title: Cellular immunotherapy as maintenance therapy prolongs the survival of the patients with small cell lung cancer.
abstract: BACKGROUND
  Small cell lung cancer (SCLC) relapses rapidly after the initial response to chemotherapy and shows drug-resistance. This study was to investigate the efficacy and safety of cellular immunotherapy (CIT) with autologous natural killer (NK), γδT, and cytokine-induced killer (CIK) cells as maintenance therapy for SCLC patients.
  
  
  METHODS
  A pilot prospective cohort study was conducted with SCLC patients who had responded to initial chemotherapy. Patients elected to receive either CIT as maintenance therapy (study group), or to be followed-up without further treatment (control group). Progression-free survival (PFS), overall survival (OS), and adverse effects were investigated.
  
  
  RESULTS
  We recruited 58 patients (29 in each group). The patient characteristics of the 2 groups were well balanced. PFS was not significantly different between the groups, but OS was significantly longer in the study group than the control (20 vs. 11.5 months, P = 0.005; hazard ratio [HR], 0.434, 95 % confidence interval [CI], 0.236-0.797, P = 0.007). Among patients with limited-stage disease, there was no difference in PFS between the groups, but OS was longer in the study group compared to the control (26.5 vs. 11.8 months, P = 0.033; HR, 0.405, 95 % CI, 0.169-0.972, P = 0.043). Among patients with extensive-stage disease, both PFS and OS were longer in the study group than the control (5 vs. 2.7 months, P = 0.037; HR, 0.403, 95 % CI, 0.162-1.003, P = 0.051, and 14.5 vs. 9 months, P = 0.038; HR, 0.403, 95 % CI, 0.165-0.987, P = 0.047, respectively). No significant adverse reactions occurred in patients undergoing CIT.
  
  
  CONCLUSIONS
  CIT maintenance therapy in SCLC prolonged survival with only minimal side effects. Integrating CIT into current treatment may be a novel strategy for SCLC therapy, although further multi-center randomized studies are needed.
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. dingxiao70070135@sina.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Ding
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. caohe2014@sina.com.
authors.forename: He
authors.initials: H
authors.lastname: Cao
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. chenxiaojdyy2014@sina.com.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. jinhaofan2014@sina.com.
authors.forename: Haofan
authors.initials: H
authors.lastname: Jin
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. liuziling2014@sina.com.
authors.forename: Ziling
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. wangguanjun2014@sina.com.
authors.forename: Guanjun
authors.initials: G
authors.lastname: Wang
authors.affiliation: Kosair Children's Hospital Research Institute, Department of Pediatrics, the University of Louisville, Louisville, KY, 40202, USA. cailu2014@sina.com.
authors.forename: Lu
authors.initials: L
authors.lastname: Cai
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. lidanjdyy2014@sina.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. niuchao2014@sina.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Niu
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. tianhuimin2014@sina.com.
authors.forename: Huimin
authors.initials: H
authors.lastname: Tian
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. yangleijdyy2014@sina.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. zhaoyuguang2014@sina.com.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. drweili@yahoo.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Cancer Center, the First Hospital of Jilin University, No. 71. Xinmin Street, Changchun, 130021, China. cuijiuwei@yahoo.com.
authors.forename: Jiuwei
authors.initials: J
authors.lastname: Cui
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055612:Cytokine-Induced Killer Cells / Q000166:cytology; D016207:Cytokines / Q000378:metabolism; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D007694:Killer Cells, Natural / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D010641:Phenotype; D010865:Pilot Projects; D011446:Prospective Studies; D055752:Small Cell Lung Carcinoma / Q000378:metabolism / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D016207:Cytokines