Risk of Pneumonitis After Stereotactic Body Radiation Therapy in Patients With Previous Anatomic Lung Resection

Abstract

Background: Stereotactic body radiation therapy (SBRT) has emerged as a standard treatment of early-stage, medically inoperable lung cancer. Limited data have evaluated the radiation pneumonitis (RP) risk with SBRT after previous anatomic lung resection (ALR). We assessed the incidence of RP and all pulmonary toxicity (PT) in patients who underwent lung SBRT after ALR and compared them with those of patients without previous ALR.

Materials and methods: We reviewed the medical records of 84 consecutively treated patients with stage T1-T2b non-small-cell lung cancer (NSCLC) treated with 88 courses of SBRT for 94 lung tumors from January 2007 to December 2014, including 17 patients with previous ALR. The rates of RP and all PT were compared between the patients with and without previous ALR.

Results: At a median follow-up duration of 18.3 months (range, 1.8-85.6 months), the crude grade 2+ RP rate was 5.9% and 2.8% for patients with and without previous ALR, respectively (P = .51). The corresponding 2-year estimates of freedom from RP were 89% and 97% (P = .51). The crude rate of all grade 2+ PT was 11.8% and 2.8% for those with and without previous ALR (P = .11), with 2-year estimates of freedom from PT of 97% and 84% (P = .11), respectively. The 2 cohorts were well matched by the mean lung dose, percentage of lung volume receiving 20 Gy (P = .86), and prescribed dose (P = .75). The 2-year estimates of local control, cause-specific survival, and overall survival were similar between the 2 cohorts.

Conclusion: The observed rates of PT were low among all patients, with a trend toward increased grade 2 and 3 lung toxicity among patients with previous ALR. Previous ALR did not increase the risk of grade 4 and 5 RP, and SBRT appears safe and effective in this population.

Keywords: Lung resection; Non–small-cell lung cancer; Radiation pneumonitis; SBRT; Toxicity.