Most randomized trials of the therapy were initiated in the 1990s and did not confirm earlier positive findings. Rather, most of these trials showed little or no benefit for women with breast cancer. The therapy's stature became even more confusing when data from a large randomized positive trial, presented on the plenary session of the 1999 American Society of Clinical Oncology, was later found to be falsified.
"It was important to do this study so it could be determined if there is any evidence of a benefit to patients, or if there is any subset of patients that benefited from the therapy," Berry says.
For their analysis, the investigators built an expansive database and looked at all 15 trials conducted in the world. More than 6,200 women were enrolled in the studies and were randomized to receive either high-dose chemotherapy (3,118 patients) or additional doses of the standard chemotherapy (3,092 patients).
The median patient follow-up was seven years and the mean age of the women enrolled in the trials was 45. Of the women, hormone receptor status was positive in 55 percent, negative in 28 percent and not available in 17 percent. The decrease in the rate of breast cancer relapse due to higher dose chemotherapy was 13 percent, which was statistically significant. However, the benefit did not translate into survival. The decrease in mortality rate was six percent.
After adjusting for age, trial, hormone status, tamoxifen use and the number of positive lymph nodes, the high-dose regimen slightly improved relapse-free survival by about eight months. However, there was no survival benefit for women who received high-dose chemot
|Contact: Laura Sussman|
University of Texas M. D. Anderson Cancer Center