A decades-old surgical assumption — that removing as many lymph nodes as possible improves colorectal cancer outcomes — is now facing a credible biological challenge. As immune checkpoint inhibitors (ICIs) reshape oncology, questions are emerging about whether the very surgery used to stage and treat colorectal cancer may inadvertently dismantle the immune architecture that makes immunotherapy work.
This perspective review from the journal Colorectal Disease examines whether routine lymphadenectomy might impair systemic anti-tumor immunity, particularly in patients with mismatch repair-deficient or microsatellite instability-high (dMMR/MSI-H) colorectal cancer — a subtype uniquely responsive to ICI therapy. The authors interrogate the conventional benchmark of retrieving ≥12 lymph nodes as a surgical quality indicator, noting that while retrospective datasets associate higher nodal yield with improved survival, causality remains confounded by tumor biology, surgical expertise, and institutional volume. Critically, preclinical evidence positions tumor-draining lymph nodes (TDLNs) not as passive conduits for metastatic spread but as active orchestrators of systemic immune surveillance and ICI efficacy. Cross-specialty comparisons with breast cancer and melanoma — where sentinel lymph node biopsy with selective nodal preservation has become standard without compromising survival — provide indirect but structurally relevant precedent.
This is a hypothesis-generating perspective rather than an interventional trial, which significantly limits the actionability of its conclusions. The immunological parallels drawn from breast cancer and melanoma are instructive but imperfect; lymphatic anatomy and the dominant systemic therapies differ substantially from colorectal disease. Nevertheless, the argument represents a meaningful conceptual inflection point. The dMMR/MSI-H subgroup, comprising roughly 15% of colorectal cancers, is already eligible for ICI-based neoadjuvant strategies in some settings, making the preservation-versus-resection tension increasingly practical. If TDLNs are indeed essential for priming durable ICI responses, then indiscriminate lymphadenectomy could represent an unrecognized iatrogenic immunosuppressive act. This is an incremental but intellectually important contribution that warrants prospective evaluation.