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Use of anastrozole in the chemoprevention and treatment of breast cancer: A literature review
Rev Assoc Med B ras 2017; 63(4):371-378 371
REVIEW ARTICLE
Use of anastrozole in the chemoprevention and treatment of breast
cancer: A literature review
Maria da Conceição Barros-Oliveira1, Danylo Rafhael Costa-Silva1, Danielle Benigno de Andrade1, Umbelina Soares Borges1,
Cléciton Braga Tavares1, Rafael Soares Borges2, Janaína de Moraes Silva3, Benedito Borges da Silva1,2 *
1Posgraduate Program of Sciences and Health, Universidade Federal do Piauí, Teresina, PI, Brazil
2Department of Mastology, Hospital Getulio Vargas, Teresina, PI, Brazil
3Universidade Estadual do Piauí, Teresina, PI, Brazil
Summary
Study conducted at Universidade Federal
do Piauí, Teresina, PI, Brazil
Article received: 7/6/2016
Accepted for publication: 10/19/2016
*Correspondence:
Address: Av. Elias João Tajra, 1.260
Teresina, PI – Brazil
Postal code: 64049-300
Aromatase inhibitors have emerged as an alternative endocrine therapy for the
treatment of hormone sensitive breast cancer in postmenopausal women. The
use of third-generation inhibitors represented by exemestane, letrozol and
anastrozole is currently indicated. Anastrozole is a nonsteroidal compound and
a potent selective inhibitor of the aromatase enzyme. Although a few studies
have shown that its pharmacodynamic and pharmacokinetic properties may be
affected by interindividual variability, this drug has been recently used in all
configurations of breast cancer treatment. In metastatic disease, it is currently
considered the first-line treatment for postmenopausal women with estrogen
receptor-positive breast tumors. Anastrozole has shown promising results in the
adjuvant treatment of early-stage breast cancer in postmenopausal women. It
has also achieved interesting results in the chemoprevention of the disease.
Therefore, due to the importance of anastrozole both for endocrine treatment
and chemoprevention of hormone-sensitive breast cancer in postmenopausal
women, we proposed the current literature review in the SciELO and PubMed
database of articles published in the last 10 years.
Keywords: aromatase inhibitors, chemoprevention, breast neoplasms,
pharmacokinetics.
Introduction
Breast cancer is one of the most commonly diagnosed
types of cancer in women, presenting high incidence rates
in developed regions of the world compared with develop-
ing ones. Incidence rates of the disease range from 27
cases per 100,000 women in Eastern Africa to 96 cases per
100,000 women in Western Europe. 1,2 Breast cancer is
characterized as a multifactorial disease and its develop-
ment has been reported as the result of complex interac-
tions between an individual’s genoma and the environ-
ment.3 Prolonged exposure to estrogene plus progesterone
plays a significant role in the etiology of breast carcinoma
and biosynthesis pathway of estrogens is thus an impor-
tant therapeutic target.4
The main enzyme involved in estrogen biosynthesis
is CYP19A1 or aromatase that belongs to the cytochrome
P450 family and is predominantly located in the liver,
adrenal glands and fatty tissue.5 However, the source of
estrogen varies widely between premenopausal and post-
menopausal women (Figure 1).6 In premenopausal wom-
en, the main source of estrogen is the ovary, while in
postmenopausal women, estrogen is derived from the
conversion of androgens into estrogens (through the
aromatase enzyme). In particular, testosterone is con-
verted into estradiol, androstenedione into estrone and
16-alpha-hydroxytestosterone into estriol (Figure 2),
originating from the peripheral tissues, including the
skin, fatty tissue and breast. Therefore, the aromatase
enzyme directly affects estrogen biosynthesis in the breast
and it is believed that this enzyme plays an important
role in the progression of breast cancer. 7,8
Aromatase inhibitors (AIs) have recently been ap-
proved as a first-line endocrine therapy for postmeno-
pausal women with hormone-sensitive and metastatic
breast cancer.9,10 There are three generations of AIs and
the last, represented by exemestane, letrozol and anastro-