Comment on recent publication : One of the first studies to examine the response to chemotherapy in lymph nodes (rather than the primary tumour itself) in oesophageal cancer. Published in the British Journal of Surgery. This is an important study because it challenges conventional assessments of chemotherapy response which is one of the most important prognostic factors in cancer treatment. How we define responders could have a major impact on which patients may be best suited to additional post-operative chemotherapy. This study is currently being validated in a large multi-centre cohort.

BACKGROUND:

The aim was to define the pathological response in lymph nodes following neoadjuvant chemotherapy for oesophageal adenocarcinoma and to quantify any associated survival benefit.

METHODS:

Lymph nodes retrieved at oesophagectomy were examined retrospectively by two pathologists for evidence of a response to chemotherapy. Patients were classified as lymph node-negative (either negative nodes with no evidence of previous tumour involvement or negative with evidence of complete regression) or positive (allocated a lymph node regression score based on the proportion of fibrosis to residual tumour). Lymph node responders (score 1, complete response; 2, less than 10 per cent remaining tumour; 3, 10-50 per cent remaining tumour) and non-responders (score 4, more than 50 per cent viable tumour; 5, no response) were compared in survival analyses using Kaplan-Meier and Cox regression analysis.

RESULTS:

Among 377 patients, 256 had neoadjuvant chemotherapy. Overall, 68 of 256 patients (26·6 per cent) had a lymph node response and 115 (44·9 per cent) did not. The remaining 73 patients (28·5 per cent) had negative lymph nodes with no evidence of regression. Some patients had a lymph node response in the absence of a response in the primary tumour (27 of 99, 27 per cent). Lymph node responders had a significant survival benefit (P < 0·001), even when stratified by patients with or without a response in the primary tumour. On multivariable analysis, lymph node responders had decreased overall (hazard ratio 0·53, 95 per cent c.i. 0·36 to 0·78) and disease-specific (HR 0·42, 0·27 to 0·66) mortality, and experienced reduced local and systemic recurrence.

CONCLUSION:

Lymph node regression is a strong prognostic factor and may be more important than response in the primary tumour.