Intermittent Letrozole Administration as Adjuvant Endocrine Therapy for Postmenopausal Women With Hormone Receptor-Positive Early Breast Cancer: A Biologic Study

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• 作者：Alessandra Balduzzi¹ ; ^{alessandra.balduzzi@ieo.it" class="auth_mail" title="E-mail the corresponding author} ; Vincenzo Bagnardi² ; ⁷ ; Maria Teresa Sandri³ ; Silvia Dellapasqua¹ ; Anna Cardillo¹ ; Emilia Montagna¹ ; Giuseppe Cancello¹ ; Monica Iorfida¹ ; Raffaella Ghisini⁴ ; Giuseppe Viale⁵ ; ⁸ ; Mattia Intra⁶ ; Alberto Luini⁶ ; Aron Goldhirsch⁴ ; Marco Colleoni¹
• 关键词：Adjuvant endocrine treatment ; Estradiol serum level ; Estrogen receptor ; Intermittent administration ; Progesterone receptor
• 刊名：Clinical Breast Cancer
• 出版年：2015
• 出版时间：October 2015
• 年：2015
• 卷：15
• 期：5
• 页码：e257-e262
• 全文大小：821 K

文摘

Letrozole withdrawal for 3 months might permit estrogenic stimulation in residual resistant breast cancer disease susceptible to letrozole reintroduction. We investigated the impact of a 3-month letrozole-free interval on serum estradiol levels in patients with early stage breast cancer.

Patients and Methods

Postmenopausal women with estrogen receptor– and/or progesterone receptor–positive (> 10% of immunoreactive cells), node-negative early breast cancer were eligible. Patients received letrozole for 5 years with a 3-month treatment-free interval after the first year of therapy. The primary end point was to evaluate the increase in serum estradiol levels after a 3-month treatment-free interval. The secondary end points were the evaluations of other biologic markers (eg, follicle-stimulating hormone, luteinizing hormone, cholesterol, high-density lipoprotein, triglycerides, osteocalcin).

Results

From November 2007 to February 2012, 130 evaluable patients were enrolled. The median age was 61 years. Mean values of estradiol levels at time of discontinuation were 5.6 pg/mL (standard deviation 1.7). Estradiol levels increased after a 3-month treatment-free interval by a mean of 3.3 pg/mL (66%; P < .0001). Follicle-stimulating hormone and luteinizing hormone levels decreased from baseline by a mean of 7.5 mU/mL (P < .0001), and 1.4 mU/mL (P = .0062), respectively. Triglycerides decreased from baseline by a mean of 8.6 mg/dL (P = .036), and osteocalcin increased by a mean of 2.8 ng/mL (P = .013).

Conclusion

Intermittent letrozole significantly affects estradiol levels.