Purpose: The purpose of this prospective study was to analyze the value of interstitial pulsed-dose-rate (PDR) brachytherapy (iBT) with regard to local control and the incidence of side effects in patients with head-and-neck cancer in a previously irradiated area.
Methods and materials: From October 1997 to September 2001, 43 patients with head-and-neck cancer in a previously irradiated area (31 patients with recurrent cancer) were treated with iBT alone or in combination with external beam radiation. Thirty-four of 43 patients received interstitial PDR brachytherapy (DREF=20-60 Gy) as part of their curative treatment regimen alone or in combination with external radiation. Nine patients were implanted for palliative purposes. The pulses were delivered 24 h/day with a time interval of 1 h between two pulses. The dose per pulse (dp) ranged from 0.4-0.7 Gy. Sixteen of 43 (37%) patients also received cisplatin or carboplatin with 5-fluorouracil during the time of the iBT. Additionally 20/43 (47%) patients were treated with interstitial hyperthermia. Thirteen of 43 (30%) patients received external beam radiation in a dose range from 20-67 Gy. A follow-up of all patients was done to analyze local control and survival, and acute and delayed toxicity. This analysis was performed after a median follow-up of 24 months (6-48 months).
Results: Local tumor control was achieved in 34 of a total of 43 patients (79%) and in 30/34 patients (88%) treated for curative intention. Distant metastases were observed in 5/43 (12%) patients. The 2-year local recurrence-free survival rates, disease-free survival rates, and overall survival rates according to the Kaplan-Meier method for all patients were 68%, 62%, and 49%, respectively, and for patients treated with curative intention they were 80%, 77% and 66%, respectively. There was no statistical difference in the probability of local recurrence in patients subgrouped by recurrent tumor vs. secondary primary, tumor size, grading and lymphangiosis. The application of chemotherapy or hyperthermia did not have significant influence on the therapy results. Soft tissue necrosis was the only serious side effect seen in 2/43 patients (4.7%). No other serious side effects were observed.
Conclusions: Interstitial pulsed-dose-rate brachytherapy for patients with previously irradiated head-and-neck cancer is an effective therapy with minimal toxicity. The role of chemotherapy and hyperthermia in these patients remains unclear. Further randomized studies with larger patient numbers are necessary to draw a definite conclusion.