Combined treatment of Lewis lung carcinoma by tumor excision and levan.

A combined treatment modality including surgical excision and daily injections of high molecular levan seemed to be effective against Lewis lung carcinoma in C57BL mice. The inhibitory effect of levan on tumor growth in mice treated by resection of the primary tumor was demonstrated as follows: (1) recurrence of primary tumors was less in levan-treated mice compared to untreated animals; (2) metastases were less numerous in the levan-treated animals; (3) levan treatment partly prevented loss in body weight, and (4) it increased the survival rate. Recurrence of primary tumors appeared to be more efficiently inhibited by local levan treatment, while systemic (i.p.) administration was more effective than local treatment in preventing metastases. The mechanism of inhibition of tumor growth was related to accumulation of macrophages around the metastases.