Screening is to identify an unknown disease in the early stage, through tests and exams or other procedures may be applied quickly to asymptomatic person.
In support screening programs as part of early detection of cancer it is important to avoid imposing a “high technology”. The success of screening depends on sufficient staff to conduct screening tests and the availability of necessary facilities and chase after treatment. In adopting a screening test must be taken into account:
– Sensitivity: the effectiveness of a test in detecting cancer in patients who have disease
– Specificity: the degree to which a test is negative in people that no cancer.
– The positive predictive value: the degree to which there is disease in subjects with a positive test.
– Negative predictive value: the degree to which there is no disease in subjects with negative test.
– Acceptability: the degree to which subjects should be screened agrees with the test.
The positive results of examinations, tests or procedures used in screening usually are not diagnostic but identify people at increased risk for this cancer authorizing further analysis.
Diagnosis of the disease is confirmed by biopsy or tissue examination that is performed in patients with positive screening tests (positive screening test may be removed by biopsy or tissue examination).
The success of the screening program depends on a few fundamental principles:
– Researched disease has to be a common form of cancer with high morbidity and mortality.
– Effective treatment must be able to reduce morbidity and mortality.
– Tests must be acceptable, safe and relatively inexpensive.
Currently available screening for breast cancer, colorectal, cervical, prostate, testicular, mouth and skin.
American Cancer Society recommendations for early detection of cancer in asymptomatic individuals:
The tests used: breast self-exam, clinical breast exam and mammography.
In women ≥ 40 years of clinical breast exam is recommended annual mammography and breast self-examination monthly.
In women between 20-39 years old recommended clinical breast exam every 3 years and breast self-examination monthly.
Screening by mammography with or without clinical examination reduces breast cancer mortality by 1/3 in women aged 50-69 years.
Its efficacy is limited to women 40-49 years.
Mammography screening method should not be introduced unless resources are available that provide an efficient and reliable screening of at least 70% of the target age group ex women ≥ 50 years.
If screening is available, the priority is to use as a diagnostic test particularly for women with breast abnormalities detected by clinical examination or self-examination.
Screening begins at age 50 and is recommended:
· Occult blood test year (THO)
· Sigmoidoscopy every 5 years.
· THO annually and sigmoidoscopy every 5 years.
· Ex. Rx. barium enema bowel every 5 years.
· Colonoscopy 10 years.
Trials carried out suggest that after an interval of 10 years could be a 20% reduction in mortality through biennial THO and slighty bigger by yearly THO.
Screening is recommended in patients over 50 years with a life expectancy of at least 10 years.
In these patients, we recommend annual PSA test and rectal examination. In men with increased risk (ie men with strong family history of one or more first degree relatives diagnosed with prostate cancer in January at an early age) it is recommended that screening begin at 45 years.
Screening begins at 3 years from the onset of sexual activity, but no later than age 21 years. Screening is done through annual Pap test. After the age of 30 years women who have had three normal Pap tests will be examined at 2-3 years.
Your doctor may suggest that screening be done more often if there are certain risk factors: infection with HIV or immune system deficiencies.
In women ≥ 70 years who have had three consecutive normal Pap tests in the last 10 years may recommend stopping screening. In women with total hysterectomy for reasons other than cervical cancer screening is not recommended.
It conducts clinical exam by a dentist or any doctor. Areas to be inspected for early detection are: floor mouth, tip and edges of the tongue, soft palate.
Examination of routine skin cancer screening increases the chance of skin in the early stages. Most melanomas arise in the skin can be seen. If an area of the skin looks abnormal biopsy is recommended.
For the general population over the age of 20 recommended a skin exam every three years and more frequently in persons with increased risk.
Screening consists of historical and clinical examination of the entire body under bright light (a day).
Most cases of testicular cancer are detected by self-examination. Some cancers are detected by clinical examination by a doctor.
Currently not recommend screening for lung cancer screening procedures because there available that reduce mortality.
Screening by chest X-ray and / or sputum cytology may decrease and increase survival stage presentation without effect on cancer mortality.
The most effective means to combat this cancer remains the prevention of smoking and smoking cessation start.
In individuals undergoing periodic health exams are recommended to conduct exams for detecting cancer and thyroid, mouth, skin, testes, lymph nodes.