Postoperative radiotherapy of little help in non-small-cell lung cancer

Reuters Health - 30/06/2021  - Postoperative radiotherapy (PORT) after complete resection and adjuvant chemotherapy does not improve disease-free or overall survival in patients with pIIIA-N2 non-small-cell lung cancer (NSCLC), according to researchers.

PORT has previously been shown to adversely affect survival in patients with NSCLC, Dr. Luhua Wang of the Chinese Academy of Medical Sciences and Peking Union Medical College, in Beijing, and colleagues note in JAMA Oncology. However, given the rapid improvement in radiotherapy techniques, in some subgroups "there is increasing evidence that PORT results in better survival."

Nevertheless, Dr. Wang told Reuters Health by email, "the definitive role of PORT using modern techniques in pIIIA-N2 NSCLC after complete resection and adjuvant chemotherapy remains controversial."

The team studied 394 patients with pIIIA-N2 NSCLC treated with complete resection and four cycles of platinum-based chemotherapy. They were randomized to PORT, including three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, or to an observation arm. The median age of the patients was 55 years, and the total dose of PORT was 50 Gy.

Median follow-up was for 46 months. In a modified intent-to-treat (mITT) analysis, three-year disease-free survival (DFS) rates were 40.5% with PORT and 32.7% with observation (P=0.2). Corresponding proportions for overall survival were 78.3% and 82.8% (P=0.93).

Locoregional recurrence-free survival (LRFS) showed a significant improvement at 66.5% versus 59.7%, however (P=0.03).

PORT also significantly improved DFS in a preplanned exploratory stratified analysis and in the per-protocol population (42.8% vs. 30.6%), but this was not the case for OS. Competing-risk analysis of first failure patterns, the researchers point out, "further revealed that the benefit in improving DFS is largely due to locoregional control."

Among limitations of the study, say the investigators, is that after randomization, in the mITT population, 21.7% of the patients in the PORT arm refused PORT and 5.6% of the patients in the observation arm actually received PORT.

Dr. Wang concluded, "PORT should not be recommended routinely for pIIIA-N2 NSCLC patients after complete resection followed by adjuvant chemotherapy. Further studies exploring patients who will optimally benefit from PORT are required."

SOURCE: https://bit.ly/3dqrk72 JAMA Oncology, online June 24, 2021.

By David Douglas



Posted on 30 June 202119 July 2021