Radiation therapy for early glottic carcinoma (T1N0M0) : The adverse effect of treatment interruption (Original Contributions)

PurposeClarification of the adverse effects of treatment interruption on the local control of early glottic carcinoma.Patients and MethodsFrom May 1982 through February 1992, 273 patients with early glottic carcinoma (T1N0M0) were treated at this department. Of 253 patients administered 60 Gy in 30 fractions 77 patients had no treatment interruption and treatment was completed within 6 weeks (group I), overall treatment time was prolonged for 176 patients: 141 patients 43 to 49 days (group II) and 35 patients 50 to 62 days (group III). Treatment was interrupted due to public holidays (156 cases), patient convenience (13 cases) and severe mucosal reactions (seven cases). The major reason was public holidays, 91% in group II and 89% and group III 80%. Survivals for groups I and II, groups II and III and groups I and III were essentially the same. At 40 Gy tumor clearance was more than 50% in the 3 groups. For complete clearance cases at 40 Gy, recurrence-free survival was essentially the same for the 3 groups although for incomplete clearance cases, statistically significant difference for groups I and III (log-rank test p=0.0004; Wilcoxon test p=0.0004) and marginally significant difference for groups II and III (p=0.0157, p=0.0045) but no difference for groups I and II (p=0.0669, p=0.0853) were noted by adjusting the p-value.ConclusionProlongation of overall treatment time and tumor clearance at 40 Gy appeared to be a factor of the local control.