Cervical metastases from unknown primaries: radiotherapeutic management and appearance of subsequent primaries

Between 1964 and 1986, 72 patients who presented with squamous or undifferentiated metastatic carcinoma to neck nodes, where the primary tumor could not be found by standard clinical procedures, were treated at the Mallinckrodt Institute of Radiology. These cases were managed in the following manner: biopsy and radiotherapy in 46 out of 72 patients, radiotherapy (RT) and a planned neck dissection in 14 out of 72, and neck dissection after failure to achieve a complete response (CR) with RT in 12 out of 72. Minimum follow-up was 2 years. The initial CR rates for stages N1, N2a, N2b, N3a, and N3b were 83%, 93%, 61%, 50%, and 33%, respectively. The long-term neck tumor control for the same stages was 83%, 71%, 67%, 44%, and 50%, respectively. One patient had soft tissue necrosis and two had carotid artery ruptures, one of which left no symptomatic sequelae. Twenty-one out of 72 patients developed subsequent primary tumor. Only one of these patients survived. This incidence was not affected significantly by prophylactic treatment of the mucosal areas except in patients with bilateral neck nodes, undifferentiated or poorly differentiated histologies, and/or posterior cervical node involvement. A multivariate analysis showed that prognosticators of an improved disease-free survival were: a complete clearance of tumor by the end of radiotherapy (p less than 0.0009) and no appearance of a subsequent primary tumor (p = 0.035). The only factor that correlated with an increased loco-regional control was having a complete response by the end of radiotherapy (p less than 0.00009). The recommended management and possible ways of preventing the appearance of subsequent primaries will be discussed.