Multimodality therapy and distant metastases. The impact of natural killer cell activity.

One hundred eighty-two previously untreated head and neck cancer patients were stratified by pretreatment-quantitated natural killer (NK) cell activity (less than 60 lytic units [LU] vs greater than or equal to 60 LU) and followed up longitudinally for the development of distant metastases (DMs). Patients with NK activity of less than 60 LU (n = 99) developed DMs at a higher rate than the remaining group. Further stratification of patients on the bases of both regional nodal disease and treatment demonstrated that the risk of DMs predominantly involved one group, ie, patients with histopathologically documented nodal metastases, NK activity of less than 60 LU, and prior treatment with combined surgery and radiation therapy (12[46%] of 26 patients). If one of these three factors was absent, the risk of DMs was not greater than 12%, regardless of the factor. Head and neck cancer patients should be stratified by pretreatment natural immune status to determine the impact of therapy on disease progression.