Hassett MJ, et al. - Researchers sought to focus on second breast event (SBE) treatment and its relationship to initial ductal carcinoma in situ (DCIS) care. They noted that a high proportion of patients with SBEs were treated with mastectomy, most especially those who previously received radiation therapy (RT) for their initial DCIS and those who developed an ipsilateral SBE. Antiestrogen therapy (AET) was administered to relatively few patients despite the occurrence of an SBE.

Methods

• Researchers identified SBEs, described patterns of care for SBEs, and examined the association between DCIS treatment choice and SBE care 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.
• Features associated with use of mastectomy, RT, or antiestrogen therapy (AET) for SBEs were identified using multivariable regression.

Results

• BCS for DCIS was performed on 2,939 women; 83% received RT and 40% received AET.
• Two hundred women (6.8%) developed an SBE (55% ipsilateral, 45% invasive) during the median follow-up of 4.2 years.
• SBEs developed in 6% of women who underwent RT for their initial DCIS compared to 11% who did not underwent RT.
• For these events, local treatment included BCS (10%), BCS/RT (30%), mastectomy (53%), or none (6%); AET was administered to only 28% of patients.
• As per findings, independent predictors of RT or mastectomy for SBEs were younger age, shorter time to SBE diagnosis, and RT or AET for the initial DCIS.