Hypofractionated Low-Dose Radiotherapy Combined with Immune Checkpoint Inhibition in Metastatic Solid Tumors

Dongqing Li; Wenyu Zhu; Juying Zhou; Mingya Peng; Qian Geng; Xiaolin Pu; Mengjie Wang; Hua Jiang

doi:10.2147/OTT.S289937

Hypofractionated Low-Dose Radiotherapy Combined with Immune Checkpoint Inhibition in Metastatic Solid Tumors

Onco Targets Ther. 2021 Feb 4:14:773-783. doi: 10.2147/OTT.S289937. eCollection 2021.

Authors

Dongqing Li^#¹, Wenyu Zhu^#², Juying Zhou¹, Mingya Peng², Qian Geng², Xiaolin Pu², Mengjie Wang², Hua Jiang^#²

Affiliations

¹ Radiotherapy Department, The First Affiliated Hospital of Soochow University, Suzhou, 215006, People's Republic of China.
² Cancer Center, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, 213001, People's Republic of China.

^# Contributed equally.

Abstract

Background: The combination of radiotherapy and immunotherapy can bring benefits to patients, especially advanced patients. However, conventional radiotherapy brings about great adverse reactions. How about the hypofractionated low-dose radiotherapy?

Materials and methods: In this retrospective cohort study, we included 32 patients with metastatic solid tumors treated with hypofractionated radiotherapy combined with an immune checkpoint inhibitor. Patients underwent radiotherapy of 4Gy/Fx on day 1, 3, and 5, and received single-drug immunotherapy of PD-1 inhibitor on day 2. We evaluated the following outcomes: objective response rate (ORR), disease control rate (DCR), change of nonirradiated and irradiated lesions, quality of life, and symptom improvement.

Results: Among the 32 patients, the ORR was 9.4% (3/32) and the DCR was 56.25% (18/32). Hypofractionated radiotherapy combined with immunotherapy showed a remarkable efficacy of local control on metastatic tumor patients. Local masses irradiated in two patients (6.25%) were complete remission, partial response rate was 37.5% (12 patients), and 56.25% was stability (18 patients). Out of those 18 patients, 15 patients had the local masses shrank more or less. The ORR of local control reached 43.75%, and its DCR was 100%. In addition, the intratumor necrosis rate was 44.4% in the SD patients. Median progression-free survival was 3.8 months (95%Cl: 2.2-5.4). By treating the local mass, the symptoms of most patients were alleviated, and the quality of life was improved.

Conclusion: Our retrospective analysis revealed that hypofractionated radiotherapy combined with immunotherapy was effective in local control, it also relieved clinical symptoms and improved quality of life. The adverse effect rate was low. However, the incidence of abscopal effects was low either. This mode was suitable for the palliative treatment and expected to improve survival for patients with metastatic tumors.

Keywords: hypofractionated radiotherapy; immune checkpoint inhibitors; low-dose radiotherapy; metastatic tumors.

Grants and funding

This study was supported by the Research Fund from the Research Fund from Changzhou Health, and Jiangsu Health and Family Planning Commission (Grant No. Z201615) and Family Planning Commission (Grant No. ZD201711), the Young Scientists Foundation of Changzhou No.2 People’s Hospital (Grant No. 2018K004).