Objective: To know relative dose intensity (RDI) in patients with breast cancer treated with chemotherapy. To determine the number of patients where RDI was < 85% of that programmed and the possible cause.
Method: Retrospective study, four-month selection period. The following were recorded: age, body surface, protocol applied, intention of treatment, frequency of administration of cycles, number of cytostatic treatments previously received and filgrastim administration. The average RDI per patient and protocol was calculated.
Results: 110 patients were analysed, the average age of them being 55.4 years (interval: 31-84), average body surface 1.7 m2 (1.3-2.4). Overall average RDI was 91.0% (SD 10.7). 93.8% (10.6), 95.8% (6.3) and 81.9% (18.5) in neoadjuvant, adjuvant and palliative treatments, respectively. 20% of the patients did not reach a RDI = 85% of that programmed, average RDI 69.5% (3.29). A delay in the administration of chemotherapy equal or greater than seven days occurred in 45.4% of the cases, average RDI 80.7% (16.0). In the episodes where the dose was reduced because of toxicity, the RDI was 75.6% (13.6). Significant inverse ratios were obtained with age (p = 0.02) and line of treatment (p = 0.03) with the RDI. In 36.8%, dose reduction was caused by neutropenia; 52.9% received filgrastim.
Conclusions: Most patients received the appropriate RDI. Age, previous treatments and intention of treatment were the variables with the greatest impact on the dose received. The delay in administering the cycle was the most frequent act minimising the toxicity and which least affected the treatment.