This protocol applies when a patient with localised rectal cancer of the lower or middle third of the rectum — managed with organ preservation as the primary intent — has not achieved a clinical complete response (cCR) following radiation-based treatment.
Localised rectal cancer in the lower or middle third of the rectum, with organ preservation as the intended goal, in patients with mismatch repair proficient (MMR-p) / microsatellite stable (MSS) tumours.
The preceding line employed radiation-based therapy — short-course radiotherapy (SCRT), chemoradiotherapy (CRT), or total neoadjuvant therapy (TNT) — selected according to stage and risk profile. The target of that line was clinical complete response (cCR), evaluated by digital rectal examination, sigmoidoscopy, and MRI at restaging approximately 12 weeks after the start of radiotherapy (with a further restaging after 4–8 weeks when near-cCR was observed). This protocol represents the next step when cCR has not been attained.
When cCR is not achieved, surgical management — with the resection method guided by clinical assessment — becomes central, though organ-preservation strategies may still be considered in selected presentations; the complete decision framework is contained in the full protocol.
Microscopically complete (R0) resection with a clear circumferential resection margin — tumour more than 1 mm from the CRM.
DOI: 10.1016/j.annonc.2025.05.528
Management of localised rectal cancer located in the lower or middle third of the rectum when organ preservation is intended.
Multimodal treatment strategies for patients with rectal cancer are increasingly incorporating a watch-and-wait approach for organ preservation.
Surgery, with the resection method depending on clinical assessment, is recommended for patients who do not achieve a cCR following CRT or TNT [I, A].
LE can be considered to achieve organ preservation in patients with baseline cT2 or cT3a N0 with a near cCR [II, B].
In case of local (endorectal) regrowth after a watch-and-wait procedure, salvage resection should be offered to all patients [IV, A].
A distance of >1 mm from tumour to CRM and other organs can be recommended [III, B].
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