Natural history, and impact of surgery and radiation on survival outcomes of men diagnosed with low-grade prostate cancer at ≤ 55 years of age: a 25-year follow-up of > 60,000 men

Purpose: Low-grade prostate cancer has low mortality rates at 10 years; however, it is unclear if the response is sustained for up to 25 years of follow-up.

Methods: Using Surveillance, Epidemiology, and End Results database, the overall and cancer-specific mortality rates were compared among men ≤ 55 years of age diagnosed with low-grade prostate cancer that either had radical prostatectomy, radiotherapy, or no known treatment.

Results: Of the 62,772 men diagnosed with low-grade prostate cancer between 1975 and 2016, about 60%, 20% and 20% of men underwent radical prostatectomy, radiotherapy, and no known treatment, respectively. At a median follow-up of 10 years, almost 2% and 7% of men died of prostate cancer and other causes, respectively. The overall mortality was significantly better in radical prostatectomy group compared to no known treatment group (HR 1.99, CI 1.84-2.15, P value < 0.001), but not between the radiotherapy and no known treatment groups. Moreover, the overall and cancer-specific mortality rates in the radiotherapy group were almost two and three times compared to the radical prostatectomy group, respectively (HR 2.15, CI 2.01-2.29, P value < 0.001 for overall mortality and HR 2.87, CI 2.5-3.29, P value < 0.001 for cancer-specific mortality).

Conclusions: The study confirms low mortality rates in men diagnosed with low-grade prostate cancer for over 25 years' follow-up. While radical prostatectomy improves survival significantly compared to no known treatment, radiotherapy is associated with an increase in overall and cancer-specific mortality, which may be related to long-term toxicities.