Microscopic cut-through of cancer in the surgical treatment of squamous carcinoma of the tongue. Prognostic and therapeutic implications.

A retrospective review was carried out of the records of 268 patients with a pathologically proved diagnosis of squamous carcinoma of the tongue treated by glossectomy at M.D. Anderson Hospital and Tumor Institute from January 1, 1970 through December 31, 1979. Pathologic findings found on frozen section analysis were correlated with the TNM stage of the tumor, histologic characteristics, perineural invasion, type of treatment, local recurrence, and survival rate. Thirty-eight patients with squamous carcinoma of the oral tongue and 16 patients with tumors of the base of the tongue had initially positive frozen section margins. Forty-one of these patients had margins that were negative at the completion of surgery. Thirteen patients never had negative margins. Positive mucosal margins were more common in smaller tumors and positive muscular margins were more common in larger tumors. Patients with perineural invasion and larger tumors had a higher percentage of positive margins. Those patients with initially positive margins that were rendered negative at the completion of the procedure and treated with surgery only had a significantly increased local recurrence rate and reduced survival compared with patients similarly treated with initially negative margins. Tumor stage, location (muscular versus mucosal) of positive margins, and the presence of perineural invasion were not significant in predicting local recurrence or decreased survival. If all patients with microscopically positive margins are considered for postoperative radiotherapy, then the routine use of intraoperative frozen section examination of the margins of resection in squamous carcinoma of the tongue may not be justified.