Main Session
Sep
28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology
Presenter(s)
Jordan Tralins, BS - Harvard Medical, Boston, MA
J. Tralins1, Y. H. Chen2, S. Schnitt3, J. R. Bellon4, F. Nakhlis3, E. Mayette5, S. Westover5, and L. Warren6; 1Harvard Medical School, Boston, MA, 2Dana Farber Cancer Institute, Boston, MA, 3Beth Israel Deaconess Medical Center, Boston, MA, 4Dana-Farber/Brigham and Women's Cancer Center, Boston, MA, 5Dana-Farber/Brigham Cancer Institute, Boston, MA, 6Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA
Purpose/Objective(s):
Following mastectomy, the significance of close or positive margins on LRR remains uncertain. This study aims to estimate the risk of LRR in breast cancer patients with close or positive surgical margins.Materials/Methods:
Records of patients undergoing mastectomy between 2013 and 2015 at a single institution were reviewed. 240 patients older than 18, without BRCA 1/2 mutations, who did not receive radiation, and had no other cancers within 5 years preceding diagnosis were included. 22 patients received preoperative systemic therapy and 218 upfront surgery; these groups were analyzed independently. Patient and tumor characteristics, including margin status for invasive and in situ disease, were assessed. Time to event was defined as the time from mastectomy to LRR, distant recurrence, other cancer, or death— whichever occurred first. Competing risk analysis (Fine and Gray methodology) evaluated the association between patient characteristics and LRR (with distant recurrence, other cancer, and death as competing events). Given small patient numbers, only patients with upfront surgery were included in the univariate analysis.Results:
Patients were divided into 3 margin categories: positive (tumor touching inked margin), close (margin < 2 mm), and negative (>2 mm). These categories included invasive or in situ disease at the superficial, deep, or nipple margin. Among the upfront surgery patients, 99 (45.4%) had invasive ductal carcinoma (IDC), 69 (31.7%) ductal carcinoma in situ (DCIS) only, 14 (6.4%) invasive lobular carcinoma, 25 (11.5%) mixed invasive histology, and 11 (5%) other. The closest margin was positive in 14 (6.5%), close in 59 (27.2%), negative in 144 (66.4%), and not evaluated in 1. At a median follow-up of 8.8 years (range 10 - 139 months), 8 patients had LRR (8-year LRR: 4.6% (95% CI 1.4%, 7.8%)). The cumulative incidence of LRR at 8-years for positive margin: 20.0% (95% CI 0 - 46.4%), close: 7.4% (95% CI 0.3% - 14.4%), negative: 1.8% (95% CI 0% - 4.2%). On univariate analysis, margin status and histology were associated with time to LRR. Positive vs negative hazard ratio: 9.7 (95% CI 1.5 - 62.2), close vs negative hazard ratio: 4.9 (95% CI: 0.9 - 26.9) (p = 0.05), DCIS vs IDC hazard ratio: 0.5 (95% CI: 0.1 - 2.3) (p <.0001). The location of the positive margin was also examined. 13 patients had positive superficial margins; 2/13 (15.4 %) developed a LRR at 90 and 92 months. One patient had a positive deep margin and did not recur. Among the 22 patients with preoperative systemic therapy (median follow-up 8.3 years), one had a positive margin and 2 had a close margin. One patient with a close deep margin had a LRR at 26 months.Conclusion:
Both positive and close surgical margins were associated with LRR. While small sample size limits subgroup analysis, the observation of an elevated LRR, particularly among patients with positive margins, suggests these patients could be considered for adjuvant radiation.