Chemoradiotherapy as an alternative to radiotherapy alone in fast proliferating head and neck squamous cell carcinomas

The aim of this pilot study was to explore the prognostic relevance of cell kinetics parameters on the local control of patients affected by head and neck squamous cell carcinoma (HN-SCC), randomly assigned to receive either alternating chemoradiotherapy or partly accelerated radiotherapy. Between 1992 and 1995, 40 patients with HN-SCC at stages III and IV entered the study. Multiple primary tumor biopsies were obtained 6 h after in vivo infusion of bromodeoxyuridine, an analogue of thymidine that is incorporated in DNA-synthesizing cells. In vivo S-phase fraction labeling index (LI), duration of S-phase (TS), and potential doubling time (Tpot) were obtained by analysis of the flow cytometric content of bromodeoxyuridine and DNA. Twenty patients were treated by alternating chemotherapy and conventional radiotherapy (arm A), whereas 20 other matching patients received partly accelerated radiotherapy alone (arm B). Univariate local control analysis showed that LI, TS, and Tpot were not prognostically significant in either arm. However, local control probability at 2 years for fast growing tumors, characterized by a LI of 9%, was higher for patients treated with alternating chemoradiotherapy than it was for those treated with partly accelerated radiotherapy alone (68 versus 39%). Conversely, local control probabilities for slow proliferating tumors (LI, <9%) treated in the two arms were similar. These results suggest a potential role for alternating chemotherapy and radiotherapy in HN-SCC patients with fast growing tumors.