Chemo doses often suboptimal in early breast Ca: large community practice-based study.(Gynecology)

SAN ANTONIO -- Nearly two-thirds of women with early-stage breast cancer experience a substantial reduction in chemotherapy dosing due to toxicity, Dr. Gary H. Lyman reported.

This finding from a very large community practice-based study is alarming. It carries important quality-of-care and public health implications. Early-stage breast cancer is a potentially curable disease, and a growing number of studies suggest failure to maintain full chemotherapy dose intensity is associated with compromised disease-free survival and other clinically important outcomes, he said at a breast cancer symposium sponsored by the Cancer Therapy and Research Center.

Dr. Lyman of the University of Rochester (N.Y.) conducted a nationwide retrospective review of the records of 20,799 early-stage breast cancer patients who underwent adjuvant chemotherapy in 1,243 community-based oncology practices during the mid-1990s through 2000.

A chemotherapy dose reduction of at least 15% below standard recommendations occurred in 36.5% of the women, while 24.9% experienced a treatment delay of at least 7 days.

All told, 55.5% of patients received less than 85% of the recommended chemotherapy relative dose intensity, which is believed to be the threshold for clinically meaningful adverse impact. Moreover, after adjustment for differences in the dose intensity of the various adjuvant chemotherapy regimens used, the proportion of patients who fell below this standard climbed to 65%.

Neutropenia constitutes the major dose-limiting toxicity of chemotherapy. It's often preventable with prophylactic administration of granulocyte colony-stimulating factor (G-CSF). However, in this national study only about one-quarter of women ...