatment-related lesions. These comments are recorded by the PWGC and included in the PWGC’s report. The PWG comments are extremely valuable to NTP personnel when reviewing the significance of study findings.

7.5 The PWG is in a unique position to comment on the biological significance of treatment-related lesions. These comments are recorded by the PWGC and included in the PWGC’s report. The PWG comments are extremely valuable to NTP staff when reviewing the significance of study findings.

7.6 The PWGC may be empowered by the PWG or NTP pathologist to make judgment calls on the final diagnoses of lesions of individual animals for which the PWG has seen representative examples.

Occasionally, the PWG may request additional tasks be performed to clarify issues raised during the PWG review. These tasks, known as Post-PWG Action Items, may include regrading lesions, resectioning blocks of specific lesions, performing special stains, performing ultrastructural examination, preparation and evaluation of step sections, or specific reviews of additional pathology materials such as slides, blocks, or wet tissues. Generally the PWGC is responsible for accomplishing the Post-PWG Action Items and it is therefore important that the Coordinator’s laboratory have the capability to perform the required tasks. Post-PWG action items are discussed with the NTP pathologist to establish reasonable deadlines. The findings of Post-PWG Action Items are included in the PWGC's report unless otherwise directed.

Photography of selected lesions may also be performed by the PWGC at the request of the NTP.

8 PWG REPORT

8.1 Drafts to final. Following the PWG, the PWGC prepares a

comprehensive report of the PWG review and PWG findings to be submitted for approval by the NTP pathologist. The report is first submitted as an electronic draft for review by the NTP pathologist, who will review and may request that revisions be made to the draft report. Multiple drafts with revisions may be reviewed by the NTP pathologist and each draft report is labeled as PWG Draft Report A, PWG Draft Report B, etc. Generally, once all electronic revisions are made and approved by the NTP pathologist a hard copy of the report is submitted as a PWG draft report #1 to DCU. Once approved by the NTP pathologist, it is submitted to DCU as a final report. The first draft PWGC report (PWG Draft Report A) is generally due to the NTP pathologist within seven business days following the PWG.

The PWGC’s report includes a brief description of the study design, relevant data, such as mortality and clinical pathology alterations, and a short summary of lesions considered by the PWG to be possibly related to treatment. In addition, each potential treatment-related lesion is discussed in detail, including the PWG’s comments regarding the biological significance of the lesion, and complete histologic descriptions and diagnostic criteria. All issues discussed and conclusions reached by the PWG are described, including the PWG’s comments, if any, about the histotechnique quality.

Diagnostic disagreements that arise during the QA and PWG review are discussed and the final resolution by the PWG is described. Any factors, which may have affected the interpretation of the results, such as survival or body weight changes, may be included in the discussion. Conclusive statements should be avoided since post-PWG tabulation and statistical analysis of the final data have not been performed at this stage. Preferred conclusions for equivocal effects would be statements such as:

“There was a potentially increased or slightly increased incidence in thyroid neoplasms”. The PWGC should comment whether the peer-reviewed findings, in general, either support or refute original findings of the study laboratory. Tables should be used sparingly in PWG reports, only to demonstrate resolution of major or complex discrepancies between the SP, QAP, and PWG.

For subchronic PWG or PPR reports, summaries of mortality data, clinical signs, body and organ weight changes, clinical pathology data, a description of gross lesions, and the “no effect” level, if determined, should be included.

The PWGC’s near-final PWG report (designated as DRAFT REPORT #1) is delivered to the NTP data coordination unit and then to the NTP pathologist who has been assigned review responsibility for the PWG. The PWG slide review worksheets (SRWS) are part of the PWG report. If a PowerPoint presentation was given, an electronic copy on disc should also be sent to DCU.

The glass slides shall be retained temporarily by the PWGC in the event that the NTP pathologist, after reviewing the reports, requests corrections that require the Coordinator to review some of the slides.

After submitting PWG DRAFT REPORT #1, it will be reviewed by both DCU staff and the NTP pathologist. Comments will be made on a single copy of the draft, which will be returned to the PWGC.

Changes indicated will be included in a new draft with updated title (DRAFT #2) and submitted as hardcopy and electronically (as a Word document attached to an e-mail) to the NTP pathologist and DCU. Any subsequent revisions will be handled similarly (all comments on a single copy of the report; new updated draft prepared and sent via e-mail). Each revised draft, if needed, should be designated with a unique designation (i.e. DRAFT #3, DRAFT #4, etc) when submitted back to the DCU. If only minor revisions are needed in a draft, the next version of the report can be submitted as final at the discretion of the NTP pathologist.

When the draft is acceptable to the NTP, the PWGC will be notified to finalize the report. This PWG Report will have “FINAL” included in the title (the phrase “Revised Final” should be avoided). The contractor should verify the personnel listed in the Final PWG report are correct (i.e. the study scientist, study pathologist, PWG participants, etc.), all required signatures are obtained, and the pdf is complete and identical to the hardcopies. If color images are present in the PWG report, then the pdf copy should also have color images. If it is necessary to submit a draft report prior to QA review, the report is marked “Unaudited Draft Report”. The audited FINAL Report should be submitted to the DCU as an original hardcopy (and two photocopies) for signatures.

An electronic PDF file of the FINAL Report with signatures should then be submitted to the DCU. The contractor’s Quality Management Specialist should ensure that the pdf report accurately reflects the FINAL Report. All study materials, including all slides, are returned to the NTP archives after the final report is submitted.

Once the signed final report is approved by the NTP pathologist it is considered final and ready for distribution. In the rare event a change needs to be made to an approved, distributed final report it shall be submitted separately as an addendum or amendment.

8.2 Post-PWG Action Items. Results of any special studies from Post- PWG Action Items recommended by the PWG or NTP are also included, depending upon the discretion of the NTP pathologist responsible for the PWG. If the post-PWG studies have not been completed before submission of the PWG report, the results can be submitted at a later date as an addendum to the report. If issues arise during the QA review or during the PWG that require additional review, generally performed as Post-PWG Action Items, before the report can be completed, the PWGC consults with the NTP pathologist responsible for the PWG to determine whether to postpone submission of the report until the additional work can be completed and the results included in the PWG report.

8.3 Attachments to the report include the PWG signature page, the PWGC’s Report table that includes the PWG diagnoses, and a copy of the original handwritten worksheets generated by the PWGC during the PWG. Copies of the original handwritten Worksheets are used by NTP personnel to ensure the PWG diagnoses on the PWGC’s Report table are correct. The copies of the original Worksheets are submitted only with the draft report.

They are not required to be submitted with the final report.

8.4 Outline of a PWG report:

TITLE PAGE – name of report (PATHOLOGY WORKING GROUP

COORDINATOR’S FINAL REPORT), date, chemical/TDMSE #, CAS #, NTP study #, Species, strain, sex, route of exposure, name and workplace of PWGC, and the following statement regarding any potential conflict of interest:

The pathologist performing this review, Dr. __________, has had no involvement with any laboratory or organization concerned with this study other than the NTP and has not been involved in the origination or any previous review of data from this study.

I. INTRODUCTION - date, chemical #, NTP study #, site, participants, background, etc

II. SUMMARY OF ORIGINAL STUDY RESULTS

a. Study design

b. Morbidity, mortalities, clinical signs, organ weights, body weights, gross findings are summarized

c. Potential treatment-related effects (list from the lab report, PDR, and QA report)

III. FINDINGS OF THE PWG/PPR

a. Conduct of the PWG (general overview)

b. Results of the PWG Review

- Approach and resolution of discrepancies

- Diagnostic disagreements between SP, QAP and PWG pathologists and consensus of PWG

- Disagreement resolution by PWGC and NTP pathologist(s)

- Agreements for potentially treatment-related lesions

- Whether the findings potentially change the conclusions of the study

- Present the histopathology in clear statements of SP findings, QAP review findings, and confirmation or lack thereof by the PWG participants and PWGC

- Include a detailed description of potentially treatment-related or unusual lesions and severity criteria for potentially treatment related lesions

- Discuss factors potentially affecting interpretation, if any

IV. HISTOTECHNIQUE QUALITY

- Briefly assess the diagnostic quality of the H&E slides for the study.

V. POST-PWG ACTIONS (if any)

VI. OTHER

VII. CONCLUSIONS OF THE PWG (summary)

- List all potential effects noted during initial and QA review and whether or not they were confirmed

VIII. REFERENCES

- List references for diagnostic criteria, grading criteria, or other pertinent pathology literature

9 DATA ENTRY / REDLINING

Following the PWG, the PWG Consensus findings are entered into the computerized PWG Module by a data entry specialist or the PWGC. New copies of the Slide Review Worksheets (SRWS) containing the findings of the PWG and the PWGC are generated (a 100% QC and QA is conducted on the slide review worksheets) using the PWG Module and submitted in place of the original worksheets to the NTP Data Coordination Unit. The SRWS are checked for accuracy and completeness using a red pen by the Clinical Pathology Coordinator of the DCU with close guidance by the NTP pathologist in a process called “redlining”, where entries in the “Action to be Taken” column of the SRWS are either confirmed with a check-mark or corrected by lining out incorrect entries and writing in the correct entries. All pages of the SRWS that have an “Action to be Taken” entry are initialed and dated during the redlining.

The materials needed for redlining the SRWS include the final Quality Assessment Report; the draft TDMSE P-14 Individual Animal Pathology Data Report; a copy of the Draft PWGC’s report with appendices and Post-PWG action items; a copy of the PWGC’s Master Worksheet (also known as the “handwritten worksheets”) used to record votes taken at any meetings prior to or at the PWG (or PPR); and any correspondence between the NTP pathologist, PWGC or other staff that contains decisions concerning diagnoses within the study.

A table, which is included with the PWGC’s Report, is generated by the PWG Module program that lists the dot number of the slide examined, the doses group and animal identification number, number of slides shown per animal, tissue, SP’s diagnosis, QAP’s diagnosis, and the PWG consensus opinion. This table is known as the PWGC’s Report Table (also called “typed worksheets”) and is also used during the redlining process. After the redlining is complete, all materials are returned to the contractor’s data entry specialist and the appropriate changes are made in the pathology data files.

10 TIMELINES OF PWG AND PPR PROCESS

10.1 The coordination and reporting of the conduct of Pathology Working

Group (PWG) is an integral part of the NTP’s pathology review process so it is important that it be timely. Timeliness depends on the efforts of NTP staff and NTP contractors. For chronic (2-year) studies, it is expected that a PWG be held within 11 weeks (range 4-16 weeks, depending on the complexity of the PWG) of assignment and delivery of the PWG package (reports and glass slides, etc) to the PWGC (PWGC). The final PWG report is expected within 30 days of the PWG, the redlining within the 14 days of the 1st draft, and the data finalized in TDMSE in 7 days.

This would mean the entire PWG process should be completed to final data in ≈130 days (or 4.5 months). Subchronic PWGs or PPRs should be completed in half as much time (≈65 days or 2 months)

10.2 In preparation for the PWG, review of uncomplicated subchronic rodent studies (presented as one package of rats and mice) should be conducted by the PWGC in about 4 weeks. Review of an uncomplicated chronic rodent study (one species) should take about 6-8 weeks (time from receiving PWG package to choosing slides/issues for PWG meeting).

10.3 TYPICAL TIMELINES FOR:

1. Subchronic PPR from package to PWGC to final report ≈ 8 weeks (4-12 weeks)

Day 1: receive package Day 7: discuss QA findings and approach with NTP pathologist Weeks 2-4: review slides and prepare for PPR/PWG, meet with NTP pathologist to discuss Week 5: hold PPR Week 6: post PPR action items, if any Week 7: write and submit first PPR draft, obtain pictures/scans of representative lesions; redlining begins Week 8 - submit final PPR report with photos (CD) after final redlining

2. Subchronic PWG from package to PWGC to final report ≈ 11 weeks (5-20 weeks)

Day 1: receive package Day 7: discuss QA findings and approach with NTP path Weeks 2-4: review slides and prepare for PPR/PWG, meet with NTP pathologist to discuss Weeks 5-6: choose slides for PWG and have scanned in Week 7: hold PWG Week 8: post PWG action items, if any Week 9: write and submit first PWG draft, obtain pictures +/- scans of

Week 11: submit final PWG report with photos (CD) after final redlining

3. Chronic PWG from package to PWGC to final report ≈ 17 weeks (10-26 weeks)

Day 1: receive package Day 7: discuss QA findings and approach with NTP pathologist Weeks 2-6: review slides and prepare for PWG, meet with NTP pathologist to discuss Week 7: choose slides for PWG and have scanned Week 9 or 10: hold PWG Weeks 10-13: post PWG action items, if any Weeks 14-15: write and submit first PWG draft, obtain pictures +/- scans of

Week 17: submit final PWG report with photos (CD) after final redlining

11. RESPONSIBILITY

It is the responsibility of the pathologist assigned as PWGC to perform all procedures connected with a PWG in accordance with these guidelines and with instructions from the NTP COTR. In addition, the PWGC is responsible for ensuring that the PWG report is completed on time and that all materials are returned to the NTP.

It is the responsibility of the contracted Pathology Support provider’s Principal Investigator to insure that the assigned PWGC has suitable training or experience and that there is appropriate support from laboratory personnel to enable timely completion of the PWG.

Approved by:

David E. Malarkey DVM, PhD, DACVP Head, National Toxicology Program Pathology Group Cellular and Molecular Pathology Branch National Institute of Environmental Health Sciences 111 Alexander Dr. Maildrop B3-O6

PO BOX 12233

Research Triangle Park, NC 27709

Phone 919-541-1745 Fax 919-541-7666 Email malarkey@niehs.nih.gov

With valuable contributions from:

Susan A. Elmore DVM, MS, DACVP NTP, NIEHS, RTP, NC

Ron Herbert DVM, PhD NTP, NIEHS, RTP, NC

Mark Cesta, DVM, PhD, DACVP NTP, NIEHS, RTP, NC

Robert Sills, DVM, PhD, DACVP NTP, NIEHS, RTP, NC

Gordon Flake, MD, DACP NTP, NIEHS, RTP, NC

Michael C. Boyle, DVM, DACVP NTP, NIEHS, RTP, NC

John C. Turnier VMD, DACVP Pathology Associates-CRL, RTP, NC

James Morrison, DVM, DACVP Pathology Associates-CRL, RTP, NC

Mike Jokinen, DVM, DACVP Pathology Associates-CRL, RTP, NC

John Peckham, DVM, PhD , DACVP Experimental Pathology Labs, RTP, NC

Mel Hamlin, DVM, PhD Experimental Pathology Labs, RTP, NC

J. Todd Painter, DVM, PhD, DACVP Integrated Laboratory Systems, RTP, NC

Georgette Hill, DVM, PhD Integrated Laboratory Systems, RTP, NC