M. Schneider

PURPOSE: To determine the expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinoma and to evaluate its prognostic value. MATERIALS AND METHODS: EGFR was determined in tumor biopsies obtained from 109 consecutive patients with head and neck cancer (100 men, nine women). Control biopsies were obtained from 94 patients in a symetric nontumoral area of the same anatomic site. EGFR was measured by a binding assay using human recombinant iodine 125-EGF. RESULTS: The presence of detectable EGFR levels was found in all explored tumors with highly marked differences between patients (median, 71 fmol/mg protein; range, 2 to 2,302). In 93 of 94 cases, EGFR levels were higher in tumor samples as compared with healthy control zones. There was no significant difference in EGFR expression according to the various anatomic sites explored or tumoral differentiation status. There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors. The tumor EGFR levels were not linked to the response to first-line chemotherapy by cisplatin (CDDP) and fluorouracil (5FU). Survival was assessable for 103 patients for overall survival and for 81 patients for recurrence. EGFR overexpression was associated with shorter relapse-free (P = .0125) and overall survival (P = .028) rates. By multivariate analysis, the only significant variable was EGFR for relapse-free survival and tumor staging for overall survival. The association of EGFR to tumor staging markedly improves the significance for overall survival predictability (P = .002). CONCLUSION: EGFR determination deserves particular attention in head and neck cancer, since it independently carries a strong prognostic value.

PURPOSE: The aim of the present study was to analyze the role of thymidylate synthase (TS; main cellular target of fluorouracil [FU]) and dihydropyrimidine dehydrogenase (DPD; rate-limiting enzyme of FU catabolism) in tumoral biopsies with respect to FU responsiveness. PATIENTS AND METHODS: This prospective study was conducted on 62 head and neck cancer patients (six stage II, 16 stage III, and 40 stage IV). All received first-line chemotherapy with biomodulated FU (5-day continuous infusion). Before treatment, a tumor biopsy and control biopsy (symmetrical nontumoral area) were obtained. Cytosolic TS and DPD activities were measured using radioenzymatic assays. RESULTS: DPD activity was detectable in all samples, without a significant difference between tumoral (median, 60 pmol/min/mg protein; range, 13 to 193) and nontumoral samples (median, 68 pmol/min/mg protein; range, 12 to 150). Tumoral TS and tumoral DPD were not significantly influenced by tumor localization or tumor staging. Among 52 tumors assessable for clinical response, we observed 46% complete responses (CRs), 33% partial responses (PRs), and 21% no responses (NRs). No relationship was demonstrated between TS activity and response to FU therapy. The comparison of tumoral DPD between complete responders and partial or nonresponders showed a trend toward significance (P = .06). In an attempt to reduce variability, we analyzed the tumoral/nontumoral DPD activity ratio; complete responders exhibited a significantly lower normalized DPD than partial or nonresponding patients (median, 0.86, 1.18, and 1.42 for CR, PR, and NR, respectively; CR v PR plus NR, P = .03). CONCLUSION: Although resistance to FU is multifactorial, the present clinical study suggests that FU catabolism in target cells is probably a determinant factor for FU responsiveness in cancer patients and justifies the clinical use of specific DPD inhibitors as FU biomodulators.