CANCER SCREENING -3
first of all there are criteria for
screening programmes and for the screening test which they are used Screening programmes -1what are the Criteria for screening programmes
A screening programme needs to fulfil certain criteria (defined by the WHO in 1966 these criteria are
• The condition is an important health problem
• Its natural history is well understood
• It's recognisable at an early stage
• Treatment is better at an early stage
• A suitable test exists
• An acceptable test exists
• Adequate facilities exist to cope with the abnormalities detected Screening is done at repeated intervals when the onset is insidious • The chance of harm is less than the chance of benefit• The cost is balanced against benefit
A screening programme needs to fulfil certain criteria (defined by the WHO in 1966 these criteria are
• The condition is an important health problem
• Its natural history is well understood
• It's recognisable at an early stage
• Treatment is better at an early stage
• A suitable test exists
• An acceptable test exists
• Adequate facilities exist to cope with the abnormalities detected Screening is done at repeated intervals when the onset is insidious • The chance of harm is less than the chance of benefit• The cost is balanced against benefit
screening test must detect the condition till an earlier stage
than it would clinically present
This
means there should be a detectable latent or pre-clinical
phase
during which interventional treatment is possible.
the screening test should be simple and cheap|cost effective
• Highly sensitive (few false negatives)
• Highly specific (few false positives) Have a high positive
predictive value Safe
non-invasive
Acceptable to patients and
, Offered to a group agreed to be at high risk
• Easy to perform and analyses and continous
non-invasive
Acceptable to patients and
, Offered to a group agreed to be at high risk
• Easy to perform and analyses and continous
Early detection of cancer is the key to success in cancer therapy. Screening for common cancers using relatively noninvasive tests expected lead to early diagnosis, allow more conservative surgical therapies with decreased morbidity, and potentially improve surgical cure rates and overall survival rates. Key factors that influence screening guidelines are the prevalence of the cancer in the population, the risk associated with the screening measure. and whether early diagnosis actually affects outcome. The value of a widespread screening measures is likely to go up with the prevalence of the cancer in a population . often determining the age cutoffs for screening. and explaining
why only common cancers are screened for. The risks involved with the screening measure are a significant consideration, especially with more invasive screening measures such as colonoscopy, The consequences of a false-positive screening test also need to be considered Screening guidelines are developed for the general baseline risk population. These guidelines need to be modified for patients who are at high risk. For example. more intensive colorectal cancer screening is recommended for individuals at increased risk because of a history of adenomatous polyps. a personal history of colorecetal cancer, a family history of either colorectal cancer or colorectal adenomas diagnosed in a first-degree relative before age 60 years, personal history of inflammatory bowel disease of significant dura tion, or family history of FAP or HNPCC
American Cancer Society Recommendations for Early Detection of Cancer in Average-Risk, Asymptomatic People
Breast screening
why only common cancers are screened for. The risks involved with the screening measure are a significant consideration, especially with more invasive screening measures such as colonoscopy, The consequences of a false-positive screening test also need to be considered Screening guidelines are developed for the general baseline risk population. These guidelines need to be modified for patients who are at high risk. For example. more intensive colorectal cancer screening is recommended for individuals at increased risk because of a history of adenomatous polyps. a personal history of colorecetal cancer, a family history of either colorectal cancer or colorectal adenomas diagnosed in a first-degree relative before age 60 years, personal history of inflammatory bowel disease of significant dura tion, or family history of FAP or HNPCC
American Cancer Society Recommendations for Early Detection of Cancer in Average-Risk, Asymptomatic People
Breast screening
population
Women. age 20+ test or procedure Breast self-examination clinical breast examination
Women. age 20+ test or procedure Breast self-examination clinical breast examination
frequency
Monthly, starting at age 20
Clinical breast examination
Every 3 years. ages 20-39
Annual, starting at age 40
Mammography
Annual, starting at age 40
Monthly, starting at age 20
Clinical breast examination
Every 3 years. ages 20-39
Annual, starting at age 40
Mammography
Annual, starting at age 40
the WHO's International Agency for Research on Cancer (IARC) concluded
that mammography screening for breast cancer reduces mortality.
The IARC working group determined
there is a 35% reduction in mortality from breast cancer among screened women aged 50-69
(ie the number needed to screen to save one life is 500)
women aged 50-64 are routinely invited for breast screening every 3 years. The aim is to extend this to women up to the age of 70. After the upper age limit women are invited to their own appointments.
there are over 90 breast screening units across the UK, each responsible for an average population of around 45 000 women. These can either be mobile, hospital-based, or permanently based in another convenient location
Colorectal screening
there is a 35% reduction in mortality from breast cancer among screened women aged 50-69
(ie the number needed to screen to save one life is 500)
women aged 50-64 are routinely invited for breast screening every 3 years. The aim is to extend this to women up to the age of 70. After the upper age limit women are invited to their own appointments.
there are over 90 breast screening units across the UK, each responsible for an average population of around 45 000 women. These can either be mobile, hospital-based, or permanently based in another convenient location
Colorectal screening
population
Men and women age 50+ test or procedure Fecal occult blood test FOBT
or
Flexible sigmoidoscopy frequency every 5 years
or
Fecal occult blood test and flexible sigmoidoscopy fequency annual FOBT and flexible sigmoidoscopy every 5 years starting at age 50
Men and women age 50+ test or procedure Fecal occult blood test FOBT
or
Flexible sigmoidoscopy frequency every 5 years
or
Fecal occult blood test and flexible sigmoidoscopy fequency annual FOBT and flexible sigmoidoscopy every 5 years starting at age 50
or
Double-contrast barium enema DCBE frequency DCBE every 5 years starting at age 50
Double-contrast barium enema DCBE frequency DCBE every 5 years starting at age 50
or
Colonoscopy frequency every 10 years starting at age of 50
Colonoscopy frequency every 10 years starting at age of 50
population Men, age 50 test or procedure
Digital rectal examination (DRE) and
prostate-specific antigen test (PSA)
Offer PSA and DRE annually, starting at age 50, for men who have life expectancy of at least 10 years
Digital rectal examination (DRE) and
prostate-specific antigen test (PSA)
Offer PSA and DRE annually, starting at age 50, for men who have life expectancy of at least 10 years
population women test or procedure pap test frequency
Cervical cancer screening beginning 3 years after first vaginal intercourse. but no later than 21 years of age; screening every year with conventional
Pap tests or every 2 years using liquid-based Pap tests; at or after age 30. women who have had three or more normal Pap tests and no abnormal Pap tests in the last 10 years. and women who
have had a total hysterectomy, may choose to stop cervical cancer screening
Cancer-related check-up screening
Cervical cancer screening beginning 3 years after first vaginal intercourse. but no later than 21 years of age; screening every year with conventional
Pap tests or every 2 years using liquid-based Pap tests; at or after age 30. women who have had three or more normal Pap tests and no abnormal Pap tests in the last 10 years. and women who
have had a total hysterectomy, may choose to stop cervical cancer screening
Cancer-related check-up screening
population
Men and women, age +20
Men and women, age +20
test or procedure
On the occasion of a periodic health examination. the cancer-related check-up should include examination of
the thyroid, testicles, ovaries, lymph nodes. oral cavity, and skin. as well as health counseling about
tobacco, sun exposure, diet and nutrition. risk factors. sexual practices. and environmental and
occupational exposures
On the occasion of a periodic health examination. the cancer-related check-up should include examination of
the thyroid, testicles, ovaries, lymph nodes. oral cavity, and skin. as well as health counseling about
tobacco, sun exposure, diet and nutrition. risk factors. sexual practices. and environmental and
occupational exposures
.jpg)
.jpg)
0 comment:
Post a Comment