Preliminary Results of High-Dose Chemotherapy in Primary Breast Cancer Show Equivalency to Intermediate-Dose Treatment; 3 Years of Additional Follow-up Required
783 women with primary breast cancer that has spread to 10 or more lymph nodes under the arm were randomized to receive either high-dose chemotherapy (cyclophosphamide, cisplatin and BCNU) with bone marrow and peripheral blood stem cell support, or intermediate-dose chemotherapy using the same drugs at doses that could be safely administered without bone marrow and peripheral blood stem cell support. All patients were initially treated with four cycles of cyclophosphamide/Adriamycin/5-fluorouracil (CAF) prior to the high- or intermediate-dose chemotherapy. All patients were to receive radiation therapy to the chest area, and tamoxifen was prescribed for women whose tumors were hormone-receptor positive or unknown.
The early results of this randomized, multi-center trial conducted by Dr. William Peters and colleagues with the Cancer and Leukemia Group B indicate that, at the present time, a patient receiving the high-dose therapy has about a 68% chance of being alive without breast cancer at three years, compared with a 64% chance for a patient receiving the intermediate-dose therapy.
The authors stress that the results are preliminary. CALGB plans to carry out another analysis about three years after the last patient was randomized (in approximately May, 2001) that will provide more information due to longer follow-up of patients enrolled in the study.
There were 29 (7.4%) treatment-related deaths among patients randomized to the high-dose therapy but no treatment-related deaths among those randomized to the intermediate-dose therapy. Although fewer breast cancer relapses have occurred in the high dose arm, at this time there is insufficient evidence to conclude that there is any difference in survival between the two treatments.
At three years, a patient's chances of being alive are 78% for the high-dose therapy and 80% for the intermediate-dose therapy. Further follow-up should clarify the relative impact of high-dose therapy on the chances of a patient surviving cancer-free over the long term, without increasing the risks of long-term toxicity.
Quality of life was addressed in this study and demonstrates no differences in quality of life between the treatments at one year following the completion of therapy.