Active specific immunotherapy in colon cancer.

Colorectal cancer is one of the leading causes of cancer-related mortality. After a series of clinical trials, the adjuvant 5-FU-based chemotherapy has established a definitive role in the management of stage III colon cancer. While the precise role for chemotherapy in stage II disease remains under investigation, less toxic treatment modalities such as active specific immunotherapy (ASI) have emerged as potentially attractive alternatives. In a randomized trial it was demonstrated that ASI, using autologous tumor cells and BCG, had a significant clinical benefit in the adjuvant treatment of stage II colon cancer. In addition, it was found that the delayed-type cutaneous hypersensitivity reactions (DTH) against autologous cells correlated significantly with survival, confirming its suitability for immunomonitoring. Nowadays, 5-FU-based chemotherapy is a standard treatment for stage III colon cancer and because there is preclinical evidence for synergism between chemotherapy and ASI, we performed a phase II study to investigate whether the combined treatment with 5-FU and ASI is tolerable and feasible. We demonstrated that 5-FU treatment hardly affected the DTH response against autologous tumor cells and that the combination treatment was well tolerated. A randomized phase III trial is now warranted to show that the combination of ASI and chemotherapy is superior to chemotherapy alone.