Mastectomy Scar Boost Results in Low Risk of Locoregional Recurrence in the Setting of Close or Involved Surgical Margins

Abstract

Background: Several Phase III randomized trials have demonstrated improved local control and survival for post-mastectomy radiotherapy in patients with high-risk pathologic features. Close or involved surgical margins were not included as high-risk in these protocols, but have been associated with increased risk of local failure; however, the impact of a boost dose following chestwall radiotherapy in this setting remains to be determined. Methods: Retrospective single-institution outcomes analysis for patients with close or involved surgical margins treated with post-operative radiotherapy is followed by a boost. Results: Between 2003 and 2011, 34 patients were identified for inclusion in the present study. The median chestwall dose was 5040 cGy (range 5000 - 5040) and median boost dose was 1080 cGy (900 - 1620). At a median follow-up of 38.4 months (10.2 - 115.6; with 29% more than 5 years), 28 patients were alive without evidence of recurrence, 3 were alive with recurrent disease (1 chestwall), and 3 had died (none with recurrent disease). The 3-year local control, disease-free survival, and overall survivals were 96.9%, 93.9%, and 93.1%, respectively. Conclusion: Chestwall radiotherapy plus boost results in low risk of early locoregional recurrence for women with close or involved surgical margin(s) at mastectomy. Further investigation of PMRT with or without boost in this setting is warranted .