Prostate cancer is common enough among our aging men to be considered of public health concern. It is currently the most common non-skin cancer and the second leading cause of cancer deaths among men worldwide according to the World Health Organisation International Agency for Research on Cancer. The American Cancer Society estimates that one out of every nine men will be found to have prostate cancer at some point in their lifetime. Interestingly, race/ethnicity is the second most significant risk factor for prostate cancer after age with blacks having the highest risks compared to other racial groups. In the American population, African-American men including those with West African ancestry have the highest risks of having and dying from prostate cancer (data from the Surveillance, Epidemiology, and End Results Programme 2020). These statistics are concerning for a country like Nigeria which happens to have the largest concentration of indigenous blacks in the world. Research studies done by a team of medical doctors from the University of Nigeria Teaching Hospital have shown that the number of new cases confirmed per year in Nigeria appears to be increasing and that a significant proportion of these confirmed cases die within two years of confirmation.
Consistent with the evidence that ethnicity is a major risk factor for prostate cancer, recent evidence has highlighted the large heritable component of the disease. While some men with prostate cancer have developed the disease without any known factor accounting for it, a significant percentage of others have inherited a mutation in a gene that is associated with an increased chance of developing the disease. These mutations can be passed down from generation to generation even when no individual in the family has previously been found to have cancer. This inheritable component is so remarkable that men with one immediate relative with prostate cancer have an increased risk of developing the disease with the risk increasing with an increasing number of affected first-degree relatives. Inheritance of these genetic mutations (“bad genes”) not only determines susceptibility to prostate cancer but also other cancers as well including breast, ovarian and endometrial cancers. It also predisposes to an earlier onset disease occurring at a younger age than the expected average age of onset (66 years), and a more aggressive disease compared to those without a predisposing inheritable genetic mutation. In fact, the increased mortality from prostate cancer in black men has been linked to the genetics of the disease amongst other factors including socioeconomics and lifestyles. This recent and evolving information is noteworthy for Nigerian men who not only are at risk of the disease by mere virtue of having a prostate gland but are also at increased risk as black men. The implications of these evolving knowledge might, therefore, become very beneficial in determining the trajectory of the disease course and outcome in this at-risk group.
Globally, these recent findings of the role of genetic mutations in determining susceptibility have begun to influence genetic testing recommendations for prostate cancer patients, prostate cancer survivors, and their male and female family members. These genetic tests to identify these mutations can tell you if you have an inherited mutation contributing to your prostate cancer and can also provide information about you and your relatives’ chances of developing cancer. This knowledge is sharpening approaches to prostate cancer care as increasing evidence suggests that identifying men with mutations in certain cancer susceptibility genes can directly impact prostate cancer treatment and risk reduction in several ways. It provides the opportunity to facilitate the delivery of precise therapy and individualised treatment to prostate cancer patients as these patients have been shown to be particularly sensitive to certain specific medications.
Also, knowledge about the mutation status of these patients impacts treatment decision regarding whether to closely monitor without any interventions (active surveillance) or to actively treat them as actively treating those with identified predisposing mutations is becoming a preferred alternative considering the severity of the type of prostate cancer found in these individuals. Importantly, genetic testing for genetic mutations predisposing to prostate cancer in these individuals not only benefits the patients but also offers healthy male and female family members the opportunity to be counselled and tested to inform their cancer risks. For healthy men at increased risk for prostate cancer, this understanding has the potential to influence a more beneficial targeted prostate cancer screening approach. This is particularly important as controversies surrounding current prostate cancer screening modality lingers on. It is obvious that the identification of inheritable mutations predisposing to prostate cancer has implications on the assessment of personal risk for men and their families. Consequently, expanding education about the role of genetics in prostate cancer and increasing access to genetic testing has the potential to differentially benefit those at the highest risk including Nigerian men.
As prostate cancer continues to be a source of concern for men of all races with advancing age, it is pertinent to understand the evolving science that has emerged in recent times concerning the disease as increasing awareness and knowledge about susceptibility to the disease may potentially shine a glimpse of hope in informing prostate cancer risk for men of this generation and the next.
- Dr. Tobechukwu Joseph Okobi is an Oncology researcher affiliated to Georgetown University, Washington D.C.