Cancer Epidemiology

1. Cancer Epidemiology Professor MostafaArafa

2. Learning Objectives • Students should be able to: • Appreciate the historical perspective of cancer control • Explain the Global impact of cancer • Identify the most prevalent cancers world wide • Identify the leading causes of cancer deaths • Understand the cancer control continuum and explain its implication to public health • Explain important factors and trends affecting cancer control and directions for future research Cancer Epidemiology

3. What is cancer? • Definition: “Cancer is a generic term for a group of more than 100 diseases that can affect any part of the body.” Other terms used are malignant tumors and neoplasm …..WHO Cancer Epidemiology

4. Progression Initiation Promotion Biologic Basis for Cancer Control Normal cell Initiated cell Pre-cancerous cell CANCER Cancer Epidemiology

5. What Is Cancer? Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death. Cancer is caused by both external factors (tobacco, infectious organisms, chemicals, and radiation) and internal factors (inherited mutations, hormones, immune conditions, and mutations that occur from metabolism). These causal factors may act together or in sequence to initiate or promote the development of cancer. Ten or more years often pass between exposure to external factors and detectable cancer. Cancer is treated with surgery, radiation, chemotherapy, hormone therapy, biological therapy, and targeted therapy Cancer Epidemiology

6. Human cancer is probably as old as the human race. It is obvious that cancer did not suddenly start appearing after modernization or industrial revolution. Cancer history Cancer Epidemiology

7. Ancient Egypt (3000 BC-1500 BC) 1 • The oldest known description of human cancer is found in 7 Egyptian papyriwritten between 3000-1500BC. • Two of them, known as the "Edwin Smith"and "George Ebers" papyri, contain details of conditions that are consistent with modern descriptions of cancer. Cancer Epidemiology

8. Hippocrates (460-370 B.C) 1 • He is the first person to clearly recognizedifference between benign and malignanttumors • His writings include description of cancers involving various body sites Cancer Epidemiology

9. Hippocrates (460-370 B.C) 2 • Hippocrates noticed that blood vessels around a malignant tumor looked like the claws of crab. • He named the disease karkinos (the Greek name for crab) to describe tumors. In English this term translates to carcinos or carcinoma. Cancer Epidemiology

10. Global Burden of Disease • Total of 58 million deaths worldwide in 2005, cancer accounts for 7.6 million (or 13%) of all deaths • Main types: • lung (1.3 million deaths/year); • Stomach (almost 1 million deaths/year); • Liver (662,000 deaths/year); • Colon (655,000 deaths/year) and • Breast (502,000 deaths/year). Cancer Epidemiology

11. Cancer incidence for the regions of the world Cancer Epidemiology

12. The global burden of cancer continues to increase largely because of the aging and growth of the world population alongside an increasing adoption of cancer-causing behaviors, particularly smoking, in economically developing countries. Based on the GLOBOCAN 2008 estimates, about 12.7 million cancer cases and 7.6 million cancer deaths are estimated to have occurred in 2008; of these, 56% of the cases and 64% of the deaths occurred in the economically developing world. Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among females, accounting for 23% of the total cancer cases and 14% of the cancer deaths. Lung cancer is the leading cancer site in males, comprising 17% of the total new cancer cases and 23% of the total cancer deaths. Cancer Epidemiology

13. Although overall cancer incidence rates in the developing world are half those seen in the developed world in both sexes, the overall cancer mortality rates are generally similar. Cancer survival tends to be poorer in developing countries, most likely because of a combination of a late stage at diagnosis and limited access to timely and standard treatment. A substantial proportion of the worldwide burden of cancer could be prevented through the application of existing cancer control knowledge and by implementing programs for tobacco control, vaccination (for liver and cervical cancers), and early detection and treatment, as well as public health campaigns promoting physical activity and a healthier dietary intake. Cancer Epidemiology

14. Cancer Epidemiology

15. Estimated Cancer Deaths Men295,280 Women275,000 Lung and bronchus 31% Prostate 10% Colon and rectum 10% Pancreas 5% Leukemia 4% Esophagus 4% Liver and intrahepatic 3%bile duct Non-Hodgkin 3% Lymphoma Urinary bladder 3% Kidney 3% All other sites 24% 27% Lung and bronchus 15% Breast 10% Colon and rectum 6% Ovary 6% Pancreas 4% Leukemia 3% Non-Hodgkin lymphoma 3% Uterine corpus 2% Multiple myeloma 2% Brain/ONS 22% All other sites Cancer Epidemiology ONS=Other nervous system. Source: American Cancer Society, 2005.

16. Estimated New Cancer Cases Men710,040 Women662,870 Prostate 33% Lung and bronchus 13% Colon and rectum 10% Urinary bladder 7% Melanoma of skin 5% Non-Hodgkin 4% lymphoma Kidney 3% Leukemia 3% Oral Cavity 3% Pancreas 2% All Other Sites 17% 32% Breast 12% Lung and bronchus 11% Colon and rectum 6% Uterine corpus 4% Non-Hodgkin lymphoma 4% Melanoma of skin 3% Ovary 3% Thyroid 2% Urinary bladder 2% Pancreas 21% All Other Sites *Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder. Source: American Cancer Society, 2005. Cancer Epidemiology

17. Regional and Local data Cancer Epidemiology

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24. Cancer Epidemiology Concepts

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

26. Challenges to Interpretation • Observational vs. Experimental Design • Cancer “clusters” • Study Design and Conduct • Study Size • Biases: misclassification, confounding, selection • Exposure assessment important • “Strong” and “weak” effects • Impact on a population level Cancer Epidemiology

27. Rates • Incidence • Prevalence • Specific • Crude • Adjusted/Standardized • SMR/SIR Cancer Epidemiology

28. Cancer EpidemiologySources • US SEER Registry System (SEER): Surveillance, Epidemiology, and End Results: http://seer.cancer.gov/ • IARC International Registries • State/Hospital Registries • Etiologic Clues • “Alert” Clinician • Experimental Studies Cancer Epidemiology

29. Known Risk Factors for Cancer • Smoking • Dietary factors • Obesity • Exercise • Occupation • Genetic susceptibility • Infectious agents • Reproductive factors • Socioeconomic status • Environmental pollution • Ultraviolet light • Radiation • Prescription Drugs • Electromagnetic fields Cancer Epidemiology

30. Cancer EpidemiologyIIdentified Associations • Tobacco & Lung Cancer • Asbestos & Lung Cancer • Leather Industry & Nasal Cancer • Dyes & Bladder Cancer • Ionizing Radiation & Many Cancers • EBV & Burkitt’s Lymphoma • HPV & Cervical Cancer Cancer Epidemiology

31. Prevention & Control

32. Comprehensive Approach • Integrated coordinated approach is needed to reduce cancer incidence, morbidity, disability and mortality through promotion, prevention, early detection, management, rehabilitation, palliative care • This involved combined work of public, private as well as civil society agencies Cancer Epidemiology

33. Primary Prevention (Risk Factor Control) • Cancer education & legislation • Tobacco / alcohol prevention and cessation • Diet: high fiber, low fat, fruits & vegetables • Weight control • STI prevention and control • Monitoring exposure to sunlight / radiation • RF control (within/outside workplace) • Lowest estrogen dose, upon prescription Cancer Epidemiology

34. Secondary Prevention • Cancer registration (hospital-based, population-based) • Early detection / screening: best during pre-invasive (in-situ) or pre-malignant stages. Examples: cervical, breast, prostate, colon, oral, skin, testis, etc • Management: multi-modal: surgical, chemotherapy, radiotherapy, pain therapy Cancer Epidemiology

35. Cancer Epidemiology

36. Lung Cancer • Risk factors • Cigarette smoking, environmental exposures, tuberculosis • Detection/Prevention • Reduce exposure to tobacco smoke Cancer Epidemiology

37. Breast Cancer • Risk Factors • Age, family history, biopsy, breast density, early menstruation, obesity after menopause, recent use of oral contraceptives, hormone therapy, late or no children, alcohol, breast feeding, exercise • Early Detection • Mammography and clinical breast exam every year after age 40 (ACS) Cancer Epidemiology

38. Prostate Cancer • Risk factors • Age, ethnicity, family history, dietary fat?, weight? • Early detection/prevention >50yrs old • PSA blood test/yr • Digital rectal exam/yr Cancer Epidemiology

39. Colorectal Cancer • Risk factors • Age, family history, smoking , alcohol, obesity, exercise, high fat diet/red meat • Early Detection/Prevention • 4 modalities recommended for people age 50 and older • Fecal occult blood test (FOBT) every year • Flexible sigmoidoscopy every 5 years • Colonoscopy every 10 years • Double-contrast barium enema every 5 years Cancer Epidemiology

40. References -1 • Adami HO, Hunter D, Trichopoulos D. Textbook of cancer epidemiology. 2nd edition. Oxford: Oxford University Press, 2008. • Dennis LK, Lynch CF, Smith EM. Cancer. In: Wallace/Maxcy-Rosenau-Last Public Health & Preventive Medicine. 15th edition. New York: McGraw, 2009. • Brownson RC, Joshu C. Cancer. In: Chronic disease epidemiology and control. 3rd edition. Washington DC: American public health association, 2010. Cancer Epi

41. References -2 • Boffetta P, La Vecchia C. Neoplasms. In: Detels R, Beaglehole R, Lansang MA, Gulligord M. Oxford textbook of public health. 5th edition. Oxford: Oxford University Press. • International agency for research on cancer. http://www.iarc.fr/ • Centers for disease control and prevention. www.cdc.gov • GCC and KSA national cancer registry. http://bportal.kfshrc.edu.sa/wps/portal/bportal/KFCC • American cancer society. http://www.cancer.org/ Cancer Epi

42. Thank you for your kind attention Cancer Epi