Hypofractionated RT Halves Tx Time for Infirm NSCLC Patients

Kate O'Rourke

September 27, 2016

BOSTON ― In patients with stage II/III non–small cell lung cancer (NSCLC) who are unable to receive surgery or chemoradiation, accelerated hypofractionated radiation can achieve outcomes similar to those achieved using conventional radiotherapy, with reduced toxicities, according to an interim analysis of a phase 3 trial.

Moreover, the use of hypofractionated radiation cut the treatment time from 6 weeks to 3 weeks.

"I hope that the completion of this study will potentially change the paradigm of how we treat these patients who cannot receive the standard-of-care treatment," said Puneth Iyengar, MD, PhD, lead author of the study and an assistant professor of radiation oncology at the University of Texas Southwestern Medical Center in Dallas.

He spoke here during a press briefing at the American Society for Radiation Oncology (ASTRO) 2016 Annual Meeting.

The current standard for stage III NSCLC is concurrent chemotherapy and radiation. For stage II patients, the standard of care is surgery.

Patients with stage II or III NSCLC who cannot receive standard-of-care surgery or chemotherapy plus radiation because of coexisting medical comorbidities or poor performance status have poor outcomes with conventional fractionated radiation alone.

Previously, Dr Iyengar and colleagues conducted a phase 1 dose escalation study that gave an indication of what a shorter radiation treatment schedule might accomplish.

In that trial, the investigators demonstrated that there was no increased toxicity from treating poorly performing patients with NSCLC with hypofractionated radiation in doses reaching 60 Gy in 15 fractions (J Radiat Oncol Biol Phys. 2015;93:72-81).

In the new phase 3 trial, investigators randomly allocated 226 patients with poor-performance stage II/III NSCLC who could not receive standard care because of comorbidities or performance status to receive image-guided conventional radiotherapy (60 Gy in 30 fractions) or accelerated hypofractionated radiation (60 Gy in 15 fractions). Fifteen institutions across the state of Texas participated in the study. Chemotherapy was permissible sequentially, either as induction or in the adjuvant setting.

In an interim analysis of 60 patients, 88% presented with stage III NSCLC, and 12% presented with stage II disease. The median age was 68 years. Roughly 53% of patients had squamous cell carcinoma, and 47% had adenocarcinoma.

For inclusion in the survival analysis, patients had to have received 24 months of follow-up; 48 patients were included in that analysis, and of those, 56% were alive at the last follow-up. The median overall survival (OS) was 14 months, and median progression-free survival (PFS) was 11.5 months. Treatment approach had no significant impact on OS or PFS.

Patients who received hypofractionated radiation experienced fewer grade 3 toxicities (10 vs 6), and the rate of death from hypoxia was lower for those patients (2 vs 1) compared with patients who received the conventional schedule. No grade 4 toxicities were attributed to radiation in either arm. No increased toxicity was seen with the more aggressive radiation treatment.

"A curative approach with accelerated, hypofractionated radiation alone offers similar OS and PFS to conventional radiation in a population of patients that cannot receive the standard of care," said Dr Iyengar. "There is limited grade 3-5 toxicity, and, as important or more importantly, the treatment time was cut in half."

George Rodrigues, MD, PhD, a radiation oncologist at London Health Sciences Center, in Ontario, Canada, who moderated the press conference and was not involved with the study, said that if the trial continues to deliver similar results, hypofractionated radiation would be a good option for patients who are not candidates for standard therapy because of comorbidities or performance status. He also noted that it would be a good option for "the population of patients that just do not want chemotherapy" or for whom travel time is an issue.

Dr Iyengar and Dr Rodrigues have disclosed no relevant financial relationships.

American Society for Radiation Oncology (ASTRO) 2016 Annual Meeting. Abstract 3110. Presented September 26, 2016.

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