This protocol applies to patients with localised rectal cancer in the lower or middle third of the rectum whose tumour is mismatch repair proficient (MMR-p) / microsatellite stable (MSS) and for whom surgery is the intended treatment. It defines the adjuvant management step taken when total mesorectal excision (TME) has been performed but critical surgical targets were not fully achieved.
Localised rectal cancer sited in the lower or middle third of the rectum, with an MMR-p/MSS tumour profile, in a patient planned for surgical resection. Total proctectomy with TME is the standard surgical procedure for locally advanced tumours at this location and has demonstrated substantial benefit in reducing local recurrence rates.
The preceding treatment step was total mesorectal excision (TME). The primary surgical target was microscopically complete (R0) resection with a clear circumferential resection margin — tumour more than 1 mm from the CRM. When that margin target was not secured, or when other defined high-risk pathological features are identified following surgery, this protocol provides the recommended next step.
Following TME, adjuvant systemic therapy incorporating a fluoropyrimidine — and potentially a second agent — may be offered based on individual clinical risk assessment. In specific post-surgical circumstances, additional locoregional treatment is also indicated. The complete decision framework, including indications, sequencing, and selection criteria, is available in the full protocol.
DOI: 10.1016/j.annonc.2025.05.528
Management of localised rectal cancer located in the lower or middle third of the rectum when surgery is intended.
The standard surgical approach for locally advanced tumours in the middle or lower third of the rectum remains total proctectomy with TME, which has demonstrated a substantial benefit in decreasing local recurrence rates.
Adjuvant therapy with a fluoropyrimidine and (potentially) oxaliplatin should be offered (according to clinical risk assessment) following TME alone [I, A] and can be considered after neoadjuvant CRT or SCRT [V, B].
In patients who did not receive preoperative RT, adjuvant CRT should be offered in case of CRM positivity, pT4b, pN2 with extracapsular spread close to the MRF or poor-quality TME [III, A].
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