What is the prognostic significance of positive lymph nodes at the circumferential resection margin in rectal cancer: a systematic review.
Ellen Groundwater, Christopher Ray, Harikrishnan Nair et al.
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In 30 seconds
This systematic review examined whether rectal cancer involving the circumferential resection margin (CRM) through metastatic lymph nodes carries the same prognosis as CRM involvement from direct tumor extension. Five studies, including 5303 patients overall and 162 with node-positive CRM, were included; heterogeneous reporting precluded meta-analysis. Across studies, node-positive CRM was generally associated with more favorable outcomes: 5-year overall survival ranged from 49% to 51%, compared with 20% to 29% for tumor-extension CRM, and local recurrence ranged from 5% to 12% versus 22% to 52%.
Key findings
- Five studies included 5303 patients, of whom 162 had CRM positivity due to lymph node involvement.
- Five-year overall survival ranged from 49% to 51% for node-positive CRM and 20% to 29% for CRM positivity from direct tumor extension.
- Local recurrence ranged from 5% to 12% with node-positive CRM, compared with 22% to 52% with tumor-extension CRM.
- Heterogeneous outcome reporting and small numbers prevented meta-analysis.
Why it matters
The findings suggest that the route by which tumor reaches the CRM may be relevant to prognosis, rather than CRM positivity having a uniform implication. Distinguishing nodal involvement from direct extension could therefore matter when interpreting outcomes and pathology. However, the evidence is not sufficient to establish this distinction as an independent prognostic factor.
What to keep in mind
Only five studies were included, with 162 node-positive CRM patients; outcome reporting was heterogeneous, preventing meta-analysis. The review calls for prospective multicenter studies with standardized pathological classification.