The effect of indomethacin on the growth of epidermoid carcinoma of the palate in rats.

The in vivo effect of indomethacin therapy in head and neck cancer was tested using rats (Fisher 344) with implanted epithelial palatal carcinoma. Indomethacin was then given to half of the rats in their drinking water, starting two weeks after tumor implantation. The animals were then killed at four weeks and the tumor volumes were measured. It was found that four (21%) of the 19 rats were complete responders and eight (42%) of the 19 rats were partial responders. The control group showed increased tumor growth in all animals. The experimental group also demonstrated five (26%) of the 19 regional metastases. No metastases were seen in the control group. Indomethacin seems to inhibit local tumor growth, perhaps through its effects on cellular and humoral immunity and its effects on the host-tissue stroma. It also may increase tumor spread through the regional lymphatics or hematogenously. Further animal studies need to be carried out to determine the effect on cancer on a cellular and biochemical level before using it for treatment of cancer in humans.