Optimum radiation fractionation for T1 N0 glottic carcinoma

Question. What is the optimum dose and fractionation schedule for the radiation treatment of patients with T1 N0 glottic (vocal cord) carcinoma? Perspectives. Evidence was selected and reviewed by one member of the Cancer Care Ontario Practice Guidelines Initiative's Head and Neck Cancer Disease Site Group (DSG). This evidence summary has been reviewed and discussed by the Head and Neck Cancer DSG, which comprises medical and radiation oncologists, surgeons, and epidemiologists. Community representatives did not participate in the development of this evidence summary, but will in future reports. Methodology. MEDLINE, CANCERLIT, and PREMEDLINE searches of the English language literature were performed for the period from 1980 to October 1998 to identify studies of patients with T1 N0 glottic carcinoma. Local control (by radiotherapy and salvage surgery) was the primary outcome of interest. Treatment toxicity (acute and late complications) was also considered. The citation lists of all retrieved articles were reviewed to identify further studies. The literature search was updated in March 2000. Search Results. Dose per fraction and tumour control rates were available from 30 case series. Benefits: The quality of evidence is insufficient to comment on the superiority of any one of the fractionation schedules described, with respect to either disease control or toxicity. Control rates ranged from 62% to 100%. Harms: One study reported excessive toxicity with fractions of 333 cGy three times weekly to 60 Gy in 6 weeks using a single field. Conclusions. The quality of the current evidence concerning the optimum dose and fractionation schedule for radiotherapy treatment of T1 N0 glottic larynx is poor; the vast majority of clinical papers are retrospective reviews of case series from single institutions. Accepted schedules are based on the delivery of a radical radiation dose with a clinically acceptable complication rate. There is no evidence for the superiority of any one treatment schedule. A 4-week course of treatment appears to be safe and effective, and is currently given at four of the eight Cancer Care Ontario Centres and at the Princess Margaret Hospital. At present, the evidence summarised above does not allow a firm clinical recommendation to be made. Please see the full report for a more detailed discussion of the evidence, an interpretive summary, and a description of the opinions of the Head and Neck Cancer Disease Site Group members.