Identifying health disparities in cancer treatment outcomes can help healthcare providers create targeted strategies to improve care. We investigated how age and race disparities in prostate cancer (PCa) survival have changed in the USA since 1973.
We analyzed PCa cases from the NCI Surveillence, Epidemiology, and End Results (SEER) database from 1973-2011. Trends in PCa incidence, grade, and stage were identified, and then specific comparisons using Cox proportional hazards models were performed by age and race. Inclusion criteria: patients diagnosed between 1973 – 2008, age ≥ 50 and < 90. Exclusion criteria: multiple primary cancers, unknown M stage.
A total of 658,916 PCa patients matched our criteria. The median follow-up time for living patients is 90 months (interquartile range: 59 – 128 m). From 1973 to 2008, the median age of diagnosis decreased from 73 to 66. Over the same time period, there was a reduction of late-stage diagnoses, with the proportion of metastatic disease (M1) decreasing from 12.4% to 3.9%, and the proportion of locally invasive disease (stage T3-4) among non-metastatic (M0) patients decreasing from 48.3% to 2.4%.
The remainder of the results are confined to M0 disease. Among all age groups, four-year cancer specific mortality decreased progressively. However, while four-year cancer specific mortality decreased from 24% to 3% amongst those aged 50-54, it only dropped from 38% to 18% for those aged 85-89 in the same time period. This is further highlighted by the hazard ratio (HR) for cancer-specific death for those aged 85-89 (reference: 50-54 y.o.) which rose from 2.70 in 1973- 9 to 15.02 in 2000-8. The widening age disparities over time were only marginally altered by incorporation of ‘tumor stage’ into the model suggesting that they are not a result of delayed diagnosis. To a lesser extent, race-related disparities also widened, with the hazard ratio for death increasing from 1.25 (1973-79) to 1.42 (2000-8) over the study period
Age- and race- related health disparities in survival outcomes for PCa patients have widened in the last 35 years, against a backdrop of greatly improved screening, diagnosis and treatment. Further work should be done to see what factors have facilitated the continuous rise in health disparities what can be done to overcome them.