SAN ANTONIO -- Total cancer mortality among middle-aged women in the United States and United Kingdom has declined markedly since 1990--and an unprecedented drop in breast cancer mortality is the biggest reason why, Sir Richard Peto, Ph.D., said at the San Antonio Breast Cancer Symposium.
Indeed, through a series of moderate gains in survival achieved via breast screening plus incremental advances in endocrine therapy, chemotherapy, and radiotherapy, breast cancer mortality in women aged 35-69 years in the United States and United Kingdom has been almost halved since 1990.
"No other common cancer can claim such success. Hodgkin's disease, yes. Testicular cancer, yes. Childhood leukemia, yes. But this absolute gain in breast cancer survival is far bigger than the absolute gain from eliminating any of those diseases," said Dr. Peto, professor of medical statistics and epidemiology at the University of Oxford (England).
A new analysis by Dr. Peto and colleagues at the Oxford-based Early Breast Cancer Trialists' Collaborative Group (EBCTCG) demonstrates how several advances in chemotherapy, each of only moderate impact, have together over the course of 3 decades added up to a massive survival benefit.
The bottom line of this analysis, based upon data on roughly 80,000 patients with early breast cancer randomized in chemotherapy trials, is: "If you give effective chemotherapy to women with or without estrogen receptor-positive disease, you'll reduce their mortality by about one-third if they're old, and by about one-half if they're young," he said.
The full EBCTCG database now includes 350,000 breast cancer patients in close to 400 randomized clinical trials worldwide. The world's trialists, who have met to share their updated data every 5 years since 1985, will do so next in 2010.
The first wave of chemotherapy trials compared cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) regimens with no chemotherapy. Those studies demonstrated that CMF-treated patients younger than age 50 experienced a 44% reduction in the risk of recurrence, and a 32% decrease in breast cancer mortality, during the first 4 years of follow-up. Women aged 50-69 years had a 25% reduction in recurrence and a 9% decrease in mortality.
Not enough women aged 70 years or older have been enrolled in randomized chemotherapy trials to draw conclusions about the treatment's effect in that age group.
The second wave of trials compared anthracycline-based regimens with CMF regimens. The relative risk of recurrence was reduced by a further 16% with anthracycline regimens, compared with CMF, in women younger than 50, and by 11% in those aged 50-69. Mortality resulting from breast cancer was reduced by 19% in anthracycline-treated patients younger than age 50, and by 10% in those aged 50-69. …