Surgical Management of Male Breast Cancer Differs Dramatically From That of Female Breast Cancer
In a study reported in the International Journal of Radiation Oncology Biology Physics, Emma C. Fields, MD, of the University of Colorado School of Medicine, and colleagues analyzed the stage-specific management of male breast cancer with surgery and radiation therapy and related them to outcomes and to female breast cancer. They found that breast conservation is less frequently performed in males with localized disease and that postmastectomy radiotherapy is greatly underutilized in males.
Study Details
This study, the largest evaluation of male breast cancer in the United States with a focus on management and outcomes, included 4,276 cases of male breast cancer and 718,587 cases of female breast cancer extracted from the Surveillance, Epidemiology, and End Results registry. Analyzable data included sex, age, year of diagnosis, race, tumor registry, grade, stage, estrogen receptor status, progesterone receptor status, type of surgery, and use of radiation therapy. Male breast cancer constituted 0.6% of all evaluable breast cancer cases, and female breast cancer constituted 99.4%.
Age at diagnosis was consolidated into three groups for the data analysis (10 to 49, 50 to 69, and ≥ 70 years), as was year of diagnosis (1973 to 1987, 1988 to 1997, and 1998 to 2008). Only 2% of the patients had grade 4 tumors; they were combined with the patients with grade 3 tumors for this analysis.
Patient Characteristics
Of the patients studied, breast cancer was diagnosed at an older age in men compared to women, with 40% of male breast cancers diagnosed after the age of 70 years vs 30% of female breast cancers. There was a higher incidence of breast cancer in women vs men, with the average incidence of female breast cancer being 164.2 cases per 100,000 females and of male breast cancer being 1.5 cases per 100,000 males (P < .0001). Unlike female breast cancer, there was no clear decline in the incidence of male breast cancer after 2003, with rates of 1.6 to 1.8 per 100,000 in the period from 2003 to 2008.
Male breast cancer and female breast cancer were diagnosed in 82.8% and 84.3% of whites, 11.6% and 8.6% of blacks, and 5.7% and 7.2% of other/unknown races, respectively. White males were more likely to have both an estrogen receptor– and/or a progesterone receptor–positive tumor than were black males (78.4% vs 71.6%, P = .019).
Treatment Outcomes
As for the treatment of breast cancer in males vs females, surgical management differed significantly: Mastectomy was used in 67.5% of men vs 38.3% of women (P < .001), and breast-conserving surgery was used in 9.7% of men vs 42.6% of women (P < .0001). Of the 1,951 males with localized disease, 70.3% underwent mastectomy, and only 4.6% were treated with lumpectomy and radiation therapy. Of the 1,461 males who had curative therapy, 94% were treated with mastectomy, and 6% had lumpectomy plus radiation therapy. In contrast, 46% of women treated curatively for localized disease were treated with mastectomy, and 54% were treated with lumpectomy plus radiation therapy (P < .0001).
Although postmastectomy radiotherapy has demonstrated an improvement in both local and regional control and survival for women with breast cancer, the study authors noted that it was “clearly underutilized” in male breast cancer. For men with regional disease who underwent mastectomy, postmastectomy radiotherapy was delivered in 33% of patients and was not associated with an improvement in cause-specific survival.
Men older than 70 years of age had a poorer cause-specific survival than did men aged 10 to 49 years (hazard ratio [HR] = 1.38, 95% confidence interval [CI] = 1.02?1.87, P < .03). Cause-specific survival was worse for black males than white males (HR = 1.98, 95% CI = 1.58?2.47, P < .0001).
Regarding treatment-related outcomes, men with localized disease treated with lumpectomy plus radiation therapy experienced improved but not significantly different cause-specific survival compared with men treated with mastectomy (HR = 1.33, 95% CI = 0.49?3.61, P = .57).
The authors concluded, “Surgical management of male breast cancer is dramatically different than for female breast cancer. The majority of males with localized disease receive mastectomy despite equivalent cause-specific survival with lumpectomy and radiotherapy. However, outcomes for male breast cancer are improving, attributable to improved therapy and its use in this unscreened population.”
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