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Cancer early detection involves detecting cancers at early stages when they can be effectively treated and cured. Improved awareness among the general public and health care providers of early cancer, as well as good access to effective health services, can lead to earlier clinical diagnosis and prompt treatment. Screening programs for asymptomatic, apparently healthy populations are resource-intensive interventions, and should be undertaken only when their effectiveness has been demonstrated, when health services are adequately developed to investigate, treat and follow up screen-positive individuals, and when there is a sufficiently high incidence of the disease to justify the effort and costs of screening.

Screening programs vary between countries in how they are conducted; they are more organized in countries such as Australia, Finland and the United Kingdom among others with systematic call and recall of target populations at regular intervals, compared with unorganized programs in countries such as the United States, France, and Germany.

Improved awareness among the general public and health care providers of early cancer symptoms/signs, as well as good access to effective health services can lead to earlier clinical diagnosis and prompt treatment.

Pap smear screening programs have substantially reduced cervical cancer incidence and mortality in several high-income countries. Alternative cervical screening tests include human papillomavirus (HPV) testing and visual inspection with acetic acid (VIA). HPV testing is shown to be more sensitive than the pap smear in detecting cervical neoplasia, and VIA is a feasible and effective intervention in low-income countries. Mammography screening and treatment improvements have reduced breast cancer deaths in many high-income countries. It is unclear whether clinical breast examination screening can reduce breast cancer mortality. Screening with fecal occult blood tests has reduced colorectal cancer mortality in clinical trials, and organized colorectal cancer screening programs are still evolving in high-income countries. Oral cancer screening, using visual inspection, has been shown to reduce oral cancer deaths among users of tobacco or alcohol or both.

In several high-income countries, cervical cancer incidence has shown a marked decrease with the advent of screening programs.

Trends in age-standardized incidence rate (world) per 100,000, 1953-2002

Download High Res Text alternative: Trends in age-standardized incidence rate, 1953-2002
Chart showing that In several high-income countries, cervical cancer incidence has shown a marked decrease with the advent of screening programs (from 1953-2002)

Although low-dose computed tomography in heavy current and former smokers has been shown to reduce lung cancer mortality and allcause mortality in a clinical trial, the implementation of screening should proceed carefully to ensure that quality is high, best practices are met, and efforts are focused on reducing the high rate of false-positive findings. Meanwhile, tobacco control remains the most important global strategy for lung cancer control. There is little evidence to support population-based screening programs for cancers of the skin, stomach, and ovary, and the benefits of prostate specific antigen (PSA) testing may not outweigh the harms associated with over-diagnosis and overtreatment.

“To keep the body in good health is a duty...otherwise we shall not be able to keep our mind strong and clear."

Buddha