Low-dose radiotherapy as a chemo-potentiator of a chemotherapy regimen with pemetrexed for recurrent non-small-cell lung cancer: A prospective phase II study

Purpose: Low-dose radiotherapy (LDR) (2 IV) and concurrent LDR (40 cGy bid on days 1 and 2) delivered to target pulmonary or metastatic disease. This cycle was repeated fourfold every 21 days. The accrual was determined by the single proportion powered analysis (α = 0.05, power = 0.8) with H0 ("bad" response probability, 9% according to literature) and H1 ("good" response probability, 35% ongoing study); 19 is the number required. Results: Nineteen patients with stage III and IV disease were enrolled. Only one patient experienced neutropenia grade 4. All patients are evaluable for clinical response of irradiated lesion: overall response rate was 42%. Conclusions: Low-dose radiotherapy combined with pemetrexed has a similar toxicity profile to chemotherapy alone. The response rate of this novel approach is encouraging, since it was higher than what was reported for pemetrexed alone (42% versus 9.1%). Additional scientific investigation of this new treatment paradigm is warranted.