The effects of Corynebacterium parvum and surgery on the Lewis lung carcinoma and its metastases.

The effects of Corynebacterium parvum on the mouse primary Lewis lung carcinoma and its metastases were studied. C. parvum was given at the same time as subcutaneous inoculation of tumour or in combination with surgical excision of the primary after 10 days' growth. When intravenous C. parvum was given at the same time as tumour there was a reduction in the primary tumour growth rate. There was a similar reduction in growth if the drug was given intravenously 7 days after tumour inoculation. Intraperitoneal and subcutaneous administration of C. parvum had no effect on the primary tumour. The number of pulmonary metastases were significantly reduced after intravenous or intraperitoneal C. parvum given at the same time as tumour. When C. parvum and surgery were combined and C. parvum was given not more than 2 days before operation there was only a slight reduction in metastases, but when the injection was given intravenously or intraperitoneally 3-4 days before operation the number of metastases was significantly reduced. Subcutaneous administration of C. parvum had little effect on metastases. There was no difference in the number of metastases in C. parvum-treated mice were killed after 21 or 28 days. C. parvum given on the same day as surgery was more effective if tumour excision was performed before day 10 when the metastases were less well established. It was concluded that in well-defined conditions C. parvum is effective against metastases of the Lewis lung carcinoma.