Impact of reduced dose intensity of adjuvant anthracycline based chemotherapy in a population based cohort of stage I-II breast cancers. A. Tinker, C. Speers, J. Barnett, I. Olivotto, S. Chia; British Columbia Cancer Agency, Vancouver, BC, Canada; British Columbia Cancer Agency, Victoria, BC, Canada Abstract: Background: Reductions in the dose intensity (DI) of adjuvant doxorubicin and cyclophosphamide (AC) chemotherapy in the treatment of early stage breast cancer are frequently required, with the impact on clinical outcome uncertain. We examined whether a reduced DI had an impact on relapse free survival (RFS), breast cancer specific survival (BCSS) or overall survival (OS) in a population-based cohort of early stage breast cancers treated with adjuvant AC. Methods: Women with stage I/II breast cancer treated with adjuvant AC (A: 60 mg/m2, C: 600 mg/m2 on a 21-day schedule) between 1990 and 1995 were retrospectively identified through the BCCA pharmacy database and linked to the BCCA Breast Cancer Outcomes Unit database. A dose reduction was defined as a reduction of at least one of the chemotherapy agents by at least 25% in any given cycle. Dose delay was defined as a delay in delivering treatment by at least 5 days. Cases were classified into the following 4 cohorts; cohort 1: entire course of treatment delivered at full doses and on time; cohort 2: one single dose reduction or dose delay; cohort 3: more than one dose reduction or dose delay; cohort 4: = 2 cycles of chemotherapy delivered. No growth factor support was utilized in any cases. Results: 484 cases were retrospectively identified (cohort 1: n = 268; cohort 2: n= 88; cohort 3: n= 89; cohort 4: n= 39) with a median follow-up of 9.6 years. The four cohorts were well matched for most baseline prognostic factors except for slight imbalances in lymph node status (p=0.05) and adjuvant hormonal therapy (p=0.05). 55% of the entire cohort had node positive disease. Overall 45% of cases had a reduced DI delivered. However, there were no significant differences in 8 year RFS (p=0.94), BCSS (p=0.87) and OS (p=0.86) between the 4 cohorts. The 8 year outcomes for cohorts 1-4 respectively were: RFS (72%, 74%, 74%, 68%), BCSS (80%, 77%, 82%, 80%) and OS (78%, 76%, 80%, 77%). Conclusions: Although reductions in the DI of adjuvant AC chemotherapy for early stage breast cancer was common, it did not appear to significantly impact on clinical outcomes in this cohort of patients with stage I-II breast cancer. Abstract No: 552 Abstract # 582 ASCO, 2004 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.