Interstitial irradiation by 192Ir seed assemblies in fixed cervical lymph node metastases

Eleven patients with fixed cervical lymph node metastases were treated using external irradiation followed by interstitial implants, 137Cs needles were used for one patient and 192Ir seed-assemblies for 10 patients. The local tumor responses were 4 CR, 6 PR and 1 NC. Acute tolerance was good, and there were no major late injuries except for one case of severe subcutaneous fibrosis. No morbidities such as local infection, bleeding or pulmonary injuries were encountered. Clear-cut dose control relationships were demonstrated; the local control of the nodes treated with intervals of more than one month between external and interstitial irradiation was poor. It is considered that adequate treatment is to give 40 Gy over 4 weeks by external irradiation first, then, after an interval of 2 weeks, to give 40-50 Gy over 4-5 days using 192Ir interstitial implants. The interstitial implants appeared to provide an improvement in local control and in the therapeutic ratio of fixed cervical lymph node metastases.