Hypofractionated Conformal Radiotherapy (HCRT) for primary and metastatic lung cancers with small dimension : efficacy and toxicity.

Purpose: To report on the clinical outcome of hypofractionated conformal radiotherapy (HCRT) for medically inoperable stage I non-small cell lung carcinoma (NSCLC) or limited pulmonary metastases ≤ 5 cm in diameter. Patients and Methods: From June 2003 to March 2007, 40 patients (42 lesions) underwent HCRT consisting of 40 Gy in five fractions over 2.5 weeks received by at least 95% of planning target volume. All patients underwent CT simulation and treatment under free shallow breathing. To evaluate target displacement under respiratory activity, two additional CT scans were performed with breath-holding during the expiratory and inspiratory phases. Of all patients enrolled, those with a follow-up ≥ 4 months were considered suitable for analysis. Local response was evaluated with CT imaging 4 months after the end of HCRT and every 3 months thereafter. Local relapse-free survival (LRFS) and overall survival (OS) were calculated with the Kaplan-Meier method. Results: Local response to the treatment was complete response, partial response, no change, and progressive disease as seen in 29%, 43%, 14%, and 7% of tumors, respectively. LRFS at 1 year and 3 years was 76% and 63%, respectively. Lung toxicities ≥ grade 2 were observed in 4/40 patients, but no grade 4. Pericardial effusion occurred in one patient. In stage I NSCLC patients (n = 15) with a median follow-up of 25 months, the 1-year LRFS and OS rates were 88% and 81%, respectively, and the 3-year rates 72% and 61%, respectively. Conclusion: HCRT is an effective and low-toxic treatment for medically inoperable early-stage lung cancers and pulmonary metastases for all clinicians lacking the aid of a dedicated stereotactic system.