From the article:
A new population-based study from The University of Texas Medical Branch at Galveston showed for the first time that exposure to testosterone therapy over a five-year period was not associated with an increased risk of aggressive prostate cancer. Further, risk of high-grade prostate cancer did not increase according to the total number of testosterone injections.
[…]
Although several longitudinal studies have shown no increased risk of prostate cancer incidence associated with testosterone use, no population-based studies have examined the association of high-grade prostate cancer with testosterone exposure beyond one year.