Sensitivity and Specificity, Part II
The controversy surrounding breast cancer screening relates to the concept that a screening tool must be both sensitive and specific. Numerous observations challenge the specificity and sensitivity of breast cancer screenings in younger women. First, the density of the breast tissue of a young woman decreases the sensitivity of both the mammogram and the exam. Also, exams in young, menstruating women are notoriously unreliable because so many changes in the breast are not specific to cancer. Finally, the chance of breast cancer in a 40-year-old woman is very low, just 1 in 1,000, leading to a very low index of suspicion.
Combined, these issues lead to problems ranging from early cancers being neither visualized nor suspected to non-cancerous changes creating misleading findings leading to unnecessary biopsies and anguish. It is true that newer and better methods are needed to screen young, high-risk women.
However, there seems to be little downside to knowing your body through self-exam, undergoing an annual physical with breast exam, and undergoing age-appropriate mammography.
It seems not a month goes by without a major news story about a scientific study calling into question the value of breast exams and mammograms. The elaborate and often complex scientific studies are reduced to 30-second sound bites that give the impression that women might as well just roll the dice when it comes to early detection of breast cancer.
Although I appreciate the science and recognize the need to scrutinize both the cost and value of all medical interventions, I remain steadfast in my support of early detection by the best-proven means available, which today is manual breast examination and mammography.
Have you been following the screening controversies in recent news? What do you think?
Dr. Bruce Feinberg