New chemotherapy regimen

New chemotherapy regimen significantly decreases risk of death for women with "node positive" breast cancer

May 18, 1998

(Los Angeles, Californnia) -- The addition of the anti-cancer drug TAXOL (paclitaxel) to standard chemotherapy dramatically reduces the risks of death or early cancer recurrence for women with breast cancer.

A landmark breast cancer trial, headed by the Cancer and Leukemia Group B (CALGB), demonstrated that administering TAXOL in addition to a standard chemotherapy regimen decreased the number of deaths by 26 percent and reduced the rate of cancer recurrence by 22 percent, compared to the previous standard treatment regimen when measured at 18 months.

These results were presented Monday, May 18, 1998 at ASCO's annual conference in Los Angeles.

The trial involved 3,170 women being treated for node-positive breast cancer--cancer that had already spread to the nearby (axillary) lymph nodes, but had not spread to distant sites.

Overall survival increased from approximately 95 percent for those receiving standard adjuvant therapy to about 97 percent for those who also received standard chemotherapy plus Taxol--a 2 percent increase in survival, but a 26 percent reduction in the death rate, from about five down to about three percent.

Disease-free survival likewise increased about four percentage points--from 86 up to 90 percent--which meant a 22 percent reduction in the recurrence rate from nearly 14 percent of patients down to about 10 percent.

The study is considered an important one by the NCI because it is the first to show that Taxol may be beneficial in the initial, post-surgical treatment of some women with localized, node-positive breast cancer. Up to now, Taxol has been used primarily for the treatment of women with more advanced disease.

"This represents the single most significant advance in the treatment of early-stage breast cancer in the past 20 years, since the introduction of doxorubicin," said Richard L. Schilsky, MD, director, University of Chicago Cancer Research Center; professor of medicine, University of Chicago; and chairman, CALGB.

"This new combination therapy has the potential to save thousands of lives worldwide each year."

There has not been a similar advance in adjuvant (chemotherapy after surgery) breast cancer therapy since the 1970s, when researchers discovered that combination chemotherapy, after surgery, substantially improved breast cancer survival compared to surgery alone.

"The results of this study are very dramatic. These data clearly demonstrate that we are substantially improving a woman's chances for remaining free of her breast cancer by adding paclitaxel sequentially to the standard regimen of doxorubicin and cyclophosphamide," said Larry Norton, MD, head, Division of Solid Tumor Oncology, Memorial Sloan Kettering Cancer Center. "Because it significantly improves survival, this regimen represents a new standard for patients with breast cancer."

"The significant increase in overall survival and reduction in recurrence at this early stage of the trial is extremely promising," he said. "Although the results are early, experience from other landmark breast cancer adjuvant trials suggest that the early benefit will be maintained with continued follow-up." The CALGB will continue to monitor the progress of those enrolled in the trial for at least 10 years.

Of the estimated 180,300 women who will be diagnosed with breast cancer in 1998 in the United States, approximately 75,500 will be candidates for adjuvant therapy.

"If we can decrease the risk of death among this large patient population by 26 percent, the implications will be staggering," said I. Craig Henderson, MD, who was the principal investigator of the trial.

As patients in the trial are followed over the next few years, more mature data should allow a better understanding of Taxol's role, noted National Cancer Institute's Jeff Abrams, MD, senior investigator in the Division of Cancer Treatment and Diagnosis. The CALGB investigators expect to collect more information on critical details, such as which subgroups of patients benefit most and which benefit least from the addition of Taxol, and how the side effects of the two regimens compare.

"The preliminary results of this trial, while encouraging, should be viewed by physicians and patients with caution as the follow-up of patients is quite short," Dr. Abrams said. "Both longer follow-up of this trial and results from other confirmatory trials are needed before the addition of Taxol or similar drugs becomes routine."

"In a challenging disease like cancer, where ground-breaking advances are often made in minor increments, this study represents a major step forward for patients," said Dr. Norton.

This trial was a phase-III adjuvant study headed by the CALGB and was designed to compare doxorubicin plus cyclophosphamide to these two drugs followed by TAXOL in women with breast cancer involving the lymph nodes under the arm. Sequential use was based on a mathematical analysis of breast cancer biology. Involvement of the lymph nodes indicates the cancer has begun to metastasize or spread. The trial involved more than 3,000 women and is the largest study ever completed with TAXOL. Other cancer cooperative study groups involved in this study were the Eastern Cooperative Oncology Group, the Southwest Oncology Group and the North Central Cancer Treatment Group, which are all sponsored and supported by the National Cancer Institute. In all, several hundred institutions participated in this study.

"These new data further the importance of screening and early breast cancer detection through consistent self-examination by all adult women. The more women we diagnose early, the more women will benefit from this important new treatment advance," said Dr. Henderson.

The CALGB is a national cooperative research group, headquartered in Chicago and sponsored by the National Cancer Institute. The CALGB was founded in 1955 with a goal of bringing together clinical oncologists and laboratory investigators to develop better treatments for cancer. Since then the CALGB has grown into a national network of 31 university medical centers, more than 200 community hospitals and more than 3,000 physicians who collaborate in clinical studies aimed at reducing the morbidity and mortality from cancer and developing new strategies for early detection and prevention of cancer. CALGB research is focused on six major disease areas: leukemia, lymphoma, breast cancer, lung cancer, gastrointestinal malignancies and prostate cancer. The most current study with TAXOL in adjuvant breast cancer is but the latest in the many advances in cancer care made by the CALGB.