Cancer screening aims to detect cancer before symptoms appear. This may involve blood tests, urine tests, other tests, or medical imaging. The benefits of screening in terms of cancer prevention, early detection and subsequent treatment should be weighed against any hazards.
Universal screening, also known as mass screening or population screening, involves screening everyone, usually in a certain age group. Selective screening identifies people who are known to be at higher risk of cancer, such as those with a family history of cancer.
Screening can lead to false positives and subsequent invasive procedures. Screening can also lead to false-negative results, where existing cancer is missed. Controversy arises when it is unclear whether the benefits of screening outweigh the risks of the screening procedure itself, and any further diagnostic and treatment tests.
The screening test should be effective, safe, and well tolerated with acceptable low levels of false negative and false-negative results. If cancer signs are detected, more definitive and invasive follow-up tests are performed to achieve the diagnosis. Screening for cancer can lead to cancer prevention and early diagnosis. Early diagnosis can lead to higher treatment success rates and prolonged life. However, it may also be mistaken to appear to increase the time to death through lead time bias or long time bias.
Video Cancer screening
Medical use
The purpose of cancer screening is to provide useful medical information that can guide medical care. A good cancer screening is what will detect when a person has cancer so that the person can seek treatment to protect his health. Good cancer screening will not be more likely to cause harm than to provide useful information. In general, cancer screening is a risk and should not be performed unless it is with medical indication.
Different types of cancer screening procedures have different risks, but a good test has several characteristics. If the test detects cancer, then the test results should also lead to the option of treatment. A good test comes with a patient explanation of why the person has a high enough cancer risk to justify the test. Part of the testing experience is for healthcare providers to explain how false positive results are common so that patients can understand the context of their outcome. If multiple tests are available, any tests should be presented along with other options.
Maps Cancer screening
Risk
Screening for cancer is still controversial in cases when it is not yet known whether the test really saved lives. Screening can lead to large false positive results and subsequent invasive procedures. Controversy arose when it was unclear whether the benefits of screening were greater than the risk of follow-up diagnostic and cancer treatment. Cancer screening is not indicated unless the life expectancy is more than five years and the benefits are uncertain above the age of 70 years.
Breast cancer screening is a medical screening of asymptomatic women, apparently healthy for breast cancer in an attempt to reach a previous diagnosis. The assumption is early detection will improve results. A number of screening tests have been used, including clinical and breast self-examination, mammography, genetic examination, ultrasound, and magnetic resonance imaging. The use of mammography in universal screening for breast cancer is controversial because it can not reduce all causes of death and to cause harm through unnecessary care and medical procedures. Many national organizations recommend it for most older women.
Cervical Cancer
Cervical screening by Pap tests or other methods is very effective in detecting and preventing cervical cancer, although there is a serious risk of overtreatment in young women up to age 20 or older, who tend to have many abnormal cells that clear up of course. There is a considerable range at the recommended age to initiate screening worldwide. According to the 2010 European guidelines for cervical cancer screening, the age at which to start screening ranges from 20-30 years, "but is privileged before the age of 25 or 30 years", depends on the burden of disease in the population and available resources.
In the United States the rate of cervical cancer is 0.1% among women under 20, so the American Cancer Society as well as the American College of Obstetricians and Gynecologists strongly recommend that screening begin at age 21, regardless of age at sexual initiation or other risk-related behaviors. For healthy women aged 21-29 who have never had an abnormal Pap smear, screening for cervical cancer with cervical cytology (Pap smear) should occur every 3 years, regardless of HPV vaccination status. The preferred screening for women aged 30-65 is "co-testing", which includes a combination of cervical cytology screening and HPV testing, every 5 years. However, it is acceptable to screen this age group with Pap smears every 3 years. In women over age 65, screening for cervical cancer may be discontinued without abnormal screening results in the previous 10 years and no history of CIN 2 or higher.
Cancer of the colon
Screening for colorectal cancer, if done early enough, is preventive because almost all colorectal cancers come from benign growths called polyps, which can be found and removed during colonoscopy (see > colon polypectomy ).
The US Preventive Services Task Force recommends screening for colorectal cancer using occult blood tests, sigmoidoscopy, or colonoscopy, in adults, beginning at age 50 and continuing through the age of 75 years. For people over 75 or those with a life expectancy of less than 10 years of screening is not recommended. The new enzyme method for colorectal cancer screening is the M2-PK Test, which is capable of detecting colorectal and non-colorectal and polypic bleeding. In 2008, Kaiser Permanente Colorado implemented a program that uses automatic dialing and sends fecal immunochemical tests for patients who are late for colorectal cancer screening. This program has increased the proportion of all eligible members filtered by 25 percent. DNA tests with Cologuard tests have been FDA approved.
In the UK, adults are screened biennially through faecal occult blood testing between the ages of 60 and 74.
Prostate cancer
When screening for prostate cancer, a PSA test can detect small cancers that will never be life-threatening, but once detected will lead to treatment. This situation, called overdiagnosis, puts men at risk of complications from unnecessary treatments such as surgery or radiation. Follow-up procedures used to diagnose prostate cancer (prostate biopsy) can cause side effects, including bleeding and infection. Prostate cancer treatment can cause incontinence (inability to control urine flow) and erectile dysfunction (erection is inadequate for sexual intercourse). The US Prevention Services Task Force (USPSTF) recommends against prophylactic-specific antigen (PSA) screening to find prostate cancer, "there are very small potential benefits and significant potential hazards" and concluded, "while everyone wants to help prevent death from prostate cancer, current PSA screening methods and screened cancer treatment are not the answer. "Most North American medical groups recommend individualized screening decisions, taking into account the risks, benefits, and personal preferences of patients.
Lung cancer
Screening research for lung cancer is only done in high-risk populations, such as smokers and workers with occupational exposure to certain substances. In 2010 recommendations by medical authorities turned to support lung cancer screening, which tends to become more widely available in developed countries.
In December 2013, the US Prevention Services Task Force (USPSTF) amended its long-term recommendation that there was insufficient evidence to recommend or reject screening for lung cancer as follows: "USPSTF recommends annual screening for low-dose lung cancer computed tomography on adults aged 55 to 80 years who have a smoking history of 30 packs per year and are currently smoking or have quit in the last 15 years Screening should be discontinued after a person has not smoked for 15 years or develop a health problem that substantially limits life expectancy or ability or willingness to undergo lung curative surgery ".
Pancreatic cancer
It is generally agreed that general screening of large groups for pancreatic cancer is currently unlikely to be effective, and beyond clinical trials there is no program for this. The European Society for Medical Oncology recommends routine examination with ultrasound endoscopy and MRI/CT imaging for those at high risk of inherited genetics, in line with other recommendations, which may also include CT.
Oral cancer
The US Preventive Services Task Force (USPSTF) in 2013 found that insufficient evidence to determine the balance of benefits and screening hazards for oral cancer in asymptomatic adults by primary care providers. The American Family Physician Academy has the same conclusion while the American Cancer Society recommends that adults over 20 years old who undergo periodic medical examinations should have oral cavities checked for cancer. The American Dental Association recommends that providers remain alert to signs of cancer during routine screening. Oral cancer screening is also recommended by several groups of dental professionals.
Other cancers
There is not enough evidence to recommend or oppose screening for skin cancer, and bladder cancer. Regular screening is not recommended for testicular cancer, and ovarian cancer.
Research
Whole body imaging
Full body CT scans are available for cancer screening, but the type of medical imaging to look for cancer in obvious asymptomatic people can cause problems such as increased exposure to ionizing radiation. However, magnetic resonance imaging (MRI) scans are not associated with radiation risk, and MRI scans are being evaluated for use in cancer screening. There is a significant risk of detecting so-called incidentalomas - benign lesions that can be interpreted as cancer and subjected to potentially hazardous investigations.
References
Further reading
- Smith, RA; Cokkinides, V; Eyre, HJ (2007). "Cancer screening in the United States, 2007: Review of current guidelines, practices and prospects". CA: Cancer Journal for Doctors . 57 (2): 90-104. doi: 10.3322/canjclin.57.2.90. PMID 17392386.
- Aziz, Khalid; Wu, George Y., eds. (2002). Cancer Screening: A Practical Guide for Doctors . Current Clinical Practice. Humana Press. ISBN: 9780896038653.
External links
- NHS cancer screening program
- Screening for cancer, Cancer Research UK
- Cancer screening picture, National Cancer Institute
- Cancer Checking in eMedicine
- ColonCancerCheck includes fact sheets in 24 languages ​​at Ontario Ministry of Health and Long-Term Care
- http://www.scotland.gov.uk/Topics/Health/health/cancer/Cancer-Screening/criteria
- How the screening recommendations have changed over time from the American Cancer Society
Source of the article : Wikipedia
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