Local treatment in the setting of de novo metastatic rectal cancer: reappraisal of prognostic factors

BACKGROUND: This retrospective study was conducted to: (1) provide more modern data on real-life local management of metastatic rectal cancer; (2) compare therapeuticstrategies; and (3) identify prognostic factors of local failure, overall survival and progression-free survival. METHODS: Data about efficacy and acute toxicity were collected. Patients were diagnosed with metastatic rectal cancer between 2004 and 2015, and were treated at least with radiotherapy. Local failure, overall survival and progression-free survival were correlated with patient, tumour and treatment characteristics using univariate and multivariate analyses. RESULTS: Data of 148 consecutive patients with metastatic rectal cancer were analysed. Median follow-up was 19months. Median overall survival was 16 months. All patients received local radiotherapy, with a median equivalent 2 Gy per fraction dose of 47.7 Gy. Rectal surgery was performed in 97 patients (65.6%). The majority of patients (86/97, 88.7%) received pre-operative chemoradiation. In multivariate analysis, rectal surgery was found to be the only independent predictor of increased overall survival (24.6 vs 7.1 months, p <0.001). Of the patients undergoing surgical treatment, 22.8% presented with significant complications that required a delay of systemic treatment.Grade 3-4 acute radiation therapy-related toxicities were observed in 6.1% of patients, mainly gastrointestinal toxicities (5.4%). CONCLUSION: Rectal surgery was a key predictive factor of increased progression-free survival and overall survival in patients receiving at least local radiotherapy. In our series of real-life patients, local surgery and radiation seemed as well tolerated as reported in selected phase III non-metastatic rectal cancer patients. These data suggested that local management could be beneficial for metastatic rectal cancer patients.