Recent research highlights importance of trials halted 10 years ago.

NSABP's B-14 trial was originally launched to evaluate whether women with lymph node – negative, estrogen receptor – positive breast cancer benefi t from tamoxifen treatment. Researchers also designed the trial to test the duration of tamoxifen therapy necessary to get the most benefi t from the drug. In late 1995, an analysis of the study data revealed that the benefi ts of 5 years of tamoxifen therapy decreased a patient's chances of breast cancer recurrence, but taking more than 5 years of tamoxifen conferred no additional benefi t. For this reason, the B-14 trial was terminated in late November 1995. Although 5 years is the generally accepted duration of tamoxifen therapy, there are more than 20,000 women enrolled in clinical trials that are attempting to confi rm the optimal duration. The ATLAS (Adjuvant Tamoxifen Longer Against Shorter) trial of 15,000 women and the aTTom (Adjuvant Tamoxifen Treatment – Offer More?) trial of more than 8,000 women are both looking at 10 years versus 5 years of tamoxifen in women with breast cancer. Despite the positive effect tamoxifen has for many breast cancer survivors, some tumors become resistant to tamoxifen, and some women need to stop taking the drug because the side effects, hot fl ashes being the most common , are intolerable. In the last few years, a newer class of drugs has come on the scene as treatment for breast cancer. Aromatase inhibitors, drugs whose method of attack was to inhibit enzymes that convert androgens into estrogen, started to be used in conjunction with, or Ten years ago, investigators from two large clinical trials ended their studies early — for entirely different reasons. For researchers heading the β-Carotene and Retinol Effi cacy Trial (CARET), intervention stopped in January 1996 when scientists observed that current and former smokers taking β-carotene and vitamin A supplements — hypothesized to reduce cancer risk — were developing lung cancer at a higher rate than participants taking a placebo. A couple of months earlier, the National Surgical Adjuvant Breast and Bowel Project (NSABP) decided to halt its study of long-term use of tamoxifen for breast cancer treatment when scientists discovered that tamoxifen provided no additional benefi t after 5 years of treatment. β-Carotene: Benefi cial or Harmful? " We have no explanation for the possible adverse effects we observed to date, " explanation was the best explanation scientists had for the 17% higher total …