Trial success with a stereotactic body radiation therapy (SBRT) regimen for centrally located non–small cell lung cancer (NSCLC) can be largely replicated in real-world practice, suggests a prospective cohort study published in Clinical Oncology.
The Radiation Therapy Oncology Group (RTOG) 0813 trial established the safety and efficacy of 50 Gy or 60 Gy given in five fractions to patients with early-stage central NSCLC (J Clin Oncol. 2019;37:1316-25). But whether similar outcomes can be achieved in routine care and how the degree of tumor centrality affects outcomes remain unclear.
Investigators led by Robert Rulach, MBChB, from the Beatson West of Scotland Cancer Centre, Glasgow, analyzed outcomes for 50 patients treated with the regimen of 50-Gy in five fractions at their institution for T1-2N0M0 stage NSCLC. All had tumors that were moderately central (within 2 cm of the trachea, bronchi, or proximal bronchial tree or having a planning target volume that abutted mediastinal pleura or pericardium); one had an additional tumor that was ultracentral (having a planning target volume that abutted the trachea).
The patients had a median age of 75.1 years. Notably, the majority were medically unfit for surgery (84%) and had an Eastern Cooperative Oncology Group performance status score of 2 or worse (56%). In 60% of patients, the diagnosis was made radiographically using PET/CT imaging; in the rest, the diagnosis was biopsy proven.
Study results showed that all patients completed the radiotherapy regimen of 50 Gy in 5 fractions on alternate days as planned, without treatment delays.
Two patients (4%) died within 90 days of treatment (1 from a chest infection, 1 from an unknown cause). A single patient each experienced early grade 3 esophagitis and grade 3 late dyspnea, for an overall rate of grade 3 toxicity of 4%. None of the patients experienced grade 4 toxicity. The 90-day rate of hospital admission was 20%.
With a median follow-up of 25.2 months, 34 patients died: 18 from causes unrelated to cancer and 16 from cancer recurrence. The cohort had a median overall survival of 27.0 months and a median cancer-specific survival of 39.8 months. The 2-year overall survival rate was 67.6%.
“For patients with early stage moderately central NSCLC, SABR [stereotactic ablative body radiotherapy] using a schedule of 50 Gy/five fractions has acceptable toxicity and overall survival comparable with the published literature, despite treating a majority of patients with a performance status of 2 or worse,” the investigators concluded.
Dr. Rulach disclosed no conflicts of interest. The study did not receive any specific funding.
SOURCE: Rulach R et al. Clin Oncol. 2019 Oct 10. doi: 10.1016/j.clon.2019.09.055.