Analysis of the effectiveness and safety of early radiotherapy intervention in oligometastatic non-small cell lung cancer / 中华放射医学与防护杂志

ABSTRACT

Objective:To investigate the prognostic factors of oligometastatic (OM) non-small cell lung cancer (NSCLC) patients and the safety and effectiveness of early radiotherapy intervention.Methods:A retrospective analysis was conducted, including 159 OM NSCLC cases (metastatic sites≤5, metastasis organs≤3) admitted to Department of Radiation Oncology in First Affiliated Hospital of Soochow University from January 2015 to December 2018. Among 159 cases, there were 107 males and 52 females, with the median age of 63 years. 137 cases were administrated via early radiotherapy intervention, and 22 cases via delayed radiotherapy intervention. The receiver operating characteristic curve (ROC) was used to determine the progression-free survival time (PFS)/overall survival time (OS) to ascertain the best cut-off value for local control and prognosis. Survival analysis was calculated by Kaplan-Meier curves, and Log rank test was used for comparison of these curves. Cox proportional hazards regression model was used for multivariate survival analysis.Results:The median follow-up time of 159 cases was 28.2 months. During the follow-up period, there were 16 cases with complete remission (10.1%), 53 cases with partial remission (33.3%), 27 cases with stable disease (17.0%), and 63 cases with progressed disease(39.6%). The local control rates at 3, 6 and 12 months were 83.9%, 59.7% and 41.0%, respectively. The median progression-free survival (PFS) of 159 patients was 8.0 months, the median survival time (OS) was 35.0 months, and 1, 2, and 3-year survival rates were 77.3%, 63.0% and 45.1%, respectively. Adverse reactions related to radiotherapy were relatively mild, mostly grade 1 and 2. PFS/OS= 0.3 is the best cut-off value for determining the patient′s local control and prognosis. The result of univariate analysis showed that gender, number of OM organs, T staging, radiotherapy intervention mode, tumor target volume absorbed dose (DT-GTVnx), PFS/OS were significantly related to median PFS ( χ2=4.175, 16.508, 4.408, 10.300, 6.842, 38.175, P<0.05); gender, pathological type, number of OM organs, initial diagnosis stage, T stage, N stage, lobectomy, radiotherapy intervention mode, tumor target volume (V-GTVnx), tumor load, local control status were significantly related to median OS ( χ2=6.672, 8.330, 21.299, 5.398, 6.874, 6.893, 5.611, 115.206, 4.017, 5.110, 21.299, P< 0.05). The result of multivariate analysis showed that delayed radiotherapy intervention ( HR=3.728, 95% CI 2.099-6.622, P<0.001) was an independent risk factor for PFS in patients with OM NSCLC, and PFS/OS>0.3 ( HR=0.123, 95% CI 0.062-0.246, P<0.001) was an independent protective factor for PFS in patients with OM NSCLC; male ( HR=1.665, 95% CI 1.024-3.043, P=0.033), high tumor burden ( HR=2.113, 95% CI 1.088-4.107, P=0.027), delayed radiotherapy interventions ( HR=15.076, 95% CI 7.925-28.680, P<0.001) were independent risk factors for OS in patients with OM NSCLC. Conclusions:OS of patients with OM NSCLC is significantly prolonged in female, low tumor burden and early radiotherapy intervention. Early radiotherapy intervention significantly improved the prognosis, and radiotherapy-related adverse reactions could be tolerated. These might suggest that local radiotherapy is safe and effective in the treatment of OM NSCLC patients.