Efficacies of different postoperative radiotherapy techniques in patients with N2 non-small cell lung cancer: a meta-analysis.

Background: With clinical trials on the use of different modern precise radiotherapy techniques in the setting of postoperative radiotherapy (PORT) in N2 non-small cell lung cancer (NSCLC) accumulating, an updated meta-analysis was performed.

Methods: A literature search identified studies that investigated PORT versus non-PORT in N2 NSCLC patients. Overall survival (OS) and locoregional recurrence (LR) were employed. The hazard ratio (HR) and relative risk (RR) with 95% confidence interval (CI) were analyzed.

Results: Overall, 33 studies comprised 8653 patients in the PORT group and 12398 in the non-PORT group. The HR for OS was 0.95 [95% CI: 0.91-0.98, P: 0.0009]. HRs of studies employing conventional radiotherapy, 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) were 0.90 [95% CI: 0.78-1.04, P: 0.16], 0.82 [95% CI: 0.72-0.93, P: 0.002] and 0.77 [95% CI: 0.64-0.91, P: 0.003], respectively. All HRs favor the PORT group. The RR for LR was 0.56 [95% CI: 0.49-0.65, P<0.00001]. RRs of studies employing conventional radiotherapy, 3D-CRT and IMRT were 0.61 [95% CI: 0.50-0.75, P<0.00001], 0.58 [95% CI: 0.46-0.72, P<0.00001] and 0.58 [95% CI: 0.45-0.73, P<0.00001], respectively.

Conclusion: PORT using 3D-CRT or IMRT benefits patients with N2 NSCLC in terms of LR and OS. PORT using conventional radiotherapy significantly decreases LR while it does not significantly increase OS.