Cancer incidence and mortality
Approximately 1,500,000 people in the USA are diagnosed with cancer every year and 600,000 people die from cancer in the same year. Estimates are that 3% to 35% of these early cancer-related deaths could be prevented by screening. Beyond the potential to prevent deaths, there is also a decrease in the morbidity of cancers caught at an early stage by screening.
Cervical cancer
The "The Papanicolaou (Pap) test reduces mortality due to cervical cancer. Mortality reductions of up to 80% were found in Icelandic, Finnish and Swedish studies. Similar results were obtained in Canada and the USA. Case-control studies show that the probability of having invasive cancer decreases 3-10 times in the screened population.
Test interval
Studies reveal that 2 months after a negative test result. It is believed that repetitions once a year are sufficient. Information from a large study within the National Breast and Cervical Cancer Early Detection Program shows that annual screening instead of every 3 years results in a very small reduction in mortality.
Human Papilloma Virus (HPV) test
Considering that practically all cervical cancers are associated with Human Papilloma Virus (HPV), HPV DNA testing seems logical. However, there is still no FDA-approved test. The currently used Hybrid Capture 2 (HC2) test identifies 13 HPV strains associated with cervical cancer. The sensitivity of a positive test in detecting CIN2-3 is around 84%. Another problem is that transient HPV infections are common and such infections have no clinical significance. HPV testing seems to be most useful in cases where ASCUS is detected. In this case, if the HPV test is negative, it can be waited and colposcopy can be avoided in 56% of patients whose lesion disappears as a result.
Breast cancer
Clinical breast examination
There is no randomized study using clinical breast examination alone as a screening method. The Canadian National Breast Screening Study compares clinical breast examination with clinical breast examination + mammography. The results were found to be similar in this study. has. Clinical breast examination performed by the National Breast and Cervical Cancer Early Detection Program on 752,081 women between 1995 and 1998 gave abnormal results in 6.9% of the patients, 3.8% of whom had invasive cancer and 1.2% had ductal carcinoma. -situ (DCIS) was detected. Sensitivity is 58.8%, specificity is 93.4% and PPV is 4.3%.
Breast self-examination
Monthly Breast self-examination is frequently recommended Although it is a method, the evidence for its effectiveness is weak. The only randomized study conducted on 266,064 women showed no difference with the control group.
Mammography
Mammography detects breast cancers too small to be palpable and ductal carcinoma in-situ. It may show DCIS. Many studies show that mammography can reduce cancer-specific mortality. However, it is controversial whether it reduces all-cause mortality. Despite all the uncertainty, the American Cancer Society recommends starting annual mammograms at age 40. For those with a family or personal history of cancer or those with a genetic mutation, this age should be lowered and additional examinations such as ultrasound and MRI should be performed.
Colorectal cancer
Hidden in the stool blood
Guaiac-based fecal occult blood test performed annually or biennially in patients between the ages of 50-80 reduces mortality due to colorectal cancer.
Flexible Sigmoidoscopy
Regular sigmoidoscopy reduces mortality due to colorectal cancer in people over 50 years of age. There is little information on how often this procedure should be performed. However, it is recommended to be performed every 5 years by various cancer organizations.
Colonoscopy
Since 2/3 of colonic neoplasms are detected in the colon in endoscopy screenings, sigmoidoscopy will miss some of these lesions. It is open. However, studies on this subject are still at an insufficient level. The American Cancer Society's recommendations on this subject for people after age 50 are as follows: Annual fecal occult blood test, Flexible sigmoidoscopy test every 5 years, Annual fecal occult blood test + Flexible sigmoidoscopy every 5 years (combination preferred), Double every 5 years contrast I barium enema, colonoscopy every 10 years. In addition, screening should be started earlier and/or continued at more frequent intervals in the following cases: history of colorectal cancer or polyps, strong familial history of colorectal cancer and/or polyps (one first-degree relative under the age of 60 or two first-degree relatives with a history of cancer or polyps at any age ), personal history of inflammatory bowel disease, having one of the colorectal cancer syndromes in the family (familial adenomatous polyposis and hereditary non-polyposis colon cancer).
Virtual colonoscopy
The method, also called CT-colonoscopy, is based on the images constructed by computer imitating conventional colonoscopy. While its sensitivity in detecting polyps of 10 mm and above is 90%, this rate decreases to 80% for polyps between 5-10 mm and 66% for polyps below 5 mm. Its biggest disadvantage is that colon preparation with laxatives is required, as in colonoscopy. Virtual colonoscopy can give us information about extracolonic anomalies that we cannot see in conventional colonoscopy. It is still not standard and extensive studies on this subject are ongoing.
Prostate cancer
There is currently no routine or standard test used in prostate cancer screening. Two commonly used methods are digital rectal examination and determination of prostate specific antigen (PSA) in serum. It should be kept in mind that these tests have false negatives and false positives. However, with screening tests, it may be possible to detect prostate cancer at an earlier stage and provide higher cure rates. The American Cancer Society recommends both tests annually for men over age 50 with a life expectancy of 10 years. The National Comprehensive Cancer Network's recommendation is slightly narrower: Men over age 50 with a life expectancy of 10 years should have an annual digital rectal exam and be offered a PSA test. Apart from this slight difference in recommendations between groups, recommendations on the frequency of testing may also vary. While the American Cancer Society recommends tests annually, the National Comprehensive Cancer Network reports that tests every 2 years will be sufficient. American Cancer Society one or more It states that the screening age should be 45 for men whose relatives have prostate cancer at an early age. The age at which screening tests will be discontinued is generally accepted as 75.
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