Prostate cancer is the most common cancer diagnosed among males, and the incidence in Pennsylvania, USA is considerably higher than nationally. Knowledge of regional differences and time trends in prostate cancer incidence may contribute to a better understanding of aetiologic factors and racial disparities in outcomes, and to improvements in preventive intervention and screening efforts. We used Pennsylvania Cancer Registry data on reported prostate cancer diagnoses between 2000 and 2011 to study the regional distribution and temporal trends of prostate cancer incidence in both Pennsylvania White males and Philadelphia metropolitan area Black males. For White males, we generated and mapped county-specific age-adjusted incidence and standardised incidence ratios by period cohort, and identified spatial autocorrelation and local clusters. In addition, we fitted Bayesian hierarchical generalised linear Poisson models to describe the temporal and aging effects separately in Whites state-wide and metropolitan Philadelphia blacks. Incidences of prostate cancer among white males declined from 2000-2002 to 2009-2011 with an increasing trend to some extent in the period 2006-2008 and significant variation across geographic regions, but less variation exists for metropolitan Philadelphia including majority of Black patients. No significant aging effect was detected for White and Black men, and the peak age group for prostate cancer risk varied by race. Future research should seek to identify potential social and environmental risk factors associated with geographical/racial disparities in prostate cancer. As such, there is a need for more effective surveillance so as to detect, reduce and control the cancer burden associated with prostate cancer.
Keywords: Hierarchical generalised linear models; Incidence rate; Prostate cancer; Spatial-temporal analysis; USA.