CP-122 First cycle neutropenia and relative dose intensity in localised breast cancer patients treated with an adjuvant AC protocol followed by weekly paclitaxel

BackgroundAn AC protocol followed by weekly paclitaxel (AC-PTXw) is a standard adjuvant treatment in women with operable breast cancer. Chemotherapy may produce neutropenia which can lead to dose delays and reductions in subsequent cycles and/or early termination of treatment, which in turn can cause a reduction in dose intensity (DI). Survival benefit is substantially higher when DI ≥85% of the planned DI is received. The ability to identify patients at risk of not achieving the planned DI according to the occurrence of neutropenia during the first cycle might help guide appropriate haematopoietic growth factor use.PurposeTo evaluate the predictive value of cycle 1 neutropenia in the chemotherapy relative dose intensity (RDI) achieved by localised breast cancer patients receiving adjuvant treatment with AC-PTXw.Material and methodsAll patients with early stage breast cancer treated with AC-PTXw were included. Dose and dates of administration of chemotherapy drugs were recorded to calculate received DI. Weight and height were also recorded to calculate body surface area suggested DI. Absolute neutrophil count on the blood test previous to cycle 2 was graded according to neutropenia severity.ResultsIn total, 194 patients were included (20 patients received only PTXw as anthracyclines were contraindicated). Myeloid growth factors were administered to 25% and 3% of patients during AC and PTXw phases, respectively. The occurrence of neutropenia after the first cycle was a statistically significant predictor for not achieving ≥85% RDI during both phases of treatment, especially when neutropenia was moderate or severe. Table 1 Risk of achieving RDI