Probability of Causation (PC) News & Updates

Revision of Guidelines on Non-Radiogenic Cancers

On March 21, 2011, the Department of Health and Human Services (HHS) proposed to treat chronic lymphocytic leukemia (CLL) as a radiogenic cancer under the Energy Employees Occupational Illness Compensation Program Act of 2000 (EEOICPA or the Act) (76 FR 15268).

CLL is now treated as being potentially caused by radiation and as potentially compensable under the Act. This reverses the earlier decision by HHS to exclude this cancer from consideration. The final rule was published on February 6, 2012. This change became effective on March 7, 2012.

• Notice of Proposed Rulemaking:
  Guidelines for Determining Probability of Causation Under the Energy Employees Occupational Illness Compensation Program Act of 2000; Revision of Guidelines on Non-Radiogenic Cancers [270 KB (8 pages)]

• Final Rule:
  Guidelines for Determining Probability of Causation Under the Energy Employees Occupational Illness Compensation Program Act of 2000 (The Act); Revision of Guidelines on Non-Radiogenic Cancers[145 KB (1 pages)]

Please Note: The Final Rule does not add CLL to the list of “specified cancers” or qualifying cancers for the Special Exposure Cohort.

Public comment on this rulemaking closed on June 20, 2011. A complete electronic docket containing reviews of CLL radiogenicity and the CLL Risk Model and public comments can be found on the NIOSH Docket page, under Docket Number 209: PC – Nonradiogenic Cancer Reconsideration.

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Changes to the NIOSH-IREP Lung Cancer Risk Model

• Draft: A Review of NIOSH’s Program Evaluation Report OCAS-PER-008, Modification of NIOSH-IREP Cancer Risk Model: Effect of “Combined” Lung Model on Non-Compensable Lung Cancer Claims (OCAS-PER-008)[414 KB (26 pages)]
  • Document Number: SCA-TR-PR2010-0008, Rev. 0
  • About this Document: Review of OCAS-PER-008
  • Approved: December 15, 2010
• OCAS-PER-0008 Rev-00: Modification of NIOSH-IREP Lung Cancer Risk Model: Effect of “Combined” Lung Model on Non-compensable Lung Cancer Claims[143 KB (4 pages)]
  • Document Number: OCAS-PER-0008 Rev-00
  • About this Document: Reports the impact of the NIOSH-IREP lung cancer model on non-compensable cases completed before February 28, 2006.
  • Approved: April 12, 2007

  The combined lung cancer risk model was introduced on 02/28/06 via the release of NIOSH-IREP Version 5.5, followed by v5.5.1 on 05/16/06. The combined lung model is programmed with two different lung cancer risk models: the NIOSH-IREP model, plus an alternative risk model created by the National Cancer Institute for use in NIH-IREP, another version of IREP (referred to hereafter as the “NIH” model). For each cancer of the lung, trachea, or bronchus, NIOSH-IREP now calculates separately the probability of causation (PC) produced by each of the two risk models and reports the higher PC at the upper 99th percentile credibility limit as the PC value of record for the claim. NIOSH-IREP v5.5 and v5.5.1 also incorporate a bias correction factor for random errors in dosimetry for “never smokers” exposed to radon. Due to a programming oversight, this correction had been omitted for “never smokers”” and was applied only to smokers in earlier versions of NIOSH-IREP. NIOSH-IREP v5.5 corrected this error.

  This “combined” lung cancer risk model was endorsed by the Advisory Board on Radiation and Worker Health, and can result in no lower PC value for the same set of claim inputs than had been calculated under previous versions of NIOSH-IREP (versions 5.4 and earlier).

  For a more detailed description of the new combined model, including the background of and rationale for the modification, please refer to OCAS-PEP-008 below.

• PEP 8: Modification of NIOSH-IREP Lung Cancer Risk Model: Impact of “Combined” Lung Model on Non-Compensable Lung Cancer Claims[132 KB (5 pages)]
  • Document Number: OCAS-PEP-008 Rev-00
  • About this Document: New document to evaluate the modification of the NIOSH-IREP lung cancer model on previously competed cases.
  • Approved: December 7, 2006

  NIOSH-IREP Version 5.5 was installed on February 28, 2006, replacing NIOSH-IREP v5.4. This updated version of NIOSH-IREP incorporates modifications to the lung cancer risk model for calculating PC for cancers of the lung, trachea, or bronchus. Specifically, NIOSH-IREP v5.5 is programmed with two alternative lung cancer risk models. NIOSH-IREP v5.5 calculates separately the PC produced under each risk model for each cancer of the lung, trachea, or bronchus, and reports the higher PC of the two models as the PC of record for the case. This risk model change was endorsed by the Advisory Board on Radiation and Worker Health, with the provision that NIOSH revisit the issue in approximately one year to determine if new evidence might warrant consideration of a single lung cancer risk model. Further details regarding this change, including copies of all relevant documents provided to the Advisory Board on Radiation and Worker Health, can be accessed below.

  NIOSH-IREP v5.5 also incorporates a bias correction factor for random errors in dosimetry for “never smokers” who were exposed to radon. Due to a programming oversight, this correction had been inadvertently omitted for “never smokers” and was applied only to smokers in earlier versions of NIOSH-IREP. NIOSH-IREP v5.5 corrects this error.

  The modifications incorporated in NIOSH-IREP v5.5 pertain only to the “Lung (162)” risk model and apply only to cancers of the lung, trachea, or bronchus. In conjunction with these revisions, NIOSH will review all relevant previously completed cases that have not been compensated to identify those for which the changes are applicable, and will re-evaluate the cases using the new guidelines. NIOSH will also apply the new guidelines to all currently active cases and any future cases. This may result in the Department of Labor calculating higher PC determinations for select lung, trachea, or bronchus cases among previously decided and current EEOICPA cancer claims. (Note: It will not result in lower PC determinations for any case.)

  • Background Information: Proposed Modification of NIOSH-IREP Lung Cancer Risk Model (October 2005)

    NIOSH proposes to install the NIH-IREP lung cancer risk model into NIOSH-IREP, but to retain the current NIOSH-IREP lung model as well. Under this proposal, EEOICPA lung cancer cases would be processed by running each case under both IREP models, separately, but NIOSH-IREP would report only the set of results associated with the higher PC at the upper 99th percentile credibility limit. Thus, the higher of the two values at the upper 99th percentile would determine compensability. Should this NIOSH-IREP change be implemented, all previously completed non-compensable EEOICPA lung cancer cases would be reevaluated.

    This proposal is based in part on recommendations obtained from four outside experts who agreed to review the IREP lung models. NIOSH concludes that the points raised by reviewers warrant erring on the side of EEOICPA claimants by adopting the methodology described above.

    A letter announcing this proposed change, along with eight supporting documents including the four expert opinions, was delivered to ABRWH members in late September 2005. These documents, taken together, provide a detailed explanation and chronology of the factors leading to this proposal. Links to the nine documents are provided below:

    • NIOSH/OCAS. Notice of intent to change the NIOSH-IREP lung cancer risk model for estimating probability of causation under EEOICPA (letter from NIOSH to ABRWH).[27 KB (3 pages)]
    • Land CE and Pierce DA. Likelihood profile for parameter alpha used in computation of statistical uncertainty for ERR/Sv in NIH-IREP lung cancer model (identified in letter to ABRWH as Enclosure #1).[36 KB (5 pages)]
    • Apostoaei AI and Trabalka JR. Differences in the estimation of lung cancer risk between NIOSH-IREP and NIH-IREP (identified in letter to ABRWH as Enclosure #2).[228 KB (27 pages)]
    • NIOSH/OCAS. Evaluation of NIH-IREP lung cancer risk model for application to NIOSH-IREP (NIOSH instructions to outside reviewers, identified in letter to ABRWH as Enclosure #3).[21 KB (4 pages)]
    • Comments from Faith G. Davis, PhD, Professor, Division of Epidemiology and Biostatistics, University of Illinois at Chicago School of Public Health (identified in letter to ABRWH as Enclosure #4).[16 KB (5 pages)]
    • Comments from Jonathan M. Samet, MD, MS, Professor and Chairman of the Department of Epidemiology, Johns Hopkins University School of Public Health (identified in letter to ABRWH as Enclosure #5).[114 KB (5 pages)]
    • Comments from David B. Richardson, PhD, Assistant Professor of Epidemiology, University of North Carolina School of Public Health (identified in letter to ABRWH as Enclosure #6).[29 KB (7 pages)]
    • Comments from David J. Brenner, PhD, Professor of Radiation Oncology and Public Health, Columbia University School of Public Health (identified in letter to ABRWH as Enclosure #7).[33 KB (4 pages)]
    • SENES Oak Ridge Inc. How should NIOSH estimate risk of lung cancer in workers covered under EEOICPA in the face of uncertainties in the interaction between smoking and low-LET radiation. (Summary and analysis of expert comments, identified in letter to ABRWH as Enclosure #8).[121 KB (18 pages)]
  • Changes to the NIOSH-IREP Lung Cancer Risk Model: Request for comments regarding a change to a scientific element underlying the determination of PC under EEOICPA
    • Changes to the NIOSH-IREP Lung Cancer Risk Model Under the Energy Employees Occupational Illness Compensation Program Act of 2000[52 KB (2 pages)]
      March 24, 2006

    NIOSH has changed a guideline for determining the PC under the EEOICPA for energy employees with cancers of the lung, trachea, or bronchus. The change affects only the NIOSH-IREP cancer risk model termed “Lung (162).” The new guideline, which became effective on February 28, 2006, with the introduction of NIOSH-IREP Version 5.5, requires the use of both a National Institutes of Health (NIH)-IREP lung model implemented by NIH in 2003 and the original NIOSH-IREP lung model implemented by NIOSH in 2002. NIOSH-IREP Version 5.5 calculates separately the PC produced under each model for each cancer of the lung, trachea, or bronchus. The result from the model that produces the higher PC at the upper 99th percentile credibility limit is reported as the PC result of record for the case. NIOSH-IREP Version 5.5 also incorporates a bias correction factor for random errors in dosimetry for those energy workers who had not smoked cigarettes (“never smokers”) and who were exposed to radon. This correction was previously applied to smokers, but had been inadvertently omitted for never smokers. These changes may result in DOL calculating higher PC determinations for select cases of cancer of the lung, trachea, or bronchus among previously decided and current EEOICPA cancer claims. The changes cannot result in any lower PC determinations. Although this change to the NIOSH-IREP lung cancer risk model took effect February 28, 2006, NIOSH will fully consider all comments received regarding this change and may reconsider this change or consider further revisions to the lung cancer risk model based on public comment.

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Radiogenicity of Specific Cancers

• Final: Report to the Senate Appropriations Committee on The Radiogenicity of Specific Cancers Under the Energy Employees Occupational Illness Compensation Program Act of 2000 as Amended[53 KB (10 pages)]
  • About this Document: In response to Senate Report (S. Rep.) 109-103 (2005), NIOSH examined the evidence for the radiogenicity1 of 11 “non-presumptive cancers,” which were not included in the list of 22 “specified cancers” referenced in the Energy Employees Occupational Illness Compensation Program Act of 2000 as Amended (EEOICPA)
  • Sent to Congress: December 17, 2009
  • Summary: Review of the evidence of radiogenicity of specific cancers indicates that there is strong epidemiologic evidence for the radiogenicity of basal cell carcinoma and insufficient evidence for larynx, CLL, lymphoma (Hodgkin’s), male genitalia, oral cavity, prostate, skin (squamous cell), uterus, and malignant melanoma.
    • Interim: Report to the Senate Appropriations Committee on the Radiogenicity of Specific Cancers under the Energy Employees Occupational Illness Compensation Program Act of 2000 as Amended[30 KB (11 pages)]
      • About this Document: In response to Senate Report (S. Rep.) 109-103 (2005), NIOSH examined the evidence for the radiogenicity1 of 11 “non-presumptive cancers,” which were not included in the list of 22 “specified cancers” referenced in the Energy Employees Occupational Illness Compensation Program Act of 2000 as Amended (EEOICPA)
      • Sent to Congress: June 2007
      • Summary: Review of the evidence of radiogenicity of specific cancers indicates that there is strong epidemiologic evidence for the radiogenicity of basal cell carcinoma and insufficient evidence for larynx, CLL, lymphoma (Hodgkin’s), male genitalia, oral cavity, prostate, skin (squamous cell), uterus, and malignant melanoma.

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Changes to the Dose Reconstruction Target Organ Selection for Lymphoma

• Target Organs for Lymphoma[17 KB (2 pages)]
  • Document Number: OCAS-PER-009 Rev-00
  • About this Document: New document to change target organs for lymphoma.
  • Approved: March 8, 2007
  • Summary: In February, 2006, OCAS determined that the internal and external dosimetry target organs used for several forms of lymphoma should be changed. The detailed rationale for this decision is described in OCAS-TIB-012. The change resulted from a detailed investigation by OCAS of the etiology of lymphoma.
• Federal Register Notice: Changes to the Dose Reconstruction Target Organ Selection for Lymphoma Under the Energy Employees Occupational Illness Compensation Program Act of 2000[133 KB (2 pages)]
  • Document Number: Federal Register / Vol. 71, No. 31, page 7969
  • Published: February 15, 2006
  • About this Document: Announced that NIOSH changed the selection of target organs used in dose reconstructions. The change responds to an evaluation by NIOSH of current scientific data on lymphoma, which revealed that the site of the radiation injury can differ from the site of the tumor or cancer origin documented in the medical files of a lymphoma cancer patient. The new process for selecting dose reconstruction target organs for energy employees with lymphoma cancers includes selecting the target organ that would have received the highest radiation dose from among relevant, possibly irradiated organs, as determined through the dose reconstruction process, when the identity of the target organ is in question. This change may result in the Department of Labor calculating higher probability of causation determinations for select lymphoma cases among previously decided and current EEOICPA cases.
• Selection for Internal and External Dosimetry Target Organs for Lymphatic/Hematopoietic Cancers[68 KB (15 pages)]
  • Document Number: OCAS-TIB- 0012, Rev. 1
  • Approved: February 10, 2006
  • About this Document: Re-evaluates target organ selection for lymphatic/hematopoietic cancers.
• Summary of NIOSH’s Re-examination of Lymphoma Target Organ Selection[17 KB (2 pages)]
  • Approved: October 31, 2005
  • About this Document: NIOSH proposed to modify the selection of target organs so that the dose to the highest plausible organ is used in the dose reconstruction.
    • Consultant Report–Dose Reconstruction Project from Dr. Mark Crowther, MD, MSc, FRCPC[15 KB (2 pages)]
    • Target Organs for Lymphatic and Hematopoietic Cancers–Comments/Suggestions by K.F. Eckerman[14 KB (4 pages)]

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New Procedure for Resolving Cases Close to 50% PC

There is a new procedure for resolving cases in which the upper 99th percentile credibility limit of probablity of causation (PC) is equal to or greater than 45% but less than 52% using the default simulation sample size of 2000 and default random number seed of “99.” This procedure became effective on June 6, 2006.

Previously, each case with an initial PC value falling between 45% and 50% at the upper 99th percentile credibility limit (C.L.) was processed by increasing the simulation sample size to 10,000, choosing a new random number seed, and rerunning the case in NIOSH-IREP. The resulting upper 99% C.L. of PC obtained with a sample size of 10,000 determined the case outcome, supplanting the initial PC value that had been obtained with a sample size of 2000. This procedure was adopted in order to provide better statistical precision for cases approaching the compensation threshold of 50%.

To achieve even greater statistical precision for cases close to the compensation threshold, the following new procedure was adopted on June 6, 2006 and replaces the procedure described above.

For cases in which the initial PC is equal to or greater than 45% but less than 52% using the default sample size of 2000:

1. The simulation sample size will be increased to 10,000.
2. 30 additional IREP runs will be performed, using a new random number seed for each run.
3. The average value (arithmetic mean) of the upper 99% C.L. of PC of the 30 runs will determine the case outcome.
4. For cases with more than one primary cancer in which the initial PC calculated from the “multiple primary” equation is equal to or greater than 45% but less than 52%, 30 runs will be performed for each primary cancer per steps 1 and 2 above. The arithmetic mean of the upper 99% C.L. of PC of the 30 runs for each cancer will then be entered into the multiple primary equation. The newly calculated PC, based upon the arithmetic mean PC value of each cancer as entered into the multiple primary equation, will determine the case outcome.

The NIOSH-IREP User’s Guide was revised to reflect this procedural change.

The following Program Evaluation Report details the effect of this new procedure on previous non-compensable cases.

• PER 16: Program Evaluation Report: Implementation of IREP Procedure for Claims near 50% Probability of Causation[132 KB (4 pages)]
  • Document Number: OCAS-PER-0016 Rev-00
  • About this Document: New document to evaluate the effect of implementing a new IREP procedure on previously completed claims.
  • Approved: September 25, 2007
  • Summary: A total of 109 previously non-compensable claims with PC values of 45% or greater were evaluated. The average PC value remained below the 50% compensation threshold for each of the 109 claims. An itemized list of claims was provided to DOL containing the final evaluation result for each of the 109 claims.

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Revision 1985 NIH Radioepidemiological Tables

• Report of the NCI-CDC Working Group to Revise the 1985 NIH Radioepidemiological Tables
  
  • Document Number: NIH Publication No. 03-5387
  • About this Document: This updated report uses epidemiological dose-response data and uncertainty analyses in providing a scientific basis for quantifying radiation-related cancer risks. The tabular version is an interactive radio-epidemiological computer program known as “NIH-IREP” and corresponds to the report. NIH-IREP can be accessed Online at http://www.irep.nci.nih.gov/.
  • Published: September 2003