International journal of radiation oncology, biology, physics vol:9 issue:2 pages:181-4
The criteria for T2 glottic cancer staging in the UICC classification are extension to the supra- or subglottic region combined or not with impaired mobility of the vocal cord. The prognostic significance of these factors is examined in this study. Patients with T2A lesions (normal mobility, 33 patients) have an uncorrected actuarial 5 year survival of 54%, and a local control rate with radiotherapy alone of 62%. Patients with T2B lesions (impaired mobility, 28 patients) have a survival of 40% and a local control rate of 65% with radiation only. After rescue surgery, local control is obtained in 81% of T2A patients and 68% of T2B patients. While local control rates with radiotherapy alone were the same in T2A and T2B patients, final survival was lower for T2B patients because of less successful salvage surgery. While no significant differences in local control were found for different mucosal spread patterns, local control was excellent (87%) with radiotherapy alone in eight patients with mobility impairment without extension beyond the true cord, indicating that impaired mobility by itself is not a bad prognostic factor, but only when it is combined with tumor extension. In 9 patients with T2B tumors, a laryngectomy was performed immediately after initial radiotherapy (40 or 50 Gy) when the tumor persisted or the vocal cord mobility did not return to normal. None of these patients had a local recurrence after surgery. The total local control in all 37 T2B patients together was 78% (compared with 81% in T2A patients). The adverse prognostic influence of impaired mobility seems to have been eliminated by the treatment policy of surgery for those patients with poor regressions after radiotherapy. A dose-response relation can not be demonstrated in T2 glottic cancer for the dose range between 50 and 70 Gy.