The landscape of use of NCCN-guideline chemotherapy regimens in stage I-IIIA breast cancer in an integrated healthcare delivery system.

PURPOSE

The National Comprehensive Cancer Network (NCCN) guidelines recommend a variety of drug combinations with specific administration schedules for the treatment of early-stage breast cancer, allowing physicians to deliver treatments recognizing individual patient complexities, including comorbidities, and patient-physician preference. While use of guideline regimens has shifted over time, there is little data to describe changes in how treatment for early-stage breast cancer has evolved over time.

METHODS

In a cohort of 34,109 women treated for stage I-IIIA breast cancer between 2006-2019 at Kaiser Permanente Northern California and Kaiser Permanente Washington, we present the changes in chemotherapy regimens over time, and explore use of NCCN-guideline regimens (GR), guideline regimens used when said regimens were not included in guidelines, referred to as time-discordant regimens (TDR), and non-guideline regimens (NGR). Results are presented by drug combination and over time.

RESULTS

Among 12,506 women receiving chemotherapy, 77.4% (n = 9681) received GRs, 9.1% (n = 1140) received TDRs, and 13.5% (n = 1685) received NGRs. In 2006, AC-T (cyclophosphamide-doxorubicin, paclitaxel) was the most common regimen, with TC (cyclophosphamide-docetaxel) becoming the most prevalent by 2019. NGRs were more common in cyclophosphamide-methotrexate-5-fluorouracil (CMF); cyclophosphamide-doxorubicin-paclitaxel-trastuzumab (ACTH); and paclitaxel-trastuzumab (TH). The use of GR has increased over time (p-trend < 0.001), while use of NGR (both in terms of administration schedule and drug combination) and TDR have decreased, although patterns vary by drug combination.

CONCLUSION

Chemotherapy delivery has changed markedly over time, with a move toward more use of GR. These data are important for understanding the landscape of chemotherapy delivery in community healthcare settings.