Bone marrow transplant still subject of debate

ON CALL

April 18, 1995|By Dr. Simeon Margolis | Dr. Simeon Margolis,Special to The Sun

Q: At the time of my operation for breast cancer, the pathology report showed that the cancer had spread to a large number of lymph nodes under my arm. Because the cancer has spread, my doctor has told us that the standard treatment offers less than a 40 percent chance of living for five more years.

I have heard that treatment involving a bone marrow transplant offers a better chance of survival than the usual form of therapy. Do you agree?

A: There is no clear answer to your question at the present time.

Both conventional treatment and bone marrow transplants are based on the use of chemotherapy, the use of drugs that can destroy cancer cells. The problem is that doses of drugs large enough possibly to kill all the cancer cells will also destroy the blood-forming cells in the bone marrow.

In a bone-marrow transplant procedure, some of the patient's bone marrow is first removed and stored, and high-enough doses of drugs are given to destroy the cancer cells. The stored bone marrow cells are then returned (transplanted) to the patient to replace and repopulate blood-forming cells.

For a few weeks, a patient must remain in the hospital under strict isolation to minimize the risk of serious infections. That's because of the marked deficiency of white blood cells, which are required to fight off infections.

If all goes well, the transplanted bone marrow cells proliferate and gradually supply enough circulating white cells to protect against infections. Between 5 and 10 percent of patients die in the period following such bone marrow transplants, mostly from infections.

Although some cancer specialists believe that bone marrow transplant is superior to standard therapy, there is no scientific evidence to support or refute this contention.

The National Cancer Institute has sponsored three large trials in an effort to determine whether one treatment is better than the other. Entry into such a trial requires that patients accept random assignment either to standard therapy or to the bone marrow transplant procedure. Breast cancer patients understandably want the most effective treatment, and many have the feeling that transplant offers the best chance.

As a result, the researchers carrying out these trials have found it extremely difficult to enroll the number of patients required to answer the question. We need to know because there are many examples of new treatments that seemed better than old ones, but turned out after careful study to be no better or even worse.

Meanwhile, the number of bone marrow transplants for breast cancer in the United States has increased from about 250 a year in 1989 to more than 1,000 last year.

Some patients cannot choose a bone marrow transplant; it costs $60,000 to $200,000, compared with $5,000 to $25,000 for conventional chemotherapy. Also, some insurance companies have refused to pay for what they see as an experimental, rather than a proven, therapy.

Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.

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