Low dose rate interstitial brachytherapy for head and neck cancer

The indication for brachytherapy is getting broader than before, because it has achieved a great deal of improvement for the reasons as follows; new implant sources available for high-dose rate brachytherapy have been developed such as Iridium-192, the exposuring dose to the operator has been reduced by using afterloading system, the methods of dose calculation by computers have been established, and the recent advance in radiology have made it easy to find smaller lesions which is a good candidate for brachytherapy. However, traditional low-dose rate brachytherapy using Cs-137 needles has been still one of the most effective modality for lingual cancer. One hundred eighty-five primary cases with squamous cell carcinoma of the tongue treated with Cs-137 needle interstitial needle implant at National Sapporo Hospital from 1978 to 1995 were reviewed. The local control rate for the primary tongue lesions was 89%. Cumulative 5 year survival rate was 71% and cause specific 5 year survival rate was 83%. In this study, we have reported mainly about the technical manipulation of the low dose rate interstitial implant for the lingual cancer and practical treatments with soft and flexible Iridium sources. We concluded that it is important to use the most appropriate brachytherapy sources from biological and clinical aspects for the individual case. Efforts to make the specialists understood the advantage of brachytherapy are essential among the correlating institutes, and well-balanced cancer therapy including advantage of brachytherapy is strongly expected. (author)