Malignant melanoma, breast cancer and other cancers in patients with parkinson disease
Cette étude de cohorte en population danoise évalue, chez 20 000 patients atteints de la maladie de Parkinson, le risque de mélanome malin, de cancers de la peau hors mélanome, et de cancer du sein
Previous studies report an atypical cancer pattern among patients with Parkinson disease. Here we evaluate the cancer pattern among people diagnosed with Parkinson disease in an extension of our previous cohort study. For this Danish population based cohort study we identified 20,000 people with Parkinson disease diagnosed in 1977–2006, from the National Danish Hospital Register. Cohort members were followed up for cancer in the Danish Cancer Registry until 31 December 2008, and their incidence rates of cancer were compared with age-, sex- and calendar period-specific rates in the general population as standardized incidence rate ratios (SIRs). In sub analyses we estimated the risk for cancer among patients with early-onset Parkinson disease and also, we compared breast tumor characteristics among Parkinson disease women to that of a control group. The overall cancer risk in our cohort was decreased (SIR, 0.86; 95% confidence interval (CI), 0.83–0.90), as were those for smoking-related (SIR, 0.65; 95% CI, 0.60–0.70) and non-smoking related cancers (SIR, 0.79; 95% CI, 0.71–0.86). The cohort had increased risks for malignant melanoma (SIR, 1.41; 95% CI, 1.09–1.80), non-melanoma skin cancer (1.29; 1.18–1.39) and female breast cancer (1.17; 1.02–1.34). Among patients with early-onset Parkinson disease the risk for cancer was comparable to that of the general population. Of breast tumor characteristics only grade of malignancy differed between Parkinson disease women and controls. This study confirms a lower cancer risk among people with Parkinson disease. Increased risks for malignant melanoma, non-melanoma skin cancer and breast cancer might be due to shared risk factors with Parkinson disease.