Clinical Effect of Adjuvant Cytokine-Induced Killer Cells Immunotherapy in Patients with Stage II-IVB Nasopharyngeal Carcinoma after Chemoradiotherapy: A propensity score analysis

As an adjuvant immunotherapy, cytokine-induced killer cells (CIKs) infusion has been demonstrated to exert potent effectiveness in several types of cancer patients who received curative treatment. However, controversy exists regarding whether nasopharyngeal carcinoma (NPC) patients can benefit from additional treatment after radical radiotherapy or chemoradiotherapy to improve their distant control and survival. In this retrospective study, we aimed to evaluate the efficacy of adjuvant CIK cells therapy in NPC patients with stage II-IVB after curative treatment. From January 1, 2005 to December 31, 2012, 85 pairs of NPC patients matching by propensity score matching (PSM) method to balance prognostic factors were included in this study: 85 cases underwent radical treatment, 85 cases received radical treatment and sequential CIKs infusion. We found that disease-free survival (DFS) and overall survival (OS) were significantly better in the CIK group than that in the control group (P = 0.009, P < 0.001, respectively). Adjuvant CIK cells immunotherapy was showed to be an independent prognostic factor for survival of the patients in further multivariate analysis. In subgroup analyses, the DFS and OS of patients with T3/4, III and IV A-B TNM (tumor-node-metastasis) stages were significantly enhanced in CIK group compared to control group. Nevertheless, both NPC patients with high and low EBV DNA benefited from adjuvant CIK cells immunotherapy. In conclusion, CIKs infusion is an effective adjuvant immunotherapy for enhancing the prognosis of NPC patients who have received the standard treatment, particularly for those with more aggressive tumor (T3/4) or advanced TNM stage.