Quality of life issues and different side effects caused by treatment may help determine which type of hormone therapy is most appropriate for postmenopausal women with ductal carcinoma in situ, particularly among women 60 years of age or older. These results were recently published in The Lancet.
Hormone-positive breast cancers, which comprise approximately 75% of all breast cancers, are stimulated to grow from exposure to the female hormones estrogen and/or progesterone.
Agents that block cancer cells from exposure to these female hormones are an important component in the treatment of hormone-positive breast cancers.
Different classes of these agents provide their anti-cancer effects through distinct mechanisms. Among postmenopausal women, anti-aromatase agents such as anastrozole, and anti-estrogen agents such as tamoxifen, are the most commonly used agents for the treatment of this disease.
Results from previous studies have indicated that anastrozole, or other anti-aromatase agents, provide superior outcomes compared with tamoxifen among women who are 60 years of age or younger with early hormone-positive breast cancer. However, among patients 60 years and older, outcomes are comparable between treatment with anastrozole and tamoxifen.
Quality of life and the severity of symptoms caused by the distinct classes of agents varies, depending upon variables such as additional health issues of the patient (co-morbidities), interactions with other medications taken by the patient, risk of severe medical conditions associated with side effects, age of a patient, and the patient’s tolerability of the side effects.
Researchers associated with the National Surgical Adjuvant Breast and Bowel Project (NSABP) recently evaluated quality of life and symptom differences experienced from treatment with anastrozole and tamoxifen among postmenopausal women with ductal carcinoma in situ (DCIS).
The study included 1,193 postmenopausal women with DCIS who were involved in the NSABP B-35 trial, in which patients were treated with a lumpectomy and radiation, as well as 5 years of either anastrozole or tamoxifen between 2003 and 2006.
Patients were given a questionnaire to assess quality of life issues at baseline, and for every 6 months thereafter for 6 years following the initiation of therapy.
The questionnaires were given to assess symptoms of treatment with both anastrozole and tamoxifen, as well as the patient’s perceived severity of these symptoms.
- Overall physical health, mental health, energy, fatigue and depression symptoms were not significantly different between patients treated with either anastrozole or tamoxifen.
- Vasomotor symptoms (symptoms associated with menopause such as night sweats, hot flashes, flushes, mood swings); difficulty with bladder control, and gynecological symptoms were significantly more severe among patients treated with tamoxifen.
- Pain of the muscles and/or joints and vaginal symptoms were significantly more severe among patients treated with anastrozole.
- Patients younger than 60 years of age experienced significantly more severe side effects of vasomotor symptoms, vaginal symptoms, weight problems, and gynecological symptoms, compared to their counterparts who were 60 years of age and older.
Based on these results, the researchers concluded that “Given the similar efficacy of tamoxifen and anastrozole for women older than age 60 years, decisions about treatment should be informed by the risk for serious adverse health effects and the symptoms associated with each drug.”
Among patients younger than 60 years of age, the researchers stated that “treatment decisions might be driven by efficacy (favoring anastrozole); however, if the side-effects of anastrozole are intolerable, then switching to tamoxifen is a good alternative.”
Patients with hormone-positive breast cancer should speak with their physician regarding their individual risks and benefits of each type of hormone therapy, as well as quality of life issues associated with the different agents.
Reference: Ganz P, Cecchini R, Julian T, et al. Patient-reported outcomes with anastrozole versus tamoxifen for postmenopausal patients with ductal carcinoma in situ treated with lumpectomy plus radiotherapy (NSABP B-35): a randomised, double-blind, phase 3 clinical trial. The Lancet. Published online December 10, 2015. Available at: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)01169-1/abstract. Accessed January 24, 2016. DOI: http://dx.doi.org/10.1016/S0140-6736(15)01169-1