Postoperative radiation benefits N2 resected NSCLC patients

By Lynda Williams, Senior medwireNews Reporter

Patients with resected, margin-negative non-small-cell lung cancer (NSCLC) with mediastinal node metastases (N2) derive significant benefit from postoperative radiotherapy (PORT), US researchers report.

Christopher Corso (Yale School of Medicine, New Haven, Connecticut) and team examined National Cancer Database information for 30,552 patients treated for stage II to IIIA NSCLC between 1998 and 2006.

In all, 11.2% of patients received PORT, rising to 23.8% of those with N2 disease, the team reports in the Journal of Thoracic Oncology.

Initial analysis indicated that 5-year overall survival (OS) was significantly poorer in patients with pathological N0 disease who received PORT than in those who did not (37.7 vs 48.0%), with a similar correlation also found for N1 patients (34.8 vs 39.4%).

By contrast, patients with N2 disease derived a significant benefit from PORT, with a 5-year OS of 34.1% versus 27.8% without PORT. Analysis confirmed that surgery plus chemotherapy and PORT was superior to surgery plus chemotherapy, surgery plus PORT or surgery alone.

However, on further examination, the team found that the impact of PORT on OS for N2 patients was significantly associated with the radiation dose received.

Thus, N2 patients given between 45 and 54 Gy had significantly better 5-year OS than those not given PORT (38.0 vs 27.8%), regardless of whether they also received chemotherapy, whereas OS did not significantly differ between patients given more than 54 Gy and those given no PORT (27.6 vs 27.8%).

Multivariate analysis adjusting for age, gender, surgery type and other confounding factors confirmed that a PORT dose of 45 to 54 Gy was significantly associated with improved OS compared with no PORT for patients with N2 disease (hazard ratio for death=0.85), while no such benefit was found for a higher PORT dose.

“We observed that delivering PORT to patients with mediastinal nodal metastases following surgery and chemotherapy results in a significant survival benefit, which is in part modified by delivered dose”, the researchers conclude.

“PORT should remain a standard treatment option for such patients pending results of ongoing randomized trials.”

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