DNA analysis as a predictor of the outcome of induction chemotherapy in advanced head and neck carcinomas.

We investigated whether flow cytometric DNA index and/or ploidy status are predictors of response to chemotherapy and survival. Fifty consecutive patients with previously untreated locally advanced squamous cell carcinomas of the head and neck received induction chemotherapy consisting of three courses of cisplatin (100 mg/m2) and a subsequent 120-hour infusion of fluorouracil (1000 mg/m2 per 24 hours) repeated every 3 weeks. Chemotherapy was followed by radiotherapy to a median target dose of 65 Gy and subsequent surgery for residual tumor. The median observation time was 27 months (range, 24 to 57 months). Flow cytometric DNA analysis was based on formalin-fixed and paraffin-embedded tissue from pretreatment tumor biopsy specimens. Complete response after induction chemotherapy was achieved in only 12% (2/17) of patients with diploid tumors compared with 39% (13/33) of those with nondiploid tumors. Among patients with nondiploid tumors, DNA index was higher for those responding to chemotherapy compared with the nonresponders. Complete response to chemotherapy was apparently a prerequisite for survival in the nondiploid group. Of the patients not responding to chemotherapy but responding to subsequent radiotherapy, survival was better among those with diploid tumors than among those with nondiploid tumors.