title: Effect of metformin on progression of head and neck cancers, occurrence of second primary cancers, and cause-specific survival.
abstract: BACKGROUND
  This study aimed to investigate the effect of metformin on progression of head and neck cancers, occurrence of second primary cancers, and cause-specific survival.
  
  
  METHODS
  This study analyzed a retrospective cohort of 1,151 consecutive patients with head and neck squamous cell carcinoma who were treated at our hospital. Patients were divided into three groups: nondiabetic, nonmetformin, and metformin. Clinical characteristics, recurrence of index head and neck cancer, occurrence of second primary cancer, and survival were compared among the different groups.
  
  
  RESULTS
  Of 1,151 patients, 99 (8.6%) were included in the metformin group, 79 (6.8%) were in the nonmetformin group, and 973 (84.5%) were in the nondiabetic group. Diabetic status and metformin exposure had no significant impact on index head and neck cancer recurrence or second primary cancer development (p > .2). The nonmetformin group showed relatively lower overall (p = .017) and cancer-specific (p = .054) survival rates than the other groups in univariate analyses, but these results were not confirmed in multivariate analyses.
  
  
  CONCLUSIONS
  Metformin use did not show beneficial effects on index tumor progression, second primary cancer occurrence, and cause-specific survival in patients with head and neck cancer compared with nonmetformin users and nondiabetic patients.
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Minsu
authors: M
authors: Kwon
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea rohjl@amc.seoul.kr.
authors: Jong-Lyel
authors: JL
authors: Roh
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Jihyun
authors: J
authors: Song
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Sang-Wook
authors: SW
authors: Lee
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Sung-Bae
authors: SB
authors: Kim
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Seung-Ho
authors: SH
authors: Choi
authors: Departments of Otolaryngology, Clinical Epidemiology and Biostatistics, Radiation Oncology, and Internal Medicine (Oncology), Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors: Soon Yuhl
authors: SY
authors: Nam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology; D003920:Diabetes Mellitus / Q000188:drug therapy / Q000473:pathology; D005260:Female; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008687:Metformin / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000473:pathology; D016609:Neoplasms, Second Primary / Q000188:drug therapy* / Q000473:pathology; D012307:Risk Factors; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D008687:Metformin
keywords: Head and neck squamous cell carcinoma; Metformin; Recurrence; Second primary cancer; Survival