The Early Breast Cancer Trialists' Collaborative Group: A brief history of results to date

This chapter describes the collaborative efforts and statistical results obtained in four five-year cycles of collection and analysis of individual patient data concerning breast cancer mortality. The presentation and discussion of preliminary results in two types of trial at a meeting in London 1984 initiated the collaborative effort. This resulted in the combination of individual data from 28 trials comparing surgery to surgery plus an additional treatment believed to inhibit tumour growth, and from a further 40 trials comparing surgery to surgery with additional chemotherapy. In total, about 40,000 woman participated in the 68 fully randomized trials followed up until 1985. The fourth cycle, which added medication thought to inhibit tumour growth and further chemotherapy, established that treatments used since the 1980s substantially reduced not only 5-year age-standardized mortality rates, but also the 15-year rates.