To have or not to have a Screening Mammogram? The Screening Debate…
Updated 10 August 2003 For males, there is no controversy for screening as the incidence of cancer is very low and does not warrant screening mammograms. Mammograms, when recommended by their doctor would be based on symptoms and signs in the breast, especially if there is suspicion of cancer. The screening debate revolves mainly around women in the age group of 40-49 years. In the USA, public health and health policy groups agree that screening mammography has a clear-cut survival benefit in women aged 50 and older. Evidence is also beginning to show that women in the 40-49 year age group often have a more aggressive type of breast cancer and that premenopausal breast cancer may have a poorer outlook than post menopausal breast cancer. This means it might be even more important that their cancer is detected at a very early stage. Regular mammography reduces the breast cancer deaths
There are many more studies where the results show an improvement in breast cancer death rate with mammography screening programmes compared to those where there was no significant reduction in death rate after implementing a mammography screening programme. In a recent paper published in the Lancet in April 2003 (Lancet 2003; 361: 1405-10), researchers found that there was significant reduction in breast cancer deaths (about 28% reduction in breast cancer mortality) in a 20 year follow up in a mammography screening service in 2 Swedish counties in those 40-69 years of age. Specifically, those in the 40-49 year age group also benefited from reduction in deaths from breast cancer. The figure of 28% already has taken into account the reduction in deaths due to improvement in treatment for breast cancer. Regular yearly mammograms does detect breast cancer at an earlier stage
In July 2003, another study was published in the journal Cancer. This time, researchers compared the breast cancers of women 40 years and older, and categorized them according to whether they had regular mammography or not. It was found that early stage cancers were found more often in the group who had regular mammography compared to those who never had a mammogram.
This study confirmed that frequent yearly mammograms have many benefits: detection of breast cancer with early tumour size and stage higher possibility of having breast conserving surgery may need chemotherapy less often because tumours were found at a very early stage survival rate should be better (because tumours are at an earlier stage)
The above study only adds to the evidence that previous researchers in the USA had found. Breast cancer is far more likely to be caught in the early stage through regular mammography screening and is therefore treated less expensively and more effectively. Although screening mammography may be expensive up front, it more than pays for itself in the long run. It is felt that regular screening starting at age 40 will shift at least 30% of the people who would otherwise be diagnosed in the later stages of breast cancer to the very early stages. Proponents of mammography feel that although diet, exercise, smoking, and other environmental factors probably influence cancer development after menopause, there are no effective strategies for premenopausal cancer, only early detection and removal. Regular self breast examinations and clinical breast examinations cannot identify many early lesions and may not detect them until it is too late! Guidelines for Mammography Screening
Guidelines for mammography screening vary from country to country. In the United Kingdom, a national breast screening programme, screens women between the ages of 50 and 64 years at 3-yearly intervals. The American Cancer Society recommends mammography screening yearly from the age of 40 years.
In Malaysia, a nationwide screening programme has not been implemented yet. Currently women who are encouraged to go for screening normally have a higher risk profile than the general public, such as having a close family member with breast cancer. 52.3% of new cases of breast cancer in Malaysian women were in those below 50 years of age. The Malaysian woman has a chance of 1 in 19 of developing breast cancer in her lifetime. (National Cancer Registry Report 2002). However when the ethnic groups are individually analysed, the Malaysian Chinese women appears to have an Age Standardised Incidence rate ( 70.1 per 100,000 population) that is similar to that of developed countries such as the United Kingdom (68.8 per 100,000), Sweden (72.9 per 100, 000), Netherlands (72.7 per 100,000) and NSW, Australia (66.6 per 100,000). In some countries, mammogram is almost a compulsory screening test and is paid for by health insurance. In these countries, there is the added analysis of cost effectiveness as it is insurance that is paying for the mammogram. We know that mammography is useful for screening women in the high-risk groups, such as those with a family history of breast cancer, or a previous history of benign breast disease, to detect early breast cancer. In such women, mammography may be recommended earlier depending on factors such as the age at which breast cancer occurred in the family member. This may be from 35 years onwards.
Are there significant disadvantages to screening mammography?
Opponents of mammography cite: radiation risk increased anxiety generated by screening procedures additional cost and inconvenience related to increased biopsies when a large proportion of the lesions detected may be benign mammography is not 100% accurate and can miss cancers in dense breasts
Concerns have arisen over the possible cancer hazard posed by repeated radiation exposure from regular mammography. It has been estimated that the risk is extremely small, not more than 1%. It should also be noted that the carcinogenic effects of radiation on the breast might not be apparent until 10-20 years after exposure. This risk is theoretical. No case of breast cancer has ever been shown to result from the low dose radiation received in mammography. According to radiology experts in mammography and the American College of Radiology, the risks of radiation associated with mammography in women in their 40s are negligible, if present at all. No doubt, screening can generate anxiety and lead to perhaps, unnecessary biopsies but in the first place, many women are already anxious about breast cancer and many women do prefer to have their breast and symptoms, if any, checked out. In many cases, the abnormal mammogram results in follow up examinations and do not necessarily lead to any invasive procedure. Today, more and more people are taking charge of their health, and they do not wait to be sick before they see the doctor! As mentioned earlier, no test in medicine is 100% accurate and not all tests qualify as a screening test. However, the mammogram has a sensitivity, specificity and accuracy that qualify it as a screening procedure in appropriately aged women.
Closing Comments
At the end of it all, it is a question of risk-benefit and cost-benefit balance. Recommendations may change or alter as more and more data emerges from extensive studies in the West, especially in the USA. It will be the same for Malaysia as we await results from more research into breast cancer in our local setting. So where does that leave women in Malaysia? Know your risk profile, discuss this with your family doctor and if you are in the right age group, consider a mammogram. Even if you feel there is nothing wrong in your breasts, the screening mammogram may detect cancer before it can be felt. Should you have any symptoms or signs, do not hesitate to check with your doctor. Do you have any views about this topic? Perhaps, you would like to discuss this issue in our Forums.
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