In some bowel and rectal cancers that have a particular genetic feature (mismatch repair deficiency), immunotherapy before surgery can work very well. This has raised the possibility that in some patients surgery could be postponed, with close monitoring, instead of being done straight away. But this approach is not yet standard and should only be done in experienced centres with regular follow-up; if the response is incomplete or the tumour comes back, surgery is still an option.
dMMR/MSI-H stage II or III rectal adenocarcinoma (and stage I to III dMMR solid tumours); investigational — this use is not in the dostarlimab FDA label
| Drug | Dose | Route | Schedule |
|---|---|---|---|
| Dostarlimab | 500 mg | IV infusion over 30 minutes | Every 3 weeks |
As in the registered trial protocol. Only in experienced centres with regular surveillance (digital rectal examination, endoscopy, pelvic MRI).
On the page “Immunotherapy and organ preservation in dMMR tumours” · Regimens from the key studies
Doses follow the trial protocol, guideline or official drug label (source given in the notes of each regimen). Before prescribing, check blood counts, renal and hepatic function, drug interactions and the patient’s condition, and adjust the dose according to the drug label.
This paper is a narrative review and no specific patients were enrolled. The subject of the review is patients with mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) colorectal cancer receiving neoadjuvant immunotherapy.
This is a narrative review with no defined primary or secondary endpoint. The topics covered include biological rationale, prospective and observational evidence, limitations of response assessment, surgical decision points, follow-up requirements, toxicity and unresolved controversies about organ preservation after neoadjuvant immunotherapy.
The abstract lists toxicity as one of the topics reviewed but gives no numerical adverse event data.
Based on the abstract, the evidence for routinely avoiding surgery is still immature. In dMMR colon cancer there is no validated standard for non-operative assessment, but in dMMR rectal cancer with cCR after PD-1 blockade, "watch and wait" may be considered in highly selected patients. It should be limited to experienced multidisciplinary programmes with molecular confirmation, multimodal assessment, reliable follow-up and access to salvage surgery. The status of clinical guidelines should be checked separately.
This is a narrative review and presents no new primary data. According to the abstract, the evidence is anatomically heterogeneous, criteria for non-operative response assessment in colon cancer have not been validated, the definition of a durable cCR after immunotherapy is uncertain, ctDNA alone is limited for local decision-making, and site-specific prospective validation is needed.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.
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