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[The depth of CO2 laser cordectomy in T1 glottic carcinoma].

OBJECTIVE
To evaluate if routine resection of thyroarytenoid muscle (TA) with T1 glottic carcinoma treated by endoscopic CO2 laser cordectomy is necessary.


METHOD
A cohort of 57 patients staged as T1 underwent endoscopic CO2 laser cordectomy at a single institution was retrospectively analyzed. Seven had Tis, 47 T1a and 3 T1b; 9 cases were treated with type I or II cordectomies, and 48 patients underwent type III, IV or V cordectomies, with resection of all or part of the TA. All histological slides from the 48 patients were re-examined under the light microscope for TA invasion by the pathologist and the surgeon. Survival and local control were calculated using the Kaplan-Meier method.


RESULT
The follow-up period for the 57 patients ranged from 4 to 119 months (mean follow-up 41.5 months). Among the 4 patients who died, 1 of them was related to the glottis carcinoma and 3 others had died of other causes with no evidence of locoregional glottic disease. The 5 year overall survival, 5 year disease-specific survival and 5 year disease-free survival were 89.1%, 96.3% and 78.1%, respectively. When the study ended, 10 (17.5%) local and 1 regional recurrences had been observed. Over a total of 57 patients, 5 (8.8%) cases showed TA invasion. Open salvage therapy was performed during follow-up. Six patients had partial laryngectomy. Four patients had total laryngectomy and one with neck dissection. One patient had radical neck dissection because of late regional relapse was proven by histopathologic examination. Thus, the larynx was preserved in 93.0% (53/57).


CONCLUSION
TA invasion found histologically in T1 glottic carcinoma. TA resection can be performed conservatively according to an accurate preoperative and intraoperative evaluation of macroscopic tumour extension.