Top Line: At ESMO 2020, we got a peak at the abstract results of the LungART trial, which showed that post-op radiation (PORT) did not improve disease-free survival (DFS) in patients with resected pN2 non-small cell lung cancer (NSCLC).
The Study: PORT-C was a single-institution trial where 394 patients with completely resected pN2 NSCLC who had completed adjuvant chemo with no evidence of progression were randomized to adjuvant radiation or observation. Surgery consisted of lobectomy and dissection of levels 4, 7, and 10 on the right or 4, 5, 6, 7, and 10 on the left. Adjuvant chemo consisted of 4 cycles of a platinum-doublet. PORT consisted of 50 Gy in 25 fractions (89% had IMRT) to the ipsilateral hilum, subcarina, and ipsilateral mediastinum. It was designed to detect a 30 → 44% improvement in 3-year DFS with PORT. In the intention-to-treat analysis (which included those who refused PORT), there was no significant difference in 3-year DFS (41% vs 33%) or overall survival (OS, 78% vs 83%) with PORT. Here’s the kicker: A whopping 22% of patients assigned to PORT refused treatment. And in the per-protocol analysis, the increase in 3-year DFS was significant (43% vs 31%) but there was still no difference in OS (83% either way). PORT significantly increased the rate of local recurrence free survival from 60 → 67% by reducing the risk of locoregional recurrence from 18 → 10%. Toxicity from PORT was limited with 9% experiencing grade 2+ esophagitis and 6% experiencing grade 2+ pneumonitis. There’s a nice figure (3) that shows patterns of failure over time, and what we see is that locoregional failure is a relatively small piece of the pie. With observation, 18-20% of patients had isolated locoregional progression while most had distant only or combined distant and loacl progression. Even though radiation had a meaningful impact on local progression, it wasn’t quite big enough to shift the larger DFS curve that’s driven by distant disease.
TBL: For resected pN2 NSCLC, PORT halves the rate of locoregional recurrence, but that does not appear to significantly improve survival outcomes. | Hui, JAMA Oncol 2021