Enhanced efficacy of bleomycin adsorbed on silica particles against lymph node metastasis in patients with esophageal cancer: A pilot study

Background. Lymph node metastases occur very frequently and extensively in patients with esophageal cancer. The aim of this pilot study was to try the targeting chemotherapy for lymph node metastases by use of bleomycin adsorbed on silica particles (BLM-SI). Methods. BLM-SI or bleomycin solution (BLM-SOL) was injected into the submucosa of the esophageal wall by means of endoscopy 3 days before operation in 16 patients with middle thoracic esophageal cancer. The distribution of bleomycin in the regional lymph nodes and surrounding connective tissues was studied. Results. When BLM-SI was administered, bleomycin activity was found in both the regional lymph nodes and connective tissues, not only in the mediastinal region but also in the cervical and abdominal region. Blemycin activity was significantly higher in all regions after BLM-SI administration than after BLM-SOL administration. Degenerative or necrotic changes were microscopically observed in 11 of 36 lymph nodes with metastatic foci. Bleomycin activity in the blood was significantly lower after BLM-SI was administered than after BLM-SOL. Serious systemic side effects except for fever were not observed in any patients. Conclusions. These results indicate that BLM-SI could be a useful treatment modality for targeting lymph node metastasis of esophageal cancer without serious side effects.