Squamous cell carcinoma of the floor of mouth: a 20-year review.

BACKGROUND

This study retrospectively examines our treatment choices and outcomes with patients diagnosed with squamous cell cancer of the floor of mouth. Because of our division's past strong surgical bias in the treatment of this disease, we have assessed the results of a patient population treated largely by surgical extirpation. This clinical information has been used to draw conclusions and formulate treatment paradigms for patients with floor of mouth cancer.

METHODS

Four hundred fifty patients with the diagnosis of squamous cell carcinoma of the oral cavity received their primary treatment at Roswell Park Cancer Center (RPCI) from 1971 to 1991. Ninety-nine had disease originating in the floor of mouth and are the basis of this retrospective review.

RESULTS

Forty-three percent of the patients had early-stage disease (stage I or II). Five-year survival for stages I through IV was 95%, 86%, 82%, and 52%, respectively. The incidence of occult cervical metastases for clinical stage I patients was 21%. For clinical stage II patients, the incidence was 62%. Local control of patients treated with surgery alone was 81%. The regional control rate for these patients was 71%. In patients where negative margins were achieved (> or = 5 mm), the local recurrence rate was 13%, regardless of T stage. Eleven percent of the patients underwent a course of postoperative radiotherapy; all had stage IV disease. When compared with advanced-stage patients undergoing surgery alone, there was a significantly improved regional control rate and a trend toward enhanced survival in the patients receiving adjuvant radiotherapy.

CONCLUSIONS

There is a significantly high incidence of occult metastatic disease (21%) for T1 lesions or greater in floor of mouth cancer to warrant elective treatment of regional lymphatics. In patients treated with surgery alone with negative margins, the local control rate was 90% versus 62% when the margins were close or positive. Adjunctive radiotherapy showed a statistically significant (p = .005) increased regional control in patients with stage IV disease. Adjunctive radiotherapy is warranted for increased regional control of disease; good local control can be achieved in floor of mouth cancer with surgery alone when negative margins are obtained.