Salvage Stereotactic Body Radiotherapy for Locally Recurrent Non-Small Cell Lung Cancer after Sublobar Resection and I125 Vicryl Mesh Brachytherapy

Beant S. Gill, David A. Clump, Steven A. Burton, Neil A. Christie, Matthew J. Schuchert, Dwight E. Heron

Locally recurrent non-small cell lung cancer (LR-NSCLC) remains challenging to treat, particularly in patients having received prior radiotherapy. Heterogeneous populations and varied treatment intent in existing literature result in significant limitations in evaluating efficacy of lung re-irradiation. In order to better establish the impact of re-irradiation in patients with LR-NSCLC following high-dose radiotherapy, we report outcomes for patients treated with prior sublobar resection and brachytherapy that subsequently underwent stereotactic body radiotherapy (SBRT). A retrospective review of patients initially treated with sublobar resection and I(125) vicryl mesh brachytherapy, who later developed LR-NSCLC along the suture line, was performed. Patients received salvage SBRT with curative intent. Dose and fractionation were based on tumor location and size, with a median prescription dose of 48 Gy in 4 fractions (range 20-60 Gy in 1-4 fractions). Thirteen consecutive patients were identified with median follow-up of 2.1 years (range 0.7-5.6 years). Two in-field local failures occurred at 7.5 and 11.1 months, resulting in 2-year local control of 83.9% (95% CI, 63.5-100.0%). Two-year disease-free survival and overall survival estimates were 38.5% (95% CI, 0.0-65.0%) and 65.8% (95% CI, 38.2-93.4%). Four patients (31%) remained disease-free at last follow-up. All but one patient who experienced disease recurrence developed isolated or synchronous distant metastases. Only one patient (7.7%) developed grade ≥3 toxicity, consisting of grade 3 esophageal stricture following a centrally located recurrence previously treated with radiofrequency ablation. Despite high-local radiation doses delivered to lung parenchyma previously with I(125) brachytherapy, re-irradiation with SBRT for LR-NSCLC results in excellent local control with limited morbidity, allowing for potential disease cure in a subset of patients.