BOSTON – Delivering stereotactic body radiation for early-stage, inoperable non–small cell lung cancer doubled overall survival rates achieved in historical series with conventional radiation, investigators reported at the annual meeting of the American Society for Radiation Oncology.
The 3-year overall survival rate reached 59.9% for 100 patients whose stage IA non–small cell lung cancer (NSCLC) was treated with stereotactic body radiation therapy (SBRT), said Dr. Yasushi Nagata. He compared results of the nonrandomized phase II trial with 31%-39% in historical series with conventional radiation.
Dr. Yasushi Nagata
The 5-year overall survival rate was 40.8%, compared with 13%-22.2% historically, added Dr. Nagata from Hiroshima University, Japan.
He described SBRT as well tolerated with only mild toxicities, making it a suitable alternative to other therapies, particularly in older patients. "Patients with early inoperable lung cancer should consider this treatment," Dr. Nagata advised in a briefing.
The investigators concluded that the treatment should be the new standard, replacing conventional radiotherapy in this population.
Similar in concept to stereotactic radiosurgery with a cyberknife, SBRT is a technique for precise high-dose targeting of tissues from multiple angles and planes, allowing delivery of much larger doses by fraction than conformal 3-dimensional or intensity-modulated radiation therapy. With SBRT, radiation therapy sessions can often be compressed into as little as 4-6 fractions delivered over 2 to 2.5 weeks, compared with 8 to 9 weeks of daily fractions for other techniques.
The phase II Japanese Clinical Oncology Group trial, JCOG-0403, is said to be the first to evaluate SBRT in both operable and nonoperable NSCLC. At the 2010 ASTRO annual meeting, the investigators reported 3-year survival rates for 64 patients with surgically resectable NSCLC: overall survival was 76%; progression-free survival, 54.5%; local progression-free survival, 68.5%; and event-free survival, 51.4%.
In the current study, 77 men and 27 women with a median age of 78 years (range 59-90 years) were enrolled; four patients were later excluded from the study, three because they developed a second primary cancer within 5 years of registration, and one was "unexpectedly" treated with SBRT and chemotherapy.
The median tumor size was 21 mm (range 9-30 mm). Fifty patients had adenocarcinomas, 40 had squamous cell carcinomas, and 14 had other tumor histologies. All patients had histologically or cytologically proven NSCLC, clinical T1N0M0 disease, and were determined by thoracic surgeons to be inoperable.
All patients completed the treatment protocol, consisting of a dose of 48 Gy at the isocenter divided into 4 fractions over 4-8 days.
The progression-free survival rate at 3 years was 49.8%; the local progression-free survival rate was 52.8%, and event-free survival, 46.8%.
Grade 3 adverse events include dyspnea in 10 patients, hypoxia in 8, pneumonitis in 7, chest pain in 2 and cough in 1. There was one case each of grade 4 dyspnea and hypoxia, but no treatment-related deaths.
The study results indicate that "SBRT, a highly effective targeted approach for selected nonoperable cancers, is a modality with acceptable toxicity to consider for lung cancer patients," commented Dr. Eric Lin Chang, a professor of radiation oncology at the University of Southern California, Los Angeles. Dr. Chang was co-moderator of a briefing at which the data were presented, but was not involved in the study.
The study was supported by Japan’s Ministry of Health. Dr. Nagata and Dr. Chang disclosed no relevant conflicts of interest.