Black Men with Low-Risk Prostate Cancer

Prostate malignancy is invariably the most common cancer among males and is associated with high morbidity and mortality in the absence of a viable treatment approach. Several risk factors have been identified by investigators to assess the risk profile in susceptible males in order to initiate early screening process. For example, positive family history of prostate cancer in the first degree relatives, high body mass index, advancing age and ethnicity are classified among the most significant risk factors.

It has long been known that the average life time risk of developing prostate cancer is twice as high in black males as compared to the general population (1). For example, based on the results of an English study, the incidence of prostate cancer is 1 in 4 black males as opposed to 1 in 8 in white males. Clinical data also indicates that the prognosis is generally poor in black males suffering from prostate cancer owing to low socioeconomic status and limited access to healthcare services. In addition, the progression of cancer to more aggressive disease is also seen more frequently in black males. So is there a logical reason that can explain poor prognosis in black men?

Black males and prostate cancer

According to a new study reported in the Journal of Urology (2), investigators identified that PSA production is comparatively lower in some black males as compared to white/ Caucasian males. Research conducted by Oleksandr N. Kryvenko and colleagues on the prostate tumor samples (obtained after radical prostatectomy procedure from 348 white males and 66 males of African American decent) suggested that:

• Despite similarities in the age, serum PSA levels and body mass indices, the relative production of PSA was found lower in the tissue samples obtained from African-American males as compared to white males. Interestingly, tumor size as well as size of primary tumor nodule was also similar in both study groups.
• The PSAD or density of PSA is also lower in African American males (0.09) when compared to white males (0.105); regardless of the fact that prostate gland are relatively heavier in black males (an average of 10g heavier).

So what does this imply?

Investigators proposed that this disparity in the characteristics of PSA levels calls for a revision in the active surveillance plan for African-American males in order to improve the prognosis. The team of researchers also explained that the current inaccuracies in the active surveillance criteria of prostate malignancy in black males is mainly attributed to this factor.

Essentials of Active Surveillance Program

The active surveillance program (ASP) was first introduced in 1995 for individuals with low risk prostate malignancies to carefully assess and track the cancer progression.  The ideology behind ASP is to encourage more people with low risk prostate cancers to opt for surveillance instead of going for curative surgical approach. The key components of ASP are:

• Periodic digital rectal examinations
• Semi-annual analysis of PSA levels
• 12-14 core biopsies (annually)

Several research studies have suggested that metastasis-free survival and cancer specific survival rates are generally high in patients who are put on active surveillance. For example, study reported in Journal of Clinical Oncology (3) suggested that metastasis-free survival at 10 and 15 years respectively is 99.9% and 99.4%; however, these findings are only applicable in white males as prostate cancer generally runs a more aggressive course in black males (which calls for a more intense surveillance program).

Based on the results and conclusions drawn by Kryvenko; an ideal approach in this regard would be to consider a lower threshold of PSA in African American males during active surveillance.

References

1. Lloyd, T., Hounsome, L., Mehay, A., Mee, S., Verne, J., & Cooper, A. (2015). Lifetime risk of being diagnosed with, or dying from, prostate cancer by major ethnic group in England 2008–2010. BMC medicine, 13(1), 171.

2. Kryvenko, O. N., Balise, R., Prakash, N. S., & Epstein, J. I. (2015). African American Men with Gleason Score 3+ 3= 6 Prostate Cancer Produce Less PSA Than Caucasian Men: A Potential Impact on Active Surveillance. The Journal of urology.

3. Tosoian, J. J., Mamawala, M., Epstein, J. I., Landis, P., Wolf, S., Trock, B. J., & Carter, H. B. (2015). Intermediate and longer-term outcomes from a prospective active-surveillance program for favorable-risk prostate cancer. Journal of Clinical Oncology, JCO-2015.