Postoperative radiotherapy option based on mediastinal lymph node reclassification for patients with pN2 non-small-cell lung cancer.

BACKGROUND

In this research, we used the mediastinal lymph node reclassification proposed by the International Association for the Study of Lung Cancer (iaslc) to screen for patients with pathologic N2 (pN2) non-small-cell lung cancer (nsclc) who might benefit from postoperative radiotherapy (port).

METHODS

The study enrolled 440 patients with pN2 nsclc who received complete surgical resection and allocated them to one of three groups: N2a1 (single-station skip mediastinal lymph node metastasis), N2a2 (single-station non-skip mediastinal lymph node metastasis), and N2b (multi-station mediastinal lymph node metastasis). Rates of local recurrence at first recurrence in patients receiving and not receiving port were compared using the chi-square test. Overall (os) and disease-free survival (dfs) were then compared using Kaplan-Meier survival analysis with log-rank test. In addition, the factors potentially influencing os and dfs were analyzed using univariate and multivariate Cox regression.

RESULTS

The rate of local recurrence for the N2a2 and N2b groups was significantly lower in patients receiving port ( = 0.044 and = 0.043 respectively). The log-rank test revealed that, for the N2a1 group, differences in os and dfs were not statistically significant between the patients who did and did not receive port ( = 0.304 and = 0.197 respectively). For the N2a2 group, os and dfs were markedly superior in patients who received port compared with those who did not ( = 0.001 and = 0.014 respectively). For the N2b group, os was evidently better in patients who received port compared with those who did not ( = 0.025), but no statistically significant difference in dfs was observed ( = 0.134). Multivariate regression analysis revealed that, in the N2a1 group, port was significantly associated with poor os [hazard ratio (hr): 2.618; 95% confidence interval (ci): 1.185 to 5.785; = 0.017]; in the N2a2 group, port was associated with improved os (hr: 0.481; 95% ci: 0.314 to 0.736; = 0.001) and dfs (hr: 0.685; 95% ci: 0.479 to 0.980; = 0.039).

CONCLUSIONS

For patients with pN2 nsclc who receive complete resection, port might be beneficial only for patients with single-station non-skip metastasis (N2a2). Patients with single-station skip metastasis (N2a1) and multi-station metastasis (N2b) might not currently benefit from port.