Two Breast Cancer Treatments Show Benefit

Results from an NCI-funded, phase III clinical trial comparing the effectiveness of the drugs paclitaxel and docetaxel, delivered over two different dosing schedules, showed that - regardless of the dosing schedule - both drugs provided similar benefits for women with stage II or III operable breast cancer. Study results were presented at the San Antonio Breast Cancer Symposium on December 8.

Both paclitaxel and docetaxel are approved for the treatment of breast cancer that has spread to lymph nodes. Although these drugs have been shown to be beneficial in treating breast cancer, this is the first time they have been directly compared in a weekly versus 3-week dosing schedule to treat early-stage breast cancer.

"Although both drugs are used as adjuvant breast cancer treatments, which drug and which schedule are most effective has been a question for many years," said Dr. JoAnne Zujewski, who oversees breast cancer trials for NCI's Cancer Therapy Evaluation Program. "Now doctors and patients will be able to consider side effects, convenience, and cost in determining treatment without concern that effectiveness will be compromised."

A total of 4,988 women were enrolled in the trial between 1999 and 2002 and were followed for a median of about 4 years. All of the women had axillary lymph node-positive or high-risk node-negative breast cancer. All women were first treated with a standard treatment protocol and were then randomly assigned to groups that received either paclitaxel or docetaxel, administered weekly for 12 weeks or every third week over a 12-week period.

Adjuvant Chemo for Stage III Colon Cancer Increasing,
but Still Lags

The use of adjuvant chemotherapy in patients with late-stage colon cancer has increased significantly since recommendations from a 1990 NIH consensus conference advised clinicians to implement the practice, a new study has found. But, the study authors report, nearly one-third of patients with stage III colon cancer still receive surgery only for treatment, particularly female and elderly patients.

In the study, Dr. John Jessup, from Georgetown University Medical Center and temporarily on assignment with NCI's DCTD, and colleagues reviewed prospective data from the National Cancer Data Base on nearly 86,000 patients treated for stage III colon cancer between 1990 and 2002. Overall, they reported in the December 7 Journal of the American Medical Association, the use of adjuvant chemotherapy increased from 39 percent in 1991 to 64 percent in 2002. When compared with surgery alone, this increase was associated with a 16-percent improvement in 5-year survival.

The 1990 recommendations were based on two large, randomized clinical trials that demonstrated significant improvements in disease recurrence and overall survival with a 12-month postsurgery chemotherapy regimen. After the recommendations' release, adjuvant chemotherapy use increased and then stabilized by the mid- to late-1990s. A second increase followed results in clinical trials that demonstrated an adjuvant regimen of 6 months of 5-fluorouracil (5-FU) and leucovorin was as effective and less toxic as the standard regimen of 12 months of 5-FU and levamisole.

With recent studies using newer agents showing increased efficacy and less toxicity than 5-FU/leucovorin, noted Drs. Eric Van Cutsem and Frederico Costa in an accompanying commentary, use of adjuvant chemotherapy should continue to expand. "Shorter and more effective therapies are easier to incorporate in daily practice," they wrote, "and might overcome…reluctance of the patient or the physician to be treated with adjuvant chemotherapy."

Breast Cancer Cluster Not Linked to Environment

Long Island has been the focus of intensive investigation to uncover reasons for the high rates of breast cancer in its Nassau and Suffolk Counties. NCI and the National Institute of Environmental Health Sciences (NIEHS) have supported research to evaluate whether environmental exposures may be responsible through the series of studies in the Long Island Breast Cancer Study Project (LIBCSP). In the December issue of Nature Reviews Cancer, Dr. Deborah Winn, of NCI's Division of Cancer Control and Population Sciences, reviewed the results of LIBCSP, as well as studies of other regions with high breast cancer rates.

In case-control studies, researchers focused on participants' exposure to organochlorines (a class of chemicals that includes pesticides and other industrial chemicals), polycyclic aromatic hydrocarbons (a pollutant caused by incomplete combustion of various chemicals including diesel fuel and cigarette smoke), and electromagnetic fields in and near participants' residences as possible causes. In general, the researchers found no significant association between the regional environment and high breast cancer incidence.

Similar results were seen in a study of women in affluent Marin County, California, where breast cancer incidence also is high. What that study did show was that heavy alcohol consumption was linked with the disease. Higher regional breast cancer rates may also be due to reproductive patterns that are correlated with affluence, including late age at first birth and fewer children.

"In the view of some, findings of no environmental association indicate failure of the research," notes Dr. Winn. "However, findings of no association that are obtained through rigorous research are important. If the evidence shows that there are no credible associations between the suspected risk factors and the disease, then research can be directed toward other potential carcinogens." She points to improved understanding of gene-environment interactions and measurement of environmental exposures as important contributions from the LIBCSP.

NIEHS and NCI are currently exploring these issues further by supporting the Breast Cancer and the Environment Research Centers (www.bcerc.org).