Early results of pulsed-dose-rate interstitial brachytherapy for head and neck malignancies after limited surgery

Abstract

Purpose: The aim of this study was to evaluate the relative incidence of toxicity and local control in patients with head and neck malignancies who underwent interstitial pulsed-dose-rate (PDR) brachytherapy (iBT). Patients and Methods: From October 1997 to December 1998, 61 patients underwent interstitial PDR brachytherapy procedures in our department; 47 were patients with head and neck cancer. Forty patients received brachytherapy as part of their curative treatment regimen, and 7 patients were implanted for palliative purposes and excluded from the analysis of therapy efficacy. Twenty-four patients had interstitial brachytherapy procedures alone with D REF = 50 Gy; in 23 patients, iBT procedures were performed with D REF = 24 Gy in combination with external radiation. A dose per pulse (dp) of 0.5 Gy was prescribed for 38/47 patients, and a dp = 0.7 Gy for 9/47 patients. The pulses were delivered 24 h a day, with a time interval of 1 h between two pulses, resulting in an effective dose rate of 0.5 Gy/h or 0.7 Gy/h. A follow-up of the patients was done to analyze acute and delayed toxicity, local control, and survival. The analysis was performed after median follow-up of 12 months (5–18 months). Results: After a median follow-up of 12 months, soft tissue necrosis was seen in one patient and bone necrosis in another. No other serious side effects were observed. Permanent locoregional tumor control was achieved in 37 of 40 patients. No distant metastases were observed. Conclusions: PDR interstitial brachytherapy with 0.5–0.7 Gy/h is a safe therapy. These preliminary results suggest that PDR interstitial brachytherapy of head and neck cancer is comparable with low-dose-rate (LDR) brachytherapy.