Delivered relative dose intensity and febrile neutropenia rate with common adjuvant chemotherapy regimens: A review

Abstract

11505 Background: Adjuvant chemotherapy for early-stage breast cancer decreases the risk of recurrence and improves survival. Prior work has pointed out that <85% of relative dose intensity (RDI) could result in compromised outcome. Methods: Among consecutively treated patients, one hundred patients treated with (AC-T) doxorubicin, cyclophosphamide (4 cycles) followed by paclitaxel (4 cycles), one hundred patients treated with (FEC-D) 5FU, epirubicin and cyclophosphamide (3 cycles) followed by docetaxel (3 cycles) and 75 patients treated with (FEC100) 5FU, epirubicin and cyclophosphamide (6 cycles) were retrospectively analyzed. Summation dose intensity (SDI) is used as a reference for RDI. To calculate SDI of each regimen, a unit dose intensity (UDI) of each drug in the combination regimen is calculated, defined as the dose of the drug required to produce 30% complete plus partial response when used as a first-line single agent in metastatic breast cancer. The dose intensity of each drug in a combination is expressed as a fraction of that drug’s UDI and fractions for all the drugs are added together. The incidence of FN was recorded as well. Results: Almost 30% of patients receiving FEC-100, 4% with AC-T and 10% with FEC-D were over 65 years. Only 4% with AC-T, 5% with FEC-D but 21% patients receiving FEC-100 had <85% RDI. About 1/3rd of FEC-100 patients but 63% of AC-T and 77% patients of FEC-D had 100% of RDI delivered. FN rates were 7% for AC-T and 23% for FEC-D. Almost all FN cases were seen with the dose of Docetaxel (19/23) in patients receiving FEC-D. Conclusions: To our knowledge, delivered RDI and/SDI for these regimens have not been reported previously and the results show the experience of an academic cancer centre. The delivered RDI for AC-T and FEC-D is excellent but for FEC-100 is sub-optimal. This variability could be due to a smaller sample, relatively elderly population and various other factors. Although the FN rate for AC-T appears to be similar as previously reported, the FN rate for FEC-D is higher. This higher rate combined with the fact that the most FN cases occurred with docetaxel appears to reflect the experience for the patients outside the clinical trial. No significant financial relationships to disclose.