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Cancer Epidemiology Professor Mostafa Arafa 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 29 April 2017 Cancer Epidemiology 2 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 29 April 2017 Cancer Epidemiology 3 Biologic Basis for Cancer Control Initiation Normal cell 29 April 2017 Progression Promotion Initiated cell Pre-cancerous cell Cancer Epidemiology CANCER 4 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 29 April 2017 Cancer Epidemiology 5 CANCER HISTORY 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. 29 April 2017 Cancer Epidemiology 6 ANCIENT EGYPT (3000 BC-1500 BC) 1 The oldest known description of human cancer is found in 7 Egyptian papyri written between 3000-1500 BC. Two of them, known as the "Edwin Smith" and "George Ebers" papyri, contain details of conditions that are consistent with modern descriptions of cancer. 29 April 2017 Cancer Epidemiology 7 HIPPOCRATES (460-370 B.C) 1 He is the first person to clearly recognize difference between benign and malignant tumors His writings include description of cancers involving various body sites 29 April 2017 Cancer Epidemiology 8 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. 29 April 2017 Cancer Epidemiology 9 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). 29 April 2017 Cancer Epidemiology 10 Cancer incidence for the regions of the world 29 April 2017 Cancer Epidemiology 11 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. 29 April 2017 Cancer Epidemiology 12 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. 29 April 2017 Cancer Epidemiology 13 29 April 2017 Cancer Epidemiology 14 Estimated Cancer Deaths Lung and bronchus 31% Prostate 10% Colon and rectum Men 295,280 Women 275,000 27% Lung and bronchus 15% Breast 10% 10% Colon and rectum Pancreas 5% 6% Ovary Leukemia 4% 6% Pancreas Esophagus 4% 4% Leukemia Liver and intrahepatic bile duct 3% 3% Non-Hodgkin lymphoma Non-Hodgkin Lymphoma 3% 3% Uterine corpus Urinary bladder 3% 2% Multiple myeloma Kidney 3% 2% Brain/ONS All other sites 24% 29 April 2017 ONS=Other nervous system. Cancer Epidemiology Source: American Cancer Society, 2005. 22% All other sites 15 Estimated New Cancer Cases Prostate 33% Lung and bronchus Colon and rectum Men 710,040 Women 662,870 32% Breast 13% 12% Lung and bronchus 10% 11%Colon and rectum Urinary bladder 7% 6% Uterine corpus Melanoma of skin 5% 4% Non-Hodgkin lymphoma 4% Non-Hodgkin lymphoma 4% Kidney 3% Melanoma of skin Leukemia 3% 3% Ovary Oral Cavity 3% 3% Thyroid Pancreas 2% 2% Urinary bladder 17% 2% Pancreas All Other Sites 21% All Other Sites *Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder. Cancer Epidemiology Source: American Cancer Society, 2005. 29 April 2017 16 Regional and Local data 29 April 2017 Cancer Epidemiology 17 29 April 2017 Cancer Epidemiology 18 29 April 2017 Cancer Epidemiology 19 29 April 2017 Cancer Epidemiology 20 29 April 2017 Cancer Epidemiology 21 29 April 2017 Cancer Epidemiology 22 29 April 2017 Cancer Epidemiology 23 Cancer Epidemiology Concepts 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 29 April 2017 Cancer Epidemiology 25 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 29 April 2017 Cancer Epidemiology 26 Rates • • • • • • Incidence Prevalence Specific Crude Adjusted/Standardized SMR/SIR 29 April 2017 Cancer Epidemiology 27 Cancer Epidemiology Sources • 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 29 April 2017 Cancer Epidemiology 28 Known Risk Factors for Cancer • Smoking • Reproductive factors • Dietary factors • Socioeconomic status • Obesity • Environmental pollution • Exercise • Ultraviolet light • Occupation • Radiation • Genetic susceptibility • Prescription Drugs • Infectious agents • Electromagnetic fields 29 April 2017 Cancer Epidemiology 29 Cancer Epidemiology IIdentified 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 29 April 2017 Cancer Epidemiology 30 Prevention & Control 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 29 April 2017 Cancer Epidemiology 32 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 29 April 2017 Cancer Epidemiology 33 Secondary Prevention • Cancer registration (hospital-based, populationbased) • Early detection / screening: best during preinvasive (in-situ) or pre-malignant stages. Examples: cervical, breast, prostate, colon, oral, skin, testis, etc • Management: multi-modal: surgical, chemotherapy, radiotherapy, pain therapy 29 April 2017 Cancer Epidemiology 34 29 April 2017 Cancer Epidemiology 35 Lung Cancer • Risk factors – Cigarette smoking, environmental exposures, tuberculosis • Detection/Prevention – Reduce exposure to tobacco smoke 29 April 2017 Cancer Epidemiology 36 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) 29 April 2017 Cancer Epidemiology 37 Prostate Cancer • Risk factors – Age, ethnicity, family history, dietary fat?, weight? • Early detection/prevention >50yrs old – PSA blood test/yr – Digital rectal exam/yr 29 April 2017 Cancer Epidemiology 38 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 • • • • 29 April 2017 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 39 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. 29 April 2017 Cancer Epi 40 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/ 29 April 2017 Cancer Epi 41 Thank you for your kind attention 29 April 2017 Cancer Epi 42