Poupuriiiii
Pedunculated or sessile polyp (adenoma), GI did a colonoscopy, did peacemeal resection of the sessile peduncle, which showed invasive cancer with good histologic features; no nodes were examined. What would you do?
1) Be angry about why the patient is coming to you; It should be followed by surgery, GI. You don't do adjuvant chemo for T1.
2) piecemeal resection is in a way “fragmented specimen,” and you would do Pelvic MRI, CT C/A/P, Labs -CBC, CMP, CEA followed by consideration of colectomy with en bloc removal of regional Lymph nodes.
Answer -- 2
Fragmented specimen or margin cannot be assessed, or unfavorable histologic features need to be referred for surgical resection (segmental colectomy).
NICHE and NICHE 2 trial
NICHE Trial- Published: 2020 (Chalabi et al.)
Early-stage, non-metastatic colon cancer (T3–T4)
Included both dMMR and pMMR tumors.
Treatment:
Single dose ipilimumab (1 mg/kg) + two doses nivolumab (3 mg/kg)
Given pre-operatively (neoadjuvant)
Surgery followed ~4 weeks later
dMMR cohort
100% pathologic response
60% pathologic complete response (pCR)
→ exceptionally sensitive to immunotherapy
pMMR cohort
Very limited benefit
Major pathologic response in ~4%
Takeaway:
Proof-of-concept that short-course neoadjuvant immunotherapy is wildly effective in dMMR localized colon cancer.
✅ NICHE-2 Trial
Presented: ESMO 2022 (updated 2023)
Population:
Neoadjuvant treatment for locally advanced dMMR colon cancer
Much larger cohort than NICHE-1 (~112 patients)
Treatment:
Same short regimen:
Ipilimumab × 1 dose
Nivolumab × 2 doses
Surgery ~5 weeks later
Results:
95% major pathologic response (MPR)
67% pathologic complete response (pCR)
0% recurrence at short-term follow-up
Treatment was well-tolerated; no surgical delays
Takeaway:
Confirms that brief neoadjuvant immunotherapy is highly effective and safe for dMMR colon cancer, potentially practice-changing.
✅ Clinical Implications (as of current practice)
For dMMR localized colon cancer, neoadjuvant immunotherapy is emerging as a new standard in trials.
pMMR tumors do not benefit—stick with standard surgery ± adjuvant chemo.
Still not routine outside trials, but rapidly evolving.