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Cancer Epidemiology. Wirsma Arif Harahap Surgical Oncologist Surgery Department - Andalas University. WHO. According to GLOBOCAN, an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occurred in 2008.
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Cancer Epidemiology Wirsma Arif Harahap Surgical Oncologist Surgery Department - Andalas University
WHO • According to GLOBOCAN, an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occurred in 2008. • 56% of new cancer cases in 2008 occur within developing regions) and cancer mortality (63% of cancer deaths).
WHO • Cancer is neither rare anywhere in the world, nor confined to high-resource countries. "Striking differences in the patterns of cancer from region to region are observed," • Cervix and liver cancers are much more common in developing regions of the world, whereas prostate and colorectal cancers are more common in developed regions.
WHO The most commonly diagnosed cancers worldwide are : lung (1.61 million, 12.7% of the total), breast (1.38 million, 10.9%) colorectal cancers (1.23 million, 9.7%). The most common causes of cancer death are lung (1.38 million, 18.2% of the total), stomach (0.74 million, 9.7%) and liver cancers (0.69 million, 9.2%).
INDONESIA ? • Cancer prevalence : 4.3 / 1000 peopleSIRS 2007 : Breast cancer 8.227 cases (16.85%). Breast cancer incidence : 26 per 100.000 women. • Cervical cancer : 16 per 100.000 women
Epidemiology “Distribution and determinants of disease frequency in human populations”
Cancer EpidemiologyHistorical Perspective 1775 British surgeon, Percival Pott reported probably the first description of occupational carcinogenesis in the form of scrotum cancer among chimney sweeps.
Cancer EpidemiologyHistorical 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.
Five Criteria for a Cause Effect Relationship ‡anatomic or molecular
Cancer EpidemiologyHistorical 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.
Cancer EpidemiologyHistorical 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
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
Types of Epidemiologic Studies • Cohort • Case-Control • Cross-Sectional (Prevalence) • Other
Methods of Cancer Epidemiology • Descriptive Studies • Incidence, mortality, survival • Time Trends • Geographic Patterns • Patterns by Age, Gender, SES, Ethnicity • Analytic Studies • Case-control • Cohort
What are the goals of epidemiology ?1. Identify the causes of cancer2. Quantify risks3. Identify risk groups4. Understand mechanisms5. Identify syndromes
PreventionPrimary = directed to susceptibility stageExample: Needle exchange to prevent AIDS, HPV vaccineSecondary = directed to subclinical stageExample: Screen for cervical cancer with Pap SmearTertiary = directed to clinical stageExample: Treat diabetic retinopathy to prevent blindness
Incidence Vs Prevalence Incidence is a measure of the risk of developing some new condition / new disease within a specified period of time. Prevalence is the ratio of the total number of cases / disease in the total population in a period of time .
Breast Cancer Average Annual Incidence per 100,000 by age, 1982 Age (years/female)
Incidence is usually more useful than prevalence in understanding the disease etiology: for example, if incidence rate of population of a disease increases, then there is a risk factor that promotes the incidence.
What is a cancer survival rate? Cancer survival rates or survival statistics tell you the percentage of people who survive a certain type of cancer for a specific amount of time. The five-year survival rate is a term for estimating the prognosis of a particular disease. Understanding Cancer Survival : Mayo Cliniic
Cancer statistics often use an overall five-year survival rate. For instance, the overall five-year survival rate for bladder cancer is 80 percent. That means that of all people diagnosed with bladder cancer, 80 of every 100 were living five years after diagnosis.
What are some dietary risk factors?High fat Colon, breastHigh calories UterineLow fiber ColonMicronutrients Lung (?)Diet contaminents Liver
What are alcohol-associated cancers?OralPharynxEsophagusLarynxLiver
Radiation • Ionizing • Non Ionizing • Ultraviolet • Electromagnetic
Ionizing Radiation :Leukemia (AML, but not CLL)BreastLungThyroidHead and neck cancer
Partial list: studies implicating cancer and Ionizing RadiationType of XRT Study Cancer ImplicatedA-Bomb Japan Breast, Leuk, Gastric, ThyA-Bomb Marshall Island ThyroidMedical Breast/Mastitis BreastMedical Hemangioma Breast, ThyroidMedical Hodgkin’s Breast, lung, ThyroidMedical TB-Flouroscopy Breast Occupation Radium Dial painters BoneOccupation Rad Technicians LeukemiaOccupation Chernobyl Cleanup ?Environmental Indoor radon Lung
Non-Ionizing Radiation (UV/sun)Basal cellSquamous cellMelanoma
OCCUPATIONAL EXPOSURES -- HUMAN CARCINOGENSEXPOSURESITE OF CANCER 4-Aminobiphenyl Bladder Arsenic Lung, skin Asbestos Lung, pleura, peritoneum Benzene Leukemia Benzidine Bladder beta-Naphthylamine Bladder Coal tars and pitches Lung, skin Mineral oils Skin Mustard gas Pharynx, lung Radon Lung Soot, tars, and oils (polycyclic hydrocarbons) Lung, skin Vinyl chloride Liver Wood dusts (furniture) Nasal sinuses
Bacteria and Stomach Cancer • Helicobacter pylori increases risk of stomach cancer
Genetic Epidemiology • Etiology, distribution, and control of disease in families and with inherited causes of disease in populations • Includes • family studies • molecular epi studies w/ genetic components • traditional cohort + case-control studies w/ family history components
CDKN2A Mutations in Familial Melanoma • CDKN2A -- major melanoma susceptibility gene • Frequency of mutations varies in families • 2 cases <5% • 3 – 5 cases 20 – 24% • >6 cases 50%
Cloned Familial Tumor Suppressor Genes Retinoblastoma RB113q14 1986Wilms’ tumor WT111p13 1990Li-Fraumeni syndrome p5317p13 1990Neurofibromatosis 1 NF117q11 1990Neurofibromatosis 2 NF222q12 1993von Hippel-LindauVHL3p25 1993Familial melanoma 1 p169p21 1994Familial breast 1 BRCA117q21 1994Familial breast 2 BRCA213q12 1995Basal cell nevus PTC9q22 1996
causal relations…..tobacco and lung cancerHigh relative risk (odds ratio)ConsistencyDose-responseTemporal relationshipPlausible mechanism
Cancer and Age Progress Report on Cancer Control in Canada, Health Canada