Decreasing Recurrence Rates for Ductal Carcinoma In Situ: Analysis of 2996 XXXX Treated with Breast-Conserving Surgery Over 30 Years.

@entity1 @entity3821 @entity0 @entity39
BACKGROUND: Randomized trials of radiation after breast-conserving surgery (BCS) for @entity3821 ( @entity3821 ) found substantial rates of recurrence, with half of the recurrences being invasive. Decreasing local recurrence rates for invasive @entity0 have been observed and are largely attributed to improvements in systemic therapy. In this study, we examine recurrence rates after BCS for @entity3821 over 3 decades at one institution. METHODS: We retrospectively reviewed a prospectively maintained database of @entity3821 @entity1 undergoing BCS from 1978 to 2010. Cox proportional hazard models were used to investigate the association between the treatment period and recurrence, controlling for other variables. RESULTS: Overall, 363 (12  %) recurrences among 2996 cases were observed. Median follow-up for @entity1 without recurrence was 75  months (range 0-30  years); 732 @entity1 were followed for >= 10  years. The 5-year recurrence rate for the period 1978-1998 was 13.6 versus 6.6  % for the period 1999-2010 [hazard ratio (HR) 0.62, p  <  0.0001]. Controlling for age, family history, presentation, nuclear grade, @entity39 , number of excisions, margin status, radiation, and endocrine therapy, treatment period remained significantly associated with recurrence, with later years associated with a lower HR (0.74, p  =  0.02) compared to earlier. After stratification by radiation use, association of recurrence with treatment period persisted in those treated without radiation (HR 0.62, p  =  0.003). CONCLUSIONS: Recurrence rates for @entity3821 have fallen over time, with increases in screen detection, negative margins, and use of adjuvant therapies only partially explaining this decrease. The unexplained decline persists in @entity1 not receiving radiation, suggesting it is not due to changes in radiation efficacy but may be due to improvements in radiologic detection and pathologic assessment.
