title: Advantage of FMISO-PET over FDG-PET for predicting histological response to preoperative chemotherapy in patients with oral squamous cell carcinoma.
abstract: OBJECTIVE
  Hypoxia, a prognostic factor in many types of cancer, can be detected by (18)F-fluoromisonidazole (FMISO) positron emission tomography (PET). It is unclear whether hypoxia reflects the response to chemotherapy in patients with oral squamous cell carcinoma (OSCC). The correlations of FMISO-PET and FDG-PET with histological response to preoperative chemotherapy were therefore assessed in patients with OSCC.
  
  
  METHODS
  This study enrolled 22 patients with OSCC undergoing preoperative chemotherapy. The T-stages were T2 in 6 patients, T3 in 3, and T4a in 13, and the N-stages were N0 in 14 patients, N1 in 3, and N2 in 5. Each patient was evaluated by both FMISO-PET and FDG-PET before surgery, and the maximum standardized uptake value (SUVmax) of FDG- and FMISO-PET and tumor-muscle ratio (TMR) of FMISO-PET were measured. The threshold for the hypoxic volume based on TMR was set at 1.25. The histological response to preoperative chemotherapy was evaluated using operative materials.
  
  
  RESULTS
  FMISO-PET and FDG-PET detected uptake by primary OSCCs in 15 (68%) and 21 (95%) patients, respectively, and median SUVmaxs of FMISO- and FDG-PET in the primary site were 2.0 (range, 1.3-3.5) and 16.0 (range, 1.0-32.2), respectively. The median of FMISO TMR was 1.5 (range, 0.99-2.96). There were five cases whose FMISO TMR was less than 1.25. Histological evaluation showed good response to preoperative chemotherapy in 7 patients (32%) and poor response in 15 (68%). Good response was significantly more prevalent in patients with negative than positive FMISO uptake (P < 0.001) and without the hypoxic area evaluated by FMISO-PET TMR (P = 0.04), whereas FDG uptake was not significantly correlated with response to chemotherapy response. Multivariate logistic regression analysis showed that FMISO uptake was an independent significant predictor of response to preoperative chemotherapy (P = 0.03, odds ratio = 0.06, 95% confidence interval = 0.004-0.759).
  
  
  CONCLUSIONS
  An advantage of FMISO-PET over FDG-PET for predicting histological response to preoperative chemotherapy in patients with OSCC was observed.
authors.affiliation: Oral Diagnosis and Medicine, Department of Oral Pathobiological Science, Graduate School of Dental Medicine, Hokkaido University, North 13, West 7, Kita-ku, Sapporo, 060-8586, Hokkaido, Japan, jun-s@den.hokudai.ac.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Hironobu
authors.initials: H
authors.lastname: Hata
authors.forename: Takuya
authors.initials: T
authors.lastname: Asaka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyakoshi
authors.forename: Shozo
authors.initials: S
authors.lastname: Okamoto
authors.forename: Tohru
authors.initials: T
authors.lastname: Shiga
authors.forename: Masanobu
authors.initials: M
authors.lastname: Shindoh
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kuge
authors.forename: Nagara
authors.initials: N
authors.lastname: Tamaki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008920:Misonidazole / Q000031:analogs & derivatives* / Q000378:metabolism; D009062:Mouth Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D049268:Positron-Emission Tomography; D057234:Preoperative Period; D016896:Treatment Outcome
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C031843:fluoromisonidazole; D019788:Fluorodeoxyglucose F18; D008920:Misonidazole