Treatment of oral cavity and oropharynx squamous cell carcinoma with perilymphatic interleukin-2: Clinical and pathologic correlations

We describe the correlations between the clinical and histologic findings in an initial series of 60 patients with T2-4, N0-3, MO squamous cell carcinoma (SCC) of the oral cavity or oropharynx enrolled in a randomized trial set up to evaluate whether the disease-free interval and survival are extended when perilymphatic injections of recombinant interleukin-2 (rIL-2) are combined with routine surgery and radiotherapy. Twenty-nine patients were operated on only (controls). The other 31 received two daily injections of 2,500 U rIL-2, one near the mastoid process on the same side as the tumor and the other under the chin, for 10 days before surgery, and further injections on the nonoperated-on side on a monthly basis for 1 year starting 4 weeks after surgery (or radiotherapy, where necessary) in an effort to upregulate the immune system and delay recurrence. Their surgical specimens displayed a significantly greater inflammatory reaction, larger areas of necrosis, and more intense sclerosis. The inflammatory tumor infiltration consisted of eosinophils, plasma cells, and CD25⁺ and human leukocyte antigen (HLA)-DR⁺ lymphocytes. However, no correlations were apparent with regard to the intensity of necrosis, eosinophil infiltration, and the number of DR⁺ cells and the clinical outcome. By contrast, the correlation between CD25⁺ cells and a significantly longer disease-free survival suggests that induction of T-cell reactivity, and perhaps specific immunity, is the only important aspect of rIL-2-induced antitumor reactivity.