NEW YORK (Reuters Health) – When used as adjuvant therapy in high-risk breast cancer or as primary treatment for metastatic breast cancer, high-dose chemotherapy (HDC) with autologous stem-cell support does not lead to a significant improvement in overall survival, according to the results of two meta-analyses of 21 trials reported in the Journal of Clinical Oncology online July 18.
“In agreement with the authors,” the authors of an accompanying editorial state, “we would conclude that HDC with autologous support for breast cancer, as it was studied in these trials, does not produce sufficient benefit to be worthwhile.”
Thousands of breast cancer patients were treated with HDC followed by stem-cell transplantation in the 1980s and 1990s, largely on evidence from preclinical studies, note Dr. Donald A. Berry, at The University of Texas MD Anderson Cancer Center in Houston, and colleagues in the first of their two papers.
There were subsequently15 randomized trials that compared control groups to groups given HDC plus autologous hematopoietic stem-cell transplantation as adjuvant therapy for high-risk breast cancer. The team pooled data from these trials, involving a total of 6210 patients who were followed for a median of 6 years.
After adjustment, the analysis indicated that HDC compared with conventional treatment prolonged relapse-free survival (hazard ratio 0.87, p<0.001) but not overall survival (hazard ratio 0.93, p=0.13).
In their second paper, the researchers analyzed pooled data from six randomized trials that evaluated HDC with stem-cell transplant support versus a control regimen without transplant support in 866 patients with metastatic breast cancer.
The authors found that a statistically significant improvement in median progression-free survival with HDC (0.91 years) compared with control treatment (0.69 years) did not translate into a significant difference in overall survival (2.16 vs 2.02 years, p=0.08).
Summing up, Dr. Berry and colleagues write, “Our conclusion in this article that HDC does not have a statistically significant benefit in overall survival (for patients with metastatic breast cancer) is supported by the conclusion in our companion report that HDC as adjuvant therapy does not have a statistically significant benefit in overall survival in primary breast cancer.”
In their editorial, Drs. Virginia F. Borges and Anthony D. Elias, at the University of Colorado School of Medicine in Aurora, point out that “the current generation of new treatments for breast cancer includes targeted agents and newer chemotherapies that do not possess a clear dose-response relationship and are not limited by hematopoietic toxicity.”
They conclude, “Thus, it is unlikely that HDC with autologous progenitor cell support will ever again play an important role in the treatment of breast cancer.”
High-Dose Chemotherapy With Autologous Stem-Cell Support As Adjuvant Therapy in Breast Cancer: Overview of 15 Randomized Trials
J Clin Oncol 2011;29.