MedPage is reporting a systematic Cochrane review concluding that breast self-examination does not reduce breast cancer mortality and may cause harm by prompting unnecessary biopsies. This recommendation is based upon studies that include almost 400,000 women.
My Take?
Long-time DrWalt.com readers have seen my reports on the large Chinese  and Russian studies that reached similar conclusions. 
Also, based upon this and similar studies, the American Cancer Society considers breast self-examination optional. In fact, the organization revised its recommendations for breast self-examination more than five years ago in response to emerging evidence of a lack of benefit.
It’s important to note that women who performed self-examination had virtually identical breast cancer mortality rates as women who did not examine their breasts.
Furthermore, women who did breast self-examination had almost twice as many negative breast biopsies as women who did not perform self-exams.
So, I no longer recommend that women do routine monthly self breast exams. However, I emphasize to women that if they notice any breast changes, that they be sure to have their physician check it out.