[A comparative study of concurrent chemoradiotherapy with S-1 or CDDP for pharyngeal or laryngeal cancer]

Adverse events and therapeutic effects were analyzed in patients with pharyngeal or advanced laryngeal squamous cell carcinomas(SCCs)receiving concurrent chemoradiotherapy (CCRT) with S-1 or weekly CDDP between 2004 and 2007. Low-dose CDDP (25 mg/m2) was administered once a week and S-1 (65 mg/m2) was administered for 3 weeks with one-week rest during conventional radiation with 2 Gy/fraction. Both of the two CCRT regimens showed little toxicity with grade 4 toxicities in less than 5%of the patients. However, CCRT with S-1 more frequently induced grade 3 and 4 oral mucositis than CCRT with CDDP. As a result, the completion rate of CCRT with S-1 was lower than that of CCRT with CDDP. The two regimens achieved a similar complete response rate of the primary sites, local control rate(LCR)and larynx preservation rate; the LCR for T1 and 2 disease was more than 70%. However, the LCR for T3 or 4 disease by the two regimens was less than 50%. CCRT with S-1 showed significantly higher LCR in patients with poorly or undifferentiated SCCs than those with well or moderately-differentiated SCCs. It is suggested that the two CCRT regimens are useful treatment modalities for patients with locally(primary site)non-advanced pharyngeal or laryngeal SCCs, and that CCRT with S-1 is highly sensitive to poorly or undifferentiated SCCs. In order to achieve local control and larynx preservation, more intensive CCRT might be necessary for patients with locally(primary site)advanced pharyngeal or laryngeal SCCs.