The cancer epidemiology is the study of factors that affect cancer, as a way to infer possible trends and causes. The study of cancer epidemiology uses epidemiological methods to discover the causes of cancer and to identify and develop better treatments.
This area of ​​study must compete with lead time bias and long time bias. Lead time bias is the concept that early diagnosis can artificially improve cancer survival statistics, without actually increasing the natural history of the disease. Long bias is a slow-growing concept, more lazy tumors more likely to be diagnosed by screening tests, but improvements in diagnosing more cases of lazy cancer may not translate into better patient outcomes after screening programs. The related concern is overdiagnosis, the tendency of screening tests to diagnose diseases that may not actually have an impact on patients' longevity. This problem is especially true for prostate cancer and PSA screening.
Some cancer researchers argue that negative clinical cancer trials lack sufficient statistical power to find benefits for treatment. This may be because fewer patients are enrolled in the study than originally planned.
Video Epidemiology of cancer
Organization
The state and regional cancer registry is an organization that abstracts clinical data about cancer from patient medical records. These institutions provide information to the state and national public health groups to help track trends in cancer diagnosis and treatment. One of the largest and most important cancer registries is Surveillance Epidemiology and End Results (SEER), administered by the US Federal government.
Health information privacy issues have led to limited use of cancer registry data in the US Department of Veterans Affairs and other institutions. The American Cancer Society estimates that about 1.690,000 new cancer cases will be diagnosed and 577,000 Americans will eventually die from cancer by 2012.
Maps Epidemiology of cancer
Study
Observational epidemiological studies showing the relationship between risk factors and certain cancers largely serve to generate hypotheses about potential interventions that can reduce the incidence of cancer or morbidity. Randomized controlled trials then tested whether hypotheses generated by epidemiological studies and laboratory studies actually resulted in decreased incidence of cancer and death. In many cases, findings from observational epidemiological studies were not confirmed by randomized controlled trials.
Risk factors
The most significant risk factor is age. According to cancer researcher Robert A. Weinberg, "If we live long enough, sooner or later we will all get cancer." Basically all the increase in cancer rates between prehistoric times and people who died in England between 1901 and 1905 was due to an increase in life span.
Although an increased risk of age-related cancers is well documented, age-related cancer patterns are complex. Some cancers, such as testicular cancer, have a peak of early incidence of life, for unknown reasons. In addition, the increased rate of age-related cancer incidence varies between types of cancer with, for example, the incidence of prostate cancer that accelerates much faster than brain cancer.
More than a third of cancer deaths worldwide (and about 75-80% of cancers in the United States) are due to potentially modifiable risk factors. Risk factors modified around the world are:
- tobacco smoking, which is strongly associated with lung, mouth, and throat cancer;
- drinking alcohol, which is associated with a small increase in oral, oesophageal, breast, liver and other cancers;
- low-fruit and vegetable diets,
- physical activity, which is associated with an increased risk of colon, breast, and possibly other cancers
- obesity, associated with colon, breast, endometrial, and possibly other cancers
- sexual transmission of human papillomavirus, which causes cervical cancer and some forms of anal cancer, vaginal cancer, vulvar cancer, penile cancer, rectal cancer, and oropharyngeal cancer.
Men with cancer are twice as likely as women to have modifiable risk factors for their disease.
Lifestyle and other environmental factors known to affect cancer risk (either beneficial or disadvantageous) include exogenous use of hormone (eg, hormone replacement therapy causes breast cancer), exposure to ionizing radiation and ultraviolet radiation, and certain occupational and chemical exposures.
Every year, at least 200,000 people die worldwide due to cancers associated with their workplace. Millions of workers are at risk of developing cancer such as pleural mesothelioma and peritoneum from inhaling asbestos fibers, or leukemia from benzene exposure in their workplace. Currently, the majority of cancer deaths caused by occupational risk factors occur in developed countries. It is estimated that about 20,000 cancer deaths and 40,000 new cases of cancer each year in the US are caused by work.
Rates and death rates
In US cancer is second only to cardiovascular disease as the leading cause of death; in the UK it is the leading cause of death. In many countries The world of cancer incidence (so far measurable) appears much lower, most likely due to higher mortality rates due to infectious diseases or injuries. With increased control over malaria and tuberculosis in some Third World countries, the incidence of cancer is expected to increase; in the Eastern Mediterranean region, for example, cancer incidence is expected to increase 100% to 180% within the next 15 years due to an increase in life expectancy, an increase in the proportion of parents, and the successful control of childhood diseases. This is called epidemiological transition in epidemiological terminology.
Cancer epidemiology closely reflects the spread of risk factors in various countries. Hepatocellular carcinoma (liver cancer) is rare in the West but is a major cancer in China and neighboring countries, most likely due to the presence of endemic hepatitis B and aflatoxins in these populations. Similarly, with tobacco smoking becoming more common in Third World countries, the incidence of lung cancer has increased in parallel.
India
According to the National Cancer Registration Program of the Indian Medical Research Council (ICMR), more than 1300 Indians die every day from cancer. Between 2012 and 2014, the mortality rate from cancer increased by about 6%. In 2012, there were 4,78,180 deaths from 2934,314 reported cases. In 2013 there were 465,169 deaths from 3016,628 cases. In 2014, 491,598 people die in 2014 from 2820,179 cases. According to the Registry Population Cancer of the Indian Council of Medical Research, the highest incidence and cancer deaths in the Northeast region of the country. Breast cancer is the most common cancer, with stomach cancer the leading cause of cancer deaths for the population as a whole. Breast cancer and lung cancer kill most women and men respectively.
Canada
In Canada, in 2007, cancer was the number one cause of death, accounting for 29.6% of all deaths in the country. The second leading cause of death was a cardiovascular disease that accounted for 21.5% of deaths. In 2011, prostate cancer is the most common form of cancer among men (about 28% of all new cases) and breast cancer is most common in women (also about 28% of all new cases).
The main cause of death in men and women is lung cancer, which accounts for 26.8% of all cancer deaths. Statistics show that between the ages of 20 and 50 years, cancer incidence rates are higher among women whereas after 50 years, the incidence rate increases in men. Predictions by the Cancer Society of Canada show that over time, there will be an increase in cancer incidence rates for men and women. Therefore, cancer will continue to be a persistent problem in the coming years.
United States
In the United States, cancer is responsible for 25% of all deaths with 30% of lung cancers. The most common cancer in men is prostate cancer (about 25% of new cases) and in women is breast cancer (also about 25%). Cancer can occur in children and adolescents, but is not uncommon (about 150 cases per million in the US), with the most common leukemia. In the first year of life, the incidence is approximately 230 cases per million in the US, with the most common neuroblastoma. Data from 2004-2008 in the United States show that overall age-adjusted cancer incidence is around 460 per 100,000 men and women per year.
Cancer is responsible for about 25% of all deaths in the US, and is a major public health problem in many parts of the world. The statistics below are estimates for the US in 2008, and can vary greatly in other countries. They exclude basal and squamous cell skin cancers, and carcinoma in situ at sites other than the bladder. As you can see, breast/prostate cancers, lung cancer and colorectal cancer account for about half of the incidence of cancer. The same is true for cancer deaths, but with lung cancer replacing breast/prostate cancer as the main cause.
By 2016, an estimated 1,685,210 new cases of cancer will be diagnosed in the United States and 595,690 people will die from the disease.
The second cancer incident on the survivor
In developed countries, one in three people will develop cancer during their lifetime. If all cancer patients survived and the cancer occurred randomly, the chances of a normal life to develop a second primary cancer (not the first cancer to spread to the new site) would be one in nine. However, cancer sufferers have an increased risk of developing a second primary cancer, and possibly around two of nine. About half of this second introduction can be attributed to a normal one-in-nine risk associated with random opportunities.
Increased risk is believed to be primarily due to the same risk factors that produce the first cancer, such as a person's genetic profile, alcohol and tobacco use, obesity, and environmental exposure, and in part because, in some cases, for treatment for the first cancer, which may include chemotherapy drugs or mutagenic antibiotics. Cancer victims may also be more likely to comply with recommended screening, and thus may be more likely than average to detect cancer.
Children
Childhood cancer and cancer in adolescents are rare (about 150 cases per million per year in the US). Leukemia (usually acute lymphoblastic leukemia) is the most common cancer in children aged 1-14 years in the US, followed by central nervous system cancer, neuroblastoma, Wilms tumor, and non-Hodgkin's lymphoma. Statistics from the SEER program of the US NCI show that childhood cancer increased 19% between 1975 and 1990, primarily due to an increased incidence in acute leukemia. Since 1990, the incidence rate has declined.
Baby
Age of peak cancer incidence in children occurs during the first year of life, in infants. The average annual incidence in the United States, 1975-1995, was 233 per million infants. Some estimated incidents exist. According to SIAP, in the United States:
- Neuroblastoma is made up of 28% of cancer cases in infants and is the most common malignancy among these children (65 per million infants).
- Leukemia as a group (41 per million infants) represents the next most common type of cancer, comprising 17% of all cases.
- Malignancy of the central nervous system consists of 13% of infant cancers, with an average annual incidence rate of nearly 30 per million infants.
- The mean annual incidence rate for malignant germ cells and malignant soft tissue tumors is basically the same in 15 per million infants. Each consists of about 6% of infant cancers.
Teratomas (germ cell tumors) are often referred to as the most common tumors in this age group, but most teratomas are removed surgically while still benign, so it is not necessarily cancerous. Before the routine use of routine prenatal ultrasound examination, the incidence of sacrococcygeal teratoma diagnosed at birth is 25 to 29 per million births.
Infants and boys basically have the same rate of overall cancer incidence, a marked difference compared to older children.
White babies have higher rates of cancer than black babies. Leukemia accounts for a substantial proportion of this difference: the average annual rate for white infants (48.7 per million) is 66% higher than for black babies (29.4 per million).
Relative survival for infants is excellent for neuroblastoma, Wilms tumor and retinoblastoma, and good enough (80%) for leukemia, but not for most other cancers.
See also
- List of countries by cancer level
- Epidemiology of breast cancer
General:
- Cluster cancer
- Cancer research
- Genetic epidemiology
- Incidentaloma, a symptom-free tumor found accidentally and treatment may not be important
References
External links
- CANCERMondial - International Agency for Research on Cancer (IARC)
- Cancer Epidemiology Resource - CancerIndex
- Supervision, Epidemiology, and Outcome - National Cancer Institute
- Global footprint owned by the company - Pulitzer Center
Source of the article : Wikipedia
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