analysis of cancer risks in populations near nuclear ... · feasibility assessment described in...

ANALYSIS OF CANCER RISKS IN POPULATIONS NEAR NUCLEAR FACILITIES: PHASE 1

John Burris Committee Chair

EMBARGOED FOR PUBLIC RELEASE UNTIL 11:00 AM ON MARCH 29, 2012

John Burris, Committee ChairBriefing to the U.S. Nuclear Regulatory Commission

March 26, 2012

TOPICS TO BE ADDRESSED

• Study Request

• Statement of Task

• Committee Membership

• Key Messages

• Findings and Recommendations

• Report Organization

2EMBARGOED FOR PUBLIC RELEASE UNTIL 11:00 AM ON MARCH 29, 2012

STUDY REQUEST

U.S. Nuclear Regulatory Commission (USNRC) approached the Academies to update the 1990 National Cancer Institute study which:

• Compared rates of cancer deaths in counties with a nuclear facility to those without

H d d t di ti• Had no data on radiation exposures

• Included only facilities that were operational as of 1982

The Academies agreed to carry out a two-phase study:

• Phase 1: Scoping study to identify scientifically sound approaches for carrying out the cancer risk assessment

• Phase 2: Cancer risk assessment informed by Phase 1 results


STATEMENT OF TASK

Methodological approaches for assessing

(1) off-site radiation dose and

(2) cancer epidemiology

including consideration of:

• Availability, completeness, and quality of information

on gaseous and liquid radioactive releases

cancer occurrence and cancer death data

• Different epidemiologic study designs

• Approaches for characterizing and communicating uncertainties


PHASE 1 COMMITTEE MEMBERSHIPJohn E. Burris, Chair, Burroughs

Wellcome Fund

John C. Bailar, III, University of Chicago (retired)

Harold L. Beck, Environmental Measurements Laboratory (retired)

Andre Bouville, National Cancer Institute (retired)

James E. Klaunig, Indiana University

Timothy Mousseau, University of South Carolina

Sharon B. Murphy, University of Texas Health Science Center (retired)

Roy E. Shore, Radiation Effects Research Foundation

D i l O St U i it f S th(retired)

Phaedra S. Corso, University of Georgia

Patricia J. Culligan, Columbia University

Paul M. DeLuca, Jr., University of Wisconsin

Raymond A. Guilmette, Lovelace Respiratory Research Institute

George M. Hornberger, Vanderbilt Institute for Energy and Environment

Margaret Karagas, Dartmouth University

Roger E. Kasperson, Clark University (retired)

Daniel O. Stram, University of Southern California

Margot Tirmarche, Institute of Radiation Protection and Nuclear Safety

Lance Waller, Emory University

Gayle E. Woloschak, Northwestern University

Jeffrey J. Wong, California Environmental Protection Agency


KEY MESSAGES

• Several challenges for carrying out the epidemiology studies.

• Several approaches possible.

• Effluent releases suitable for dosimetry.

• Two study designs recommended.

• Pilot study needed.

• Stakeholder engagement important.


FINDING 1There are several challenges for carrying out epidemiology studies of cancer risks in populations near U.S. Nuclear Regulatory Commission-licensed nuclear facilities in the United States, including the following:

• Uneven availability and quality of data on cancer mortality and incidence at geographic levels smaller than a county.

• Uneven availability and quality of data on nuclear facility effluent releases.

• Inability to reliably capture information on population mobility, risk factors, and potential confounding factors.

• Low expected statistical power.

The committee paid close attention to these challenges as it assessed the scientific merit of various epidemiology study designs. 7


FINDING 2

An assessment of cancer risks in populations near nuclear facilities could be carried out using several study designs. Each design has strengths and limitations for estimating cancer risks.

• Risk projection models.

A l i t d b d ti t f l l t• An ecologic study based on estimates of exposure levels at the census-tract level.

• Variations of cohort studies tracking estimates of individual exposure levels and recording case incidence.

• Variations of case-control studies comparing estimates of individual exposure levels between cancer cases and controls.


FINDING 3

Effluent release, direct exposure, and meteorology data, if available, can be used to obtain rough estimates of annual variations in dose as a function of distance and direction from nuclear facilities.

• Facility-specific evaluations will be required to determine lit d il bilit f d tquality and availability of data.

• Environmental monitoring data have limited usefulness for estimating absorbed doses from effluent releases.

• Computer models have been developed to estimate absorbed doses from airborne and waterborne radioactive effluent releases.


RECOMMENDATION 1Should the U.S. Nuclear Regulatory Commission decide to proceed with an epidemiology study of cancer risks in populations near nuclear facilities, the committee recommends that this investigation be carried out by conducting the following two studies, subject to the feasibility assessment described in Recommendation 2:

1. An ecologic study of multiple cancer types of populations living near nuclear facilities;

2. A record-linkage based case-control

study of cancers in children born near

nuclear facilities.

Absorbed doses to individual organs will be estimated for those living/born within approximately 50 km of nuclear facilities.

50 km


RECOMMENDATION 2

A pilot study should be carried out to assess the feasibility of the committee-recommended dose assessment and epidemiology studies and to estimate the required time and resources.

Suggested sites for pilotSuggested sites for pilotDresden, IllinoisMillstone, ConnecticutOyster Creek, New JerseyHaddam Neck , Connecticut Big Rock Point, MichiganSan Onofre, CaliforniaNuclear Fuel Services, Tennessee


RECOMMENDATION 3

The epidemiology studies should include processes for involving and communicating with stakeholders. A plan for stakeholder engagement should be developed prior to the initiation of data gathering and analysis for these studies.


RECOMMENDED STUDIES ARE COMPLEMENTARY, MUTUALLY INDEPENDENT, AND COULD BE CARRIED

OUT INDIVIDUALLY OR TOGETHER

Questions such studies could answer:

Ecologic: Are observed cancer incidence/mortality rates higher in census tracts with higher estimated exposures (as estimated from reported releases from the nuclear facility)?

Record-based case-control: Among children born within 50 km of a nuclear facility, are pediatric cancers associated with higher exposure at maternal residence at time of birth?


THE COMMITTEE EMPHASIZES THAT:

In any of the studies considered, population sizes, estimated doses, and resulting risk estimates may be too low to demonstrate statistically significant increased risks near nuclear facilities. Extremely large sample sizes are required.


DECISIONS ON IMPLEMENTATION OF THE RECOMMENDED STUDIES INVOLVE POLICY AND

OTHER CONSIDERATIONS

• Which age groups and cancer types are most important to address in the epidemiology study or studies?

• How much time is available to carry out the study or studies?studies?

• How much funding is available to carry out the study or studies?

• Which public concerns are most in need help with addressing?

Some of these considerations are outside the charge for this Phase 1 study


REPORT ORGANIZATIONSummary: 3 Findings, 3 Recommendations

Chapter 1: Introduction

Chapter 2: Effluent Releases

Chapter 3: Radiation Dose AssessmentChapter 3: Radiation Dose Assessment

Chapter 4: Epidemiology Studies

Chapter 5: Risk communication and public engagement

Appendices (radiation as a carcinogen and literature review, committee bios, presentations and visits, origin of radioactivity in nuclear facilities, RETS and REMP programs, letter templates to cancer registries, other)


ACKNOWLEDGMENTSUSNRC

• Brian Sheron

• Terry Brock

• Vered Shaffer

• Marilyn Diaz

• John Tomon

• Scott Burnell

• Dave McIntyre

• Richard Conatser

• John Cassidy

• Don Stearns

For supporting facility visits

• Willie Harris and Robert Osgood, Dresden

• Kathy Yhip and Mike Russell, San Onofre

• Marie Moore and Mark Elliott, NFS

Nuclear Energy Institute

• Ralph Andersen

• Andrew Mauer

For guidance on sources of health & population data

• Robert Anderson, CDC

• Christie Eheman CDCDon Stearns

Presenters at the committee’s information-gathering meetings

Members of the public and non- governmental organizations

For written advice on study design

• The Electric Power Research Institute

• Raid Amin, University of West Florida

• Steve Wing, University of North Carolina

Pacific Northwest National Laboratory

• Rosanne Aaberg

• David Baker

• Christie Eheman, CDC

• Kevin Ward, Georgia Center for Cancer Statistics,

• Scott Boggess, U.S. Census Bureau

Directors and staff of state departments of public health, cancer registries, and vital statistics offices


BACKUP SLIDES


STUDY SCHEDULE

• Study approved by NAS: July 2010

• Study start date: October 2010

• Committee approved: December 2010

• Five committee meetings: February - October 2011

• Independent report review: February 2012

• Prepublication copy of report to be released: March 29, 2012

• Public comments on Phase 1 report: April-May 2012


INFORMATION GATHERING

• Expert opinions of committee members

• Briefings from subject-matter experts

• Nuclear site visits

• Public comments

• Literature and report reviews

• Letter-requests to offices that collect health and other information

• Phone and other communication

• Original analyses


NUMBER OF CASES IN THE AT RISK ZONE (<= 5 KM FROM A FACILITY) IN EUROPEAN STUDIES OF LEUKEMIA

Country Reference Study Years

Cases (<= 5km)

Germany Kaatsch et al., 2008 23 37

France Sermage-Faure et al., 2012

17 24

Britain COMARE, 2011 35 20

Switzerland Spycher et al., 2011 24 8

Kaatsch, P., C. Spix, et al. (2008). "Leukaemia in young children living in the vicinity of German nuclear power plants." Int J Cancer 122(4): 721-726.Sermage-Faure C., Laurier D., Goujon-Bellec S., Chartier M., Guyot-Goubin A., Rudant J., Hémon D., Clavel J., Childhood leukemia around French nuclear power plants – the Geocap study, 2002-2007, International Journal of Cancer, accepted preprintCOMARE (2011). Fourtheenth report: Further consideration of the incidence of childhood leukemia around nuclear power plants in Great Britain.Spycher, B. D., M. Feller, et al. (2011). "Childhood cancer and nuclear power plants in Switzerland: a census-based cohort study." Int J Epidemiol.


STATISTICAL POWER1:1 matching 1:5 matching

Riskincrease

Cases Years Leukemia

Years Breast ca

Cases Years Leukemia

Years Breast ca

20% 14,000 31 2 8,200 18 1

40% 3,800 8 <1 2,200 5 <140% , ,

200% 765 1.7 <1 <1 <1 <1

Demographic parameters and simplifying assumptions1. In 2010, about 15% of the US population lived within 50 km (30 miles) and

0.3% lived within 8km (5 miles) of a nuclear facility2. Distribution of demographics and risk factors do not differ by distance3. Two categories of exposure: 0-5 miles, 5-30 miles from the facility


RECOMMENDED ECOLOGIC STUDY WOULD UPDATE AND IMPROVE THE 1990 NCI STUDY

1. Reduce the size of the geographic unit.

2. Use the current nuclear facility inventory.

3. Include years of mortality and incidence data that are relevant to the years of exposure.

4. Incorporate estimated exposure levels for each geographic unit.

5. Use stronger analytic methods • Direct adjustment for possible confounding variables

• Population mobility

• Temporal changes in the socio-demographic characteristics


ECOLOGIC VERSUS RECORD-BASED CASE-CONTROL APPROACH

ECOLOGIC RECORD-BASED CASE-CONTROLExamines groups. Examines individuals.

Examines all cancers, all ages. More cases, more statistical power.

Restricted to childhood cancers. Fewer cases, less statistical power.

Examines both incidence and mortality. Examines incidence only.

No control needed. Control selection is required.

Examines associations based on residence Examines associations based on birth place

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at diagnosis or death. which can be considered more relevant.

Can control for confounding only by using aggregate data.

Relevant information is available in the birth certificates.

Can only estimate average in- and out-migration rates.

In-migration of cancer cases (but not controls) can be estimated; less mobile population.

Particularly subject to “false positive”findings.

“False positive” findings are an issue.

IRB approvals may be needed and are likely to be undemanding.

IRB or equivalent body approvals will be needed.

Hypothesis generating. Hypothesis testing.

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UNCERTAINTIES

• Dose reconstruction

• Completeness of cancer case ascertainment

• Population mobility

V i bilit i i k f t d t ti l f di• Variability in risk factors and potential confounding

• Inability to distinguish risks from different sources of radiation

• Statistical uncertainty


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