UCSF

IMPORTANCE: Patients with Parkinson disease (PD) who harbor LRRK2 G2019S mutations may have increased risks of nonskin cancers. However, the results have been inconsistent across studies. OBJECTIVES: To analyze pooled data from 5 centers to further examine the association between LRRK2 G2019S mutation and cancer among patients with PD and to explore factors that could explain discrepancies. DESIGN, SETTING, AND PARTICIPANTS: Clinical, demographic, and genotyping data as well as cancer outcomes were pooled from 1549 patients with PD recruited across 5 movement disorders clinics located in Europe, Israel, and the United States. Associations between LRRK2 G2019S mutation and the outcomes were examined using mixed-effects logistic regression models to estimate odds ratios (ORs) and 95% CIs. Models were adjusted for age and ethnicity (Ashkenazi Jewish vs others) as fixed effects and study center as a random effect. MAIN OUTCOMES AND MEASURES: All cancers combined, nonskin cancers, smoking-related cancers, hormone-related cancers, and other types of cancer. RESULTS: The overall prevalence of the LRRK2 G2019S mutation was 11.4% among all patients with PD. Mutation carriers were younger at PD diagnosis and more likely to be women (53.1%) and of Ashkenazi Jewish descent (76.8%) in comparison with individuals who were not mutation carriers. The LRRK2 G2019S mutation carriers had statistically significant increased risks for nonskin cancers (OR, 1.62; 95% CI, 1.04-2.52), hormone-related cancers (OR, 1.87; 95% CI, 1.07-3.26) and breast cancer (OR, 2.34; 95% CI, 1.05-5.22) in comparison with noncarriers. There were no associations with other cancers. There were no major statistically significant differences in the results when the data were stratified by Ashkenazi Jewish ethnicity; however, there was some evidence of heterogeneity across centers. CONCLUSIONS AND RELEVANCE: This multinational study from 5 centers demonstrates that LRRK2 G2019S mutation carriers have an overall increased risk of cancer, especially for hormone-related cancer and breast cancer in women. Larger prospective cohorts or family-based studies investigating associations between LRRK2 mutations and cancer among patients with PD are warranted to better understand the underlying genetic susceptibility between PD and hormone-related cancers.