Non-Small Cell Lung Cancer with Malignant Pleural Effusion May Require Primary Tumor Radiotherapy in Addition to Drug Treatment.

Purpose: The impact of primary tumour radiotherapy on the prognosis for non-small-cell lung cancer (NSCLC) with controlled malignant pleural effusion (MPE-C) (MPE-C-NSCLC) is unclear. This study aimed to analyze the efficacy and safety of primary tumor radiotherapy in patients with MPE-C-NSCLC.

Patients And Methods: A total of 186 patients with MPE-C-NSCLC were enrolled and divided into two groups. The patients in the D group were treated with only drugs. Those in the RD group were treated with drugs plus primary tumour radiotherapy. The Kaplan-Meier method was used for survival analysis, and the Log rank test was used for between-group analysis and univariate prognostic analysis. The Cox proportional hazards model was used to perform multivariate analyses to assess the impacts of factors on survival. Propensity score matching (PSM) was matched based on clinical characteristics, systematic drug treatment and drug response to further adjust for confounding factors.

Results: The overall survival (OS) rates at 1, 2, and 3 years for the RD group and D group were 54.4%, 26.8%, and 13.3% and 31.1%, 11.5%, and 4.4%, respectively; the corresponding MSTs were 14 months and 8 months, respectively ( =15.915, p<0.001). There was a significant difference in survival by PSM (p=0.027).Before PSM, multivariate analysis showed that metastasis status (organ≤3 and metastasis≤5), primary tumour radiotherapy, chemotherapy cycles≥4, and drug best response (CR+PR) were independent predictors of prolonged OS. After PSM, primary tumour radiotherapy and drug best response (CR+PR) were independent predictors of prolonged OS were still independent predictors of prolonged OS. There were no grade 4-5 radiation toxicities.

Conclusion: For MPE-C-NSCLC, the response of systemic drug treatment plays a crucial role in survival outcomes, and we also should pay attention to primary tumour radiotherapy in addition to systematic drug treatment.