Oncology & Cancer Case Reports

John Bandelow^{* *}Correspondence: John Bandelow, Managing Editor, Journal of Oncology and Cancer Case Reports Chaussee de la Hulpe 181, Watermael-Boitsfort, Belgium, Email:

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Editorial

Cancer epidemiology is the study of the distribution and determinants of the likelihood of cancer development. Cancer epidemiology can be used to identify events that increase or decrease cancer incidence in specific populations. Epidemiologic research plays an important role in the development of cancer screening modalities and prevention strategies. Cancer prevention focuses on decreasing incidence by lowering risk through changes in lifestyle patterns and behavior. Cancer prevalence is defined as the number of living people who have ever been diagnosed with cancer. It includes people diagnosed with cancer in the past as well those who were recently diagnosed.

Epidemiologists continue to search for factors that cause cancer (like tobacco use, obesity, ultraviolet radiation), as well as those things that can help protect against cancer (such as physical activity and a healthy diet). This research provides evidence to guide public health recommendations and regulations. The most common type of cancer on the list is breast cancer, with 284,200 new cases expected in the United States in 2021. The next most common cancers are prostate cancer and lung cancer. Because colon and rectal cancers are often referred to as "colorectal cancers," these two cancer types are combined for the list.

This area of study must contend with problems of lead time bias and length time bias. Lead time bias is the concept that early diagnosis may artificially inflate the survival statistics of a cancer, without really improving the natural history of the disease. Length bias is the concept that slower growing, more indolent tumors are more likely to be diagnosed by screening tests, but improvements in diagnosing more cases of indolent cancer may not translate into better patient outcomes after the implementation of screening programs. A related concern is over diagnosis, the tendency of screening tests to diagnose diseases that may not actually impact the patient's longevity. This problem especially applies to prostate cancer and PSA screening. Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans

In the 16^th and 17^th centuries, it became more acceptable for doctors to dissect bodies to discover the cause of death. The German professor Wilhelm Fabry believed that breast cancer was caused by a milk clot in a mammary duct. The Dutch professor Francois de la Boe Sylvius, a follower of Descartes, believed that all disease was the outcome of chemical processes, and that acidic lymph fluid was the cause of cancer. His contemporary Nicolaes Tulp believed that cancer was a poison that slowly spreads, and concluded that it was contagious.