Danish Randomized Trial Comparing Breast Conservation Therapy with Mastectomy: Six Years of Life-table Analysis. Danish Breast Cancer Cooperative Group

The Danish Breast Cancer Cooperative Group (DBCG) conducted a randomized trial comparing breast conservation with mastectomy in patients with invasive mammary carcinoma. From January 1983 to March 1989, the trial accrued a total of 1153 women. Of this number, 905 patients (79%) were randomly assigned to one of the two treatment options, whereas 248 patients (21%) did not accept randomization. Of the randomly assigned patients, 90% received the surgical option to which they had been originally assigned. In the breast conservation arm the tumor was excised with the intention of obtaining free margins determined at gross examination, and radiotherapy was subsequently administered to residual breast tissue. The axilla was dissected in all instances. Patient and tumor characteristics were similar in the two randomization arms. The median follow-up time was 40 months. At 6 years of life-table analysis the probability of recurrence-free survival was 70% in the breast conservation arm against 66% in the mastectomy arm. Survival figures were 79% against 82%, respectively.