(P108) Stereotactic Body Radiation Therapy for the Treatment of Large (> 5 cm) Primary Non–Small-Cell Carcinoma

Michael C. Roach, MD, Sana Rehman, MD, Dan Mullen, DDS, Jeff D. Bradley, MD, Cliff G. Robinson, MD; Washington University

PURPOSE: Patients with inoperable large primary non–small-cell lung carcinoma (NSCLC) present a therapeutic challenge, given the concern for radiation delivered to a large volume of the lung. As such, these patients have so far been excluded from most prospective trials of stereotactic body radiation therapy (SBRT). We evaluated the outcomes of SBRT in the treatment of large primary NSCLC at our institution.

MATERIALS AND METHODS: A total of 25 patients with biopsy-proven large NSCLC treated with SBRT alone with definitive intent were identified from an institutional review board (IRB)-approved prospective thoracic SBRT registry. Tumors were defined as large if they were greater than 5 cm in diameter on computed tomography (CT) (American Joint Committee on Cancer [AJCC] T2b or T3). All had positron emission tomography (PET) scans without evidence of nodal metastasis. Patients were treated to 45–60 Gy in three or five fractions. Patients were reviewed for overall survival (OS), local control (LC), progression-free survival (PFS), and toxicity, with survival and control calculated from completion of therapy using the Kaplan-Meier method. Toxicity was graded according to Common Terminology Criteria for Adverse Events version 4.03 (CTCAE v4.03).

RESULTS: Mean follow-up was 21 months (range: 2–83 mo). Median tumor size was 5.5 cm; 23 patients had T2b, and 2 had T3 tumors. Actuarial 2-year OS was 39%, and median survival was 20.1 months. The 2-year PFS was 68%. One patient failed in the mediastinum, two failed locally and in the mediastinum, one failed distantly, and one failed both locally and distantly. Both distant failures occurred in the two patients with T3 tumors. Two patients developed second primaries in different lobes. At 2 years, the actuarial rates of local failure and of distant failure were both 9%. Treatment was well tolerated, with 24% developing any chest wall toxicity (12% grade 1, 8% grade 2, and 4% grade 3). A single patient (4%) developed a rib fracture, and another developed a chest wall ulcer. A single patient (4%) required steroids for pneumonitis.

CONCLUSIONS: The use of SBRT for T2bN0 primary NSCLC is a safe, effective, and well-tolerated treatment.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org