Dem Bones, Dem Bones, Dem Dry Bones

I wanted to share some of the feedback I've received on my clinical trial question.

Generally, people have asked whether I can replicate the benefits of taking the osteoporosis drugs by improved diet and exercise. My sense is that a targeted diet and exercise regimen would help to prevent osteoporosis, but I'm not sure it would be as beneficial as the drugs in warding off a recurrence of breast cancer.

Our bones are constantly regenerating. Old bone is broken down by cells called osteoclasts (the demolition teams), and new bone is created in its place by another group of cells, the osteoblasts (the construction teams). This process keeps bones strong and flexible. As we age, and lose estrogen, however, the demolition teams outpace the construction crews, resulting in bone loss. Genetics, diet and exercise all influence this balance.

This process is further complicated when breast cancer cells show up at the construction sites. Once they enter the bone marrow, breast cancer cells indulge their destructive natures and habitually sign on to the demolition parties, which just can't be a good thing. As I understand it, osteoporosis drugs, or bisphosphonates, work by interrupting the relationship between breast cancer cells and the osteoclasts. Doctors already use these drugs to treat metastatic bone cancer. The two-fold question being investigated in the clinical trial is, first, whether bisphosphonates will help to prevent breast cancer recurrence, as the European study showed, and, second, which drugs and dosages are most effective.

Elizabeth Edwards's story is a good case to consider. After her initial diagnosis in 2004, she underwent surgery, chemo, and radiation, although not necessarily in that order. Most women who follow this treatment remain cancer free. Three years later, however, she learned that her breast cancer had metastasized to the bone. The question for the researchers sponsoring the clinical trial is could she have avoided the involvement of her bones had she taken bisphosphonates in 2004 as an on-going part of her treatment?

Although I'm not completely sure of this, let's assume that diet and exercise can generate bones that are strong enough to inhibit cancer cells from entering them. That would be a real plus. However, in the event that a few cancer cells survived the chemo/radiation and did find their way into the bone marrow, it seems too late for diet and exercise to have any benefit. Since bone is the most common site for breast cancer metastasis, researchers are hoping that bisphosphonates will deter cancer cells already in the skeletal system from making it their second home.

Another point that you've raised in e-mails is the type of bone that bisphosphonates create. Because these drugs work by inhibiting the osteoclasts from breaking old bone down, the resulting bone may be denser, but it's also old and brittle. Bisphosphonates don't generate the new, flexible bones that osteoblasts build naturally, which may explain the problems that some women have experienced with their jaws.

Finally, I've been asked to consider the holistic effect of all of the forms of treatment I've completed or will eventually complete -- surgery, chemotherapy, radiation, estrogen suppressant -- plus the possible addition of bisphosphonates. What is the cumulative impact of all of this? This is a good question for the oncologist, but I'm not scheduled to see him again until the end of April. We will also do the bone scan, or DEXA study, then. Meanwhile, I'm moving ahead with the planning sessions to get radiation underway.

I still have a little time to think about the clinical trial, and I'm finding your e-mails and comments very helpful. Your questions are pointing me in new directions and giving me new angles to consider. It's no secret that I thoroughly enjoy delving into a topic, so keep the feedback coming.