cancer epidemiology1.pdf

Cancer epidemiology Dr: Nuri Enwail Epidemiology Comes from Greek words epi meaning “on or upon” Demosi meaning “people” Logos meaning “the study of” Study of distribution and determinants.  Epidemiology Epidemiolog...

Cancer epidemiology Dr: Nuri Enwail Epidemiology Comes from Greek words epi meaning “on or upon” Demosi meaning “people” Logos meaning “the study of” Study of distribution and determinants.  Epidemiology Epidemiology is the “study of distribution and determinants of health-related states among specified populations and the application of that study to the control of health problems.” Distribution – burden, pattern Determinants – causes, risk factors Application – prevention, control Cancer epidemiology is the study of the distribution, determinants, and frequency of malignant disease in specific populations. Objective: ✓ to define causative factors to formulate preventive strategies for control of the disease. ✓ Epidemiologic assessment provides the clinician with a quantification of cancer risk ✓ Outlines the basis for screening modalities for high-risk populations, ✓ Determines the efficacy of any preventive intervention.  Incidence rate: refers to the number of new cases of a disease observed in a defined population in a specific time period divided by the population size, Prevalence rate: is defined as the proportion of a population that has a disease at a specific time point (prevalent cases divided by population size), where prevalent cases include both new cases of disease and the number of previously diagnosed cases who are still alive in a population In summary, you'll see “prevalence” to refer to the number of people currently diagnosed with a disease, and you'll see “incidence” when referring to the new cases being diagnosed over a period of time Age-Standardized Rate (ASR) A major factor in the comparison of different populations is the difference in age-distribution across the different populations Both cancer incidence and mortality generally increase markedly with age, and comparisons of populations with different age distributions using crude rates can therefore be misleading. The procedure requires adjusting (or standardizing) rates so they are representative of the age distribution of some reference population. Global burden Source of data: The International Agency for Research on Cancer (IARC) is the specialized cancer agency of the World Health Organization https://gco.iarc.fr/  Cancer is a leading cause of death worldwide, accounting for nearly 10 million deaths in 2020, or nearly one in six deaths. The most common cancers are breast, lung, colon and rectum and prostate cancers. Around one-third of deaths from cancer are due to tobacco use, high body mass index, alcohol consumption, low fruit and vegetable intake, and lack of physical activity. Cancer-causing infections, such as human papillomavirus (HPV) and hepatitis, are responsible for approximately 30% of cancer cases in low- and lower-middle-income countries. Many cancers can be cured if detected early and treated effectively.  The most common in 2020 (in terms of new cases of cancer) were: ❑ Breast (2.26 million cases); ❑ Lung (2.21 million cases); ❑ Colon and rectum (1.93 million cases); ❑ Prostate (1.41 million cases); ❑ Skin (non-melanoma) (1.20 million cases); and ❑ Stomach (1.09 million cases).  The most common causes of cancer death in 2020 were: Lung (1.80 million deaths) Colon and rectum (916 000 deaths) Liver (830 000 deaths) Stomach (769 000 deaths); and Breast (685 000 deaths).  Situation in Libya Total population 6 871 287 Number of new cases 7 661 Number of deaths 4 750 Age-standardized incidence rate (World) 132.2 Benghazi Cancer Registry Benghazi Cancer Registry covers the residents in a vast area of the Eastern Libya with a population were approximately 1.5 million inhabitants Summary of results Total number of 1097 new cases were registered by Benghazi Cancer Registry during 2004. 564 (52.4%) were males and 513 (47.6%) were females. In men the most frequent cancer site was the lung (19%), followed by colon and rectum (11%) and bladder (9%). In women the most frequent cancer sites was breast (23%), colon andrectum (11%) and uterus (7%). The Age Standardized Rate (ASR) for all cancer combined was 127 per 100,000 for males and 102 per 100,000 for females. Causes of cancer Slide Title  RR = 1 means that exposure does not affect the outcome RR > 1 means that the risk of the outcome is increased by the exposure, which is a "risk factor" RR < 1 means that the risk of the outcome is decreased by the exposure, which is a "protective factor" Age: The incidence rates for cancer overall climb steadily as age increases, from fewer than 25 /100,000 in age groups Advancing age is the most important under 20, to about 350 /100,000 risk factor for cancer overall among those aged 45–49, to more than 1,000/ 100,000 people in age groups 60 years and older. the median age of a cancer diagnosis is 66 years the median age at diagnosis is 62 years for breast cancer, the median age at diagnosis is 67 years for colorectal cancer, the median age at diagnosis is 71 years for lung cancer, the median age at diagnosis is 66 years for prostate cancer. Smoking Tobacco use causes many types of cancer, including cancer of the lung, larynx, mouth, esophagus, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum, and cervix, as well as acute myeloid leukemia. People who use smokeless tobacco (snuff or chewing tobacco) have increased risks of cancers of the mouth, esophagus, and pancreas. Obesity People with obesity may have an increased risk of several types of cancer, including cancers of the breast, colon, rectum, endometrium, esophagus, kidney, pancreas, and gallbladder. Conversely, eating a healthy diet, being physically active, and keeping a healthy weight may help reduce risk of some cancers. These healthy behaviors are also important to lessen the risk of other illnesses, such as heart disease, type II diabetes, and high blood pressure.  Cancers of the oral cavity, pharynx, larynx, esophagus, liver, and breast can be caused by heavy alcohol Alcohol Use drinking, with the risk varying by cancer site, but increasing for all sites with greater consumption and resulting in an estimated 5 percent of attributable cancer deaths in LMCs  ✓ Human papillomavirus (HPV) increases the risk for cancers of the cervix, penis, vagina, anus, and oropharynx. Infections ✓ Hepatitis B and hepatitis C viruses increase the risk for liver cancer. ✓ Epstein-Barr virus increases the risk for Burkitt lymphoma. ✓ Helicobacter pylori increases the risk for gastric cancer.  Occupational Exposures The International Labor Organization (ILO) estimates that 2 million deaths per year worldwide, among 2.7 billion workers, are attributable to workplace exposures. About 25 chemicals or mixed chemical exposures for which exposures are mostly occupational have been identified by IARC as established human carcinogens, and an equal number are probably carcinogenic