Patients with Parkinson’s disease have an estimated relative risk for melanoma of 1.95, according to research published online in the September 3 Archives of Neurology. Relatives of patients with Parkinson’s disease also have a significantly increased risk of melanoma. The risk of death with Parkinson’s disease is 1.65 among patients with melanoma and significantly increased among their relatives.
In addition, patients with Parkinson’s disease have an estimated 1.71 relative risk for prostate cancer, noted Seth A. Kareus, MD, chief resident of neurology at the University of Utah School of Medicine in Salt Lake City. These patients’ relatives also have a significantly increased risk for prostate cancer. The risk for death with Parkinson’s disease is 1.39 among patients with prostate cancer and significantly increased among their relatives.
To analyze links between Parkinson’s disease and various cancers, Dr. Kareus and colleagues identified 2,998 individuals from the Utah Population Database for whom Parkinson’s disease was listed as a cause of death. The researchers also examined data from the Utah Cancer Registry for 100,817 individuals with a diagnosis of cancer. Relative risk for cancer was calculated for patients with Parkinson’s disease and their first-, second-, and third-degree relatives, and risk for Parkinson’s disease was calculated for individuals with cancer and their relatives.
“Decreasing relative risks with increasing genetic distance are strongly supportive of a genetic interpretation for increased cancer occurrence in relatives,” stated Dr. Kareus. “These data argue strongly for a significant shared genetic risk for specific cancers on the one hand and neurodegeneration on the other.”
“Clinically, it is important to explain to patients with Parkinson’s disease and their family members that the genetic predisposition to Parkinson’s disease is restricted to patients with younger onset of symptoms,” said Walter A. Rocca, MD, Professor of Epidemiology at the Mayo Clinic in Rochester, Minnesota, in an accompanying editorial. “Family members may experience a wide range of clinical manifestations, not simply Parkinson’s disease. Knowledge of this clustering of disease within families may also guide preventive interventions … for family members of patients with Parkinson’s disease who may be at particularly high risk,” he added.