Introduction: Neck node metastases from an unknown primary carcinoma represent an infrequent but challenging problem for oncologists. The management of such patients is controversial, but radiotherapy alone or as part of a multimodal approach is often indicated. Patients with inoperable lesions usually receive radiotherapy alone at palliative doses. In an attempt to increase local control in patients with locally advanced neck disease from an unknown primary carcinoma, local hyperthermia was combined with definitive radiotherapy.
Material and methods: Between 1982 and 1993, radiotherapy and local microwave hyperthermia were used to treat 15 patients with metastatic neck nodes from an unknown primary site. The patients had previously undergone only biopsy or fine needle biopsy, and showed no signs of metastases beyond the clavicle. Radiation to the nodes and the potentially primary sites in the head and neck was delivered by a 6 MV linear accelerator or a Cobalt 60 unit, to a total dose of 57.50-74.40 Gy (median 70 Gy). Hyperthermia was added using a BSD 1000 unit at an operating frequency of 280-300 MHz for 2-7 sessions (mean 3.1; median 2) at a desired minimum temperature of 42.5 degrees C. Two patients also received i.v. cisplatin 20 mg/m2/week as a radiosensitizer.
Results: Nine patients achieved a complete, and four a partial response for an overall response rate of 86.5%. Acute and late toxicity was mild: four patients experienced pain during hyperthermia, two moist cutaneous desquamation, and one cutaneous necrosis. The actuarial probability of maintaining local control at 5 years is 64.5% and the actuarial overall survival 29%. Five patients developed distant metastases and died of disease, two experienced nodal recurrence and two died of other unrelated causes.
Conclusion: The addition of local microwave hyperthermia to radiotherapy in the treatment of metastatic squamous cell carcinoma of the neck in patients with an unknown primary site leads to good local control with moderate toxicity. No definite conclusions are possible because of the small number of patients involved in this phase II trial.