Retrospective analysis of the efficacy of cytokine‐induced killer cell immunotherapy combined with first‐line chemotherapy in patients with metastatic colorectal cancer

Abstract Objectives Fluoropyrimidine‐based chemotherapy regimens are the current first‐line treatment for metastatic colorectal cancer (mCRC); however, the outcome is often unsatisfactory. The present study aimed to determine the effect of combined cytokine‐induced killer (CIK) cell immunotherapy and first‐line chemotherapy in patients with mCRC. Methods This retrospective study included 252 patients with mCRC treated with first‐line chemotherapy. Among them, 126 patients received first‐line chemotherapy only (control group), while the other 126 patients, with similar demographic and clinical characteristics, received CIK cell immunotherapy combined with first‐line chemotherapy (CIK group). Overall survival (OS) and progression‐free survival (PFS) were compared between the two groups using the Kaplan–Meier method. Results The median OS for the CIK group was 54.7 versus 24.1 months for the controls, and the median PFS for the CIK group was 25.7 versus 14.6 months for the controls. Univariate and multivariate analyses indicated that CIK cell treatment was an independent prognostic factor for patients' OS and PFS. Subgroup analyses showed that CIK cell treatment significantly improved the OS and PFS of patients with metastatic colon cancer, but not those with metastatic rectal cancer. Additionally, the change in CD3+CD56+ subsets after the fourth treatment cycle might be an indicator of successful CIK cell treatment: Patients with increased CD3+CD56+ subsets had better survival than those with decreased CD3+CD56+ subsets. Conclusion Cytokine‐induced killer cell immunotherapy combined with first‐line chemotherapy could significantly improve the OS and PFS of patients with mCRC, particularly for patients with metastatic colon cancer.