Dose Delay Amongst Cancer Patients Undergoing Chemotherapy

Background. Cancer patients often have their chemotherapy dose delayed or reduced to mitigate chemotherapy-induced side effects such as thrombocytopenia, neutropenia, anemia, etc. In situations where the patient is responding to the chemotherapy, such dose delay and dose reduction may minimize the effectiveness of the chemotherapy and lead to poorer clinical outcomes. In this study, we analyzed the characteristics of dose delay among cancer patients on chemotherapy in the US.

Methods. Pooled data over the period 2000–07 from a large electronic database of 15 community and 3 hospital-based outpatient oncology clinics in the US were analyzed. Adult patients with a cancer diagnosis were grouped as: lung, breast, ovarian, H&N, colorectal, other solid cancers, hematologic and mixed cancers. Chemotherapies used were grouped into platinum, anthracycline, gemcitabine, taxane-based and other regimens. Among patients with complete chemotherapy plan information, each subsequent cycle of the chemotherapy regimen after the first cycle was examined. The planned cycle duration was compared to the actual duration between the start of one cycle and start of the next. Any delay of more than 7 days was defined as a cycle delay. Demographic and clinical characteristics of patients with delays were further analyzed.

Results. The dataset included 47,159 cancer patients (mean age 61, male 42%) and 75,243 chemotherapy regimens. A total of 26,317 patients (113,175 chemo cycles) had complete chemotherapy plan information in the database. Of these, 5,961 patients (22.7%) experienced chemo delays. A total of 9,293 chemotherapy cycles (8.2%) were delayed. The average chemo delay was 17 days (SD, 8 days; median, 14 days). 25% of the delays were more than 3 weeks. Tumor types of the 5,961 patients with cycle delays included, colorectal cancer 20.3%, NSCLC 18.6%, breast cancer 15.2%, ovarian 4.4%, and H&N 2.9%. The reasons for delaying chemo were not specified in the database. However, 60% of these patients experienced anemia (Hb<11g/dL) and 62% had thrombocytopenia (<150,000/μl) at some point during their chemotherapy. Baseline and clinical characteristics of patients with chemo delays were similar to the overall population in the database.

Conclusions. Chemotherapy cycle delays were relatively common in this large group of cancer patients. While the decision to delay therapy was multi-factorial, further research is needed to investigate the reasons, preventable measures, clinical and cost outcomes of such delays.