Tumour regression after radiotherapy for rectal cancer – Results from the randomised Stockholm III trial

•After neoadjuvant radiotherapy in rectal cancer, patients with complete tumour regression or pathology graded complete response have a significantly better survival and fewer recurrences, compared to patients with less tumour response.•5 × 5 Gy with delayed surgery induces more tumour regression and pCR compared to 25 × 2 Gy.•Overall treatment time must exceed 4 weeks to achieve pCR after 5 × 5 Gy.