A recent article in the journal Cancer reported that there is an association for men being treated for prostate cancer with androgen deprivation therapy (ADT) and a risk of developing blood clots.
The article, written by Edhaie et al. analyzed the Surveillance, Epidemiology and End Results (SEER) –Medicare database to identify 154,611 men over the age of 65 years with non-metastatic prostate cancer.
They then searched this population for men who had used any form of ADT (both medical and surgical ADT) as well as for an occurrence of deep venous thrombosis, pulmonary embolism, or arterial embolism (thrombotic event). With a median follow up of 52 months their analysis found that 38% of the men in this cohort had experienced at least one thrombotic event.
Fifty five percent (55%) of those men who had an event had also received ADT while only forty five percent (45%) had not had any event.
They drew the following conclusions:
1- ADT was associated with an increased risk of having a thrombotic event (adjusted hazard ratio = 1.56.
2- A longer duration of ADT treatment increased the risk of experiencing more events.
The take away messages are:
1- Because there seems to be an increased risk of having a thrombotic event because of using ADT it would be a good idea to have a man evaluated prior to starting ADT. This is a practice that is rarely done in the normal course of events. However, with these findings in mind, there is no reason that standard operating procedures not incorporate a prior evaluation before beginning ADT.
2- There is no direct evidence that ADT causes thrombotic events, the evidence is that they are associated. It is possible that the increased risks are caused by an increase in body fat or a decrease in exercise by a man because of their increased general fatigue.
Despite the issue of association and causation men need to be cautious and press their doctors to act in a more cautious manner.
We now need additional information along this issue. Will intermittent ADT be associated with less thrombotic events than continuous ADT?
Joel T Nowak, M.A., M.S.W.