Tuesday, January 4, 2011

There are more benefits from breast cancer screening than simply saving a woman's life

This past year saw the eruption of a fresh controversy in breast cancer screening. The United States Preventive Services Task Force (USPSTF) issued a report to the Obama administration advising against x-ray mammographic screening for women in their forties. The journal Science reported on the controversy and published a reply letter which was also published here at Spotlight-on-Science. The article pointed out that the USPSTF task force accepted a particular conservative estimate about the number of women in their forties that needed to be screened by x-ray mammography in order to save one life (1900 need to be screened by this estimate). I pointed out that when a fully developed screening program is applied to a large population such as the United States, the use of screening still adds up to many lives saved.

There are associated harms with breast cancer screening such as biopsy procedures performed on women who don’t have cancer, breast compression during the examination and associated stress while waiting for a diagnosis. However, the benefits of breast cancer screening are not limited to the simple measure of how many lives it saves. When a malignant tumour is caught at an earlier stage of development, the associated treatments are easier on the patient and have a higher success rate (as demonstrated in the fact that there is a mortality reduction). X-ray mammography is capable of catching DCIS (ductal carcinoma in situ - an early stage of breast cancer) whose treatment success rates are very high.

The devastating effects that a breast cancer death has on the victim’s loved ones is also worthy of consideration. Breast cancer deaths regularly leave dozens of surrogate victims among the woman’s partner, family, friends and colleagues. Women who die of breast cancer typically leave behind many devastated people who typically aren’t part of the discussion of the benefits and harms of choosing whether to be screened for breast cancer.

It should also be mentioned that according to the American Cancer Society, women at elevated risk for breast cancer should get MRI based screening (if their lifetime risk is greater than 20%). Furthermore, there is also a need for more data on identifying women with an unusually low risk for breast cancer as a potentially identifiable group to be studied. The harms of screening may be associated with no benefit in an identifiable subgroup of the population. There may be some excellent potential for harm reduction of the overall screening process by identifying women at unusually low risk for cancer and determining whether screening is still saving lives in this group of the population. One possible idea could involve studying women with absolutely no personal and no family history of breast or ovarian cancers. Hopefully we will see this question satisfactorily answered.

Jacob Levman