Extended adjuvant therapy with letrozole: reducing the risk of recurrence

Approval summary: letrozole (Femara® tablets) for adjuvant and extended adjuvant postmenopausal breast cancer treatment: conversion of accelerated to full approval

On April 30, 2010, the U.S. Food and Drug Administration converted letrozole (Femara®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor-positive early breast cancer. The initial accelerated approvals of letrozole for adjuvant and extended adjuvant treatment on December 28, 2005 and October 29, 2004, respectively, were based on an analysis of the disease-free survival (DFS) outcome of patients followed for medians of 26 months and 28 months, respectively. Both trials were double-blind, multicenter studies. Both trials were unblinded early when an interim analysis showed a favorable letrozole effect on DFS. In updated intention-to-treat analyses of both trials, the risk for a DFS event was lower with letrozole than with tamoxifen (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.77-0.99; p = .03) in the adjuvant trial and was lower than with placebo (HR, 0.89; 95% CI, 0.76-1.03; p = .12) in the extended adjuvant trial. The latter analysis ignores the interim switch of 60% of placebo-treated patients to letrozole. Bone fractures and osteoporosis were reported more frequently following treatment with letrozole whereas tamoxifen was associated with a higher risk for endometrial proliferation and endometrial cancer. Myocardial infarction was more frequently reported with letrozole than with tamoxifen, but the incidence of thromboembolic events was higher with tamoxifen than with letrozole. Lipid-lowering medications were required for 25% of patients on letrozole and 16% of patients on tamoxifen.

Bone mineral density and bone turnover in postmenopausal women treated for breast cancer

Chemotherapy and endocrine treatments for breast cancer are believed to increase risk of osteoporosis by causing early menopause in premenopausal women and by further depleting estrogen levels in postmenopausal women. Multivariate analyses were used to evaluate the contributions of 7 predictors (age, body mass index [BMI], family history of osteoporosis, months since menopause, past use of chemotherapy, and current use of tamoxifen or aromatase inhibitors) in explaining variability in bone mineral density (BMD) at the hip and the spine and bone turnover in 249 postmenopausal women who are breast cancer survivors. This report was an analysis of baseline data from a federally funded (1 R01 NR07743-01A1) intervention study on osteoporosis prevention. Mean age of the women was 58.5 years, and average BMI was 26.7 kg/m; 98% were white. All had measurable bone loss, 167 had chemotherapy, 76 were on tamoxifen, and 21 were on aromatase inhibitors. Women with higher BMI had higher BMD at the hip (P < .001) and the spine (P = .004). Women on tamoxifen had lower measures of bone formation (Alkphase B) (P < .001), suggesting less bone turnover, and higher BMD at the hip (P = .035). There was a trend for women who had received chemotherapy to have lower BMD at the spine (P = .06). The implications of these findings are discussed in the article.

Clusterin expression and univariate analysis of overall survival in human breast cancer

The aim of this research is to investigate the significance of clusterin (CLU) expression as a risk factor for breast cancer through tissue microarray technology and univariate analysis of overall survival. Formalin-fixed, paraffin-embedded tissues from 158 cases of breast cancer and 31 cases of normal adjacent tissues assembled into a tissue microarray. Cytoplasmic CLU expression in tumor tissues was measured by immunochemistry. Survival analysis was used to investigate the relationship between CLU expression and prognosis, tumor volume, pathological classification, and recurrence. Survival time of patients with CLU expression, lymph node metastasis, and limited post-surgery chemotherapy (<6 cycles of treatment) was significantly shorter than that of patients with no detectable CLU expression (P=0.000), without lymph node metastasis (P=0.000) and more comprehensive post-surgery chemotherapy (>/=6 cycles of treatment) (P=0.035). CLU expression in tumor cells was higher than in normal adjacent breast epithelial cells (P=0.03). The CLU expression staining coefficient of cancer tissues with lymph node metastasis was higher than those without lymph node metastasis (P=0.000). Cytoplasmic CLU expression was found to be a prognostic factor for human breast cancer.