The Response, Outcome and Toxicity of Aggressive Palliative Thoracic Radiotherapy for Metastatic Non-Small Cell Lung Cancer Patients with Controlled Extrathoracic Diseases

Abstract

Background and purpose: For metastatic non-small cell lung cancer (NSCLC) patients with controlled extrathoracic disease after systemic treatment, stable or progressive primary lung lesions may cause respiratory symptoms and increase comorbidities. In the present study, we sought to investigate whether aggressive palliative thoracic radiotherapy (RT) can enhance local control and improve the survival for this subgroup of patients.

Materials and methods: Between March 2006 and December 2014, 56 patients with metastatic NSCLC who had responsive or stable extrathoracic diseases after chemotherapy and/or molecular targets, and received thoracic RT for stable and progressive primary lung lesions were included. RT with a median dose of 55 Gy (range, 40-62 Gy) was administered in 1.8-2.5 Gy fractions to primary lung tumor and regional mediastinal lymph nodes using modern RT technique. Overall survival (OS) from diagnosis, and locoregional progression-free survival (LRPFS), and survival calculated from radiotherapy (OS-RT) were estimated using the Kaplan-Meier method.

Results: There were 37 men and 19 women with a median age of 60 years at diagnosis. The median interval from the diagnosis of metastatic disease to thoracic RT was 8 months. Following thoracic RT, 26 patients (46%) achieved complete or partial response (overall response rate, ORR). Patients with squamous cell carcinoma or poorly-differentiated carcinoma had a higher ORR than those with adenocarcinoma (63% vs. 34%, P = 0.034). EGFR mutations was closely associated with a better ORR (45% vs. 29%, P = 0.284). At a median follow-up time of 44 months, the median OS, LRPFS after RT, and OS-RT were 50 months, 15 months, and 18 months.

Conclusion: Radical palliative throractic RT is safe and might be beneficial for primary lung lesions of metastatic NSCLC patients with controlled extrathoracic diseases.

Fig 1. Schema of 56 NSCLC patients received aggressive palliative thoracic RT with and without systemic treatment.

Numbers and proportions of patients with or without altered systemic therapy regimens after thoracic RT depending on the treatment response and clinical adjustment. RT, radiotherapy; N, number.

Fig 2. One patient presented with complete remission of thoracic tumor after radiotherapy.

This 66-year-old man had initial lung to lung metastasis, and the disease was controlled by chemotherapy with docetaxel and cisplatin. However, tumors at left upper lobe and mediastinum progressed 5 months after diagnosis. Mediastinal lesions improved after chemotherapy with gemcitabine and vinorelbine, but left upper lung tumor remained stationary. Thoracic radiotherapy (RT) with 55 Gy in 25 fractions was applied to left lung tumor and 45 Gy in 25 fractions to mediastinal lymphatics using IMRT. Complete remission of thoracic lesions was achieved five months after completing RT. Only grade 1 radiation pneumonitis was noted. He remained disease-free 17 months after RT without systemic chemotherapy. (A) Chest CT scan before thoracic RT. (B) Chest CT scan two months after thoracic RT. (C) Chest CT scan five months after thoracic RT.

Fig 3. Survival rates of 56 patients receiving aggressive palliative thoracic RT.

(A) Overall survival (OS) of all patients (B) Overall survival rate calculated from radiotherapy (OS-RT).