Interstitial irradiation for squamous carcinoma of the oral cavity.

Interstitial radiation delivered by iridium 192 implants was used to treat 38 patients with squamous carcinoma of the oral cavity. Thirty-six patients had either T1 or T2 tumours and no patient had palpable nodes at the time of implantation. Control of the primary tumour was achieved in all but 2 patients; these 2 were successfully treated by surgery. Fifteen patients (39%) went on to develop metastatic neck nodes. Nine were cured by radical neck dissection but the remaining 6 died of their disease. This gives a 5-year actuarial survival of 81%. Since all deaths occurred after the development of metastatic disease in the neck with control of the primary lesion, the evidence for and against prophylactic treatment of the neck lymphatics in clinically negative necks was reviewed. Prophylactic irradiation of the neck is probably preferable to any form of neck dissection but clear evidence that this improves long-term survival compared with careful follow-up and radical neck dissection for palpable nodes is still lacking.