Five-Fraction Stereotactic Body Radiation Therapy for Centrally Located Lung Tumors
Posted: Wednesday, May 29, 2019
Standard treatment of patients with inoperable, node-negative non–small cell lung cancer (NSCLC) involves stereotactic body radiation therapy (SBRT). Those with centrally located tumors (within a 2-cm radius of large airways), however, tend to experience higher rates of toxicity with highly ablative doses of radiation and so often are excluded from most protocols of SBRT. According to the findings of the NRG Oncology/RTOG 0813 trial, a five-fraction SBRT schedule may represent a safe and effective alternative for this patient population.
“NRG Oncology/RTOG 0813 is an important study with implications for practice because the ability to treat patients with centrally located node-negative tumors in multiple institutions across the United States and Canada while maintaining plan qualities and achieving good patient outcomes and relatively modest rates of toxicity is an important achievement,” said Andrea Bezjak, MD, of Princess Margaret Cancer Centre, Toronto, Ontario, Canada, and her U.S. colleagues in the Journal of Clinical Oncology.
A total of 120 medically inoperable patients with biopsy-proven, positron-emission tomography–staged T1 to T2 (up to 2 cm) N0M0 centrally located NSCLC took part in the study. They were assigned to a dose-escalating, five-fraction SBRT schedule, ranging from 10 to 20 Gy/fraction delivered over 1.5 to 2.0 weeks. Most of the patients were elderly and had a performance status of 0 to 1.
At a median follow-up of 37.9 months, 5 patients experienced dose-limiting toxicities—defined as any treatment-related grade 3 or worse predefined toxicity that occurred within the first year. The maximum tolerate dose (defined as the SBRT dose at which the probability of a dose-limiting toxicity was nearest 20% without going over it) was 12.0 Gy/fraction, and the probability of a dose-limiting toxicity at this dose was 7.2%. In terms of outcomes, the 2-year rates for the 71 evaluable patients in the 11.5 and 12.0 Gy/fraction cohorts were 89.4% and 87.9% for local tumor control, 67.9% and 72.7% for overall survival, and 52.2% and 54.5% for progression-free survival, respectively.
Disclosure: The study authors’ disclosure information may be found at ascopubs.org.