Histologic findings in patients with head and neck squamous cell carcinoma receiving perilymphatic natural cytokine mixture (IRX-2) prior to surgery.

Abstract

To induce tumor regression with immunotherapy and to characterize the histology. National Institute of Cancerology, Mexico City, Mexico. Thirteen patients with advanced squamous cell carcinoma of the head and neck region. A 21-day cycle of preoperative immunotherapy, including a single intravenous infusion of low-dose cyclophosphamide (300 mg/M2), 10 daily perilymphatic injections of a natural cytokine mixture (approximately 150 units interleukin-2 equivalence by enzyme-linked immunosorbent assay), daily oral indomethacin, and daily oral zinc with multivitamins. Pretreatment biopsies were performed to confirm the diagnosis and to characterize the lesion by standard pathologic criteria, including the degree of tumor-associated lymphocytes. Clinical responses were assessed at surgery, and the specimen was analyzed with respect to changes in tumor morphology and lymphoid and inflammatory infiltration (T and B lymphocytes, plasma cells, macrophages, granulocytes, and giant cells). The presurgical and postsurgical characteristics were ascribed percentages based on a representative section. Prior to treatment, on average the biopsies demonstrated 77% solid tumor with 14% stroma and 9% sparse infiltration of lymphocytes. After treatment, one patient had a complete clinical response and showed only residual inflammatory cells and fibrosis. One patient had no clinical or histologic response. Of the remaining 11 patients, 4 had partial, 6 had minor, and 1 had no response. Tumors were reduced an average of 41% (16% solid and 25% fragmented) and lymphoid infiltration increased to 45% without change in residual stroma. The pathologic changes viewed in the context of the clinical findings indicate that this immunotherapy protocol induces immune regression of the tumor, mediated predominantly by T and B lymphocytes, and thus elicits a tumor-specific immune reaction.