Breast cancer screening is a medical examination 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.
Clinical or self-examination of the breast involves breast feelings for lumps or other abnormalities. Medical evidence, however, does not support its use in women with typical risks for breast cancer.
The use of mammography in a universal screening for controversial breast cancer because it can not reduce all causes of death and to cause damage through unnecessary care and medical procedures. Many national organizations recommend it for most older women. In the United States female mammography screening at normal risk for breast cancer, it is recommended only every two years in women between the ages of 50 and 74. Several tools are available to help target breast cancer screening for older women with a longer life expectancy. Similar imaging can be done with magnetic resonance imaging but less evidence.
Early, more aggressive, and more frequent screening is recommended for women at high risk for breast cancer, such as those with confirmed BRCA mutations, those who have previously had breast cancer, and those with a family history the strongest of breast and ovarian cancers.
Abnormal findings on further screening were investigated by surgery removing a piece of suspicious lump (biopsy) to examine them under a microscope. Ultrasound can be used to guide the biopsy needle during the procedure. Magnetic resonance imaging is used to guide treatment, but not an established screening method for healthy women.
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Breast exams
Breast examination (either clinical breast examination (CBE) by a health care provider or by self-examination) has been widely recommended. However they are not supported by evidence and may, such as mammography and other screening methods that produce false-positive results, contribute to harm. The use of screening in asymptomatic and low-risk women is thus controversial.
A Cochrane 2003 review found screening with breast self-examination unrelated to lower mortality rates among women who reported doing breast self-examination alone and not, like other breast cancer screening methods, increased the danger, in terms of increasing the number of identified benign lesions and increased number of biopsies performed. They concluded "at this time, breast self-examination can not be recommended". There is no high-quality evidence to pay attention to clinical breast examination.
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Mammography
Mammography is a common screening method, as it is relatively fast and widely available in developed countries. Mammography is the type of radiography used in the breast. This is usually used for two purposes: to assist in the diagnosis of a woman who has symptoms or has been recalled for follow-up visits (called diagnostic mammography ), and for a medical examination apparently a healthy woman (called mammography screening ).
Mammography is not very useful in finding breast tumors in the characteristics of dense breast tissue of women under 40 years. In women over 50 without dense breasts, breast cancer detected by mammography screening is usually smaller and less aggressive than that detected by patients or doctors as breast lumps. This is because most aggressive breast cancer is found in dense breast tissue, in which mammograms perform poorly.
The presumption is that by detecting cancer at an early stage, women will be more likely to be cured with care. This statement, however, has been challenged by recent reviews that have found the importance of this net benefit to be less for women at the average risk of dying from breast cancer.
Mechanism
Screening mammography is usually recommended for women who are most likely to develop breast cancer. In general, this means women who have risk factors such as having a personal or family history of breast cancer or being an older woman, but not a weak old woman, are unlikely to benefit from treatment.
Women who agree to be screened should be tortured with X-rays on a special X-ray machine. It exposes a woman's breast to a small amount of ionizing radiation, which has a very small, but not zero, chance of causing cancer.
An X-ray image, called radiography, is sent to a doctor who specializes in interpreting these images, called radiology experts. Images may be on ordinary photography films or digital mammography on a computer screen; Although the cost of digital systems is much higher, the two methods are generally considered equally effective. Equipment may use computer-aided diagnosis (CAD) systems.
There is considerable variation in interpreting images; the same image may be declared normal by one radiologist and suspected by another. It would be helpful to compare images with images taken earlier, as changes over time may be significant.
If suspicious signs are identified in the picture, then women are usually called for a second mammogram, sometimes after waiting six months to see if the site develops, or a breast biopsy. Most of this will prove to be a false positive, so sometimes anxiety is debilitating over nothing. Most of the women who are called will undergo additional imaging only, without further intervention. Call prices are higher in the US than in the UK.
Effectiveness
On balance, mammography screening in older women improves medical care and saves a small number of lives. Usually, it has no effect on the results of detected breast cancer. Targeted screening for women at an above-average risk results in more benefits than screening women at a low or average risk for breast cancer.
Overview Cochrane 2013 estimates that mammography in women between 50 and 75 years results in a 15% reduction in the risk of death from breast cancer and an absolute risk reduction of 0.05%. However, when the analysis included only the least biased trial, women who had regular screening mammograms were likely to die from all causes, and most likely to die specifically from breast cancer, such as women who did not. The effect size may be less in real life compared to results in randomized controlled trials because factors such as increased self-selection rates among women are concerned and an increase in the effectiveness of adjuvant therapy. The Nordic Cochrane Collection (2012) says that advances in diagnosis and treatment may make mammography screening less effective in saving lives today. They conclude that screening is "no longer effective" to prevent death and "therefore no longer makes sense" to screen for breast cancer at any age, and warn of misleading information on the internet. The study also concluded that "half or more" cancers detected by mammography would disappear spontaneously without treatment. They found that most of the earliest cell changes discovered by mammography screening (carcinoma in situ) had to be left alone because this change would not develop into invasive cancer.
The deliberate destruction of mammography screening has been underestimated. Women who experience mammograms end up with surgery, chemotherapy, radiotherapy and other potential procedures resulting from over-detection of harmless lumps. Many women will experience important psychological distress for months because of false positive findings. Half of the suspicious findings will not become dangerous or will disappear over time. As a result, routine mammography values ​​in women with low risk or controversial rates. With the unnecessary treatment of ten women for every woman whose life is extended, the authors concluded that routine mammography may be more dangerous than good. If 1000 women in their 50s are screened every year for ten years, the following results are considered typical in the developed world:
- A woman's life will be prolonged because of early detection of breast cancer.
- 2 to 10 women will be overdiagnosed and not treated for cancer that will stop growing alone or not cause harm during the life of the woman.
- 5 to 15 women will be treated for breast cancer, with the same results as if the cancer has been detected after symptoms appear.
- 500 will be misinformed that they may have breast cancer (false positives).
- 125 to 250 will undergo a breast biopsy.
The results are worse for women in their 20s, 30s, and 40s, as they are much less likely to have life-threatening breast cancer, and are more likely to have dense breasts that make interpreting mammograms more difficult. Among women in their 60s, who had somewhat higher rates of breast cancer, the proportion of positive outcomes against harm was better:
- For women in their 40s: About 2,000 women need to be checked annually for 10 years to prevent one death from breast cancer. 1,000 of these women will experience false positives, and 250 healthy women will undergo an unnecessary biopsy.
- For women in their 50s: Approximately 1,350 women need to be screened every year for 10 years to prevent one death from breast cancer. Half of these women will experience a positive error, and a quarter will undergo an unnecessary biopsy.
- For women in their 60s: Approximately 375 women need to be screened every year for 10 years to prevent one death from breast cancer. Half of these women will experience a positive error, and a quarter will undergo an unnecessary biopsy.
Mammography is generally not regarded as an effective screening technique for women on average or low risk of cancer that is less than 50 years old. For women with a normal risk of 40 to 49 years, the risk of mammography outweighs the benefits, and the US Preventive Services Task Force says that evidence supporting a routine examination of women under 50 is "weak". Part of the difficulty in interpreting mammograms in younger women comes from breast density. Radiographically, dense breasts have excess glandular tissue, and younger age or estrogen hormone replacement therapy contributes to breast density mammography. After menopause, the breast gland tissue is gradually replaced by fatty tissue, making the mammography interpretation much more accurate.
Recommendations
Recommendations for attending mammography screening vary across countries and organizations, with the most common difference being the age at which screening should begin, and how often or whether it should be done, among women at typical risk for developing breast cancer. In November 2016 the European Commission issued a recommendation indicating an asymptomatic woman with an average risk for attending regular screening between 45 and 74 years.
In the UK, all women are invited to screen every three years starting at age 50, although this changes to early at age 47 of 2016. Some other organizations recommend mammograms beginning at age 40 in women at normal risk, and taking more placement often, up to once every year. Women at higher risk may benefit from screening early or more frequently. Women with one or more first-degree relatives (mothers, sisters, daughters) with premenopausal breast cancer often begin screening at an earlier age, perhaps at age 10 years younger than the age when you are diagnosed with breast cancer.
In 2009, the United States Task Force recommended that women over the age of 50 receive mammography every two years.
Cochrane Collaboration (2013) states that the best quality evidence does not show a decline in both certain cancers, as well as a reduction in all-cause mortality from mammography screening. When less rigorous tests were added to the analysis there was a decrease in breast cancer-specific mortality from 0.05% (relative decrease of 15%). Screening results at a 30% increase in over-diagnosis and over-treatment rates resulted in a view that it is unclear whether mammography screening is better or harmful. On their Web site, Cochrane currently concludes that, due to recent improvements in the treatment of breast cancer, and false positive risks of breast cancer screening leading to unnecessary treatment, "it is therefore no longer plausible to attend breast cancer screening" on every age.
Breast density
Breast consists of breast tissue, connective tissue, and adipose tissue (fat). The number of each of the three types of tissue varies from woman to woman. Breast density is a measurement of the relative amounts of these three tissues in a woman's breast, as determined by their appearance on an X-ray image. Breasts and connective tissue are radiographically denser (they produce bright white on X-rays) rather than adipose tissue on a mammogram, so a woman with more breast tissue and/or more connective tissue is said to have greater breast density. Breast density is assessed by mammography and expressed as the percentage of mammograms occupied by dense radiological tissue ( percent mammography density or PMD). About half of middle-aged women have dense breasts, and breasts generally become less dense as they get older. Higher breast density is an independent risk factor for breast cancer.
Breast cancer is difficult to detect via mammograms in women with high breast density because most cancers and dense breast tissue have similar appearance to mammograms. As a result, higher breast density is associated with higher rates of false negatives (missed cancers).
Health program
In 2005, approximately 68% of all US women aged 40-64 years had mammograms in the past two years (75% of women with private health insurance, 56% of women with Medicaid insurance, 38% of uninsured women, and 33% women uninsured for more than 12 months). All US states except Utah require private health insurance plans and Medicaid to pay for breast cancer screening. In 1998, Medicare (available to those aged 65 years or older or who have undergone Social Security Insurance for more than 2 years) pays for annual screening mammography in women aged 40 or older.
Three of twelve (3/12) breast cancer screening programs in Canada offer clinical breast examination. All twelve offer mammography screening every two years for women aged 50-69, while nine out of twelve (9/12) offer mammography screening for women aged 40-49 years. In 2003, about 61% of women aged 50-69 in Canada reported having mammograms in the past two years.
The NHS Breast Screening Program in the UK, the first in the world, began in 1988 and reached national coverage in the mid-1990s. It provides free mammography of breast cancer every three years for all women in the UK between the ages of 50 and 70; the current age range is being expanded to 47 to 73, to be completed by 2016. As of 2006, about 76% of women aged 53-64 residents in the UK have been examined at least once in the previous three years.
Australia's national breast screening program, BreastScreen Australia, began in the early 1990s and invited women aged 50-69 to screen every 2 years. No routine clinical examination was performed, and free screening costs got to the point of diagnosis.
Singapore's national breast screening program, BreastScreen Singapore, is the nationally funded public breast screening program in Asia and enrolls women aged 50-64 for screening every two years. Like the Australian system, there is no routine clinical examination. Unlike most national screening systems, however, clients must pay half of the cost of screening mammograms; This is in line with the core principles of the Singapore health system of collective payments for all health services.
Criticism
Most women significantly overestimate their own risk of dying from breast cancer and the effects of screening mammography can occur. Some researchers worry that if women correctly understand that screening programs offer little benefit, but statistically significant, more women will refuse to participate.
The contribution of mammography to early cancer diagnosis is controversial, and for those found with benign lesions, mammography can create high psychological and financial costs. Most of the women who participated in the mammography screening program received a false positive memory risk, and the majority did not feel very sad. Many patients feel that their memory is very frightening, and very relieved to know that it is a false positive, because about 90% of women do it.
The main effect of routine breast screening is to greatly improve the rate of early detection of breast cancer, especially for non-invasive ductal ductal carcinomas in situ (DCIS), sometimes called "pre-breast cancer", which almost never form lumps and generally can not detected except through mammography. While the ability to detect these very early breast malignancies is at the heart of the claim that mammography screening can improve survival from breast cancer, it is also controversial. This is because a very large proportion of such cases will not develop to kill patients, and thus mammography can not really claim to have saved lives in such cases; in fact, it will lead to increased illness and unnecessary surgery for such patients.
As a result, finding and treating many cases of DCIS is overdiagnosis and overtreatment. Treatment is given to all women with DCIS as it is currently impossible to predict which patients with DCIS will have an indolent, non-fatal course, and that few will surely develop into invasive cancer and premature death if left untreated. As a result, all patients with DCIS are treated in the same way, with at least extensive local excision, and sometimes a mastectomy if the DCIS is very wide. The healing rate for DCIS if handled appropriately is very high, partly because the majority of DCIS cases are harmless in the first place.
The phenomenon of finding pre-invasive malignancies or nonmalignant benign diseases is common in all forms of cancer screening, including pap smears for cervical cancer, fecal occult blood tests for colon cancer, and testing of prostate antigen specific to prostate cancer. All of these tests have the potential to detect asymptomatic cancer, and all have a high false positive rate and lead to invasive procedures that are not beneficial to the patient.
Molecular breast imaging
Molecular breast imaging is a nuclear medicine technique currently under study. This shows promising results for the imaging of people with dense breast tissue and may have comparable accuracy with MRI. Probably better than mammography in some people with dense breast tissue, detecting two to three times more cancers in this population. However it carries a greater risk of radiation damage so it is inappropriate for general breast cancer screening. It is possible to reduce the radiation dose used.
An earlier alternative technique suitable for dense breast tissue, scintimammography is now not recommended by the American Cancer Society, which states, "This test can not show whether the abnormal area is cancer as accurate as mammogram, and it is not used as a screening test.Some radiologists believe this test may be useful in looking at the suspicious areas found by mammograms, but the exact role of scintimmgography remains unclear. "
Ultrasonography
Medical ultrasonography is a diagnostic aid for mammography. Adding ultrasound tests to women with dense breast tissue improves breast cancer detection, but also increases false positives.
Magnetic resonance imaging
Magnetic resonance imaging (MRI) has been shown to detect cancer not seen in mammograms. The main strength of breast MRI is its very high negative predictive value. A negative MRI can rule out the presence of cancer to a high degree of certainty, making it an excellent tool for screening in patients with high genetic risk or radiographic dense breasts, and for pre-treatment staging where disease levels are difficult to determine. on mammography and ultrasound. MRI can diagnose benign proliferative changes, fibroadenomas, and other benign findings at a glance, often eliminating the need for expensive or unnecessary biopsies or surgical procedures. The spatial and temporal resolution of breast MRI has increased sharply in recent years, making it possible to detect or exclude the presence of small in situ cancers, including ductal carcinoma in situ.
Despite the help provided from MRI, there are some disadvantages. For example, although 27-36% more sensitive, it is claimed to be less specific than mammography. As a result, MRI research may have up to 30% more false errors, which may have undesirable financial and psychological costs to the patient. Also, the MRI procedure is expensive and includes intravenous injection of gadolinium contrast, which has been implicated in a rare reaction called nephrogenic systemic fibrosis (NFS). Although NSF is rare, other patients with a history of renal failure/disease will not be able to undergo MRI scans. Breast MRI is not recommended for screening all breast cancer patients, but is limited to patients at high risk of developing breast cancer that may have a high family risk or mutation in BCRA1/2 genes. MRI breast is not a perfect tool despite its increased sensitivity to detect breast cancer mass when compared with mammography. This is because the ability of MRI to miss some cancers will be detected by conventional mammography, as a result, MRI screening for breast cancer is most effective as a combination with other tests and for certain breast cancer patients. In contrast, the use of MRI often confines in patients with the integration of body metals such as patients with tattoos, pacemakers, tissue expansion, and so on.
The proposed indications for using MRI for screening include:
- A strong family history of breast cancer
- Patients with BRCA-1 or BRCA-2 oncogene mutations
- Evaluate women with breast implants
- History of previous lumpectomy or breast biopsy surgery
- Axillary metastases with unknown primary tumors
- Very dense or scarred breast tissue
In addition, breast MRI may help to screen for women who have undergone breast enlargement procedures involving intramammary injections of various foreign substances that can mask the appearance of breast cancer in mammography and/or ultrasound. These substances include silicone oil and polyacrylamide gel.
BRCA test
Genetic tests do not detect cancer, but can reveal a tendency to develop cancer. Women who are known to have a higher risk of developing breast cancer typically perform more aggressive screening programs.
The clinical practice guidelines by the US Prevention Services Task Force recommend routine reference for genetic counseling or routine testing for BRCA mutations, with fair evidence that the harm is greater than the benefits. It also encourages referral for counseling and testing in women with a family history that indicates they have an increased risk of BRCA mutation, on a fair proof of benefit. About 2% of American women have a family history that shows an increased risk of having a medically significant BRCA mutation.
More
Nipple aspiration tests are not indicated for breast cancer screening.
Optical imaging, also known as diaphanography (DPG), multi-scan transillumination, and light scanning, is the use of transillumination to differentiate network variations. This is the initial stage of the study.
References
External links
- Breast cancer in Curlie (based on DMOZ)
- Breast cancer screening page of the National Cancer Institute
- Breast Cancer Screening from AARP.org
- Breast cancer screening statistics (Eurostat - Statistics Explained, EHIS data collection WAVE I 2008)
Source of the article : Wikipedia
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