| dc.description.abstract | Effectiveness of cimetidine medication on melanomas in 40 grey horses.
Nienke M. Helle1, Coby Lettinga1, Na Liu2, Chao Sha2, Joop B. A. Loomans1,2
1. Fac. Veterinary Medicine, Departement Equine Health Sciences, Utrecht University, The Netherlands
2. Heilan International Equestrian Club, Xin qiao, Jiangsu, China
J.B.A.Loomans@uu.nl
Introduction
The melanoma is one of the most common cutaneous tumors in horses and consists mainly of melanocytes.1,3,4 Common localizations are the perineal and perianal region, the external genitalia and the ventral surface of the tail.2. Several therapies for the treatment of melanomatosis exist, including the administration of the H2 receptor antagonist Cimetidine. Cimetidine has been found to slow down growth of the primary tumor and preventing disease progression, by acting as an immunomodulator. 3,5 The aim of this study was to try to confirm the positive effects of cimetidine on melanomas in a group of 40 grey horses.
Materials and Methods
Forty grey horses with ages ranging between 5 and 19 years on the Heilan International Equestrian Club with different degrees of melanomatosis were given Cimetidine (2,5mg/kg/TD) during 90 days in a watery solution in their forage. Every 30 days the size, the localization and the amount of the melanomas of each horse were registered. Differences in number of melanomas after three months were tested using descriptive statistics and the Wilcoxon signed test. The total surface area was used as the standard for size and was calculated by multiplying the narrowest and broadest point of the melanomas and adding these numbers to give one measurement value per horse per time period. Statistical significance of the total surface area was tested using the linear mixed model method.
Results
In this population of horses 65% had melanomas. After the three months of cimetidine administration a significant growth in number of melanomas was found comparing the first and the last measurement. See figure 1. The total surface area of the melanomas of each horse of the fourth measurement was not significantly different from the total surface area of each horse at the first measurement.
Conclusions
In this study the positive effects of cimetidine on melanomas cannot be confirmed. In contrast, we found an actual growth in number of melanomas after three months of cimetidine administration and did not lead to a reduction of the total melanoma surface area.
References
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3. LeRoy BE, Knight MC, Eggleston R, Torres-Velez F, Harmon BG. Tail-base mass from a “horse of a different color”. Blackwell Publishing Ltd 2005;34:69-71
4. MacGillivray CK, Sweeney RW, Del Piero F. Metastatic melanomas in horses. Blackwell Publishing Ltd 2002;16:452-456
5. Siegers CP, Andresen S, Keogh JP. Does Cimetidine Improve Prospects for cancer patients? Digestion 1999;60:415-421 | |
