Background: Women with a history of ductal carcinoma in situ (DCIS) are at increased risk for developing a second breast cancer (SBC). A prior meta-analysis of randomized studies of radiotherapy (RT) for DCIS has shown a trend toward increased breast cancer–specific mortality after SBC, but it did not have the power needed to detect a significant difference, due to a limited number of recurrences. This study sought to evaluate the impact of RT for DCIS on mortality after SBC in a larger cohort. Patients and Methods: Using the SEER database, 3,407 patients were identified who received breast-conserving therapy with or without RT for primary DCIS in 2000 through 2013 and subsequently developed a stage I–III invasive SBC within the same time period. Fine-Gray competing risk models were used to study the association between receipt of RT and mortality after SBC. Results: Prior RT was found to be associated with higher rates of breast cancer–specific mortality (hazard ratio [HR], 1.70; 95% CI, 1.18–2.45; P=.005), even after controlling for cancer stage. Interaction analysis suggested that this risk trended higher in patients with ipsilateral versus contralateral SBC (HR, 2.07 vs 1.26; P=.16). Furthermore, compared with patients who developed contralateral SBC, those with ipsilateral SBC were younger (P<.001) and more often lacked estrogen receptor expression (P<.001). Conclusions: Patients who previously received RT for DCIS had higher mortality after developing an invasive SBC than those who did not receive RT. This finding may have implications for initial treatment decisions in the management of DCIS.
Puyao C. Li, Zilu Zhang, Angel M. Cronin and Rinaa S. Punglia
Michael J. Hassett, Wei Jiang, Melissa E. Hughes, Stephen Edge, Sara H. Javid, Joyce C. Niland, Richard Theriault, Yu-Ning Wong, Deborah Schrag and Rinaa S. Punglia
Background: Because of screening mammography, the number of ductal carcinoma in situ (DCIS) survivors has increased dramatically. DCIS survivors may face excess risk of second breast events (SBEs). However, little is known about SBE treatment or its relationship to initial DCIS care. Methods: Among a prospective cohort of women who underwent breast-conserving surgery (BCS) for DCIS from 1997 to 2008 at institutions participating in the NCCN Outcomes Database, we identified SBEs, described patterns of care for SBEs, and examined the association between DCIS treatment choice and SBE care. Using multivariable regression, we identified features associated with use of mastectomy, radiation therapy (RT), or antiestrogen therapy (AET) for SBEs. Results: Of 2,939 women who underwent BCS for DCIS, 83% received RT and 40% received AET. During the median follow-up of 4.2 years, 200 women (6.8%) developed an SBE (55% ipsilateral, 45% invasive). SBEs occurred in 6% of women who underwent RT for their initial DCIS versus 11% who did not. Local treatment for these events included BCS (10%), BCS/RT (30%), mastectomy (53%), or none (6%); only 28% of patients received AET. Independent predictors of RT or mastectomy for SBEs included younger age, shorter time to SBE diagnosis, and RT or AET for the initial DCIS. Conclusions: A sizable proportion of patients with SBEs were treated with mastectomy, most especially those who previously received RT for their initial DCIS and those who developed an ipsilateral SBE. Despite the occurrence of an SBE, relatively few patients received AET. Future studies should investigate optimal treatment approaches for SBEs, including the benefit of mastectomy versus lumpectomy for an ipsilateral SBE and the benefit of AET for a hormone-receptor–positive SBE contingent on AET use for the initial DCIS diagnosis.