Thursday, January 2, 2014

Osteoclasts versus osteoblasts

Osteoclasts help break down the bone and osteoblasts help build them back up. Numerous factors influence their activities; estrogen, the parathyroid, activity, Ca levels...

For most women, these cells are in balance until menopause. Estrogen levels drop and the osteoclasts seem to take over leading to osteopenia and then worse, osteoporosis. One quick fix is to replace the estrogen but this increases the chances for breast cancer, both synthetic and so-called bioidentical estrogens are implicated. A better though not necessarily a reliable method, is weight bearing exercise. This stimulates the osteoblasts into action by an unknown (to me) mechanism. Another method is to inhibit the formation of the osteoclasts by taking a class of drugs call bisphononates. These have some issues too such as necrosis of the jaw especially for the most effective inhibitor, Zometa, which is reserved for BC patients who either have bone mets or ones who are at a great risk for bone mets.

The situation gets especially tricky for women who have estrogen positive BC, the most common kind. Treatment includes blocking estrogen for five years. For postmenopausal women, aromatase inhibitors are prescribed which effectively block the hormone from forming. However many patients experience severe joint pain from them. Not sure of the mechanism of this either but it seems to be a constant even with the different AIs out there. Also the patients are more at risk for osteoporosis. For premenopausal BC patients, an estrogen level modulator Tamoxifen is prescribed for 5 years. Now they recommend it for riskier cases for 10 years. Tamoxifen actually preserves bone strength while decreasing the amount of estrogen available to breast tissue. Unfortunately it is an estrogen stimulant in uterine tissue leading to overgrowth of the lining and in some cases, uterine cancer. It also has a list of unpleasant side effects such as depression, joint pain, hot flashes, sexual dysfunction.

I have a friend who is five years out from her ER+ BC diagnosis. She has been gritting her teeth putting up with all the negative side effects of Tamoxifen for 5 years eagerly awaiting the day that she would be off it. She was told that there was not much advantage preventing mets by taking it for ten years in her case. But at a recent check-up, the onc said he was keeping her on it because with her very frail frame, she was at great risk for osteoporosis. Indeed she had osteopenia at diagnosis which seemed to improve on Tamoxifen. But she is so unhappy on it..did she communicate this to the doctor? Not adequately, some people are hesitant to complain lest they sound like an unhappy crab. But the onc should have presented alternatives.

Being tall with strong bones is actually a risk factor for breast cancer, I assume just for the estrogen BC. I am the poster child for a high risk estrogen positive patient: tall, strong bones, dense breasts, alcohol user, used those cancer causing replacement hormones,overweight (fat cells produce estrogen)strong family history. Last month when I was told I had a new area of suspicion, I assumed it would be ER+ versus TNBC.  A moot point as what I had wasn't cancer. The risk factors for TNBC aren't as well defined aside from the genetic ones. Patients are much younger and more likely to be minorities. It was suggested that I take Zometa as part of a clinical trial to possibly prevent bone mets. This would involve a monthly infusion for 2 years. Would my strong bones bolstered from years of running prevent bone mets ? Haven't seen any studies on who is likely to have bone mets. One 'positive' of TNBC is that if one does develop mets, they occur sooner than later. For the soft tissue mets (the scariest: liver brain and lungs)recurrence peaks at 18 months. Bone mets tend to recur later so they remain  my fear however diminishing.

Hercules continues to spoil my routine with even more snow. Steve has been diligently shoveling but I guess I will take over in a few hours once there is a break in the snowfall. I could try to ski again. Maybe my balance has returned. I have plenty of things to do around the house that I keep putting off. So far the only thing productive I have done is find out that my dream of saving $120/year getting my former companies drug has been dashed. It isn't made any more.

And finally, from Aggressive/Passive notes, a funny:

1 comment:

Anonymous said...

Your Blog is always interesting, no matter what the theme. I appreciate the time it takes to compose a post and upload photos.
So Thank You!
Hope you can travel more in 2014.


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