The clinical relevance of regional lymph node microarchitecture in oesophageal cancer patients - Results from the UK MRC OE02 trial.
BACKGROUND: In oesophageal cancer (OeC) patients, neoadjuvant chemotherapy followed by surgery improves survival. Anti-tumour immune responses are mediated by lymph node (LN) microarchitecture. We investigated whether neoadjuvant chemotherapy and/or presence of tumour changes LN microarchitecture, and whether such changes are associated with survival. METHODS: Microarchitectural features (lymphocytes, germinal centres (GermC), histiocytes) were quantified morphometrically in 433 LNs from 333 OE02 trial patients (165 neoadjuvant chemotherapy+surgery (CS), 168 surgery alone (S)). Features were compared between tumour-negative (LNneg) and tumour-positive LN (LNpos) by treatment group. Associations with clinicopathological variables and overall survival (OS) were evaluated. RESULTS: LNneg GermC density was lower in CS patients than in S patients (median: 1% vs 2%; p = 0.0004). No other microarchitectural features differed by treatment group or LN status (LNneg vs LNpos). Low histiocyte content in LNneg and LNpos was associated with improved OS in S patients only (HR:0.67, 95%CI: 0.46-0.97, p = 0.03). Multivariable analysis confirmed the independent prognostic significance of LNneg histiocytes (HR:0.62, 95%CI: 0.42-0.9, p = 0.01). CONCLUSION: These findings suggest that LN microarchitecture may be a biomarker for treatment-related immune modulation and prognosis in patients with resectable OeC. These findings warrant independent validation and further investigation to determine whether LN microarchitectural features could inform personalised therapeutic strategies.