Danielle Rodin1,2, Rinku Sutradhar3,4, Sharon Nofech-Mozes5,6, Sumei Gu3, Neil Faught3, Ezra Hahn7,8, Cindy Fong3, Sabina Trebinjac9, Lawrence Paszat8,3,4,9, Eileen Rakovitch8,3,9. 1. Radiation Medicine Program, Princess Margaret Cancer Centre, 700 University Avenue, Room 7-611, Toronto, ON, M4R 1M3, Canada. danielle.rodin@rmp.uhn.ca. 2. Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada. danielle.rodin@rmp.uhn.ca. 3. Institute for Clinical Evaluative Sciences, Toronto, ON, Canada. 4. Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada. 5. Department of Laboratory Medicine and Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON, Canada. 6. Department of Pathology, University of Toronto, Toronto, ON, Canada. 7. Radiation Medicine Program, Princess Margaret Cancer Centre, 700 University Avenue, Room 7-611, Toronto, ON, M4R 1M3, Canada. 8. Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada. 9. Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
Abstract
PURPOSE: The paucity of data on women with large (≥ 40 mm) DCIS tumors lead to uncertainty on the safety of breast-conserving surgery (BCS) for these patients. We evaluated the impact of large tumor size on local recurrence (LR) among women with DCIS treated with BCS ± radiotherapy (RT). METHODS: Treatment and outcomes were ascertained through administrative databases for all women with DCIS in Ontario from 1994 to 2003 treated with BCS ± RT with negative margins; 82% had pathology review. Cox proportional hazards model was used to evaluate the impact of tumor size on LR. 10- and 15-year LR-free survival (LRFS) were calculated using Kaplan-Meier method. RESULTS: The cohort includes 2049 women treated by BCS (N = 1073 with RT). Median follow-up is 14 years (IQR 9-17 years). Referenced to tumors ≤ 10 mm, the risk of LR following BCS was significantly higher for larger tumors: HR ≥ 40 mm = 3.67 (95% CI 2.13, 6.33; p < 0.001), HR 26-39 mm = 2.27 (95% CI 1.47, 3.50, p < 0.001), and HR 11-25 mm = 1.42 (95% CI 1.06, 1.92, p = 0.02). However, for individuals with BCS + RT, large tumor size was not associated with a significantly increased risk of LR (HR ≥ 40 mm = 1.92 (95% CI 0.97, 3.79); HR 26-39 mm = 1.81 (95% CI 1.09-2.99)). For women with tumors ≥ 40 mm, 10-year LRFS risk for those treated by BCS alone, BCS + RT without boost, and BCS + RT with boost was 58.9%, 82.8%, and 83.9%. CONCLUSION: Large DCIS lesions ≥ 40 mm are associated with higher risks of LR following BCS, but high long-term LRFS rates can be achieved with the addition of breast RT.
PURPOSE: The paucity of data on women with large (≥ 40 mm) DCIS tumors lead to uncertainty on the safety of breast-conserving surgery (BCS) for these patients. We evaluated the impact of large tumor size on local recurrence (LR) among women with DCIS treated with BCS ± radiotherapy (RT). METHODS: Treatment and outcomes were ascertained through administrative databases for all women with DCIS in Ontario from 1994 to 2003 treated with BCS ± RT with negative margins; 82% had pathology review. Cox proportional hazards model was used to evaluate the impact of tumor size on LR. 10- and 15-year LR-free survival (LRFS) were calculated using Kaplan-Meier method. RESULTS: The cohort includes 2049 women treated by BCS (N = 1073 with RT). Median follow-up is 14 years (IQR 9-17 years). Referenced to tumors ≤ 10 mm, the risk of LR following BCS was significantly higher for larger tumors: HR ≥ 40 mm = 3.67 (95% CI 2.13, 6.33; p < 0.001), HR 26-39 mm = 2.27 (95% CI 1.47, 3.50, p < 0.001), and HR 11-25 mm = 1.42 (95% CI 1.06, 1.92, p = 0.02). However, for individuals with BCS + RT, large tumor size was not associated with a significantly increased risk of LR (HR ≥ 40 mm = 1.92 (95% CI 0.97, 3.79); HR 26-39 mm = 1.81 (95% CI 1.09-2.99)). For women with tumors ≥ 40 mm, 10-year LRFS risk for those treated by BCS alone, BCS + RT without boost, and BCS + RT with boost was 58.9%, 82.8%, and 83.9%. CONCLUSION: Large DCIS lesions ≥ 40 mm are associated with higher risks of LR following BCS, but high long-term LRFS rates can be achieved with the addition of breast RT.
Authors: Seth A Kaufman; Eleanor E R Harris; Lisa Bailey; Manjeet Chadha; Sharon C Dutton; Gary M Freedman; Sharad Goyal; Michele Y Halyard; Kathleen C Horst; Kristina L M Novick; Catherine C Park; W Warren Suh; Deborah Toppmeyer; Jennifer Zook; Bruce G Haffty Journal: Oncology (Williston Park) Date: 2015-06 Impact factor: 2.990