Prognostic significance of lymphocyte infiltration following preoperative chemoradiotherapy and hyperthermia for esophageal cancer

Purpose: Lymphocyte infiltration (LI) around cancerous lesions is an important immune response. The purpose of this study is to evaluate the prognostic significance of LI after preoperative treatment for esophageal cancer. Methods and Materials: Preoperative chemoradiotherapy (CR therapy), either bleomycin 30 mg or cisplatin 120 mg/m² plus radiation 30 Gy, was performed on 51 cases with esophageal cancer, while hyperthermo-chemoradiotherapy (HCR therapy) was also indicated in 71 cases. Using resected specimens, both the histopathologic effectiveness and degree of LI to cancerous lesions were evaluated. Results: The incidences of the cases in which preoperative treatment was effective were 56% and 92.3% in LI (-) and LI (++) group (p < 0.05). The presence of LI resulted in favorable prognosis; the 5-year survival rates of LI (++) and LI (+) patients were 75.5% and 46.1%, both of which were significantly better than LI (-) (27.8%, p < 0.05 and p < 0.01, respectively). Especially among cases whose preoperative treatment was moderately effective, a multivariate analysis revealed LI to be a favorable prognostic factor independent of other clinicopathologic factors (p = 0.0171). Regarding the preoperative treatment, the incidence of LI (++) was higher in the HCR group (16.9%) than in the CR group (2.0%, p < 0.01). Conclusions: LI appears to be a prognostic predictor after preoperative CR therapy while, in addition, simultaneous hyperthermia may stimulate LI in cases with esophageal cancer.