Predictors of durable no evidence of disease status in de novo metastatic inflammatory breast cancer patients treated with neoadjuvant chemotherapy and post-mastectomy radiation

Abstract

Abstract Introduction Definitive locoregional therapy including surgery and post-mastectomy radiation therapy (PMRT) has been offered to select IBC patients with de novo metastatic disease. Herein we examined predictive factors for progression-free survival after comprehensive PMRT radiation +/- locoregional treatment of metastatic sites. Methods Charts of T4d, any N, M1 (de novo) patients who completed PMRT to ≥ 50 Gy from 2006–2011 were reviewed. Patients who received doses <50Gy to the primary site, received radiation at another facility or were treated pre-operatively were excluded. The remaining 36 patients formed the study cohort. Progression-free survival post-PMRT (PFSx) was assessed from the last day of radiation. Median dose to primary fields was 51 Gy. Boost doses ranged from 6–16 Gy. Results Median age at diagnosis was 54 (range 33–70). Median follow up from primary irradiation completion was 31 months. Sixteen patients were Stage IV NED at last follow-up (IR 37–60 mo). Fifteen patients died of disease. Five patients experienced an in-field recurrence, three of which resulted from local recurrence at the medial edge of the field. Actuarial 5 year locoregional control (LRC) was 86%. Median PFSx was 20 months. All sites of gross disease were treated with radiation in 21/36 patients. Location of metastatic disease had no correlation with PFSx. Estrogen receptor (ER)- patients had shorter 5-yr actuarial PFSx (28% vs. 66%, P = 0.03) and 5 year actuarial OSx (37% vs 71%, P = 0.02). Nine patients (25%) developed a pathological complete response (pCR) after chemotherapy and with a median follow-up of 59 months, 7 remained without evidence of disease. Conclusions Despite the poor prognosis associated with metastatic IBC, our data suggest that select patients may be appropriate candidates for locoregional therapy. Patients who achieve a pCR or those with ER + disease have a favorable PFSx. It remains unclear whether all gross disease needs to be addressed with locoregional therapy to provide benefit.