Bone/Muscle Cancer:
New Research and Technology
David M. King, MD
Medical College of Wisconsin Orthopedic Oncologist
The musculoskeletal oncologists at Froedtert & Medical College of Wisconsin of Wisconsin are active in finding new ways to treat cancer of the bone and muscles. Dr. David King tells us about the latest research in the field and talks about technological breakthroughs that are transforming treatment.
Q. Could you tell us about the "research scene" for bone and muscle cancers?
One of the difficult things with bone and soft tissue cancer is that it is considered an "orphan disease." Statistically, there are very few cases of it compared to breast cancer, for example, or some of the carcinomas that are more common. Obviously, research dollars are going to be funneled more toward where you can get the biggest bang for your buck.
Nationally, because these tumors are so rare, we tend to form consortiums or groups that study these issues together. For instance, right now we have a study for soft tissue sarcomas through the University of Chicago and some other tertiary medical centers. The study is evaluating the effects of combining chemotherapy and radiation therapy in a certain sequence.
Q. What sequence are you testing?
We start with chemotherapy up front, right after diagnosis. Then, before surgery, we use radiation therapy between cycles of chemotherapy. We allow the tumor to shrink, then we remove the tumor. After surgery, the patient gets further chemotherapy and, if the cancer cells haven't been completely removed, radiation therapy.
This is an experimental protocol. It's taking a lot of the ideas we use normally, and combining them. We've had a couple patients enrolled in this study and overall it's going very well.
Q. What other research projects are you working on?
Dr. Hackbarth [Donald A. Hackbarth, MD, Medical College of Wisconsin orthopedic oncologist] and I are doing biomechanical studies to evaluate different methods for replacing large segments of bone.
Q. What is that all about?
Sometimes, when you remove a bone tumor, you have to replace that segment of bone with something to save the patient's leg. If you put in an allograft – a cadaver bone – the patient's body will remodel it over time and create its own bone on the ends. The middle of the bone, however, stays dead and over time it will fracture, usually in 10 to 15 years.
I have a study in which we are looking at the different ways to fix allograft replacements and see which provides the most stability. This study won't involve patients, it will take place in the lab.
Q. Is there any new technology in your field?
With pediatric sarcoma, the patient is young and is still growing physically. If you take out the bone, you take out the growth plates as well. It has been a real problem in the past to try to lengthen patients' limbs to keep pace with their growth.
Both Dr. Hackbarth and I have started using a new prosthesis called a Repiphysis on select patients. This new prosthesis allows for noninvasive lengthening. You place an electromagnetic coil over the patient and then, without actually opening the patient up, a coil inside the patient lengthens. Eventually, when the patient reaches skeletal maturity, you can take out the Repiphysis and put in a permanent implant.
At the time that I put in the last few Repiphysis implants, there had only been about 50 placed in the United States.
Q. What other new technologies are you working with?
In combination with the interventional radiologists, we are using radio frequency probes to heat up tumors, particularly metastatic tumors [tumors spread from other parts of the body]. We have been using this technology with liver tumors, and now bone tumors.
We're just signing on to do a study using a radio frequency probe for patients who have metastatic disease to the bone and who are having pain. We will see if we can heat up the tumor with the probe and eliminate the pain.
Q. What treatments lie ahead for musculoskeletal cancer?
There is a lot of research being done on creating bone to fill bone deficits and on regenerating bone.
There is also some new metal implant technology that I think is going to be useful in the next two to three years-a sort of "scaffold" that will allow bone to grow into large defects.
There is going to be targeted therapy for certain tumors. The idea is to find a specific defect in the DNA of a tumor type and then target that defect directly with a drug, one that would be more specific than just treating the tumor with regular chemotherapy.