Radiation following surgery for oral cancer: impact on local control

The use of postoperative radiation therapy (RT) is commonly used in the treatment of patients with high-risk squamous cell carcinoma of the head and neck. However, few data exist that quantitate the incremental benefit of RT when administered following surgery. The retrospective study was designed to measure the incremental benefit of adjuvant RT after surgery on control of the primary lesion when compared with patients undergoing surgical therapy alone for squamous cell carcinoma of the oral cavity.

Retrospective chart.

Previously untreated patients with squamous cell carcinoma of the floor of mouth or oral tongue who were treated between 1974 and 1998 were eligible for study. A minimum follow-up of 2 years was required. Tumor site, stage, and RT data were correlated with local control.

Patients with missing or incomplete data and those lost to follow-up or dead as a result of intercurrent disease with follow-up of less than 2 years were censored. A group of 211 patients who could be evaluated was available for the study. Radiation therapy was administered postoperatively to 58 patients, and 153 patients were treated with surgery alone. In the group treated with combined therapy, the average irradiation dose was 5850 cGy; this group included 35 patients who received more than and 16 who received less than 5700 cGy.

The incremental benefit in terms of control of tumor at the primary site for patients receiving postoperative RT was between 0% and 7%. Surgery alone controlled 80% to 85% of primary tumors. The dose of postoperative RT did not correlate with local control.