title: Combination radiofrequency ablation and local injection of the immunostimulant bacillus Calmette-Guérin induces antitumor immunity in the lung and at a distant VX2 tumor in a rabbit model.
abstract: OBJECTIVE
  To evaluate whether the combination of radiofrequency (RF) ablation and local injection of the immunostimulant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces systemic antitumor immunity.
  
  
  METHODS
  Japanese White rabbits with lung and auricle VX2 tumors were randomized into three groups: control (n = 8; no treatment), RF ablation only (n = 8; RF ablation to the lung tumor), and RF ablation with local BCG injection into the lung tumor (n = 8). Treatments were performed 1 week after tumor implantation. Survival was evaluated with Kaplan-Meier method and log-rank test. Weekly mean volume and specific growth rate (SGR) of auricle tumors were calculated, and comparisons were made by Mann-Whitney test.
  
  
  RESULTS
  Median survival of control, RF-only, and RF/BCG groups were 23, 41.5, and 103.5 days, respectively. Survival was significantly prolonged in the RF-only and RF/BCG groups compared with the control group (P = .034 and P =.003, respectively), but no significant difference was found between the RF-only and RF/BCG groups (P = .279). Only in the RF/BCG group was mean auricle tumor volume decreased 5 weeks after implantation. No significant difference in SGR was found between the control and RF-only groups (P = .959), but SGR in the RF/BCG group was significantly lower than in the control group (P = .005).
  
  
  CONCLUSIONS
  The combination of RF ablation and local injection of BCG resulted in distant tumor suppression compared with the control group, whereas RF ablation alone did not produce this effect. Therefore, the combination of RF ablation and local injection of BCG may induce systemic antitumor immunity.
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hamamoto
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okuma
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.. Electronic address: loveakirayamamoto@gmail.com.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kageyama
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Ueki
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsuoka
authors.affiliation: Department of Radiology, Osaka City University, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Miki
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage; D001500:BCG Vaccine / Q000008:administration & dosage*; D017115:Catheter Ablation / Q000379:methods*; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy / Q000379:methods; D004428:Ear Neoplasms / Q000175:diagnosis / Q000276:immunology* / Q000628:therapy*; D005260:Female; D007114:Immunization / Q000379:methods; D015552:Injections, Intralesional; D008175:Lung Neoplasms / Q000276:immunology* / Q000628:therapy*; D011817:Rabbits; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D000276:Adjuvants, Immunologic; D000970:Antineoplastic Agents; D001500:BCG Vaccine