Patterns of recurrence from head and neck cancer. An immunologic perspective

The influence of pretreatment natural killer (NK) cell activity on patterns of disease recurrence in patients with head and neck cancer was studied. One hundred eighty-three patients were followed prospectively for disease recurrence following definitive therapy (median disease-free follow-up = 15 months). Pretreatment peripheral blood NK cell activity against K562 target cells was measured for each patient and expressed in lytic units (LU). The risk of death caused by recurrent disease was greatest in those patients with peripheral blood NK cell activity less than 60 LU (P less than 0.05). The site of recurrence could also be distinguished by LU value. As a percentage of total recurrences, locally recurrent disease was predominant in the patients with NK function greater than 60 LU whereas distant metastases predominated in the group of patients with peripheral blood NK cell activity less than 60 LU. These patterns were maintained when patients were stratified by clinical N stage (N = 0 versus N+), T stage (T-1 or T-2 versus T-3 or T-4), and treatment regimen (surgery alone versus surgery and postoperative radiation therapy). Natural killer cell activity appears to have prognostic significance, both for disease-free survival and for site of recurrence independent of clinical stage. The indications for multimodality therapy for patients with head and neck cancer when stratified by NK cell function need to be clarified.