This protocol addresses patients with localised rectal cancer in the upper third of the rectum that is confirmed mismatch repair proficient (MMRp) / microsatellite stable (MSS). At this anatomical level, the benefit of radiotherapy is very limited, and management follows an approach analogous to colon carcinoma.
Patients reaching this protocol will have completed a prior course of neoadjuvant chemotherapy — comprising CAPOX or FOLFOX, or total neoadjuvant therapy (TNT) incorporating radiotherapy for higher-risk or margin-threatened disease. The escalation trigger is failure to demonstrate adequate primary tumour downsizing on MRI restaging performed 3–4 weeks after completion of neoadjuvant chemotherapy. This absence of the expected response drives the transition to a definitive surgical step.
The next step involves definitive surgical resection; the specific resection strategy and the criteria that determine which approach applies — including considerations for locally advanced disease — are laid out in the full structured protocol.
The objective is a microscopically complete (R0) resection with the tumour situated more than 1 mm from the circumferential resection margin (CRM).
DOI: 10.1016/j.annonc.2025.05.528
For carcinomas in the upper third of the rectum, the benefit of RT is very limited; therefore, a procedure analogous to the approach for colon carcinoma may be preferred.
Algorithms for the management of localised rectal cancer in the upper third of the rectum are shown in Figures 1 and 2.
PME and TME are both equally recommended [III, A].
LE is recommended as an alternative to PME or TME for low-risk tumours (pT1 without unfavourable pathological features) [III, A].
The distal mesorectal margin should be 5 cm [III, A].
In case of MRF+ or T4b, beyond-TME surgery is recommended [III, A].
A distance of >1 mm from tumour to CRM and other organs can be recommended [III, B].
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