Cancer Res Treat.  2017 Apr;49(2):454-463. 10.4143/crt.2016.259.

Efficacy of Letrozole as First-Line Treatment of Postmenopausal Women with Hormone Receptor–Positive Metastatic Breast Cancer in Korea

• Beom SH
• Oh J
• Kim TY
• Lee KH
• Yang Y
• Suh KJ
• Moon HG
• Han SW
• Oh DY
• Han W
• Kim TY
• Noh DY
• Im SA

• KMID: 2378118
• DOI: http://doi.org/10.4143/crt.2016.259

Abstract

PURPOSE
Letrozole showed efficacy and generally favorable toxicities, along with the convenience of oral administration in postmenopausal patients with hormone receptor (HR)-positive metastatic breast cancer (MBC). To the best of our knowledge, there have been no reports of the clinical outcomes in Korean patients, although letrozole is widely used in practice. Therefore, this studywas conducted to affirm the efficacy and toxicities of letrozole in Korean patients.
MATERIALS AND METHODS
This study retrospectively analyzed 84 HR-positive MBC patients who had been treated with letrozole from January 2001 to December 2012. Clinicopathological characteristics and treatment history were extracted from medicalrecords. All patients received 2.5 mg letrozole once a day until there were disease progressions or unacceptable toxicity. Progression-free survival (PFS) was the primary endpoint, and secondary endpoints were overall survival (OS), objective response rate (ORR), and toxicity.
RESULTS
The median age of the subjects was 59.3 years. Letrozole treatment resulted in a median PFS of 16.8 months (95% confidence interval [CI], 9.8 to 23.8) and a median OS of 56.4 months (95% CI, 38.1 to 74.7). The ORR was 36.9% for the 84 patients with measurable lesions. Multivariate analysis revealed symptomatic visceral disease (hazard ratio, 3.437; 95% CI, 1.576 to 7.495; p=0.002) and a disease-free interval ≤ 2 years (hazard ratio, 2.697; 95% CI, 1.262 to 5.762; p=0.010) were independently associated with shorter PFS. However, sensitivity to adjuvant hormone treatment was not related to PFS. Letrozole was generally well tolerated.
CONCLUSION
Letrozole showed considerable efficacy and tolerability as a first-line treatment in postmenopausal patients with HR-positive MBC.

Keyword

Letrozole; Hormone receptor-positive; Metastatic breast cancer; First-line treatment; Korea

MeSH Terms

Administration, Oral
Breast Neoplasms*
Breast*
Disease Progression
Disease-Free Survival
Female
Humans
Korea*
Multivariate Analysis
Retrospective Studies

Figure

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  Fig. 1. CONSORT diagram of patients included in analysis. SNUH, Seoul National University Hospital.

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  Fig. 2. Progression-free survival (PFS) and overall survival (OS) of first-line letrozole treatment.

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  Fig. 3. Progression-free survival (PFS) (A) and overall survival (OS) (B) based on disease-free interval (DFI). Median PFS for initial metastasis, DFI ≤ 2 years and DFI > 2 years: 9.3 months vs. 11.2 months vs. 22.8 months, p=0.004, log-rank test; median OS: 32.4 months vs. 44.9 months vs. 74.0 months, p=0.001, log-rank test. PFS (C) and OS (D) based on subgroups of dominant metastatic sites. Median PFS for bone, lymph nodes (LNs) or soft tissues, asymptomatic visceral metastasis, and symptomatic visceral metastasis: 18.5 months vs. 17.8 months vs. 40.6 vs. 8.8 months, p=0.002, log-rank test; median OS: 67.8 months vs. 56.4 months vs. 89.5 vs. 24.2 months, p=0.004, log-rank test.

Reference

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