Cyrosurgery and Immunotherapy of Squamous cell Carcinoma in Cattle
An investigation was conducted to assess the incidence and. identify the predisposing factors of bovine squamous cell carcinoma in Kenya. The incidence, breed susceptibility, sites of origin and age distribution of squamous cell carcinoma found in the four breeds of grade cattle in Kenya are reported along with the observed correlation between lack of pigmentation of the bovine vulvae and occurrence of bovine vulva carcinoma. Typical examples of the histology of bovine squamous cell carcinoma which were observed during histological diagnosis are also shown. The data of 18 cattle with vulva carcinoma and 48 cattle with ocular carcinoma on which immunotherapy trials were conducted are reported. The details of the preparation of the saline phenol extract of bovine squamous cell carcinoma used in the study are outlined. The methods by which immunotherapy trials were conducted are described. rIt was found that bovine vulva carcinoma and bovine ocular carcinoma on the eyelid skins did not respond to the extracts while bovine ocular carcinoma on the cornea,sclera and third eyelid responded favourably to the extract. It was noted that the larger the lesion the poorer were the prospects of regression. It is concluded that immunotherapy is a promising modality of therapy for bovine ocular car( cinomaon the cornea, sclera and third eyelid but must as yet be considered as experimental and additional trials are needed to determine its therapeutic efficacy, mechanism of action and the active antigenic substance in the extract. The data of 62 cattle with vulva carcinoma on which cryosurgery trials were conducted are reported. The methods by which cryosurgery trials were conducted and the equipment used are described. It was found that bovine vulva carcinoma responded favourably to cryosurgery trials. It was noted that the larger the lesions the poorer were the prospects 6f achieving a complete cure and that the use of thermocouple needles was imperative for safe and effective treatment. It is concluded that cryosurgery is a safe and practicable technique with few complications and that it should be regarded as one of the treatments of ,choice for bovine vulva carcinoma especially of early clinical lesions. The results of the immunotherapy phase of this study categorize bovine squamous cell carcinoma into two groups viz: Ci) bovine vulva carcinoma and bovine ocular carcinoma on the eyelid skins Cii) bovine ocular carcinoma on the cornea, sclera and third eyelid. The type of this malignancy in group I is thought to be caused by exposure of unpigmented or partly pigmented skins of the vulvae and eyelid to high levels of solar irradiation while the type of this malignancy in group II is thought to be caused by a virus. A hypothesis is advanced that breeding programmes designed to raise Ayrshire cows with high levels of melanin pigmentation on their vulvae and Hereford cattle with red around their eyes are feasible long term measures to eradicate the group I type of this malignancy. The results of the immunotherapy phase of this study indicate that the application of active-specific immunotherapy is the hope Of the future in treating the group II type of this malignancy.