The association between prostate cancer and Parkinson’s disease (PD) is a link that scientists have been researching for years. Neurodegenerative disorders such as Parkinson’s may share some disease causing mechanisms with some cancers says Dr. Stefan Pulst of the University of Utah. Researchers suggest that an association between PD and melanoma may be based on the treatments given to PD patients.
About Parkinson’s disease
Parkinson’s is a degenerative neurological movement disorder. People with PD experience damage to nerve cells in the brain that produce the neurotransmitter dopamine. The reduction or absence of dopamine results in symptoms that can affect changes in a person’s movement and emotions. Although scientific research is advancing, there is currently no known cause or cure. Genetic and environmental factors are both thought to contribute to cause PD. Although Parkinson’s treatment is individualized; the first line treatment is generally with dopamine replacement medications that help to reduce tremors and muscle rigidity, and improve motor function.
The prostate is a small gland that is part of the male reproductive system. The prostate is a gland within the male reproductive system that makes and secretes seminal fluid. This fluid is clear-to-white and mixes with sperm produced in the testes to form semen. Prostate cancer (PC) is one of the leading causes of cancer in men. The most common form is adenocarcinoma which is treatable and generally not life-threatening.
Parkinson’s and prostate cancer are both age-related diseases. There have been studies demonstrating an association between having PD and an increased likelihood of developing prostate cancer. Genetic links, protein mutations, and certain medications continue to be evaluated.
Levodopa, the first line medication given to people with PD is involved in production of melanin (biologic pigments). These dopaminergic drugs may increase the risk of developing prostate cancer and skin cancer according to Dr. Susan Bressman from Beth Israel Deaconess Medical Center. There is evidence that people with PD treated with certain medication combinations had a higher incidence of prostate cancer than those in a control group.
The Utah Population Data Base has extensive genealogic information on more than 2.2 million people over 15 generations. It is linked to the statewide cancer registry. A large-scale study out of the University of Utah reviewed records containing information on birth, death and family relationships. They identified 3,000 people with 3 generations who had PD listed as the cause of death.
Results from this extensive data set suggest that the risk of prostate cancer and melanoma within the population was significantly higher than expected. In fact, the increased risk was also evident amongst relatives of people with PD. The Utah database was able to assess risk in first, second and third-degree relatives.2 The findings are statistically significant with first- and second-degree relatives.
The study sought to validate its results by cross-examining data. Researchers identified people diagnosed with melanoma or prostate cancer and found that they were also at a significantly increased risk of death from Parkinson’s disease.1
Genetic or Environmental Factors
Underlying functional changes are part of the disease process for prostate cancer, PD and melanoma.1 PD and cancer seem to have opposite effects on cells. PD degenerates nerve cells and cancer causes cells to grow out of control. Identifying any genetic links between these diseases may help direct future screening and development of treatment protocols. Similarly, environmental factors may play an influential role. The Utah study had a geographically controlled and genetically similar population.
Not everyone agrees
Controversy exists within the medical arena regarding the association between PC and PD.3 Scientific findings over the years have suggested a decreased cancer rate in people with Parkinson’s compared to the general population. The risk of developing prostate cancer was said to lessen with the number of years a man has had Parkinson’s disease.
However, the Utah study and other findings, support the need for further epidemiological and clinical research to explore the common pathways of both diseases. Future studies should consider ethnicity, time of PD diagnosis and PD treatment regimens as part of investigating the association between Parkinson’s disease and risk of prostate cancer.3 Scientists do not yet agree on either a causative or protective link between PC and PD. The literature can be confusing. Make sure to talk to your doctor about any concerns or symptoms you may have. Individual monitoring is, for right now, still the best way to enable the best medical care.