Intraoperative electron beam radiotherapy for previously irradiated advanced head and neck malignancies.

Purpose: This is a retrospective review to evaluate the role of surgery and intraoperative electron beam radiotherapy (IOERT) in the treatment of patients with previously irradiated advanced head and neck cancers.
Methods and Materials: Between January 1992 and March 1997, 38 patients (31 males, 7 females; median age of 62 years) with recurrent head and neck cancer were treated with maximal resection and IOERT at the Ohio State University (OSU). All had been previously treated with full-course radiotherapy (median 65.1 Gy, range 50-74.4 Gy). Twenty-nine patients (76%) had previously undergone one or more surgical procedures. After maximal surgery the tumor bed was treated with IOERT (single field in 36 patients and 2 fields in 2 patients), most commonly with 6 MeV electrons (87%). The dose administered (at 90% isodose line) was 15 Gy for close or microscopically positive margins in 34 patients and 20 Gy for gross disease in 1 patient. Further external beam radiation therapy (EBRT) was not given.
Results: After a median follow-up of 30 months (range 8-39 months), 24 of the 38 patients (66%) recurred within the IOERT field. Median time to IOERT failure was 6 months (95% CI: 4.3-7.7). The 6-month, 1-, and 2-year control rates within the IOERT volume were 41%, 19%, and 13%, respectively. Thirty of the 38 patients (79%) recurred in locoregional areas. Median time to locoregional failure was 4 months (95% CI: 3.3-4.7). The 6-month, 1-, and 2-year locoregional control rates were 33%, 11%, and 4%, respectively. Distant metastases occurred in 7 patients, 5 in association with IOERT failure and 2 with locoregional failure. Median overall survival was 7 months (95% CI: 4.7-9.3). The 6-month, 1-, 2-, and 3-year actuarial survival rates were 51%, 21%, 21%, and 8%, respectively. Major treatment-related complications occurred in 6 patients (16%).
Conclusion: IOERT alone, at the dose used, is not sufficient for control of recurrent, previously irradiated head and neck cancers. Since higher IOERT doses are associated with high morbidity, we are currently evaluating the addition of limited EBRT dose and/or brachytherapy to improve the local control of these poor prognostic recurrent tumors, with acceptable morbidity.