Adding chemotherapy to the estrogen-blocking drug tamoxifen improves the survival of early breast cancer, according to the results of two studies conducted by the Adjuvant Breast Cancer (ABC) Trials Collaborative Group.
In the ABC Chemotherapy trial, Dr. Judith Bliss, from The Institute of Cancer Research in Sutton, United Kingdom, and colleagues assessed the outcomes of 1,991 patients between 28 and 81 years of age who received prolonged (five years) tamoxifen therapy with or without standard chemotherapy. Some of the premenopausal women were also treated with ovarian removal (ablation) or suppression, which stops the glands from secreting hormones.
The chemotherapy group experienced fewer recurrences of their cancer than the comparison group, but the difference fell short of statistical significance, according to the report in the Journal of the National Cancer Institute. Still, chemotherapy did reduce the overall risk of death by 17 percent.
The benefit of chemotherapy in reducing cancer recurrence emerged early, while it took at least five years for the survival benefit to become apparent, the researchers note.
Further analysis showed that chemotherapy provided the greatest survival benefit in women younger than 50 years, especially premenopausal women not treated with ovarian ablation or suppression.
To better understand the benefits, if any, of ovarian ablation/suppression, Bliss' team conducted the ABC Ovarian Ablation or Suppression trial, which involved 2,144 women, who were premenopausal or just beginning menopause, who were given tamoxifen, with or without chemotherapy, and were randomly selected to receive or not receive ovarian ablation/suppression.
Ovarian ablation/suppression provided no improvement in survival, nor reduced cancer recurrences, the report indicates.
Despite these findings, the authors note that there may be a role for ovarian ablation/suppression in women younger than 40, especially those not given chemotherapy, but further studies are needed.