A nomogram associated with high probability of malignant nodes in the surgical specimen after trimodality therapy of patients with oesophageal cancer

Background: The presence of malignant lymph nodes (+ypNodes) in the surgical specimen after preoperative chemoradiation (trimodality) in patients with oesophageal cancer (EC) portends a poor prognosis for overall survival (OS) and disease-free survival (DFS). Currently, none of the clinical variables highly correlates with +ypNodes. We hypothesised that a combination of clinical variables could generate a model that associates with high likelihood of +ypNodes after trimodality in EC patients. Methods: We report on 293 consecutive EC patients who received trimodality therapy. A multivariate logistic regression analysis that included pretreatment and post-chemoradiation variables identified independent variables that were used to construct a nomogram for +ypNodes after trimodality in EC patients. Results: Of 293 patients, 91 (31.1%) had +ypNodes. OS (p = 0.0002) and DFS (p< 0.0001) were shorter in patients with +ypNodes compared to those with -ypNodes. In multivariable analysis, the significant variables for +ypNodes were: baseline T-stage (odds ratio [OR], 7.145; 95% confidence interval [CI], 1.381-36.969; p = 0.019), baseline N-stage (OR, 2.246; 95% CI, 1.024-4.926; p = 0.044), tumour length (OR, 1.178; 95% CI, 1.024-1.357; p = 0.022), induction chemotherapy (OR, 0.471; 95% CI, 0.242-0.915; p = 0.026), nodal uptake on post-chemoradiation positron emission tomography (OR, 2.923; 95% CI, 1.007-8.485; p = 0.049) and enlarged node(s) on post-chemoradiation computerised tomography (OR, 3.465; 95% CI, 1.549-7.753; p = 0.002). The nomogram after internal validation using the bootstrap method (200 runs) yielded a high concordance index of 0.756. Conclusion: Our nomogram highly correlates with the presence of +ypNodes after chemoradiation, however, considerably more refinement is needed before it can be implemented in the clinic.