Delivering adjuvant chemotherapy to women with early-stage breast carcinoma: current patterns of care

Background: Variations in practice patterns are markers for the quality of patient care in general medicine, but little is known about variation in care delivered to cancer patients. This study's purpose was to describe chemotherapy use, variations in chemotherapy delivery, and the incidence of complications in community practice settings.

Methods: Data describing adjuvant chemotherapy for patients with early-stage breast carcinoma (ESBC) were collected from an ongoing Oncology Practice Pattern Study at 13 large managed care, academic, and community practices (1111 patients). Data collection included information about diagnoses and adjuvant chemotherapy treatments, laboratory results, supportive care, complications, and treatment modifications.

Results: The median patient age was 50 years, and most patients had zero to three positive lymph nodes. Chemotherapy regimens consisting of cyclophosphamide, methotrexate, and 5-fluororacil (CMF) and of doxorubicin and cyclophosphamide (AC) accounted for 76% of the adjuvant therapies used. Overall, 30% of patients had delivered average relative dose intensities </= 85% of the referenced targets. Delivered summation dose intensities (SDIs) frequently were well below targeted SDIs. Neutropenia-related dose modifications occurred for 27.6% of patients and recurred with a 60.7% rate. AC was the regimen delivered with a dose intensity closest to the referenced target. However, patients who were treated with AC regimens and with regimens consisting of cyclophosphamide, doxorubicin, and 5-fluorouracil had significantly higher rates of chemotherapy-related complications compared with patients who were treated with CMF regimens in the most recent treatment years.

Conclusions: Adjuvant chemotherapy for patients with ESBC frequently is not administered as referenced in off-protocol community settings. Variation in the delivered SDI raises concerns about potential treatment outcomes and warrants strategies to identify patients who are at risk for complications early in therapy.