FMISO-PET predicts the pre-operative chemotherapy response in patients with oral squamous cell carcinoma

Objectives Hypoxia environment is an important prognostic factor for tumor control. Hypoxia also contributes to resistance against chemotherapy agents. The 18F-fluoromisonidazole (FMISO-) PET can detect tumor hypoxia. However, it is unclear whether FMISO-PET can predict the pre-operative chemotherapy response in patients with oral squamous cell carcinoma (OSCC). The aim of this study was to elucidate the relationship between FMISO-PET images and pre-operative chemotherapy response in OSCC.

Methods A total of 17 patients (Age: 42-83; M/F: 11/6) with OSCC who underwent pre-operative chemotherapy were enrolled in this study. The T-stage of the cancer was T2 in 5 cases, T3 in 2 cases, and T4a in 10 cases. The N-stage was N0 in 10 cases and N+ in 7 cases. Each patient underwent FMISO- and FDG-PETs before surgery. The histological response of pre-operative chemotherapy was evaluated using operative materials. Less than one third of viable cancer cells were defined as good response for chemotherapy.

Results FMISO-PET detected uptake in primary site in 12/17 patients (71%) and SUV max was 1.84±0.32 (range: 0.8-2.7). The chemotherapy agents were oral tegaful-uracil (UFT): 2 cases and oral tegafur-gimeracil-oteracil-potassium (S-1): 15 cases (median; 14 days, range 6-31 days). The histological response of chemotherapy was good response in 5 cases and poor response in 12 cases, respectively. The rate of good response was significantly higher in cases without FMISO uptake than those with uptake (P < 0.025). Univariate logistic regression analysis also revealed the significant correlation between FMISO uptake and chemotherapy response (P = 0.03, odds ratio; 0.05; 95%CI: 0.003-0.72).

Conclusions This study suggests that the FMISO-PET of OSCC may predict the response of pre-operative chemotherapy.