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Abstract

PURPOSE:

Radiotherapy (RT) after breast-conserving surgery (BCS) is a standard treatment option for the management of ductal carcinoma in situ (DCIS). We sought to determine the survival benefit of RT after BCS on the basis of risk factors for local recurrence.

PATIENTS AND METHODS:

A retrospective longitudinal cohort study was performed to identify patients with DCIS diagnosed between 1988 and 2007 and treated with BCS by using SEER data. Patients were divided into the following two groups: BCS+RT (RT group) and BCS alone (non-RT group). We used a patient prognostic scoring model to stratify patients on the basis of risk of local recurrence. We performed a Cox proportional hazards model with propensity score weighting to evaluate breast cancer mortality between the two groups.

RESULTS:

We identified 32,144 eligible patients with DCIS, 20,329 (63%) in the RT group and 11,815 (37%) in the non-RT group. Overall, 304 breast cancer-specific deaths occurred over a median follow-up of 96 months, with a cumulative incidence of breast cancer mortality at 10 years in the weighted cohorts of 1.8% (RT group) and 2.1% (non-RT group; hazard ratio, 0.73; 95% CI, 0.62 to 0.88). Significant improvements in survival in the RT group compared with the non-RT group were only observed in patients with higher nuclear grade, younger age, and larger tumor size. The magnitude of the survival difference with RT was significantly correlated with prognostic score (P < .001).

CONCLUSION:

In this population-based study, the patient prognostic score for DCIS is associated with the magnitude of improvement in survival offered by RT after BCS, suggesting that decisions for RT could be tailored on the basis of patient factors, tumor biology, and the prognostic score. 

Author information

Sagara Y1, Freedman RA2, Vaz-Luis I2, Mallory MA2, Wong SM2, Aydogan F2, DeSantis S2, Barry WT2, Golshan M2.

1Yasuaki Sagara, Melissa Anne Mallory, Fatih Aydogan, and Mehra Golshan, Brigham and Women's Hospital; Yasuaki Sagara, Harvard T.H. Chan School of Public Health; Rachel A. Freedman, Ines Vaz-Luis, Stephen DeSantis, and William T. Barry, Dana-Farber Cancer Institute, Boston, MA; Stephanie M. Wong, McGill University Health Centre, Montreal, Quebec, Canada; and Fatih Aydogan, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey. yasuaki@sagara.or.jp.

2Yasuaki Sagara, Melissa Anne Mallory, Fatih Aydogan, and Mehra Golshan, Brigham and Women's Hospital; Yasuaki Sagara, Harvard T.H. Chan School of Public Health; Rachel A. Freedman, Ines Vaz-Luis, Stephen DeSantis, and William T. Barry, Dana-Farber Cancer Institute, Boston, MA; Stephanie M. Wong, McGill University Health Centre, Montreal, Quebec, Canada; and Fatih Aydogan, Cerrahpasa Medical School, Istanbul University, Istanbul, Turkey.