Hi, I’m Dr. Scholz. Let’s talk about prostate cancer.
In this video, we’re going to cover a common side effect of hormonal blockade (otherwise
known as androgen deprivation or testosterone blockade). Men with low testosterone levels
from therapy develop accelerated calcium loss from their bones. The consequences are something
called Osteoporosis. When it progresses to a certain point men can develop unexpected
fractures. These are particularly serious if they’re at the hip which can even be
fatal. Many men don’t even recover from that. The other problem are fractures in the
spine. When we think of people getting shorter as they get older, they’re losing height
because the bones that are lined up in the vertebrae are compressing.
So there are ways to prevent this and to treat it, and there are also ways to diagnose because
this is a silent process until suddenly a fracture occurs. Men who are starting on hormone
blockade, in general, should consider going on medications with the initiation of the
hormone blockade so bone loss is prevented.
The way that we test for bone loss to make sure that someone doesn't already have pre-existing
osteoporosis is a scan called the bone density scan of which there are two types. One, the
most common one, is called a DEXA scan. It’s a simple imaging study that checks the hip;
it’s not very accurate for the back. And another study called a QCT which is very accurate
for the back but is not as widely available. Either of these scans are reasonably accurate
and helpful.
Our policy, however, is to start preventative medicine even if men have normal bone density
when they’re on hormone blockade so that they can keep that normal bone density.
So what is the treatment?
Well everyone should be taking vitamin D, perhaps 1,000-2,000 units a day. Vitamin D
levels can be checked in the blood to make sure that you’re getting an adequate amount.
The use of calcium particularly at bedtime where it’s more active is also an appropriate
intervention--250-500mg every evening.
But these measures are not enough to prevent bone loss when men are on testosterone blockade.
In addition, they need to have some sort of a pharmaceutical agent. These fall into two
different categories: The bisphosphonates and a medicine called Denosumab. Denosumab
is an injectable medicine that is given monthly or every three months or every six months,
and it comes in different doses: A low dose form called Prolia and a higher dose form
called Xgeva. The bisphosphonates come in both IV and oral forms. The IV form is called
Zometa and the oral forms are called Fosamax, Boniva, or Actonel. There’s no clear evidence
that any specific medicine is better than the rest for preventing osteoporosis so they’re
all reasonable considerations. Cost and convenience should all come into factoring whether one
of the medicines is selected over another one.
What about side effects from these medicines?
Well, the oral bisphosphonates can occasionally cause some irritation of the stomach and people
who have a history of ulcers should be thinking of injections or infusions rather than pills.
The main concern with all these medicines of all categories is a condition called osteonecrosis.
In this situation, people can have gum tissue recede back and expose the underlying jaw
bone. This is serious because the bone can then become infected, it can be painful, and
it can be very slow to resolve. Osteonecrosis does appear to resolve in most cases after
the medicines are stopped, but it is important to detect it early, and it is important to
get off the medicines quickly as the problem can be abrogated at an earlier stage and it
will heal more quickly. The main concern is people who need to have a tooth extracted
because the jaw metabolism is slowed down by these medications. So prior to initiating
therapy people should be evaluated to make sure that there’s no impending loss of a
tooth, and then if while on treatment a tooth needs to be extracted all these medicines
should be held for a period of time before the tooth is removed.
So in summary medicines to correct osteoporosis are very effective. They need to be managed
wisely to limit the risk of osteonecrosis, but all men who are on hormone blockade should
be advised that they’re at high risk for calcium loss and the development of osteoporosis
because the methods to prevent it are effective and should be utilized.