Predictors of reduced dose intensity in patients with early-stage breast cancer receiving adjuvant chemotherapy.
BACKGROUND
This retrospective study was undertaken to define risk factors for reductions in dose intensity of adjuvant chemotherapy in women with early stage breast cancer (ESBC).


METHODS
A nationwide survey of 190 community oncology practices was conducted between 1998 and 2002 with data collected retrospectively on 3,707 patients treated with adjuvant chemotherapy for ESBC. End points included reductions in dose intensity, delivered relative dose intensity (RDI) <85%, and the incidence of chemotherapy dose delays >/=7 days and dose reduction >/=15%. Demographic and clinical characteristics, incidence of febrile neutropenia (FN), and patterns of use of granulocyte colony-stimulating factor (G-CSF) were also assessed.


RESULTS
Average RDI for all regimens was 88%, with 30% of patients receiving <85% of standard for their regimen. Seventeen percent of the reduction in average RDI was planned from the start of therapy, and 13% was unplanned. In univariate analysis, significant predictors of reduced RDI were: age >/=65 years (41%, P < 0.001), body surface area (BSA) >2 m(2) (37%, P < 0.001), negative lymph nodes (33%, P < 0.001), FN (36%, P = 0.013), and comorbidities (40%, P = 0.013), particularly renal disease (86%, P = 0.004). Dose reduction was less with prophylactic G-CSF (24%, P < 0.001). In multivariate analysis, significant independent predictors of reduced RDI included: advanced age, greater BSA, comorbidities, anthracycline-based regimens, a 28-day schedule and FN, while primary G-CSF prophylaxis was associated with a significant reduction in risk.


CONCLUSIONS
A significant proportion of patients with potentially curable ESBC continue to experience planned and unplanned reductions in RDI.
Shayne
Michelle
M
James P. Wilmot Cancer Center, University of Rochester Medical Center, 601 Elmwood Avenue, Box 704, Rochester, NY 14642, USA. michelle_shayne@urmc.rochester.edu
Crawford
Jeffrey
J
Dale
David C
DC
Culakova
Eva
E
Lyman
Gary H
GH
D000367:Age Factors; D000368:Aged; D018943:Anthracyclines / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001830:Body Surface Area; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D015897:Comorbidity; D004334:Drug Administration Schedule; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D019538:Health Care Surveys; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology; D008198:Lymph Nodes / Q000473:pathology; D008875:Middle Aged; D009503:Neutropenia / Q000139:chemically induced / Q000517:prevention & control; D016017:Odds Ratio; D018579:Patient Selection; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic; D016179:Granulocyte Colony-Stimulating Factor