1. Introduction to Cancer Epidemiology
Faina Linkov, PhD
Research Assistant Professor of Medicine and Epidemiology
University of Pittsburgh Cancer Institute
(preferred mode of communications): fyL1 (at) pitt.edu

2. University of Pittsburgh Graduate School of Public Health, one of the oldest school to advocate for chronic disease epidemiology research

3. What this course is about
Learning more about cancer epidemiology
Investigating risk factors implicated in cancer development
Learning to write grants and critique articles
Learning to be passionate about chronic disease epidemiology

4. Smoking causes lung cancer
True or False?
Smoking causes lung cancer
False
From epidemiological point of view, there is a good association between smoking and lung cancer. This does not mean causation. Many people who smoke never develop lung cancer

5. Large percentage of cancers are preventable
True or False?
Large percentage of cancers are preventable
True

6. True or False?
In the past 20 years tremendous improvements in the treatment of all cancers have been achieved
False
We have seen improvement in detection, monitoring, and treatment for some cancers. However, there is large number of cancers, where we have seen little improvement, such as pancreatic and ovarian.

7. Preventing cancer is easier than treating cancer
True or False?
Preventing cancer is easier than treating cancer
True

8. Screening tests are available for most cancers
True or False?
Screening tests are available for most cancers
False
Screening tests are available for some cancers, such as prostate, colorectal, and breast.
There are many cancers for which we do not have screening tests yet, such as pancreatic, brain, etc.

9. Epidemiology
“Distribution and determinants of disease frequency in human populations”
John Snow (15 March 1813 – 16 June 1858) was a British physician and a leader in the adoption of anesthesia and hygiene. He is considered to be one of the fathers of epidemiology, because of his work in tracing the source of a cholera outbreak in Soho, England, in 1854.

10. Cancer Epidemiology Historical Perspective
1775
British surgeon, Percival Pott reported probably the first description of occupational carcinogenesis in the form of scrotum cancer among chimney sweeps.
The actual association between this occupational hazard and scrotum cancer was increased incidence of squamous cell carcinoma due to exposure to soot.

11. Cancer Epidemiology Historical Perspective
Tight corsets and cancer
1842
Rigoni-Stern, Italian physician, observed that married women in the city were getting cervical cancer, but nuns in nearby convents weren’t. He also observed that nuns had higher rates of breast cancer, and suggested that the nuns’ corsets were too tight.
This interesting cancer epidemiology study was conducted in Verona. It represented one of the first statistical analysis in this field.
Perhaps the first modern epidemiological study of cancer was conducted in 1842 by Rigoni-Stern, who attempted to
quantify the risks of uterine cancer among nuns compared with other women in the city of Verona; he showed that
the disease was significantly less common in the former group.

12. Five Criteria for a Cause  Effect Relationship
Risk Factor for Disease
1) Timing
Exposure occurs before development
of disease or during its progression
2) Strength
Is dose-dependent
Cessation of exposure can modify disease
3) Prevalence
Occurs in multiple populations
4) Relationship to
other risk factors
Is independent
Can also act synergistically
5) Plausibility
Produces structural‡ or functional changes
which are events in mechanism of disease
‡ anatomic or molecular

13. Cancer Epidemiology Historical Perspective
1700s: tobacco and cancer
Reports of cancer risks associated with tobacco in the 18th century included snuff taking and nasal cancer, reported by Hill in 1761, and pipe smoking and lip cancer by von Soemmering in 1795.

14. Cancer Epidemiology Historical Perspective
Tobacco and Lung Cancer
Asbestos and Lung Cancer
Leather Industry and Nasal Cancer
Dyes and Bladder Cancer
Ionizing Radiation and Many Cancers
DES and Vaginal Adenocarcinoma
EBV and Burkitt’s Lymphoma
HPV and Cervical Cancer

15. Cancer Epidemiology An Introduction
The Epidemiologic Perspective
Aims of Cancer Epidemiology
Methods of Epidemiology
Historical Perspective and Examples
Contemporary Studies
The Future

16. Aims of Cancer Epidemiology
Uncover new etiologic leads
study of the distribution of cancer
quantify the risk associated with different exposures and host factors
Promote insights into the mechanisms of carcinogenesis
Assess efficacy of preventive measures
Investigate predictors of survival

17. Types of Epidemiologic Studies
Cohort
Case-Control
Cross-Sectional (Prevalence)
Other

18. Methods of Cancer Epidemiology
Descriptive Studies
Incidence, mortality, survival
Time Trends
Geographic Patterns
Patterns by Age, Gender, SES, Ethnicity
Analytic Studies
Case-control
Cohort

19. Challenges to Interpretation
Observational vs. Experimental Design
Cancer “clusters”
Study Design and Conduct
Study Size
Biases: Misclassification, confounding, selection
Exposure assessment important
Epidemiology and “strong” and “weak” effects
Impact on a population level
Replication critical

20. Cancer Epidemiology Sources
US SEER Registry System
IARC International Registries
State/Hospital Registries
Etiologic Clues
“Alert” Clinician
Experimental Studies
The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute (NCI) is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 26 percent of the US population. SEER coverage includes 23 percent of African Americans, 40 percent of Hispanics, 42 percent of American Indians and Alaska Natives, 53 percent of Asians, and 70 percent of Hawaiian/Pacific Islanders. (Details are provided in the table: Number of Persons by Race and Hispanic Ethnicity for SEER Participants.) The SEER Program registries routinely collect data on patient demographics, primary tumor site, tumor morphology and stage at diagnosis, first course of treatment, and follow-up for vital status. The SEER Program is the only comprehensive source of population-based information in the United States that includes stage of cancer at the time of diagnosis and patient survival data.
SEER began collecting data on cancer cases on January 1, 1973, in the states of Connecticut, Iowa, New Mexico, Utah, and Hawaii and the metropolitan areas of Detroit and San Francisco-Oakland. In , the metropolitan area of Atlanta and the 13-county Seattle-Puget Sound area were added. In 1978, 10 predominantly black rural counties in Georgia were added, followed in 1980 by the addition of American Indians residing in Arizona. Three additional geographic areas participated in the SEER program prior to 1990: New Orleans, Louisiana ( , rejoined 2001); New Jersey ( , rejoined 2001); and Puerto Rico ( ). The National Cancer Institute also funds a cancer registry that, with technical assistance from SEER, collects information on cancer cases among Alaska Native populations residing in Alaska. In 1992, the SEER Program was expanded to increase coverage of minority populations, especially Hispanics, by adding Los Angeles County and four counties in the San Jose-Monterey area south of San Francisco. In 2001, the SEER Program expanded coverage to include Kentucky and the remaining counties in California (Greater California); in addition, New Jersey and Louisiana once again became participants. For the expansion registries (Kentucky, Greater California, New Jersey, and Louisiana), NCI funds are combined with funding from the Centers for Disease Control and Prevention (CDC) through the National Program of Cancer Registries and with funding from the states.
NCI staff work with the North American Association of Central Cancer Registries (NAACCR) to guide all state registries to achieve data content and compatibility acceptable for pooling data and improving national estimates. The SEER team is developing computer applications to unify cancer registration systems and to analyze and disseminate population-based data. Use of surveillance data for research is being improved through Web-based access to the data and analytic tools, and linking with other national data sources. For example, a new Web-based tool for public health officials and policy makers, State Cancer Profiles, provides a user-friendly interface for finding cancer statistics for specific states and counties. This Web site is a joint project between NCI and CDC and is part of the Cancer Control PLANET Web site which provides links to comprehensive cancer control resources for public health professionals.
The SEER Program is considered the standard for quality among cancer registries around the world. Quality control has been an integral part of SEER since its inception. Every year, studies are conducted in SEER areas to evaluate the quality and completeness of the data being reported.
The International Agency for Research on Cancer (IARC) is part of the World Health Organization. IARC's mission is to coordinate and conduct research on the causes of human cancer, the mechanisms of carcinogenesis, and to develop scientific strategies for cancer control. The Agency is involved in both epidemiological and laboratory research and disseminates scientific information through publications, meetings, courses, and fellowships.

21. Cancer disparities is an interesting topic in the area of cancer epidemiology. This graph demonstrates the disparities between US Whites and African Americans

22. Cancer Epidemiology Current/Future Topics
Infectious Agents
Cancer and inflammation
Obesity
Physical Activity
Diet
Hormones
Immunologic Factors
Cancer disparities
Inherited Susceptibility (Polymorphisms)
Cancer and inflammation is receiving attention, partly because of new evidence about the relationship between inflammatory markers and cancer development.
Obesity, which is a growing problem in the US and around the world, is becoming one of the leading risk factors for cancer development

23. Cancer Epidemiology Current/Future Topics
Tumor (somatic) Alterations
Cancer Classification
Biomarkers of Exposure/Effect
Vaccines
Survivorship
Cancer and disability
Alternative therapy
Some progress has been made in the area of cancer vaccines (such as HPV) and the interest in this area is growing. Cancer vaccines can target cancer before it ever develops (such as HPV and cervical cancer), but also existing tumors (evident by early work in the area of ovarian tumors).