Endocrinologist Dr Ada Cheung
Testosterone replacement therapy is not a straightforward choice in men presenting with low testosterone or symptoms of hypogonadism after treatment for testicular cancer.
Speaking at the 2019 COSA ASM in Adelaide, endocrinologist Dr Ada Cheung said testicular cancer was managed reasonably well.
“Treatments for testicular cancer are really quite good and the survival rate is excellent,” she said. “What I’m interested in is that it causes low testosterone in about 20% of people.”
Dr Cheung, a clinician and NHMRC Research fellow at the University of Melbourne, said the intensity of cancer treatment was the major risk factor for hypogonadism in these men.
“Chemotherapy in addition to surgery, radiotherapy in addition to surgery, the more non-conventional chemotherapy or the more infradiaphragmatic radiotherapy, the more likely they are to have low testosterone.”
She said testosterone replacement therapy was appropriate in patients with low levels (<10 nmol/L).
“It’s really the people who have borderline low levels [10 – 12 nmol/L] that we are unsure about. We don’t know if testosterone replacement is of benefit or not.”
“There are risks with testosterone treatment and unless it is clear cut – definitely hypogonadism with symptoms – then I am not convinced.”
She said once patients started on testosterone it was usually forever. Risks of treatment included polycythemia, cardiovascular disease, and suppression of spermatogenesis.
“A lot of these men are young and they want to have babies and if you give someone testosterone, it makes them infertile. So that is another consideration if they are planning to have a family.”
She said most oncologists or urologists follow standard surveillance schedules for monitoring testicular cancer survivors.
However she emphasised that testosterone levels should always be checked on fasting samples taken first thing in the morning and that a single low reading should always be confirmed with a repeat test.
“And if it is a clear cut low then that’s easy. But when it’s not clear-cut, then it’s not so easy. I get a lot of referrals from oncologists saying this man has borderline low testosterone levels, should I treat?”
Dr Cheung said exercise prescription might be a more evidence based management strategy.
“I think we need to tackle lifestyle recommendations before we proceed down the path of testosterone therapy. Exercise is really important and it has been shown in randomised controlled trials to have benefit and testosterone hasn’t.”
She said a 2018 Canadian study had found that 12 weeks of high-intensity interval training improved cardiovascular risk factors, Framingham risk score, quality of life and VO2 peak compared to usual care.
“So maybe for people who have borderline levels, we should just be getting them all onto exercise.”
She admitted it was difficult to get patients engage in supervised high intensity exercise. And the lack of Medicare reimbursement didn’t help.
“Exercise is not very sexy and patients don’t like doing it. However, having an exercise physiologist as part of the team is helpful,” she said.
She added that a Danish RCT was currently underway looking at testosterone replacement therapy versus placebo in testicular cancer survivors with mild Leydig cell insufficiency.