Consolidative high-dose thoracic radiotherapy for limited metastatic nonsmall cell lung cancer: Focusing on oligo-progressive disease.

AIM: Prior clinical data have shown a significant survival benefit of consolidative local radiotherapy for patients with limited metastatic non-small cell lung cancer (NSCLC). Therefore, this study aimed to evaluate the impact of consolidative high-dose thoracic radiotherapy on local control rates and survivals in patients with limited metastatic NSCLC, especially focusing on oligo-progressive disease. METHODS: We retrospectively reviewed the medical records of 45 patients with limited metastatic NSCLC who received consolidative high-dose thoracic radiotherapy at the Korea University Guro Hospital between March 2015 and December 2020. In the current study, we included patients who showed partial response, stable disease, or oligo-progressive disease on tumor response evaluation after systemic treatment. All patients underwent stereotactic body radiation therapy (23 patients) or intensity-modulated radiation therapy (IMRT, 22 patients). RESULTS: The median follow-up time was 42 months (range: 5-88 months). The overall 2-year disease-free survival (DFS) and overall survival (OS) rates were 80.7% and 88.4%, respectively. Among the 45 patients, only two patients treated with IMRT showed in-field local recurrence. There was no local failure among the patients who showed oligo-progressive disease after systemic treatment. In addition, the response to systemic treatment was not a significant factor for either DFS or OS rates (p = .471 and p = .414, respectively) in univariate analysis. CONCLUSIONS: Consolidative high-dose thoracic radiotherapy improves local control rates and helps achieve long-term survival in patients with limited metastatic NSCLC. It is also effective and should be considered in patients with oligo-progressive disease after systemic treatment.