Comparison of short course radiotherapy with chemoradiotherapy for locally advanced rectal cancers in the elderly: a multicentre, randomised, non-blinded, phase 3 trial
Mené en France entre 2016 et 2019 sur 103 patients âgés atteints d'un adénocarcinome rectal de stade localement avancé (âge : au moins 75 ans), cet essai randomisé multicentrique de phase III évalue l'efficacité, du point de vue du taux de résection R0 et du maintien de l'autonomie, d'une radiothérapie de courte durée par rapport à une chimioradiothérapie
Background: There is no specific guideline for the treatment of locally advanced rectal cancers in the elderly. Here we compared R0 resection rate and degradation of autonomy based on the IADL score between neoadjuvant, short course radiotherapy, and chemoradiotherapy in this specific population. Patients and methods: Patients ≥75 years with resectable T3-T4 rectal adenocarcinoma within 12 cm of the anal verge or T2 of the very low rectum, were randomised between short course radiotherapy (5x5 Gy in one week) and chemoradiotherapy (50 Gy, 2 Gy/f, 5 weeks with capecitabine: 800 mg/m2 twice daily, 5 days per week), with delayed surgery 7 ± 1 weeks for the two arms. Results: One hundred and three eligible patients were enrolled between January 2016 and Decembre 2019 when the trial was closed due to poor accrual. The R0 resection rate (first coprimary objective) was 84.3%; CI95% [73.26 - 94.18] in the short course group and 88%; CI95% [77.77 - 96.60] in the chemoradiotherapy group (non inferiority p=0.28). The deterioration of the IADL score was not different during the pre-operative phase, it was significantly more deteriorated in the chemoradiotherapy group at 3 months post-operative (44.8% vs 14.8%; p= 0.032), but was not different at 12 months post-operative (second co-primary objective). During pre-operative phase, 9.8% of patients in short course group and 22% of patients in chemoradiotherapy group presented a serious adverse event, but we observed no difference during the post-operative phase between the two groups. Conclusion Although the main objectives of the study were not achieved, the short course radiotherapy followed by delayed surgery could represent a preferred treatment option in patients ≥75 years with locally advanced rectal cancer; a new study must be performed to confirm the improvement in overall and specific survival results.