Interpreting the RAPIDO trial: factors to consider

• Published in: The lancet oncology Vol. 22; no. 3; p. e86
• Main Author: Kumar, Naveena A N
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-03-2021; Elsevier Limited
• Subjects: Cancer therapies; Chemoradiotherapy; Chemotherapy; Chemotherapy, Adjuvant; Histology; Humans; Radiation therapy; Rectal Neoplasms; Rectum; Surgery; Tumors
• ISSN: 1470-2045; 1474-5488
• DOI: 10.1016/S1470-2045(21)00011-5

In the experimental group (short-course radiotherapy followed by chemotherapy before total mesorectal excision [TME]), only 32% of tumours were stage cT4, 22% were low rectal, and 10% were poorly differentiated, whereas upper rectal or rectosigmoid tumours, stage cT2 and cT3 tumours, and tumours with a favourable histology were more common, contributing to a high rate of pathological complete response after neoadjuvant chemotherapy. By contrast, the Polish II study,3,4 which included a majority of cT4 and low-lying tumours, had a similar pathological complete response rate, local recurrence rate, and survival outcomes between groups receiving short course radiotherapy with consolidation chemotherapy and patients receiving long-course chemoradiation. The rate of locoregional failure in the RAPIDO experimental group was 8·7% (95% CI 5·8–10·8), with most locoregional failures in the experimental group occurring in patients with cT4 low rectal cancer with poor histology and poor response to neoadjuvant chemotherapy.