Bostock D E, Curtis R
Vet Rec. 1984 Apr 7;114(14):341-2. doi: 10.1136/vr.114.14.341.
The variation in prevalence of neoplasms over time and location has been of value in identifying environmental carcinogens. Studies on the relative frequency of the different histological types of canine oropharyngeal malignant neoplasm have shown that squamous cell carcinoma of the tonsil occurs four times more commonly in south east England, and twice as frequently in the United States of America as in Melbourne, Australia. The prevalence of tonsillar squamous cell carcinoma in London in 1950 was 15 times greater than that currently experienced in Melbourne and four times greater than that now found in other areas of south east England.
肿瘤患病率随时间和地点的变化，对于识别环境致癌物具有重要价值。对犬口咽恶性肿瘤不同组织学类型的相对频率研究表明，扁桃体鳞状细胞癌在英格兰东南部的发病率是其他地区的四倍，在美国的发病率是澳大利亚墨尔本的两倍。1950年伦敦扁桃体鳞状细胞癌的患病率比目前墨尔本的患病率高15倍，比现在英格兰东南部其他地区的患病率高4倍。
