Tonsillar carcinoma in rural dogs

ACCORDING to several reports, the prevalence of tonsillar carcinoma among dogs in London and Philadelphia is relatively high1–5. Because the prevalence in a rural population was never available for comparison, it was only speculation that the rate was higher for urban than for rural dogs. Carcinoma of the tonsil was the most common oral-pharyngeal tumour in both London and Philadelphia dogs. Withers5 estimated that the prevalence of tonsillar carcinoma in London dogs was 12 per 10,000. The prevalence was 9.1 per 10,000 in the Philadelphia study2. It has been proposed that an increased prevalence of carcinoma of the tonsil may be due to the presence of carcinogenic substances in the atmosphere of industrialized cities1.