A team from Nagoya, Japan, investigated the effects of cimetidine in colorectal cancer patients.
A total of 64 colorectal cancer patients, who received curative operation, were examined for the effects of cimetidine treatment on survival and recurrence.
The cimetidine group was given 800 mg of cimetidine per day orally, together with 200 mg of 5-fluorouracil per day. The control group received 5-fluorouracil alone.
Treatment was initiated 2 weeks after the operation and terminated after 1 year.
Robust beneficial effects of cimetidine were noted: the 10-year survival rate of the cimetidine group was 85%, whereas that of control group was 50%.
In previous studies, the authors observed that cimetidine blocked the expression of E-selectin on vascular endothelium and inhibited the adhesion of cancer cells to the endothelium. Thus, the researchers further stratified the patients according to the expression levels of sialyl Lewis antigens X (sLx) and A (sLa).
It was found that cimetidine treatment was particularly effective in patients whose tumor had higher sLx and sLa antigen levels.
|10-year survival for patients with high sLx levels:|
Cimetidine group: 96%
| British Journal of Cancer |
For example, higher CSLEX staining was used to recognize tumors expressing high levels of sLx antigens. The 10-year cumulative survival rate of these patients in the cimetidine group was 96%, whereas that of control group was 35%.
In contrast, in the group of patients with no or low levels of CSLEX staining, cimetidine did not show significant beneficial effect. Here the 10-year survival rate of the cimetidine group was 70% and that of the control group was 86%.
Dr S. Matsumoto, of the Fujita Health University in Nagoya, concluded on behalf of the group, "These results clearly indicate that cimetidine treatment dramatically improved survival in colorectal cancer patients with tumor cells expressing high levels of sLx and sLa."
In an accompanying Editorial, Drs D. Eaton and R. E. Hawkins, of Manchester, England, commented that these results were striking.
"The results appear to justify further investigation of the effect of cimetidine on E-selectin expression and the consequences of this interaction on sLx and sLa expressing colonic carcinoma," they said.
"Subsequent large-scale clinical trials appear warranted," they concluded.