Cancer surveillance in the U.S.: can we have a national system?

History of the Surveillance, Epidemiology, and End Results (SEER) Program

The Surveillance, Epidemiology, and End Results (SEER) Program established in 1973 was the first laboratory for experimenting with new methods for cancer data collection and translating the data into population-based cancer statistics. The SEER Program staff have been instrumental in the development of the International Classification of Disease-Oncology and successfully implemented the routine collection of anatomic and prognostic cancer stage at diagnosis. Currently the program consists of 21 central registries that generate cancer statistics covering more than 48% of the US population and an additional 10 research support registries contributing to certain research projects, such as the National Childhood Cancer Registry. In parallel with the geographical expansion, the program built an architecture of methods and tools for population-based cancer statistics, with SEER*Explorer as the most recent online tool for descriptive statistics. In addition, SEER releases annual updates for a comprehensive data product line, which includes SEER*Stat databases with an annual caseload of more than 800 000 incident cases. Furthermore, the program developed a full suite of analytical applications for population-based cancer statistics that include Joinpoint (regression-based trend analysis), DevCan (risk of diagnosis and death), CanSurv (survival models), and ComPrev and PrejPrev (cancer prevalence), among others. The future of the SEER Program is closely aligned to the overall goals of the "war on cancer." The program aims to release longitudinal treatment data coupled with a comprehensive genomic characterization of cancers with a declared goal of decreasing the cancer burden and disparities across a wide spectrum of diseases and communities.

A Prostate Cancer Composite Score to Identify High Burden Neighborhoods

This study presents a novel geo-based metric to identify neighborhoods with high burdens of prostate cancer, and compares this metric to other methods to prioritize neighborhoods for prostate cancer interventions. We geocoded prostate cancer patient data (n = 10,750) from the Pennsylvania cancer registry from 2005 to 2014 by Philadelphia census tract (CT) to create standardized incidence ratios (SIRs), mortality ratios (SMRs), and mean prostate cancer aggressiveness. We created a prostate cancer composite (PCa composite) variable to describe CTs by mean-centering and standard deviation-scaling the SMR, SIR, and mean aggressiveness variables and summing them. We mapped CTs with the 25 highest PCa composite scores and compared these neighborhoods to CTs with the 25 highest percent African American residents and the 25 lowest median household incomes. The mean PCa composite score among the 25 highest CTs was 4.65. Only seven CTs in Philadelphia had both one of the highest PCa composite scores and the highest percent African American residents. Only five CTs had both the highest PCa composites and the lowest median incomes. Mean PCa composite scores among CTs with the highest percent African American residents and lowest median incomes were 2.08 and 1.19, respectively. The PCa composite score is an accurate metric for prioritizing neighborhoods based on burden. If neighborhoods were prioritized based on percent African American or median income, priority neighborhoods would have been very different and not based on PCa burden. These methods can be utilized by public health decision-makers when tasked to prioritize and select neighborhoods for cancer interventions.

Systematic Review of Hospital Based Cancer Registries (HBCRs): Necessary Tool to Improve Quality of Care in Cancer Patients

Introduction:

Incidence and mortality rate of cancer is increasing in all countries including low and middle-income countries. Hospital based cancer registry (HBCR) is an important tool for administration purpose and improvement of the quality of care. It is also important resource for population based cancer registries. In this study we reviewed HBCRs in different countries.

Methods:

We searched the published literature using the MEDLINE (PubMed), Google scholar, Scopus, ProQuest and Google. We also reviewed websites of the HBCRs in different countries. The search was carried out based on proper keywords in English for all motor engines including “hospital-based”, “clinical” and “data quality” combined with “registry”, “cancer” and “tumor” including all subheadings. We reviewed objectives, developer institutions, minimum datasets, data sources, quality control indicators and processes.

Results:

In total we found 163 papers in the first step. After screening of the titles, abstracts and the full texts, 14 papers remained for analysis. Analysis of the 14 papers showed that the improvement of the quality of the care were the most important objectives among the registries. HBCRs collect information about patients, tumor diagnosis, treatment and follow-up. Generally, indicators such as completeness and validity were used for quality control.

Conclusion:

Because of the increases in cancer burden in the world, more attention is needed to be paid on cancer surveillance systems, including HBCRs. We evaluated and highlighted the importance and characteristics HBCRs and believe that this paper would help the hospitals and policy makers for planning and establishment of new HBCRs. We suggest the establishment of a worldwide network for coordination and collaboration between HBCRs.

Associations between cancer and Alzheimer's disease in a U.S. Medicare population

Several studies have reported bidirectional inverse associations between cancer and Alzheimer's disease (AD). This study evaluates these relationships in a Medicare population. Using Surveillance, Epidemiology, and End Results (SEER) linked to Medicare data, 1992-2005, we evaluated cancer risks following AD in a case-control study of 836,947 cancer cases and 142,869 controls as well as AD risk after cancer in 742,809 cancer patients and a non-cancer group of 420,518. We applied unconditional logistic regression to estimate odds ratios (ORs) and Cox proportional hazards models to estimate hazards ratios (HRs). We also evaluated cancer in relation to automobile injuries as a negative control to explore potential study biases. In the case-control analysis, cancer cases were less likely to have a prior diagnosis of AD than controls (OR = 0.86; 95% CI = 0.81-0.92). Cancer cases were also less likely than controls to have prior injuries from automobile accidents to the same degree (OR = 0.83; 95% CI = 0.78-0.88). In the prospective cohort, there was a lower risk observed in cancer survivors, HR = 0.87 (95% CI = 0.84-0.90). In contrast, there was no association between cancer diagnosis and subsequent automobile accident injuries (HR = 1.03; 95% CI = 0.98-1.07). That cancer risks were similarly reduced after both AD and automobile injuries suggest biases against detecting cancer in persons with unrelated medical conditions. The modestly lower AD risk in cancer survivors may reflect underdiagnosis of AD in those with a serious illness. This study does not support a relationship between cancer and AD.

Population-based risks for cancer in patients with ALS

OBJECTIVE

To estimate the risks for cancer (overall and site-specific) in an amyotrophic lateral sclerosis (ALS) cohort.

METHODS

In this observational longitudinal study, ALS and cancer cases were identified in a computerized Utah genealogy database (Utah Population Database) linked to a statewide cancer registry and death certificates. Hazard ratios (HRs) were estimated as the ratio of observed to expected number of cancers. Site-specific rates for cancer were estimated within the Utah Population Database; sex, birth year (5-year range), and birth state (Utah or not) cohorts were used to estimate the expected number of cancers among ALS cases. To account for an overall shortened lifespan, Cox regression was used to include years at risk in estimation of cancer risks for ALS cases.

RESULTS

An overall decreased hazard (hazard ratio [HR] 0.80, p = 0.014, 95% confidence interval [CI] 0.66-0.96) was found for cancer of any site in 1,081 deceased patients with ALS. A decreased hazard was found for lung cancer (HR 0.23, p = 0.002, CI 0.05-0.63). An increased hazard was found for salivary (HR 5.27, p = 0.041, 95% CI 1.09-15.40) and testicular (HR 3.82, p = 0.042, 95% CI 1.06-9.62) cancers. A nonsignificant hazard was observed for cutaneous malignant melanoma (HR 1.62, p = 0.12, 95% CI 0.88-2.71) for which increased risk has previously been reported.

CONCLUSIONS

Using a unique population database, the overall risk of cancer of any site was found to be significantly reduced in cases with ALS, as was the risk of lung cancer. Significantly increased risk was observed for salivary and testicular cancers.

Age-Period-Cohort approaches to back-calculation of cancer incidence rate

A compartment model for cancer incidence and mortality is developed in which healthy subjects may develop cancer and subsequently die of cancer or another cause. In order to adequately represent the experience of a defined population, it is also necessary to allow for subjects who are diagnosed at death, as well as subjects who migrate and are subsequently lost to follow-up. Expressions are derived for the number of cancer deaths as a function of the number of incidence cases and vice versa, which allows for the use of mortality statistics to obtain estimates of incidence using survival information. In addition, the model can be used to obtain estimates of cancer prevalence, which is useful for health care planning. The method is illustrated using data on lung cancer among males in Connecticut.

The association between cancer and amyotrophic lateral sclerosis

OBJECTIVE

Increasing evidence suggests that some neurodegenerative disorders, such as Parkinson's disease, are inversely related to cancer. Few epidemiologic studies have examined the relationship between cancer and amyotrophic lateral sclerosis (ALS), another major neurodegenerative disease. This study addresses that gap.

METHODS

Using data from 16 population-based cancer registries of the Surveillance, Epidemiology, and End Results (SEER) Program of the U.S. National Cancer Institute and death certificates, we followed 2.7 million cancer survivors who were diagnosed between 1973 and 2007, and who survived at least 1 year following cancer diagnosis. The standardized mortality ratio (SMR) of observed to expected ALS deaths in cancer survivors was calculated.

RESULTS

A total of 1,216 ALS deaths were reported among 1 year survivors of cancer over 16.6 million person-years of follow-up. ALS mortality was not significantly associated with the incidence of total cancers [SMR = 1.00 (95 % confidence interval (CI), 0.95-1.06)]. There was, however, a significantly elevated risk of ALS death among survivors of melanoma [SMR = 1.49 (95 % (CI), 1.17-1.85)] and of tongue cancer [SMR = 2.57 (95 % CI, 1.41-4.32)], and a significantly reduced ALS death risk among prostate cancer survivors [SMR = 0.86 (95 % CI, 0.76-0.96)].

CONCLUSIONS

Cancer at certain sites may be related to risk of ALS death. Possible biologic factors linking ALS to these cancers are discussed. Future studies should attempt to confirm these associations using incident ALS outcomes. Establishing relationships between cancer and neurodegenerative diseases, such as ALS, opens new opportunities for understanding related pathophysiologic and therapeutic possibilities for these diseases.

Increased risk of second primary cancers after a diagnosis of melanoma

OBJECTIVE

To quantify the risk of subsequent primary cancers among patients with primary cutaneous malignant melanoma.

DESIGN

Population-based registry study.

SETTING

We evaluated data from 9 cancer registries of the Surveillance, Epidemiology, and End Results program from 1973-2006.

PARTICIPANTS

We included 89 515 patients who survived at least 2 months after their initial melanoma diagnosis.

RESULTS

Of the patients with melanoma, 10 857 (12.1%) developed 1 or more subsequent primary cancers. The overall risk of a subsequent primary cancer increased by 28% (observed to expected [O:E] ratio = 1.28). One quarter of the cancers were subsequent primary melanomas (O:E = 8.61). Women with head and neck melanoma and patients younger than 30 had markedly increased risks (O:E = 13.22 and 13.40, respectively) of developing a subsequent melanoma. Second melanomas were more likely to be thin than were the first of multiple primary melanomas (thickness at diagnosis <1.00 mm, 77.9% vs 70.3%, respectively; P < .001). Melanoma survivors had increased risk of developing several cancers; the most common cancers with elevated risks were breast, prostate, and non-Hodgkin lymphoma (O:E = 1.10, 1.15, and 1.25, respectively).

CONCLUSIONS

Melanoma survivors have an approximately 9-fold increased risk of developing subsequent melanoma compared with the general population. The risk remains elevated more than 20 years after the initial melanoma diagnosis. This increased risk may be owing to behavioral factors, genetic susceptibility, or medical surveillance. Although the percentage of subsequent primary melanomas thicker than 1 mm is lower than for the first of multiple primary melanomas, it is still substantial. Melanoma survivors should remain under surveillance not only for recurrence but also for future primary melanomas and other cancers.

Development of a telemedicine model for emerging countries: a case study on pediatric oncology in Brazil

This article discusses a telemedicine model for emerging countries, through the description of ONCONET, a telemedicine initiative applied to pediatric oncology in Brazil. The ONCONET core technology is a Web-based system that offers health information and other services specialized in childhood cancer such as electronic medical records and cooperative protocols for complex treatments. All Web-based services are supported by the use of high performance computing infrastructure based on clusters of commodity computers. The system was fully implemented on an open-source and free-software approach. Aspects of modeling, implementation and integration are covered. A model, both technologically and economically viable, was created through the research and development of in-house solutions adapted to the emerging countries reality and with focus on scalability both in the total number of patients and in the national infrastructure.

A new method to evaluate the completeness of case ascertainment by a cancer registry

Background

Epidemiologic research into cancer and subsequent decision making to reduce the cancer burden in the population are dependent on the quality of available data. The more reliable the data, the more confident we can be that the decisions made would have the desired effect in the population. The North American Association of Central Cancer Registries (NAACCR) certifies population-based cancer registries, ensuring uniformity of data quality. An important assessment of registry quality is provided by the index of completeness of cancer case ascertainment. NAACCR currently computes this index assuming that the ratio of cancer incidence rates to cancer mortality rates is constant across geographic areas within cancer site, gender, and race groups. NAACCR does not incorporate the variability of this index into the certification process.

Methods

We propose an improved method for calculating this index based on a statistical model developed at the National Cancer Institute to predict expected incidence using demographic and lifestyle data. We calculate the variance of our index using statistical approximation.

Results

We use the incidence model to predict the number of new incident cases in each registry area, based on all available registry data. Then we adjust the registry-specific expected numbers for reporting delay and data corrections. The proposed completeness index is the ratio of the observed number to the adjusted prediction for each registry. We calculate the variance of the new index and propose a simple method of incorporating this variability into the certification process.

Conclusions

Better modeling reduces the number of registries with unrealistically high completeness indices. We provide a fuller picture of registry performance by incorporating variability into the certification process.

Research recruitment through US central cancer registries: balancing privacy and scientific issues

Cancer registries are a valuable resource for recruiting participants for public health-oriented research, although such recruitment raises potentially competing concerns about patient privacy and participant accrual. We surveyed US central cancer registries about their policies for research contact with patients, and results showed substantial variation. The strategy used most frequently (37.5% of those that allowed patient contact), which was among the least restrictive, was for investigators to notify patients' physicians and then contact patients with an opt-out approach. The most restrictive strategy was for registry staff to obtain physician permission and contact patients with an opt-in approach. Population-based studies enhance cancer control efforts, and registry policies can affect researchers' ability to conduct such studies. Further discussion about balanced recruitment approaches that protect patient privacy and encourage beneficial research is needed.

The Future of Cancer Surveillance

Cancer surveillance is entering an exciting era where the scope of its activities will be expanded and the amount, quality, and depth of information on cancer will be richer and more readily available to practitioners, decision makers and the public. This future is being built on a solid history of accomplishment that has placed cancer foremost among all chronic diseases in the organization and implementation of a systematic and integrated monitoring enterprise that is of essential value in both clinical medicine and public health. The future of cancer surveillance will be driven not only by innovations in methods of cancer surveillance itself, but also by developments in information technology and communication and by revolutionary new tools used in the delivery of medical care. At the same time, it will be a challenge to ensure levels of privacy and confidentiality needed to maintain the public trust. In the Cancer Surveillance and Information Summit, a 2004 conference sponsored by C-Change, experts from the field and from allied and related disciplines in both the public and private sectors met to consider the future of the cancer surveillance enterprise. Seven recommendations, detailed in this article, emerged from the conference to guide future growth and development. Steps that can and should be taken by all individuals and groups involved in cancer surveillance were included. The shared view is that cancer surveillance and information is essential to fulfill a vision for a future where cancer is prevented, detected early, and either cured or managed successfully as a chronic illness.

Reducing the Global Breast Cancer Burden: The Importance of Patterns of Care Research

Breast cancer treatment guidelines are not uniformly followed in clinical practice, with evidence for substantial variations in treatment patterns, quality of care, and patient outcomes among and within countries. The factors that drive treatment decisions are unclear. Furthermore, the impact of different treatment strategies on survival is poorly understood outside the clinical trial setting. Sources of patterns of care information often have limitations in completeness, quality, timeliness of reporting, and relevance to the larger population. Patterns of care studies frequently lack details on cancer stage at diagnosis, tumor biology, and treatment received. It is difficult to compare data between studies and/or track changes over time because of variations in data sources and collection techniques. Thus, the design and implementation of a global registry is sorely needed in order to prospectively evaluate worldwide patterns of care and outcomes in patients with breast cancer. Components of this registry should include random selection of centers of variable practice settings in multiple countries and accurate and rapid data reporting at prestudy and follow-up timepoints. Data collected would include tumor and demographic factors, staging information, treatment rendered, and survival. Variables that influenced the treatment selected would be assessed. This unique international effort would allow the development of strategies to improve diagnostic and treatment-related standards of care and survival outcomes, thus reducing the breast cancer burden worldwide.

Amyotrophic lateral sclerosis mortality in 1.9 million US cancer survivors

BACKGROUND

Large cancer registries offer the opportunity to explore and generate hypotheses about the pathogenesis of cancer and other diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS).

METHODS

Using data from nine population-based cancer registries of the Surveillance, Epidemiology, and End Results (SEER) Program of the US National Cancer Institute (NCI) and death certificates, we followed 1.9 million cancer survivors who were diagnosed between 1973 and 2000 and who survived at least 1 year, through the year 2000. The outcome of interest was the standardized mortality ratio (SMR) of observed to expected ALS deaths among cancer survivors. To assess the validity of the study design, we also examined associations with Parkinson's disease mortality, which we expected to be inversely associated with smoking-related cancers.

RESULTS

There was no significantly increased risk or deficit of ALS mortality for all cancer sites combined (SMR = 1.0). Parkinson's disease mortality was, as expected, significantly and inversely associated with smoking-related cancers. Both ALS and Parkinson's disease mortality were significantly elevated following melanoma (SMR = 1.6; 95% CI = 1.1-2.2; SMR = 1.5; 1.2-1.8, respectively). Contrary to previous hypotheses, ALS was unrelated to lymphomas or lymphoproliferative malignancies and was not associated with smoking-related cancers.

CONCLUSIONS

In this exploratory study, we observed a modest, significant association between melanoma and both ALS and Parkinson's disease mortality. It would be useful to explore these findings in other large national databases that are able to link cancer and ALS and Parkinson's disease.

A national framework for cancer surveillance in the United States

Enhancements to cancer surveillance systems are needed for meeting increased demands for data and for developing effective program planning, evaluation, and research on cancer prevention and control. Representatives from the American Cancer Society, Centers for Disease Control and Prevention, National Cancer Institute, National Cancer Registrars Association, and North American Association of Central Cancer Registries have worked together on the National Coordinating Council for Cancer Surveillance to develop a national framework for cancer surveillance in the United States. The framework addresses a continuum of disease progression from a healthy state to the end of life and includes primary prevention (factors that increase or decrease cancer occurrence in healthy populations), secondary prevention (screening and diagnosis), and tertiary prevention (factors that affect treatment, survival, quality of life, and palliative care). The framework also addresses cross-cutting information needs, including better data to monitor disparities by measures of socioeconomic status, to assess economic costs and benefits of specific interventions for individuals and for society, and to study the relationship between disease and individual biologic factors, social policies, and the environment. Implementation of the framework will require long-term, extensive coordination and cooperation among these major cancer surveillance organizations.

Challenges of recruitment and retention in multisite clinical research

This article reviews recruitment and retention issues in a multisite, multistate (California, New York, Connecticut, Georgia, Alabama) 6-month prospective cross-sectional study focused on quality of life among 230 women with lung cancer. Recruitment of women into clinical trials and their retention are important, yet understudied. To date, few articles have described the challenges associated with recruiting women with lung cancer to participate in clinical research. Data from this trial were used to investigate the most effective strategies for recruitment across sites, to identify the most common reasons for refusal and attrition, and to identify challenges and potential solutions to recruitment and retention issues associated with multisite clinical research studies. Strategies for recruitment included letters from physicians, posters, announcements in community support groups, and newspaper and radio advertisements. Three sites allowed the researchers to contact potential participants directly, whereas 2 sites required the potential participants to contact the researchers for further information. Enrollment included 63% of the women eligible for the study (n = 230). The most common reasons for refusal were health limitations (n = 60), lack of interest (n = 46), and inconvenience (n = 16). The most common reasons for attrition (24% of the sample) were death (n = 21) and severity of illness (n = 13). Challenges related to recruitment and retention varied by geographic location.

Existing data on breast cancer in African-American women: what we know and what we need to know

BACKGROUND

Much of what is known about breast cancer in African-American (AA) women is based on existing cancer surveillance data. Thus, it is important to consider the accuracy of these resources in describing the impact of breast cancer in AA populations.

METHODS

National cancer surveillance data bases are described, their most recent findings are presented, their limitations are outlined, and recommendations are made for improving their utility.

RESULTS

Breast cancer characteristics have been studied well in urban (but not in rural) and Southern AA populations. The recent Surveillance, Epidemiology, and End Results (SEER) Program expansion and the continued improvement of state cancer registry operations will provide opportunities to study larger and more diverse AA subpopulations. Recommendations for improving the utility of surveillance data bases include adding new items to better describe correlates of advanced stage at diagnosis and reduced survival of AA women with breast cancer by linking surveillance data bases with other large data bases to provide area-level socioeconomic status, health insurance status, and retrieving new information about patient comorbidities and biomarkers from medical records; improving the completeness and accuracy of treatment and survival information already collected for all patients; working to improve the dissemination of appropriate cancer data to nonresearch consumer communities, including clinicians, patients, advocates, politicians, and health officials; and the development of new training programs for cancer registrars and researchers.

CONCLUSIONS

The continued improvement of cancer surveillance systems should be considered important activities in this research agenda, because these data will play a far-reaching role in the prevention and control of breast cancer in AA women.

Making effective use of tumor registries for cancer survivorship research

BACKGROUND

The growing number of cancer survivors has created an increased need for survivorship research; however, the identification and recruitment of cancer survivors present some challenges. This report describes how two hospital cancer registries were used to recruit a large sample of breast cancer survivors (BCS) for a study examining the late reproductive effects of breast cancer treatments. Limitations and opportunities associated with this type of recruitment strategy are described, and the overall success of recruitment using this approach is presented.

METHODS

Tumor registries from a comprehensive cancer center and a community hospital were used to identify BCS who met the study screening criteria. Invitations and response forms were mailed to all potentially eligible women, and those who did not respond by mail also were contacted by telephone. Women who indicated interest and met the study requirements were asked to give written consent, were enrolled in the study, and were sent a self-report questionnaire.

RESULTS

Seventy percent of the eligible women (n = 733 women) responded to the mailing. Seventy-seven percent of the 512 respondents indicated a willingness to participate and were sent a questionnaire. Of these, 78% (n = 368 women) completed questionnaires. BCS recruited from the cancer center registry were more likely than those from the community hospital registry to respond to the invitation form (P = 0.033) and were more likely to return a completed questionnaire (P = 0.001). However, the community hospital provided access to a more ethnically diverse sample of survivors.

CONCLUSIONS

The two participating cancer registries were an excellent source for identifying a large sample of long-term BCS, and the different types of registries provided greater sample size and diversity. Although there are some limitations to this approach, including nonresponse of a significant number of BCS, tumor registries represent an important resource for the rapid identification of cancer survivors for research studies. Findings from this study suggest several enhancements for future studies that may increase the yield from registry recruitment.

Annual report to the nation on the status of cancer (1973 through 1998), featuring cancers with recent increasing trends

BACKGROUND

The American Cancer Society, the National Cancer Institute (NCI), the North American Association of Central Cancer Registries, and the Centers for Disease Control and Prevention, including the National Center for Health Statistics (NCHS), collaborate to provide an annual update on cancer occurrence and trends in the United States. This year's report contains a special feature that focuses on cancers with recent increasing trends.

METHODS

From 1992 through 1998, age-adjusted rates and annual percent changes are calculated for cancer incidence and underlying cause of death with the use of NCI incidence and NCHS mortality data. Joinpoint analysis, a model of joined line segments, is used to examine long-term trends for the four most common cancers and for those cancers with recent increasing trends in incidence or mortality. Statistically significant findings are based on a P value of.05 by use of a two-sided test. State-specific incidence and death rates for 1994 through 1998 are reported for major cancers.

RESULTS

From 1992 through 1998, total cancer death rates declined in males and females, while cancer incidence rates declined only in males. Incidence rates in females increased slightly, largely because of breast cancer increases that occurred in some older age groups, possibly as a result of increased early detection. Female lung cancer mortality, a major cause of death in women, continued to increase but more slowly than in earlier years. In addition, the incidence or mortality rate increased in 10 other sites, accounting for about 13% of total cancer incidence and mortality in the United States.

CONCLUSIONS

Overall cancer incidence and death rates continued to decline in the United States. Future progress will require sustained improvements in cancer prevention, screening, and treatment.

Minorities, women, and clinical cancer research: the charge, promise, and challenge

Significant progress has been made since the war against cancer was launched. Discoveries in molecular medicine, genetics, and epidemiology have led to the recognition that certain cancers are potentially preventable and that elements of lifestyle, along with genetic, hormonal, and metabolic factors can be altered to reduce cancer risk. Advances in medical technology have led to the development of new imaging methods and computer technologies that can aid in efforts to detect, diagnosis, and treat cancer. Since the offensive against cancer was initiated, cancer treatments have become more powerful, more precise, less drastic, and safer. As a result, cancer incidence and mortality have begun to decline. Yet, while the nation boasts of the progress being achieved relative to cancer incidence and mortality, and federal research agencies retort that research applies to all populations, it is apparent that the declines do not translate to all populations in the United States. Clinical research is essential to cancer prevention and control. Within the oncology community, clinical cancer research trials are viewed as an efficient and economical way for patients to secure state-of-the-science medical care. Recognizing the need to improve access to state-of-the-science cancer treatment and control programs, minority and female participation in clinical cancer research trials has been encouraged. This recommendation is based on the belief that increased participation in well-designed clinical cancer research trials adhering to strict protocols and quality controls will, not only help validate the application of research findings to minority and female populations, but also result in better patient outcomes. Born out of a commitment to social equity, justice, beneficence, and the desire to ensure that data relevant to cancer prevention and control are both valid and generalizable to populations across the United States, several programs of research aimed toward increasing the representation of women and minorities in clinical cancer research have been pursued by the National Cancer Institute. This issue of the Annals of Epidemiology Minorities, Women, and Clinical Cancer Research presents issues and challenges that face the research community and descriptions of effective models, strategies, and practices that may be used to increase the participation of minorities and women in clinical cancer research trials and facilitate the conduct of research directed toward reducing the cancer burden within the United States.

The potential and limitations of data from population-based state cancer registries

Cancer incidence varies markedly among states because of population heterogeneity regarding risk, genetic, and demographic factors. Population-based cancer registries are essential to monitoring cancer trends and control. The Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries, through the National Program of Cancer Registries, are helping state registries generate more and better data nationwide. The National Program of Cancer Registries has supported the enhancement of 36 registries and the creation of 13 new registries in 45 states, 3 territories, and the District of Columbia, providing national standards for completeness, timeliness, and quality; financial support; and technical assistance. Users must be aware of diverse issues that influence collection and interpretation of cancer registry data, such as multiple cancer diagnoses, duplicate reports, reporting delays, misclassification of race/ethnicity, and pitfalls in estimations of cancer incidence rates. Attention to these issues and intense use of the available data for cancer surveillance will enable maximum societal benefit from the emerging network of population-based state cancer registries.