280 likes | 372 Views
Evaluation and Implementation of State Comprehensive Cancer Control Plans: Evolving Lessons. APHA 2005 Annual Meeting Epidemiology Section Session 3187.0 12:30–2:00 PM Monday, December 12, 2005. Assessing cancer burden: Estimating and utilizing prevalence. Presented by:
E N D
Evaluation and Implementation of State Comprehensive Cancer Control Plans: Evolving Lessons APHA 2005 Annual Meeting Epidemiology Section Session 3187.0 12:30–2:00 PM Monday, December 12, 2005
Assessing cancer burden:Estimating and utilizing prevalence Presented by: Judith B. Klotz, DrPH UMDNJ-School of Public Health
Co-authors of this presentation include: Stanley H. Weiss, MD Xiaoling Niu, MS Jung Y. Kim, MPH Daniel M. Rosenblum, PhD
Context: Capacity and Needs Assessment at County Level • Focus on seven NJ-CCCP priority cancers • Breast, Cervical, Colorectal, Lung, Melanoma, Oral/Oropharyngeal, Prostate • Need for estimates of burden of cancer in the population • Prevalence = number of people living with a disease at a point in time • Cancer prevalence estimates are useful supplements to incidence and mortality statistics, and help determine the level of cancer control efforts needed
Uses of Prevalence Data Include • Assessing current burden of disease • Predicting future burden of disease • Planning of health services • Allocation of medical resources • Planning and administering health care facilities • Guiding health care research programs
A Limitation of Incidence and Mortality Statistics • Adjusted rates do not reflect actual burden of disease or number of persons affected
Institute of Medicine (IOM)2006 Report on Cancer Survivors • Over 10,000,000 prevalent cases today in U.S. • Dearth of coordinated clinical and support follow-up services for patients and their families
IOM Report: Follow up needs for patients and families • Rehabilitation and quality-of-life issues • Psychological stresses • e.g. potential for recurrence • Acute or chronic pain or other side effects from cancer treatment • Risks of additional cancer from radiation/ chemotherapy • Needs for continuing treatment and/or screening • Insurance issues
Types of Prevalence • Prevalence (count): Number of people living with the disease at a point in time • Prevalence rate: Number of prevalent casesdivided by the total population
Types of Prevalence, cont. • “Complete Prevalence” • Usually preferred for cancer • Includes all survivors, regardless of years since diagnosis • Rationale: long-term needs of patients and families for medical and psychosocial services • “Limited Duration Prevalence” • Includes those who were diagnosed within specified number of years (e.g., 2, 5, 10, 20) • So does NOT include those who survive after the number of years at which follow-up is truncated
Typical Sources of Prevalence Data • Population Surveys • Estimation from combination of incidence and survival data • Cannot simply combine mortality and incidence data in a particular year because they pertain to different, specific persons: • Most people who die in a particular year were diagnosed in an earlier year
Current Availability ofTotal Prevalence Estimates • Conducted by NCI for U.S. based on longest cancer registries and complex modeling • Connecticut Tumor Registry: since 1935 • New models developed in Italy and adapted by NCI • New SEER*Stat program • Newly available as of August 2005 (after C/NA was completed) • Provides counting method for limited duration prevalence • Years since diagnosis depend on inception of state cancer registry • New utility, “COMPREV” estimates complete prevalence from limited-duration prevalence
Capacity and Needs AssessmentPrevalence Estimates for Counties Basic method for C/NA, 2003–2004 • This method was reviewed and approved by the Evaluation Committee of Governor’s Task Force • Use the ratio of prevalence rate to crude incidence rate from national (NCI SEER) data, • By specific cancer • By gender • Apply this ratio to county-specific crude incidence rate • Wide variability among counties expected due to variations in population size and demographics
Capacity and Needs AssessmentPrevalence Estimates for Counties Source Data a. Total populations for each county (by gender),from the 2000 Census b. Incidence counts for 1996–2000 for each county, as provided by the NJ State Cancer Registry These were used to calculate crude incidence rate, separately for each gender: Crude incidence rate = x 100,000
Simplifying Assumptions • County survival rates assumed to resemble national survival rates by gender, for each cancer, whereas these may in fact vary • Migration in and out of counties assumed not to affect prevalence counts, whereas migration after diagnosis could alter the true number of affected people still living in a given county
Simplifying Assumptions, cont. • Racial and ethnic distributions assumed not to alter county survival rates, whereas these demographic differences could affect numbers of survivors in any county • Crude incidence is approximated by 1996–2000 data, whereas current incidence may now differ
Prevalence to Incidence Ratios* Of the prevalence to incidence ratios forthe 7 NJ-CCCP priority cancers, Lowest ratio: Lung cancer (males) = 1.4 Highest ratio: Cervical cancer = 17.0 Interpretation: There are about 17 times as many living women who have been diagnosed with cervical cancer as have been newly diagnosed during one year. * Ratio of national estimated complete prevalence rate to national incidence rate
SEER*Stat Prevalence Estimates for NJ and its Counties • Calculated a 20-year duration limited prevalence • NJ State Cancer Registry began 1979, so that there is data for more than 20 years • Data currently available through 2003 • Used January 1, 1999 as the sample point in time • These prevalence statistics have not yet been published by NJ Dept of Health and Senior Services
SEER*Stat Prevalence Estimates for NJ and its Counties • For long-survival cancers,SEER*Stat count estimates were markedly lower than C/NA complete prevalence estimates • e.g. Limited/complete ratio for cervical cancer State: 0.64 Counties: 0.56–0.84 • Note: It is to be expected that estimates for counties will vary markedly from each other
SEER*Stat Prevalence Estimates for NJ and its Counties • For short-survival cancers,SEER*Stat limited duration estimates were in closer agreement with C/NA complete prevalence estimates, both statewide and for many counties: • e.g. Limited/complete ratio for lung cancer State: 1.1 Counties: 0.93–1.3
Ratios of Estimate Counts for SEER*Stat Limited Prevalence toC/NA Complete Prevalence Results discussed above are highlighted in yellow
Comparison with SEER*Stat Estimates for NJ Counties, cont. • Gender differences in prevalent case estimates for colorectal cancer were shown by C/NA method but not SEER*Stat • perhaps related to longer lifespan of women • Limitations of prevalence estimates currently available from State Cancer Registries using SEER*Stat • Duration depends on year of inception of Registry • For 15 states: less than 10 years available
Comparisons of Estimated Counts– Some Examples * Male + female combined
Comparison with SEER*Stat Estimates for NJ Counties, cont. Future analyses: • We anticipate using SEER’s new COMPREV to estimate Complete prevalence from the Limited-Duration prevalence, and then to compare these results to the C/NA method used in 2003–2004
Use of County Prevalence Estimates to date County cancer control planners and county cancer coalitions have found prevalence estimates useful for: • Estimation of relative burden of disease among county populations of different cancers • Recommendations for priority actions
County Use of Prevalence Data in Assessing Needs for Cancer Control An Example: • "The four most prevalent NJ-CCCP priority cancers in Somerset County are breast, prostate, colorectal cancer, and melanoma.... [and] the goals and strategies in the NJ-CCCP that are of highest priority for Somerset County are outlined below for each of these four cancers.” Source: Somerset County, Capacity and Needs Assessment Executive Summary 2003
Acknowledgments and Websites • We acknowledge: • Cancer Epidemiology Services, New Jersey Department of Health and Senior Services: Lisa Roché, PhD Betsy Kohler, MS, CTR • County Evaluators of the NJ-CCCP Capacity and Needs Assessment • NCI SEER*Stat website:http://srab.cancer.gov/comprev/ • Evaluation Committee website:http://www.umdnj.edu/evalcweb/