Compliance and tolerability of short-course radiotherapy followed by preoperative chemotherapy and surgery for high-risk rectal cancer – Results of the international randomized RAPIDO-trial

Maxime J M Van Der Valk ,Denise E Hilling,Renu R Bahadoer,Mathijs P Hendriks,Annet G.H Roodvoets,Corrie A.M Marijnen,Derk Jan A De Groot,Tone Fokstuen,Hein Putter,Geke A.P Hospers,Boudewijn Van Etten,Cornelis J.H Van De Velde,Jaume Capdevila,Per J Nilsson,Esmée A Dijkstra,Bengt Glimelius,Albert J Ten Tije ,Elma Meershoek‐Klein Kranenbarg ,Andrés Cervantes ,Ibrahim Edhemović

doi:10.1016/j.radonc.2020.03.011

Abstract

BackgroundPreoperative chemoradiotherapy (CRT) followed by total mesorectal excision is widely accepted as the standard of care for high-risk rectal cancer. Adjuvant chemotherapy is advised in several international guidelines, although the survival benefit remains unclear and compliance is poor. The current multidisciplinary approach has led to major improvements in local control, yet the occurrence of distant metastases has not decreased accordingly. The combination of short-course radiotherapy (SCRT) and chemotherapy in the waiting period before surgery might have several benefits, including higher compliance, downstaging and better effect of systemic therapy. MethodsThis is an investigator-initiated, international multicentre randomized phase III trial. High-risk rectal cancer patients were randomized to SCRT followed by chemotherapy (6 cycles CAPOX or alternatively 9 cycles FOLFOX4) and subsequent surgery, or long-course radiotherapy (25–28 × 2–1.8 Gy) with concomitant capecitabine followed by surgery and optional postoperative chemotherapy (8 cycles CAPOX or 12 cycles FOLFOX4) according to local institutions’ policy. The primary endpoint is time to disease-related treatment failure. Here, we report the compliance, toxicity and postoperative complications in both study groups. FindingsBetween June 2011 and June 2016, 920 patients were enrolled. Of these, 901 were evaluable (460 in the experimental arm and 441 in the standard arm). All patients in the experimental arm received 5 × 5 Gy radiotherapy, and 84% of all patients received at least 75% of the prescribed chemotherapy. In the standard arm, the compliance for CRT was 93% and 58% for postoperative chemotherapy. Toxicity ≥grade 3 occurred in 48% of patients in the experimental arm, compared to 25% of patients in the standard arm during preoperative treatment and 35% of patients during postoperative chemotherapy. No statistically significant differences in surgical procedures or postoperative complications were observed. InterpretationHigh compliance (84%) of preoperative systemic treatment could be achieved with the experimental approach. Although considerable toxicity was observed during preoperative therapy, this did not lead to differences in surgical procedures or postoperative complications. Longer follow-up time is needed to assess the primary endpoint and related outcomes.

Highlights

Preoperative chemoradiotherapy (CRT) followed by total mesorectal excision is widely accepted as the standard of care for high-risk rectal cancer
High-risk rectal cancer patients were randomized to short-course radiotherapy (SCRT) followed by chemotherapy (6 cycles CAPOX or alternatively 9 cycles FOLFOX4) and subsequent surgery, or long-course radiotherapy (25–28 Â 2–1.8 Gy) with concomitant capecitabine followed by surgery and optional postoperative chemotherapy (8 cycles CAPOX or 12 cycles FOLFOX4) according to local institutions’ policy
Patients diagnosed with rectal cancer, less than 16 cm from the anal verge at endoscopy and with high-risk features on MRI were randomised with a 1:1 ratio to either the experimental treatment consisting of SCRT (5x5 Gy in one week), followed by 18 weeks of chemotherapy and subsequent total mesorectal excision (TME); or the standard treatment arm, consisting of long-course radiotherapy (25–28 Â 2–1.8 Gy) with concomitant capecitabine followed by TME after a 6–10 week waiting period, and subsequently optional 24 weeks of postoperative chemotherapy according to the local institutions’ policy (Fig. 1)

Summary

Introduction

Preoperative chemoradiotherapy (CRT) followed by total mesorectal excision is widely accepted as the standard of care for high-risk rectal cancer. The combination of short-course radiotherapy (SCRT) and chemotherapy in the waiting period before surgery might have several benefits, including higher compliance, downstaging and better effect of systemic therapy. High-risk rectal cancer patients were randomized to SCRT followed by chemotherapy (6 cycles CAPOX or alternatively 9 cycles FOLFOX4) and subsequent surgery, or long-course radiotherapy (25–28 Â 2–1.8 Gy) with concomitant capecitabine followed by surgery and optional postoperative chemotherapy (8 cycles CAPOX or 12 cycles FOLFOX4) according to local institutions’ policy. The compliance for CRT was 94% and 57% for postoperative chemotherapy. Toxicity !grade 3 occurred in 48% of patients in the experimental arm, compared to 25% of patients in the standard arm during preoperative treatment and 35% of patients during postoperative chemotherapy. No statistically significant differences in surgical procedures or postoperative complications were observed

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