Seven Years of Watch and Wait With Rectal Cancer-Reflections and Optimisations

Sir Charles Gairdner Hospital (SCGH) commenced an observation strategy in patients with a complete clinical response, Watch and Wait (W&W), for rectal adenocarcinoma in 2017 using a rigorous surveillance protocol. Our earlier results (2017-2019) have been published. We report updated results and present a revised treatment pathway and surveillance protocol.

A retrospective review of a prospectively maintained database and medical records was performed. All patients from 2017 to 2023 referred for long-course chemoradiotherapy (LCCRT) as part of rectal adenocarcinoma treatment with curative intent were included.

A total of 142 patients were referred for induction LCCRT for rectal cancer. Consolidation chemotherapy usually followed. Six patients did not complete treatment; 31 had a complete or near-complete clinical response and were enrolled in W&W. Six patients declined surgery and were offered W&W. Of the 31 patients in W&W, 5 patients had suspected local regrowth and underwent surgical resection. Two of five had pCR on histopathology. Regrowth cases were identified within 9 months by flexible sigmoidoscopy and sometimes on imaging (PET or MRI). A total of 95 patients did not have cCR and had surgical resection; of these, 20 had pCR.

A total of 24% of patients referred for LCCRT at SCGH achieved cCR, and this was sustained in 84%. Sixteen percent of W&W patients had suspected local regrowth. Our surveillance protocol detected regrowth early, and surgical salvage was always possible. Twenty percent of patients undergoing surgery having pCR despite not having cCR highlights the difficulty of avoiding TME in all patients who have a pCR but suggests optimisations of our practice are possible. We propose a reduction in the length and intensity of our current protocol.