Multicentre study of short-course radiotherapy, systemic therapy and resection/ablation for stage IV rectal cancer

Background: The optimal treatment sequence for patients with rectal cancer and synchronous liver metastases remains unclear. The aim of this study was to evaluate the feasibility and effectiveness of short-course pelvic radiotherapy (5 × 5 Gy) followed by systemic therapy and local treatment of all tumour sites in patients with potentially curable stage IV rectal cancer in daily practice. Methods: This was a retrospective study performed in eight tertiary referral centres in the Netherlands. Patients aged 18 years or above with rectal cancer and potentially resectable liver ± extrahepatic metastases, treated between 2010 and 2015, were eligible. Main outcomes included full completion of treatment schedule, symptom control and survival. Results: In total, 169 patients were included with a median follow-up of 49·5 (95 pr cent c.i. 43·6 to 55·6) months. The completion rate for the entire treatment schedule was 65·7 per cent. Three-year progression-free survival and overall survival (OS) rates were 24·2 (95 per cent c.i. 16·6 to 31·6) and 48·8 (40·4 to 57·2) per cent respectively. Median OS of patients who responded well and completed the treatment schedule was 51·5 months, compared with 15·1 months for patients who did not complete the treatment (P < 0·001). Adequate symptom control of the primary tumour was achieved in 87·0 per cent of all patients. Conclusion: Multimodal treatment leads to relief of symptoms in most patients, and is associated with good survival rates in those able to complete the schedule. [Correction added on 12 February 2020, after first online publication: the Conclusion has been reworded for clarity]