Prostate cancer-specific mortality rates: Afro-Caribbeans and African-Americans

At a quick glance one could get the idea from a new study that men of African ethnicity in the Caribbean were fundamentally more likely to die of prostate cancer than men of African ethnicity in the USA. However, a more careful reading of the study data suggests that this may not, really, be the case.

Mutetwa et al. have used data from cancer registries for Brooklyn, NY and for two countries in the Caribbean (Guyana and Trinidad and Tobago) to estimate 5-year survival after a diagnosis of prostate cancer. They also used these data to investigate whether Black race or Caribbean birthplace could be used to predict prostate cancer survival among males of African ethnicity living in the USA.

The data from their analysis showed that:

  • Patients in Guyana and in Trinidad and Tobago were diagnosed at a greater average age than those in the US (Guyana: 74.5 years, Trinidad and Tobago: 72.4 years, Brooklyn: 65.8 years).
  • Patients in Guyana and in Trinidad and Tobago had a worse 5-year survival rate compared to those in the US (41.6 vs. 84.4 percent).
  • Caribbean-born prostate cancer patients living in the US had a 5-year survival rate similar to that of African-Americans (78.1 vs. 81.4 percent).
  • A mean age of > 65 years and clinical stage IV disease at diagnosis, but not ethnicity, were found to be independently associated with the risk of prostate cancer-specifiuc mortality.

There are extensive data today to show that earlier diagnosis and treatment have significant impact on 5-year survival data after a diagnosis of prostate cancer. While the combination of lead-time bias with data from the PLCO and ERSPC studies do not yet demonstrate that mass population-based screening and early diagnosis have a definitive impact on overall survival of prostate cancer, what we do know is that men who are diagnosed and effectively managed early in the evolution of their disease have a relatively low risk of death from prostate cancer within 5 years. So — as stated by the authors of this paper — it seems highly likely that the apparent 5-year survival disadvantage for patients diagnosed in and living in Guyana or Trinidad and Tobago compared to African Americans in Brooklyn is due (at least in part) to diagnosis at a greater age and therefore later in the evolution of their disease.

As Mutetawa et al. also point out, this would suggest that interventions focused on early detection and education about prostate cancer would lower the 5-year prostate cancer-specific mortality in Caribbean populations. Whether it would have any real impact on 10-year and 20-year prostate cancer-specific mortality rates in Caribbean populations is a harder question to answer.

2 Responses

  1. More confirmation for the necessity that African-Americans and others of African descent receive increased awareness of the prevelance of prostate cancer as well as increased mortality rates in this ethnic background and the importance of earlier detection.

  2. This study seems to say that if you diagnose one group of men — black US residents — at age 65 you will find more of them alive after 5 years than if you diagnose black Caribbean residents at age 75, which would lead me to say, “well, yes … and …?”

    The men in the Caribbean group clearly lived longer than 5 years after age 65, even though they had no treatment — otherwise they could not have been diagnosed at age 75!!

    A comparison between US residents and Caribbean residents of the same age might have been more relevant, I think.

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