- Design
- Retrospective multicentre cohort with training and validation sets
- Population
- 2,611 resected pT1 colorectal cancers, six Chinese centres
- Primary outcome
- Lymph node metastasis
- Effect
- Independent predictor in both cohorts (P below 0.05); budding and clusters not consistently independent
A study of 2,611 endoscopically or surgically resected pT1 colorectal cancers from six Chinese centres defined peritumoral malignant cellular foci as any non-glandular focus of one or more tumour cells at the invasive front. This deliberately removes the five-cell cutoff that separates tumour budding from poorly differentiated clusters.
Across training and validation cohorts, tumour budding and poorly differentiated clusters did not show a consistent independent association with lymph node metastasis. Peritumoral malignant cellular foci did, in both cohorts and across subgroups by age, sex, site and BMI. They were also linked to more involved nodes and more strongly to apical (D3) nodal spread than to D1 or D2. The abstract does not give effect sizes.
If validated, this would simplify a contentious count and could sharpen the decision on completion surgery after endoscopic resection. The proposal is attractive because it uses features pathologists already see.
It comes from one country and has not been tested externally or adopted by any reporting standard. For now, consider noting such foci alongside, not instead of, the established high-risk features, and await validation before letting it drive surgical referral.
- Keep reporting tumour budding grade and other established high-risk features.
- Consider also noting any non-glandular tumour foci at the invasive front.
- Do not use this feature alone to recommend or withhold completion surgery yet.
- Watch for external validation and for any change to reporting datasets.
Why it matters
It questions whether the five-cell budding cutoff is the right line to draw.
Don't overread it
No reporting standard has adopted this; the evidence is retrospective and from one country.
The statistics, in plain English
The study reports significance levels but not the size of the association in the abstract, so how much better it discriminates than budding is unclear. Validation within the same country is weaker evidence than validation elsewhere.
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