Background: We investigated the efficacy and safety of adjuvant immunochemotherapy and adjuvant chemotherapy for colorectal cancer, using different combinations of the intracutaneous streptococcal preparation OK-432 and the oral pyrimidines 1-hexylcarbamoyl-5-fluorouracil (carmofur, HCFU) and uracil/tegafur (UFT).
Methods: Patients with stage II, III, or IV (Dukes' B, C) colorectal cancer were enrolled and randomly assigned to one of three groups: an immunochemotherapy group (mitomycin C [MMC] + 5-fluorouracil [5-FU] + HCFU + OK-432), a chemotherapy group (MMC + 5-FU + HCFU), and a control group (surgery alone) for those with colon cancer (study 1); and an immunochemotherapy group (MMC + 5-FU + UFT + OK-432), a chemotherapy group (MMC + 5-FU + UFT), and a control group (surgery alone) for those with rectal cancer (study 2).
Results: A total of 760 patients with colon cancer and 669 patients with rectal cancer were entered into this randomized clinical trial (RCT). The incidence of side-effects was in the order of: immunochemotherapy group >> chemotherapy group >> control group in both the cohort of patients with colon cancer and the cohort with rectal cancer. In particular, the frequency of leucopenia and skin disorders was significantly higher than control groups. There were no severe adverse events such as death related to the adjuvant therapy. In both the colon cancer and rectal cancer cohorts, no significant difference in the 5-year survival rate and disease-free survival rate was noted among the three groups.
Conclusion: The results of an RCT demonstrated that the combination of MMC + 5-FU + HCFU + OK-432 for colon cancer and that of MMC + 5-FU + UFT + OK-432 for rectal cancer could not prolong the survival of patients with surgically resected colorectal cancer, but that both combinations were well tolerated as adjuvant therapy. We investigated the efficacy and safety of adjuvant immunochemotherapy and adjuvant chemotherapy for colorectal cancer, using different combinations of the intracutaneous streptococcal preparation OK-432 and the oral pyrimidines 1-hexylcarbamoyl-5-fluorouracil (carmofur, HCFU) and uracil/tegafur (UFT).