Purpose: The aim of this study was to analyze long-term outcomes and prognostic factors associated with survival in patients with locoregional oligo-recurrent (LROR) pelvic malignancies treated in a multimodal protocol.
Methods: Patients with an histologic diagnosis of LROR pelvic cancer (rectal 50 %, gynecological 50 %) with absence of distant metastases, undergoing surgery with radical intent and intraoperative radiotherapy (median dose 12.5 Gy) were considered eligible for participation in this study. Additionally, 48 % received external beam radiotherapy (EBRT) (median dose 50 Gy).
Results: From 1995 to 2012, a total of 143 patients from a single institution were analyzed. With a median follow-up time of 48 months (range 2-189), 5-year locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) were 53, 44, and 46 %, respectively. On multivariate analysis, no EBRT treatment to the locoregional (p ≤ 0.001), R1 margin status (p = 0.03), time interval from primary tumor diagnosis to LROR <24 months (p = 0.05), and fragmentation in the resected specimen (p = 0.004) retained significance in relation to LRC. On multivariate analysis we found that only R1 margin status (p = 0.003), primary tumor diagnosis to LROR <24 months (p = 0.02), and high histological grade (p = 0.02) were significantly associated with OS.
Conclusions: From this analysis emerges the fact that EBRT influences local control but, given the high risk of distant metastases, DFS remains modest. Margin status, tumor fragmentation, no EBRT to the LR, and time interval from primary tumor diagnosis to LROR are the dominant factors for subsequent locoregional recurrence (LRR). Accordingly, future prospective studies might be designed which adapt treatment according to the predicted risk of subsequent LRR.