Assessment of tumor hypoxia by super(62)Cu-ATSM PET/CT as a predictor of response in head and neck cancer: a pilot study

Objective: In radiotherapy and chemotherapy tumor hypoxia is recognized as a major obstacle to effective treatment. We undertook a pilot study in patients with locally advanced head and neck cancer to determine whether there is a relationship between tumor uptake of super(62)Cu-ATSM and response to chemoradiotherapy. Methods: Seventeen patients were studied using PET/CT with super(62)Cu-ATSM and super(18)F-FDG prior to the initiation of radiotherapy and chemotherapy. All patients had locally advanced head and neck cancer (stage III or IV). Tumor uptake in all patients was measured by region of interest analysis using the maximal standardized uptake value (SUVmax). A total dose of 50.4-70.2Gy (median 70.2Gy) was delivered in 29-39 fractions (median 39 fractions) to tumor. In patients with (non CR) and without (CR) residual/recurrent tumors at 2-year post irradiation, the statistical significance of the differences in tumor super(62)Cu-ATSM SUVmax, T/M ratio, super(18)F-FDG SUVmax and tumor volume were analyzed using Student's t test and Welch test. The relationship between clinical outcome and super(62)Cu-ATSM/ super(18)F -FDG uptake patterns was analyzed using Kruskal-Wallis test. The correlation between SUVmax of super(62)Cu-ATSM and super(18)F-FDG was compared by Spearman's rank correlation test. Results: Two of the 17 patients that were enrolled in our study were excluded from the final analysis. Of the 15 remaining patients, 9 patients were free of disease and 6 patients had residual/recurrent tumors. The SUVmax differed significantly (p5.00 had residual/recurrent tumor, whereas all of the 5 patients with tumors SUVmax