Radiation Therapy Underused After Nipple-Sparing Mastectomy

TOPLINE:

Despite experiencing higher rates of positive margins and pathologic node involvement, patients with early-stage breast cancer who undergo nipple-sparing mastectomy are less likely to receive adjuvant radiation therapy than are those who have breast-conserving surgery.

METHODOLOGY:

• Nipple-sparing mastectomy has become increasingly popular for treating early-stage breast cancer given the cosmetic and functional benefits of the procedure. However, appropriate use of adjuvant radiation therapy following nipple-sparing mastectomy has not been characterized.
• Researchers compared outcomes and appropriate uses of radiation therapy among 624,075 women diagnosed with cT1-3N0M0 invasive ductal or lobular breast cancer between 2004 and 2017 who underwent breast-conserving surgery (n = 611,907; median age, 63 years) or nipple-sparing mastectomy (n = 12,168; median age, 50 years).
• The researchers compared the rates of postoperative radiation therapy for two standard indications — positive margins and pathologic node involvement — in patients who had breast-conserving surgery or nipple-sparing mastectomy.
• The team also compared overall survival outcomes in patients with positive margins and node involvement.

TAKEAWAY:

• Patients who had nipple-sparing surgery had higher rates of positive margins (4.5% vs 3.7%; P < .001) and, on multivariable analysis, a 15% higher risk for positive margins compared with those who had breast-conserving surgery (odds ratio [OR], 1.15; P = .005).
• Similarly, patients who had nipple-sparing surgery had significantly higher rates of node involvement compared with those who had breast-conserving surgery (22.5% vs 13.5%) and, on multivariable analysis, an 8% higher risk for node involvement (OR, 1.08; P < .001).
• Despite higher rates of positive margins and node involvement in the nipple-sparing surgery group, these patients were significantly less likely than those in the breast-conserving surgery group to receive adjuvant radiation therapy (OR, 0.07). Overall, only 17.2% of patients who underwent nipple-sparing mastectomy received postoperative radiation therapy compared with 83.3% of those undergoing breast-conserving surgery — an almost fivefold difference (P < .001).
• In the overall study sample, overall survival in the two surgical groups did not differ significantly among patients with positive margins (OR, 0.62; 95% CI, 0.30-1.31; P = .21) and those with node involvement (OR, 1.01; 95% CI, 0.80-1.28; P = .93).

IN PRACTICE:

The researchers emphasized that although overall survival outcomes were comparable in the two surgery groups, the “current standard indications and guidelines for post-mastectomy radiation are not being appropriately” used after nipple-sparing mastectomy.

SOURCE:

The study, led by Wesley J. Talcott, MD, MBA, Department of Radiation Medicine, Northwell Health, New York City, was published online in Advances in Radiation Oncology.

LIMITATIONS:

Data on locoregional recurrence, cause-specific mortality, and all pathologic details were not available. The relatively short median follow-up period might not capture differences in the long-term survival outcomes.

DISCLOSURES:

The study did not receive any funding support. The authors disclosed no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article first appeared on Medscape.com.