According to the results of a study published in the journal Lancet Oncology, use of postmenopausal hormones increases the risk of lobular and tubular breast cancers more than other types of breast cancer.
As women reach menopause and beyond, more than 80% will experience symptoms such as hot flashes, night sweats, sleep disturbance, and vaginal dryness.
Estrogen, with or without progestin, is the most effective treatment for many of these symptoms. Recent studies, however, have raised concerns about the health effects of postmenopausal hormone therapy.
Use of estrogen plus progestin has been linked with an increased risk of heart disease, breast cancer, stroke, and blood clots and a decreased risk of fractures and colorectal cancer. Use of estrogen alone, which is generally reserved for women who have had a hysterectomy, has been linked with an increased risk of strokes and a decreased risk of fractures.
A question that has remained uncertain is whether the link between postmenopausal hormones and breast cancer varies by type of breast cancer. To explore this question, researchers evaluated information from the U.K. Million Women Study. The study enrolled over one million women between the ages of 50 and 64.
During follow-up, roughly 14,000 of the women were diagnosed with breast cancer. Close to 12,000 of these diagnoses were invasive breast cancer (ductal, lobular, mixed ductal-lobular, tubular, medullarly, and mucinous) and the remainder was in situ breast cancer (either ductal or lobular).
- Compared to women who had never used postmenopausal hormone therapy, women who were current users had a roughly 60% increased risk of invasive ductal or invasive mucinous cancers, and a more than two-fold increased risk of invasive lobular or invasive tubular cancers. Postmenopausal hormone use was not linked with risk of invasive medullary cancers.
- Current use of postmenopausal hormone therapy increased the risk of lobular carcinoma in situ (LCIS) to a greater extent than ductal carcinoma in situ (DCIS).
- Risk of breast cancer was greater in current users of postmenopausal hormone therapy than in past users.
- For each type of breast cancer, use of combined estrogen plus progestin carried a greater risk of breast cancer than use of estrogen alone.
- The link between postmenopausal hormone use and breast cancer was weaker among women with a high body mass index (BMI).
The results of this study suggest that postmenopausal hormone therapy increases the risk of lobular and tubular breast cancers to a greater extent than other types of breast cancer. Risk of breast cancer appeared to be higher among current users of postmenopausal hormones than among past users, and was also higher among users of combined estrogen plus progestin than among users of estrogen alone. The link between postmenopausal hormones and breast cancer was weaker among women with a high body mass index.
 Gracia CR, Freeman EW. Acute consequences of the menopausal transition: the rise of common menopausal symptoms. Endocrinol Metab Clin N Am. 2004;33:675-689.
 NIH State of the Science Panel. National Institutes of Health State-of-the-Science Conference Statement: Management of Menopause-Related Symptoms. Ann Intern Med. 2005; 142:1003-1013.
 Rossouw JE, Anderson GL, Prentice RL et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial. JAMA. 2002; 288:321-33.
 Anderson GL, Limacher M, Assaf AR et al. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: the Women’s Health Initiative randomized controlled trial. JAMA . 2004; 291:1701-1712.
 Reeves GK, Beral V, Green J, Gathani T, Bull D for the Million Women Study Collaborators. Hormonal Therapy for Menopause and Breast Cancer Risk by Histological Type: a Cohort Study and Meta-analysis. Lancet Oncology. 2006;7:910-18.
Copyright © 2018 CancerConnect. All Rights Reserved.