Proton beam radiotherapy (PBT) administered concurrently with chemotherapy may provide clinical benefit to patients with unresectable non–small cell lung cancer (NSCLC), according to a study published in JAMA Oncology.1

Chemoradiotherapy (CRT) is recommended for patients with unresectable NSCLC, but patients often experience significant treatment related comorbidities and poor outcomes. Previous studies show that PBT may decrease toxic effects from therapy, but there are insufficient long term prospective data for PBT.

For this prospective study (ClinicalTrials.gov Identifier: NCT00495170), researchers enrolled 64 patients with unresectable NSCLC to receive concurrent passively scattered PBT (74-Gy relative biological effectiveness) and weekly infusions of carboplatin-paclitaxel.

The median follow-up period was 27.3 months for all patients.

The median overall survival (OS) was 26.5 months (5-year OS, 29%; 95% CI, 18%-41%); 5-year progression-free survival (PFS) was 22% (95% CI, 12%-32).

Five-year actuarial distant metastasis occurred in 54% of patients, and 5-year locoregional recurrence occurred in 28% of patients.

The most frequently observed adverse event (AE) was grade 2 to 3 acute esophagitis, occurring at 28% and 8% of patients, respectively.

Grade 2 acute pneumonitis occurred in 2% of patients, and grade 2 to 3 late grade pneumonitis occurred in 16% and 12% of patients, respectively. Late AEs were rare.

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The results of the study demonstrated that PBT leads to favorable clinical outcomes and low rates of AEs. The authors concluded that these “results have implications for ongoing issues regarding the role of dose escalation in this population, further optimization of proton therapy such as [intensity-modulated proton therapy], and cost effectiveness.”

Reference

  1. Chang JY, Verma V, Li M, et al. Proton beam radiotherapy and concurrent chemotherapy for unresectable stage III non–small-cell lung cancer: final results of a phase 2 study. JAMA Oncol. 2017 Jul 20. doi: 10.1001/jamaoncol.2017.2032 [Epub ahead of print]