Awareness key to improved outcomes in male breast cancer

Although breast cancer predominantly occurs in women, men still are at risk.

An estimated 2,600 cases of male breast cancer will be diagnosed in the United States this year, according to the American Cancer Society.

Harold J. Burstein

Although the exact risk factors have not been established and treatment protocols primarily are based off of those for women, research is underway examining the disease specifically in men.

HemOnc Today spoke with Harold J. Burstein, MD, PhD, associate professor of medicine at Harvard Medical School and an ASCO expert, about the incidence of male breast cancer, why screening in this population is so difficult and what new research may be on the horizon.

Question: How common is male breast cancer?

Answer: It is a lot less common than female breast cancer, but it does occur. There is about one case of male breast cancer for every 100 cases of female breast cancer.

Q: Has incidence increased over time?

A: The incidence has been fairly stable. There is more awareness and advocacy thanks to social media, and this is a good thing. People are getting more information and becoming aware of the possibility of a male breast cancer diagnosis. To me, there is no downside to this or concern of people becoming inappropriately fearful or raising false alarms.

Q: What do the data sugges t in terms of survival and prognosis?

A: The outcomes are generally the same for men and women with breast cancer. Men almost always have ER–positive breast cancer, which is a slightly more favorable breast cancer because we can use effective antiestrogen therapies. Most female breast cancers also are ER positive, but between 15% and 20% are ER negative and historically have a more aggressive natural history. In general, however, the outcomes for men and women are about the same.

Q: What are some of the causes of male breast cancer?

A: We do not know a lot about the causes of male breast cancer. A small percentage of cases are linked to hereditary breast cancers with specific gene mutations. Most are without obvious cause.

Q: Men or their physicians may not suspect breast cancer. Consequently, i s breast cancer in men diagnosed at a later stage compared with women?

A: It is something that is tough to measure, but the general consensus is that the cancers often are diagnosed at a further stage in men. We do not have screening mammograms for men, but these allow us to detect very small cancers in women.

Q: In your opinion, should there be screening in men?

A: No. The problem is that we cannot really use mammograms for men. The machine takes advantage of the size of the female breast and the contrast between the fattiness of the female breast and other tissues that allow us to see the breast cancer. This is not the case for men. The other issue regarding screening the general population for any health problem is that when the problem is rare, the likelihood that screening helps goes way down. That is because of Bayes’ theorem, which says that the likelihood of a screening test being important is related to the prevalence of the disease in the population. It is hard enough these days to show mammography is important for women. When we switch to men, and the prevalence is 1% of that for women, it makes screening futile.

Q: Are treatments for men similar to those for women?

A: Treatments generally are similar, although most men will have a mastectomy as opposed to a lumpectomy because there is, in general, less focus on preserving the breast in men compared with women. Because most men have ER–positive breast cancers, the vast majority of them will get antiestrogen medications. This is true for most women who have ER–positive breast cancers, as well. We occasionally use chemotherapy in men, but that depends upon the stage of the cancer.

Q: We hear a lot about genetic makeup of breast cancer ( eg, BRCA and other mutations), but that typically is in the context of breast cancer in women. Do men have these same types of mutations?

A: Breast cancer in men is rare enough that almost all cases warrant genetic testing. The classic teaching is that there is an increased risk for male breast cancer, especially in BRCA2. This is a very small percentage of the population, but it does occasionally happen. BRCA2 mutations are more common in people of eastern European ancestry, but I am not aware of racial factors that affect male breast cancer risk.

Q: Is there anything else in the research pipeline ?

A: Because male breast cancer is so uncommon, there are few clinical trials just for men. Most of what we know about male breast cancer, we have derived from what we have learned treating women with breast cancer. There is obviously a lot going on in the space of discovery for women, but there are relatively few specific trials looking at male breast cancer. However, men are getting the benefit of this golden era of research in female breast cancer. In the era of precision medicine, we are getting much more comfortable with the idea of niche populations of patients, whether this is defined by rare tumors or unusual molecular variants of rare cancers or things of this nature. Male breast cancer certainly fits this model, and there probably are more cases of male breast cancer than there are for other cancer types that we often think about and for which we have robust clinical trials. Although male breast cancer is rare, there are still about a couple of thousand cases per year, and this makes it different from other rare cancers. I am certainly hopeful that we will begin to see more clinical trials for men with breast cancer. Having said this, we do already know a lot about male breast cancer from the huge voluminous literature on female breast cancer, and I think that this is generally good news for men who are diagnosed with breast cancer, because we actually have a large amount of literature to draw upon.

Q: Is there anything else you would like to add ?

A: The general point is that, although male breast cancer is rare, men who notice changes in their breast should have it evaluated. I have met male patients who have not paid attention to changes in the breast because they did not think it was possible for men to get breast cancer. – by Jennifer Southall

For more information:

Harold J. Burstein, MD, PhD, can be reached at Dana-Farber Cancer Institute, 450 Brookline Ave., Boston, MA 02215; email: hal_burstein@dfci.harvard.edu.

Disclosure: Burstein reports no relevant financial disclosures.