[Practice-changing clinical trials in gastrointestinal radiation oncology]

Current events in radiotherapy oncology are marked by the results of strategic trials, particularly for esophageal and rectal cancers. For resectable esophageal adenocarcinoma, results of the ESOPEC study showed a benefit in overall survival from the perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin and docetaxel compared to chemoradiotherapy (41.4Gy radiotherapy and carboplatin/paclitaxel chemotherapy). In definitive setting, the CONCORDE study did not show any benefit from dose escalation and the standard dose remains 50Gy. For resectable pancreatic cancer, the NRG/RTOG0848 study that compared adjuvant chemotherapy with or without chemoradiotherapy found a significant increase of the 5-year disease-free survival rate in the subgroup of node-negative patients. For rectal cancers, the 7-year update of PRODIGE 23 study confirmed the benefit in disease-free- and overall survival of neoadjuvant folinic acid, fluorouracil, irinotecan and oxaliplatin chemotherapy before chemoradiotherapy of T3, T4 or N+ adenocarcinoma, while the update of the RAPIDO study revealed an unacceptable local recurrence rate in the experimental arm. The update of the OPRA study shows a significantly higher 5-year organ preservation rate in favor of the chemoradiotherapy arm followed by consolidation chemotherapy compared to induction chemotherapy followed by CRT. A phase 2 study, including 41 patients with mismatch repair deficient, locally advanced rectal cancer reported that exclusive treatment with anti-PDL1 immunotherapy (dostarlimab) for 6 months resulted in complete clinical response without the need of additional treatment (neither radiotherapy nor surgery). For anal carcinoma, the analysis of survival and toxicity profiles of patients treated for a small stage T1 or T2 tumor were compared depending on whether they received exclusive radiotherapy or chemoradiotherapy. The addition of chemotherapy to radiotherapy did not show any survival benefit but significantly increased toxicity and the risk of radiotherapy disruption.