Use of simultaneous radiation boost achieves high control rates in patients with non-small-cell lung cancer who are not candidates for surgery or conventional chemoradiation

Background Intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) has improved the local disease control at a variety of anatomic sites. However, little is known about its use in lung cancer, especially in the context of shorter treatment schedules (hypofractionation). We analyzed the feasibility, toxicity, and patterns of failure of this approach for patients with non-small-cell lung cancer (NSCLC) who were not candidates for surgery or standard concurrent chemoradiation therapy. Patients and Methods We retrospectively identified 71 patients with NSCLC who received IMRT+SIB in 15 fractions to 52.5 Gy from January 2007 to February 2013. Toxicity and local control were evaluated for all patients. Results Of the 71 patients, 11 (16%) had stage I to II NSCLC, 15 (21%) stage III, and 45 (63%) stage IV. The esophagitis rate was grade 0 to 1 in 55%, grade 2 in 39%, and grade 3 in 6%. One patient developed a bronchoesophageal fistula 6 months after radiation. The pneumonitis rate was grade 0 to 1 in 93%, grade 2 in 6%, and grade 3 in 1%. At the time of analysis, 17 (24%) patients had local failure at a median of 5.2 months (range, < 1-16.1) after treatment. All but 1 failure occurred within the higher dose region. Conclusion Hypofractionated IMRT+SIB is a viable option for some patients with NSCLC, with little high-grade toxicity overall. Nearly all local failures occurred within the higher dose region, implying strong radioresistance or some other mechanism for recurrence in a subgroup of patients.