Prognostic Significance of the T-cell Response at the Tumor Margins in Squamous Cell Carcinoma of the Oral Cavity

Biopsied cancer tissues from 33 patients with primary squamous cell carcinoma of the oral cavity were examined immunohistopathologically as to the responsiveness of the host against its own cancer cells. We have previously reported that T-cells were predominant over B-cells, and T-cells surrounded the cancer nests, infiltrated at the marginal parts of the cancer nests. We have also noted that the grade of T-cell infiltration in the biopsied specimens at time of diagnosis correlated well with the size of tumor, and the existance of cervical lymph node metastasis. All patients were treated by induction chemotherapy and surgery and were followed up for 5 years. Twenty-five patients were alive 5-years after surgery, 5 patients had died of their cancer and 3 patients had died of intercurrent disease.In the present study, we have attempted to determine whether the grade of T-cell infiltration at around tumor margins is related to the clinical outcome after surgical excision of the primary tumor and prognosis, retrospectively, Recurrence rate was 14.2% for patients with marked T-cell infiltration, 33.3% for patients with moderate T-cell infiltration and 50.0% for patients with none or slight T-cell infiltration, although the differences noted were not statistically significant because of the small sample size. Patients with marked T-cell infiltration at the tumor margins achieved 100% determinate 5-year survival rate which is better than for patients with moderate, and none or sight T-cell infiltration. Thus, increased grade of T-cell infiltration in the tumor tissues at the marginal parts of the cancer nests was associated with a more favorable prognosis. These results suggested that T-cells might inhibit the development and spreading of the cancer cells.