Superior Survival in Conservatively Treated Male Breast Cancer
By Peter M. Goodwin
CHICAGO—Men who had breast-conserving therapy (BCT) including radiation for their early breast cancer lived longer than those who had total or partial mastectomy (with or without radiation) in findings from a large retrospective survey of male breast cancer reported at the 2018 ASCO Annual Meeting (Abstract 565).
In a poster presentation, Sarah Bateni, MD, a surgery resident at the University of California Davis Medical Center in Sacramento, reported survival outcomes from an analysis of National Cancer Database (NCDB) records of 11,406 men who had stage I, II, or III breast cancer between the years 2004 and 2015.
Although mastectomy was more commonly used among these men, the study found that BCT was associated with longer survival. And the researchers concluded that these findings supported the use of BCT as a viable treatment for male breast cancer and that cancer doctors should consider using this option more widely. They emphasized that radiation was an important component of BCT.
“After controlling for demographic differences as well as clinical and treatment differences with regard to adjuvant therapies, breast-conserving therapy showed better survival compared to total mastectomy alone,” Bateni noted.
The survey was done partly because of the scarcity of data about treatment for men with breast cancer, who have generally had their disease managed with protocols for female breast cancer guided by findings from randomized controlled trials in women. The NCDB records provided a substantial body of data from men revealing statistically meaningful outcome differences between therapy options while allowing for subgroup differences and the influence of confounding variables.
With BCT already proven to be the equivalent of mastectomy (in terms of clinical efficacy) for women, the study made it possible to compare overall survival differences with sufficient power to make clinical recommendations for men, too.
The analysis grouped patients according to the surgical and radiation therapy they had opted for, including BCT, lumpectomy alone, total or partial mastectomy alone, and total and partial mastectomy with radiation. Overall survival was compared by treatment group and the analysis controlled for demographic, clinical, and pathologic differences.
The statistical assessment compensated mathematically for the influence of variables including age, race, medical comorbidities, income, insurance status, facility type, histology, tumor grade, receptor status, T/N overall stage, axillary nodal surgery, surgical margins, chemotherapy, and hormone therapy.
More than half of the patients (55%) had total or partial mastectomy alone, and a further 19 percent had mastectomy with radiation. Eighteen percent of the cohort received BCT, and 7 percent had lumpectomy alone.
The patients receiving BCT were younger (62 years) on average than those who opted either for mastectomy (66 years) or for mastectomy combined with radiation (63 years). And they had smaller tumors. The median tumor size was 1.5 cm for the BCT group compared with at least 2.0 cm for the other groups. And patients treated with BCT had lower rates of nodal disease (21% compared with rates ranging from 31% to 81% for the other groups).
The hazard ratio (HR) for survival in favor of patients who had BCT was 1.69 compared with patients treated with total of partial mastectomy with or without radiation. When compared specifically with the combination of mastectomy plus radiation, the survival benefit was slightly diminished—but still superior—with an HR of 1.52. But the HR was even better—1.91—when patients treated with BCT were compared with those receiving lumpectomy alone, illustrating the importance of including radiotherapy in BCT protocols.
Not surprisingly, increased age, tumor stage, nodal status, histological grade, and triple-negative hormone receptor status were all associated with poorer survival.
“The clinical implication is that men should be given the option for breast-conserving therapy and not just total mastectomy,” Bateni told Oncology Times. “Currently, even though the guidelines say that you can give men the option of breast-conserving therapy, men tend to get total mastectomy just because historically it has been done,” she said.
Bateni said that, while mastectomy remained an option for men with breast cancer, there was now an alternative. “They should [also] have the option of having a lumpectomy followed by radiation therapy.”
When she was asked about the degree of benefit from BCT, she said the greatest difference was in 10-year overall survival. “At that point it was almost 20 percent difference between the groups because radiation ended up being such an important component with respect to the survival difference,” she explained.
And she recommended that, since BCT conferred better survival than lumpectomy alone, patients should be advised to have radiation therapy as part of it.
Bateni’s colleague Candice A. M. Sauder, MD, MEd, a breast surgical oncologist at UC Davis Medical Center, mentioned that men were increasingly “conscientious” about their cosmetic outcomes—just as women were. “So this is an applicable way that is not inferior to give men breast-conserving therapy as long as they understand that, just as for women, breast-conserving therapy includes radiation as part of their treatment plan.”