Older chemotherapy drugs from the 1980s reduced breast cancer mortality by nearly a quarter. But a new meta-analysis of 123 randomized trials that assessed nearly 100,000 breast cancer patients over a period of 40 years shows that modern chemotherapy regimens decrease mortality by about one-third. This means that these newer drug treatments have added 17 percent of all patients to the ranks of survivors, as compared to the older regimens.
According to the study results, which were published in The Lancet, modern chemotherapies have proved to be more effective than the older ones. Researchers led by a breast cancer research group from the University of Oxford, found that the improved mortality applied to all women, independent of age, tumor size, whether the cancer spread to local lymph nodes, and regardless of whether tumors were estrogen-receptor (ER) positive.
For women with ER-positive breast cancer, however, the results showed that adding endocrine therapy estrogen blockers to chemotherapy was more effective than chemotherapy alone. And as Sir Richard Peto, one of the study leaders, noted, Most breast cancers are ER-positive, and for ER-positive disease that appears to have been completely removed by surgery, the 10-year risk of recurrence and death from breast cancer can be reduced by at least half by giving a few months of modern chemotherapy plus five years of endocrine therapy.
ACSH's Dr. Gilbert Ross adds, Of course we knew chemotherapy was effective in reducing breast cancer mortality, but now this recent study tells us by approximately how much.