Abstract P2-14-06: Prediction of local recurrence following mastectomy

Abstract

Abstract Background: Rates of local recurrence following mastectomy vary considerably in the literature, ranging from 1.7% to 11.5%. Previous studies have attempted to identify risk factors for recurrence and whether these relate to aggressive disease or to inadequate local treatment. We aimed to identify local recurrence rates at our institution to determine risk factors associated with local recurrence. Methods and materials: A retrospective study of all women undergoing mastectomies for unilateral T1-T3 breast cancer between 2000-2005 was undertaken. Kaplan-Meier curves were created and the log-rank test calculated to assess for differences between groups. The incidence of local, regional and systemic recurrence was identified at 5 and 8 years post-mastectomy. Incomplete excision/margin involvement was defined as margins 1mm or less. Demographic, biological and treatment-related factors associated were used to identify predictors of local recurrence. Results: In total, 581 women were studied (mean age: 59; range: 22-96); 462 simple mastectomies (SM) and 106 skin-sparing mastectomies (SSM) which included 199 (34%) screen-detected and 382 (66%) symptomatic cancers. Mean follow up was 6.7 years (range: 5-12.4) and longest was 12.4 years. SSM patients had a lower mean age (p=<0.001), with a smaller tumour size (p=0.022), fewer positive lymph nodes (p=<0.001) and less co-existing ductal carcinoma in situ (DCIS) (p=<0.001) than SM patients. Recurrence rates for SM were 5.6% and 6.9% and for SSM, recurrence rates were 5.7% and 9.0% at 5 and 8 years respectively. Recurrence in node negative patients was 2.2% at 5 years. Predictors of local recurrence were node positivity (HR 8.03; 95% CI 3.2-20) and margin involvement/close margins (HR 3.34; 1.64-6.8). Conclusion: No significant difference between recurrence rates in SSM and SSM groups was identified. The presence of over four positive lymph nodes and incomplete excision margins indicates an increased risk of recurrence and in these patients, immediate SSM reconstruction should be considered prudently. Citation Format: Sarah Al-Himdani, Simon Timbrell, Kian Tan, Julie Morris, Nigel Bundred. Prediction of local recurrence following mastectomy [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-14-06.