A woman receives a mammogram at the Naval Medical Center San Diego Breast Health Center. Photo by U.S. Navy/Joseph Moon/Wikimedia Commons Catching some cancers early on can save lives, but we rarely hear about how cancer screening might not be meeting our expectations.
This idea - that some screening might not help all patients - has received much attention, and a recent study in the British Medical Journal supports the notion that breast cancer screening may not reduce mortality.
Scientists pose the question: Is early screening driving a reduction in breast cancer mortalities or can fewer deaths be attributed to access to better health services and treatments?
After examining World Health Organization data from three pairs of neighboring European countries that implemented breast screening programs at different times, researchers studied the relationship between screening services offered and cancer mortality.
Data gathered from these countries between 1989 and 2006 showed that neighboring country pairs with similar breast cancer rates and access to health care did not differ much when it came to patient mortality from the condition. Countries that put forward screening programs earlier did not see fewer deaths when compared to countries that created programs later.
Though screening for breast cancer didn't appear to reduce deaths in this analysis, screening for other conditions such as cervical cancer have been shown to reduce deaths, the authors write.
What we're seeing is a diversification of cancers and how doctors deal with them. After the introduction of breast and prostate cancer screening, the prevalence of the two cancers also increased, which makes sense. But there's also evidence that cancer-related deaths have dropped in time, but it's hard to associate fewer mortalities with screening - at least for people with no signs or symptoms of cancer.
For mammograms, a common method to screen for breast cancer, it's important to weigh the costs and benefits. For instance, mammograms require experts to use X-rays to image a woman's breasts, exposing her to ionizing radiation that's known to increase one's risk of cancer. There are also cases in which women are mistakenly diagnosed, or "false-positives." If doctors believe an area might be cancerous, women may be encouraged to undergo a biopsy for doctors to study the tissue in the lab. The process can negatively affect the mental health of women dealing with the anxiety of believing they have cancer.
Yet figuring out who would benefit from screening is also tricky because some women are more at risk than others. For these women, the benefits outweigh the risks of screening.
In the United States, current recommendations from the U.S. Preventative Services Task Force suggest women between the ages of 50 and 74 receive a mammogram every other year. Because the risk of developing breast cancer increases with age, reserving screening for at-risk groups is more recommended than screening all women.