A Better Treatment for Breast Cancer
The key: increasing frequency of chemotherapy
THURSDAY, Dec. 12, 2002 (HealthDayNews) -- Simply increasing the frequency of chemotherapy for breast cancer increases survival rates, shortens the time needed for treatment, and reduces side effects, a new study finds.
"Usually when you get an improvement in survival you pay a price in toxicity or length of treatment," says Dr. Clifford Hudis, chief of the breast cancer medicine service at Memorial Sloan-Kettering Cancer Center in New York City, and a leader of the study. "In this case, you do get a win, win, win effect."
The study, presented today at the 25th annual San Antonio Breast Cancer Symposium, included 2,005 women whose breast cancer had spread to the lymph nodes, but not beyond them. They were given standard chemotherapy for breast cancer, but some got the drugs every two weeks, while others got them every three weeks -- currently the common practice.
After four years, 82 percent of the women in the "dose-dense" treatment group were alive and free of the disease, compared to 75 percent of those who got treatments every three weeks.
In addition, the treatment time was shorter for the women receiving the drugs every two weeks. And one notable side effect of chemotherapy, neutropenia, a decline in white blood cell levels, was less common in the "dose-dense" group. Those women were also given a relatively new drug, granulocyte colony stimulating factor, discovered at Memorial Sloan-Kettering, which stimulates growth of white cells.
"This is not some random event," Hudis says. "It was entirely predicted by mathematical models of how cancers respond to treatment. If anything, we would have been disappointed if we had not gotten better results."
The mathematical model was developed by Dr. Richard Simon of the National Cancer Institute (NCI) and Dr. Larry Norton, then at NCI and now head of the division of solid tumor oncology at Memorial Sloan-Kettering.
"While I was a clinical associate at NCI, I observed the growth of tumors in the patients I was treating," says Norton. "I have a mathematical background, so I tried different modeling approaches at fitting the data that I was observing. I saw that a node-positive tumor will shrink during treatment at a rate proportional to its rate of growth. I added one hypothesis, that the tumor is dose-sensitive."
Essentially, more frequent doses of cancer-killing drugs gives the cancer cells less time to grow back again after each treatment, Norton says. The finding prompted the study, which was coordinated by the NCI.
The results already are benefiting many women, Hudis says. "This was a multi-center trial with the participation of hundreds of doctors and dozens of centers," he says.
Other centers are expected to adopt the new treatment schedule after its presentation at the San Antonio meeting, Norton says.
Breast cancer patients might not be the only ones to benefit, Norton says: "I would love to see it attempted in other [cancers]. There is every reason to believe it will work."
Several trials of the new dosing regimen for other cancers are starting. "We are starting trials on prostate and lung cancer," Norton says.
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