Local control after the use of adjuvant electron beam intraoperative radiotherapy in patients with high-risk head and neck cancer: the UCSF experience

Abstract

Purpose: We assess the effect of electron beam intraoperative radiotherapy (EB-IORT) on local-regional control and any associated complications in patients with locally advanced or recurrent head and neck cancer.

Materials and methods: The records of 30 patients with head and neck cancer who received EB-IORT from March 1991 to December 1994 were retrospectively reviewed. The indications for EB-IORT in 25 patients were recurrent or persistent disease despite previous treatment with full-course external-beam radiotherapy and/or one or more resections. In five other cases the indication was extensive primary disease with multiple high-risk factors for local recurrence, including extension into the base of the skull, advanced extensive disease, and perineural or bony invasion. All patients had a Karnofsky performance score > or = 70 prior to EB-IORT. Median age was 65 years. Final pathology revealed positive or close surgical margins in all patients. The areas treated were generally inaccessible to catheter placement for brachytherapy. The most common histology was squamous cell carcinoma. EB-IORT was given as a single fraction of 1500 cGy to the 90% isodose with 6 or 9 Mev electrons using cone sizes ranging from 2.5 to 7 cm in diameter. Data were analyzed to determine the local-regional control rate, survival, and complications after EB-IORT.

Results: With a median follow-up time of 30 months, nine patients (27%) had only local recurrence. Of these, only one recurrence was inside the EB-IORT field and eight were outside the EB-IORT field. Two patients (7%) developed distant metastases only and one patient (3%) had both local recurrence and distant metastasis. Seven patients died, five with disease. Twenty-two patients are known to be alive, 15 (68%) of whom have no evidence of disease. One patient was lost to follow-up after 12 months; when last examined he was free of disease. Five patients (16%) have had mild-to-moderate transient complications probably related to EB-IORT. The 3-year actuarial local-regional control rate was 60%.

Conclusions: Our data suggest that EB-IORT may play an important role in decreasing local recurrence in patients with multiple high-risk factors. Despite previous full-course external beam radiotherapy and extensive resections, EB-IORT did not confer significant additional long-term morbidity. Although results are encouraging, randomized studies are required to definitively establish the role of EB-IORT in the management of advanced or recurrent head and neck cancer.