Efficacy and Safety of SCRT Versus TNT in Older Patients With Locally Advanced Rectal Cancer

Patients will receive 5 daily fractions of radiotherapy. Each fraction will consist of 5 Gy for a total dose of 25 Gy.

The choice of the adjuvant chemotherapy is to the investigator's discretion.

"Surgery must be performed according to the principles of total mesorectal excision. A watch \& wait approach is allowed for those subjects who have clinical complete response according to the local assessment."

"The choice of the TNT is left to the investigator's discretion.~If RAPIDO:~* SCRT (5 fractions of 5 Gy), followed by~* Up to 18 weeks of oxaliplatin based chemotherapy (mFOLFOX6 or CAPOX)~If RAPIDO light:~* SCRT (5 fractions of 5 Gy), followed by~* Up to 12 weeks of oxaliplatin based chemotherapy (mFOLFOX6 or CAPOX)~If OPRA with induction chemotherapy:~* Up to 16 weeks of oxaliplatin-based chemotherapy (mFOLFOX6 or CAPOX), followed by~* CRT (25-28 fractions of 1.8-2.0 Gy each +/- a boost to the primary tumour and involved lymph nodes, for a total of 50-56 Gy of radiation combined with either continuous infusion fluorouracil or capecitabine)~If OPRA with consolidation chemotherapy:~* CRT (25-28 fractions of 1.8-2.0 Gy each +/- a boost to the primary tumour and involved lymph nodes, for a total of 50-56 Gy of radiation combined with either continuous infusion fluorouracil or capecitabine) followed by~* Up to 16 weeks of oxaliplatin-based chemotherapy (mFOLFOX6 or CAPOX)"