Clinicopathologic features and histochemical analyses of proliferative activity and angiogenesis in small cell carcinoma of the esophagus

We investigated clinicopathologic features in patients with esophageal small cell carcinoma (SCEC), and its proliferative activity and angiogenesis. Ten patients with SCEC from 335 esophageal carcinoma patients were analyzed clinicopathologically. For analyses of cell proliferation, apoptosis, and angiogenesis of SCEC, Ki-67 immunostaining, the TUNEL method, and CD31 and CD68 immunostaining were used. Esophagectomy was performed in nine patients, while one with extensive SCEC was treated by repeated chemotherapy and radiotherapy. Four patients received chemotherapy both before and after surgery, one only before surgery, and four only after surgery. Cisplatin and etoposide were given to five patients, while irinotecan and cisplatin were given to three. Five survived more than 18 months, and two more than 36 months. One of these two had limited SCEC treated by surgery and chemotherapy, whereas the other had extended SCEC treated by repeated chemotherapy and radiotherapy. The microvessel count and the Ki-67 labeling index of SCEC were higher than those of squamous cell carcinoma (P = 0.0033 and P = 0.0005, respectively). Between SCEC with and without preoperative chemotherapy, the Ki-67 labeling index was lower (P = 0.027) and the apoptotic index was higher in the treated SCEC (P = 0.014). Between SCEC patients who survived more or less than 18 months, the microvessel count was lower in those who survived more than 18 months (P = 0.049). Esophagectomy may be indicated for limited SCEC combined with chemotherapy. SCEC has high proliferative activity and rich neovascularization, and its proliferative activity may be suppressed by chemotherapy.