GIVING HOPE TO CANCER PATIENTS

Dr. Martin Malawer

When Martin Malawer, MD, began his orthopedic practice in the early 1970s, the standard of treatment for patients with most bone and soft tissue cancers was amputation – at the joint, above where the cancer was located. The majority of these patients were young – children or adolescents – and faced the prospect of a lifetime of limited function and mobility due to the loss of an entire arm or lower extremity.

Dr. Malawer was convinced there had to be a way to save these patients' limbs by creating an endoprosthetic bone and adjacent joint to replace the cancerous one. He set out to transform the phrase “you have cancer,” to “you have hope.” He devoted his life to combining his passions for anatomy, engineering and metallurgy to saving these patients' lives and limbs. Thanks to his work and that of other dedicated surgeons, today only about six percent of patients in America with bone or soft tissue cancer must face amputation. However, this remarkable improvement in patient care did not come easily.

Dr. Malawer began his career as an orthopedic oncologist as junior chief resident under the two fathers of the field, Ralph Marcove, MD and Ken Francis, .D, at Memorial-Sloan Kettering Cancer Center and the New York University Medical Center. “The field of orthopedic oncology started when these two physicians developed new and exciting surgical techniques based on the biology of the tumor, combined with newly introduced chemotherapy agents, to see if they could do something different for these patients aside from amputation,” said Dr. Malawer. He was eager to train with the two pioneers in this field.

These three physicians developed the first set of orthopedic endoprostheses – which included artificial bone and joint replacements – in the early 1970s. They were large, long and heavy pieces of metal that had to be custom-ordered from a manufacturing company per the physician's specifications, which were based primarily on X-ray generated measurements. These original prostheses were problematic because they took up to four months to create – too long for many cancer patients to wait.

In addition, these custom implants often did not fit correctly: they were either too large or small for the specific patient because the X-ray measuring technique was not entirely precise. As the doctors worked with these implants in the operating room, they discovered that they needed to be smaller than the actual human bones they were replacing to ensure a proper fit and easy wound closure. Dr. Malawer and some devoted engineers set out to correct this problem and develop better implants for patients while also eliminating the excessively long manufacturing time frame.

A BETTER SOLUTION 

In 1983, after performing with two years of surgeries using the custom prostheses, Dr. Malawer began to think of new prosthetic solutions that would allow for a safer, faster and more cost-effective way of performing the surgery. What he came up with was a bone replacement system that could be customized during the surgery. He envisioned a system where a surgeon could create the prostheses in the operating room by selecting from some 100 interchangeable sterilized prosthetic pieces for the joint, bone and stem that could be combined to fit almost any patient at the time of the surgery.

Dr. Malawer sought to make this system a reality. He presented his idea to the same medical technology company that had developed the customized prostheses. The company was as excited and committed to the idea as Dr. Malawer was, and together they began the development process. Dr. Malawer worked directly with the engineers at the company to begin the outline of this new system, using their combined knowledge of anatomy, surgery, bones, metals and engineering. “We knew that the joint piece would need to be made out of a highly polished metal surface that was wear resistant, and that the body of the device would be made out of a stronger metal, like titanium,” said Dr. Malawer.

He worked with the company to test the modular devices in clinical settings. During these clinical trials, they implanted the prostheses in animals to test their durability and to see how they held up within the body. They also did a series of simulator tests during which the engineers would gauge the durability of the knee during life-like model testing where the knees would undergo pressure similar to that of walking or running. They also tested the prostheses on cadavers to see anatomically how the prostheses should be implanted. Dr. Malawer performed the first successful human modular implant in 1988, on a shoulder bone, with the surgeons of the Surgery branch at the National Cancer Institute in Bethesda, Md.

IMPROVING AN INNOVATION

“There has been a constant series of improvements made on the technology since it was originally conceived,” said Dr. Malawer. Advances included changes to the size of the prosthetic, improved coating on the metals to enhance their durability, and the use of porous materials – which feature indents – that allow tissue to grow into the prosthesis, keeping it firmly in place. In addition, improvements have been made to the instrumentation used to implant the modular prosthetics to facilitate accurate and reliable usage by other orthopedic oncologists. “The engineers at the device company really made a huge difference in this process and helped facilitate these improvements,” said Dr. Malawer. During this continued evolution, company engineers drew upon technology advances in other industries, such as aerospace and automotive, to provide incremental improvements in the implants and related instrumentation.

In recent years, physicians have been exploring additional improvements in the technology, especially for young patients who are not yet finished growing. “It used to be that patients couldn't grow much taller without feeling some pain or discomfort from the prosthesis coming loose,” said Dr. Malawer. Now, new technologies are being developed that utilize mechanisms like spring-coiled systems, which allow implants to “grow” along with the patient, saving them from additional surgeries and additional risks.

The impact on patient outcomes for this technology has been outstanding. According to Dr. Malawer, in addition to the dramatic decrease in amputations, research has found that the technology provides real value to the health care system. Although some may view the initial cost of the implant as being high, the cost of amputation is almost five times higher over time because the prosthetic extremity used for amputees wears out and must be replaced every few years during adolescence.

Bringing Hope to the World

Dr. Malawer now teaches others about the field of orthopedic oncology. Aside from writing the definitive surgical textbook on the subject as well as four training manuals for the prosthetic system, he has helped surgeons from around the world learn how to perform these surgeries and benefit from this technology. He has trained physicians from Africa, China and the Middle East in the field of orthopedic oncology and has prepared them to save cancer patients' limbs in their home countries. Recently, the first limb-sparing resection for a bone sarcoma was performed at the King Hussein Cancer Center in Jordan by one of his trained fellows.

Dr. Malawer still meets every three months with engineers from device manufacturing companies to discuss continued improvements, and he is extremely devoted to training more surgeons to do these procedures, especially in underdeveloped countries. “Personalized one-on-one training with technical and surgical experts is really the way you learn to perform this surgery, and is critical to its success,” said Dr. Malawer.

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1. American Cancer Society. Detailed Guide: Bone Cancer. http://www.cancer.org/docroot/cri/content/
   cri_2_4_1x_what_are_the_key_statistics_for_bone_cancer_2.asp . (6 November 2006).