Antitumor efficacies of maltose tetrapalmitate immunotherapy alone and in combinations with radiotherapy and with cyclophosphamide chemotherapy against dimethylhydrazine induced colon and anal cancers in CDI mice.

Treatment of human colonic cancer in early stages when the process is still limited to the colonic wall is primarily surgery. We wished to see if maltose tetrapalmitate (MTP) immunotherapy alone or in combination with radiotherapy (R) and cyclophosphamide (C) chemotherapy would be effective against primary colon cancer in a fashion similar to that reported by us for primary liver cancer (Anticancer Research 6: 245-250, 1986). One hundred female CD1 mice were subjected to dimethylhydrazine (DMH) treatment once a week for 26 weeks, a period one week before which, colon cancer was histologically documented in each animal of a group that was sacrificed. Surprisingly, many of the animals harboured early anal cancer as well. At 28 weeks, 85 of the available animals were divided into 6 groups that received: Gr. 1, no treatment; Gr. 2, MTP alone (M); Gr. 3, radiotherapy alone (R); Gr. 4, cyclosphophamide alone (C); Gr. 5, R + C; Gr. 6, M + R + C. Criteria of treatment efficacy were: number, size and staging of colorectal tumors and the incidence and the size of anal tumors at death. Mean survival time was also determined although it remained a questionable criterium since most animals died due to complication (hepatic toxicity, pyelonephritis, thrombose) elicited by DMH, R and C toxicities and not as a result of colonic tumor size or metastases. As a single therapy, M appeared to be superior to either R or C alone. However, R + C combination was effective and was further improved upon by its association with M. With the triple combination, (M + R + C), lesions of both cancers decreased in size and/or number and the colon cancer histologically eclipsed from 46% of the treated animals.