Abstract PS1-16: Ipsilateral breast cancer recurrence: Treatment and long-term oncological results at a high volume center
Authors: Gentile Damiano , Sagona Andrea , Anghelone Chiara Annunziata Pasqualina , Barbieri Erika , Marrazzo Emilia , Gatzemeier Wolfgang , Canavese Giuseppe , Errico Valentina , Testori Alberto , Tinterri Corrado 
Published: February 2021

Background A small proportion of patients with primary breast cancer who receive breast conserving surgery (BCS) will develop an ipsilateral breast cancer recurrence (IBCR). In these patients, mastectomy is still considered the treatment of first choice, even if a second conservative surgical approach is technically feasible. The aims of our study are to analyze the characteristics of patients with IBCR after BCS, evaluate and compare the different treatment modalities (repeat BCS vs. mastectomy) in terms of patients and tumor characteristics, disease-free interval (DFI), disease-free survival (DFS), and overall survival (OS).MethodsOur prospectively maintained institutional database was queried, and 309 patients with IBCR after BCS who underwent either repeat BCS or mastectomy, between January 2008 and December 2018, were identified. Ipsilateral breast cancer recurrence was defined as a local tumor reappearance in the same breast or in the surgical scar. Exclusion criteria were: age &lt;18 years, primary cancer treated with mastectomy, residual disease, controlateral recurrence, recurrent benign disease, only distant or axillary recurrence, IBCR not treated surgically, follow-up &lt;24 months, and DFI &lt;6 months.ResultsThe mean age of patients at primary breast cancer was 55.3 years. The majority of primary tumors were ductal (87.4%), luminal A-B (81.2%) breast cancers. After BCS, 222 (71.8%) patients underwent radiotherapy. Out of 309 patients with IBCR after BCS, 143 underwent repeat BCS and 166 underwent mastectomy. At multivariable analysis, young age, &lt;65 years (59.6% vs. 37.1% if age ≥65 years, odds ratio (OR)=2.374, 95% confidence interval (95%CI)=0.02-0.24, p= 0.018) and short DFI &lt;24 months (15.7% vs. 10.5% if DFI ≥24 months, OR=2.705, 95%CI=0.02-0.17, p= 0.007) were found to significantly increase the probability to receive mastectomy for IBCR after BCS. After IBCR, DFS rate at 3-, 5-, and 10-years was 79.2%, 68.2%, 36.9%, and 77.2%, 65.9%, 55.3%, in patients receiving repeat BCS or mastectomy, respectively (p = 0.842). Overall-survival rate at 3-, 5-, and 10-years was 95.4%, 91.4%, 68.5%, and 87.3%, 69.3%, 57.9%, in patients receiving repeat BCS or mastectomy, respectively (p = 0.018).ConclusionsThe best candidates for repeat BCS in the treatment of IBCR are patients ≥65 years with a DFI ≥24 months. Young patients (&lt;65 years) with early onset of recurrence (DFI &lt;24 months) have a high probability to receive mastectomy for the treatment of IBCR. Mastectomy does not improve survival in patients with IBCS after BCS. The information about the risk of poor long-term prognosis after mastectomy should be shared with the patient and a repeat BCS could be proposed.

Citation Format: Damiano Gentile, Andrea Sagona, Chiara Annunziata Pasqualina Anghelone, Erika Barbieri, Emilia Marrazzo, Wolfgang Gatzemeier, Giuseppe Canavese, Valentina Errico, Alberto Testori, Corrado Tinterri. Ipsilateral breast cancer recurrence: Treatment and long-term oncological results at a high volume center [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-16.