Neurodegenerative disorders and cancer are two of the most common groups of conditions in our world. Some studies have proposed that neurodegenerative disorders may be protective of the development of cancer.

We tested this hypothesis using two neurodegenerative disorders with different molecular pathophysiology – Alzheimer’s disease (AD) and Huntington’s disease (HD) – to see if the inverse relationship between cancer and neurodegeneration was generalizable. Five-year cancer incidence was determined in two large datasets: AD using the C-Path Online Date Repository (CODR) database (n = 6383) and HD using the ENROLL-HD database (n = 2608). Cancer incidence was determined in the populations and compared to normal population data for Australia, United Kingdom and the United States of America. Age-sex standardized rates of cancer were determined and expressed as 95% confidence intervals. We describe an age-sex standardized cancer rate of 1179.6/per 100,000 population to 1253.7/per 100,000 population in normal populations.

The rate in AD was 815.2/per 100,000 population (95% CI 813.32–817.5/per 100,000 population) and for HD 1296.6/per 100,000 population (95% CI 1288–1308.2/per 100,000 population).

We conclude that patients with AD have a reduced age-sex standardized rate of developing cancer not shared with HD, a finding that hints at different molecular mechanisms.

神经退行性疾病和癌症是我们世界上最常见的两类疾病。一些研究提出，神经退行性疾病可能对癌症的发展有保护作用。

我们使用两种具有不同分子病理生理学的神经退行性疾病——阿尔茨海默病 (AD) 和亨廷顿病 (HD)——检验了这一假设，以查看癌症和神经退行性疾病之间的反比关系是否可以概括。五年癌症发病率在两个大型数据集中确定：使用 C-Path 在线日期存储库 (CODR) 数据库 (n = 6383) 的 AD 和使用 ENROLL-HD 数据库 (n = 2608) 的 HD。在人群中确定癌症发病率，并与澳大利亚、英国和美国的正常人群数据进行比较。癌症的年龄性别标准化率被确定并表示为 95% 置信区间。我们描述了 1179.6/每 100,000 人口到 1253.7/每 100,000 正常人群的年龄-性别标准化癌症发病率。

AD 的发生率为 815.2/每 100,000 人（95% CI 813.32–817.5/每 100,000 人）和 HD 的比率为 1296.6/每 100,000 人（95% CI 1288–1308.2/每 100,000）。

我们得出的结论是，AD 患者的年龄性别标准化癌症发病率降低，这与 HD 不同，这一发现暗示了不同的分子机制。