Introduction: In the pre-PSA era, prostate cancer in younger men was associated with a poor prognosis although more recent data no longer supports this. However, there remains a pervasive view within parts of the urological community that prostate cancer occurring in younger men must be different and inherently more dangerous than the same disease occurring in an older man. So far studies considering this have been from single centres, relatively small, or used indirect techniques.
Objective: To determine if there are differences in the pathological characteristics of prostate cancer in younger men compared to the disease when it occurs in older men.
Methods: A retrospective cohort study was conducted using the prospectively collected prostate cancer database of a multi-institution Australian pathology service. Two age cut offs were used: men 45 years old and younger and 50 years old and younger, and univariant analysis was done using both cut offs. This was done to minimise the risk of Type II errors.
Results: Data was extracted for all prostate cancer cases between 2011–2017 in 11,551 men. 100 men were 45 years old and younger and 413 were 50 years old and younger.
Statistically significant differences were found in a number of pathological characteristics between younger and older men. A greater portion of younger men had Grade Group 1 and 2 disease compared to older men (84.9 and 77.5% for younger men vs 58.4%, p<0.001 and 0.001). Younger men also had statistically significantly lower rates of adverse pathological characteristics, including Extra Prostatic Extension (EPE), Lymph Node positivity, Lymphovascular Invasion, and Seminal Vesical Involvement.
To control for confounding, a sub-group analysis was conducted of men with Grade Group 2 disease. Markedly lower rates of adverse pathological features were apparent, including EPE (17.5 and 23.0% for younger men vs 34.4%, p=0.003 and <0.001), and intraductal carcinoma (0.9 and 2.3% vs 4.8%, p=0.129 and 0.020). There were trends towards superiority in other features.
Conclusion: This is the largest study of its kind, and compliments the findings of others. Our results demonstrate that prostate cancer in younger men is more likely to be lower grade disease with much less risk of adverse pathological characteristics. These results resolve beyond any doubt the longstanding misconceptions regarding prostate cancer in younger men, and should have an impact on disease management and counselling of these patients.
