Breast cancer patients who switched to Aromasin® (exemestane) after 2-3 years of Nolvadex® (tamoxifen) reported a similar quality of life to patients who continued on Nolvadex. These results were published in the Journal of Clinical Oncology.
Each year, breast cancer is diagnosed in over 200,000 women in the U.S. alone. Many of these breast cancers will be hormone receptor-positive, meaning that they are stimulated to grow by the circulating female hormones estrogen and/or progesterone.
Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen. These therapies include Nolvadex as well as a group of drugs referred to as anti-aromatase agents. Nolvadex acts by blocking estrogen receptors, whereas anti-aromatase agents suppress the production of estrogen. Aromasin is an anti-aromatase agent.
Previously, a clinical trial known as the Intergroup Exemestane Study reported that breast cancer patients who switched to Aromasin after 2-3 years of Nolvadex experienced longer cancer-free survival than patients who continued on Nolvadex.
In the current report, researchers evaluated the effect of switching to Aromasin on quality of life and frequency of symptoms. This study included 582 of the 4724 women who participated in the Intergroup Exemestane Study. The women were postmenopausal, had been treated for early breast cancer, and received a total of five years of hormonal therapy. Women were randomly assigned to receive Nolvadex for the entire five years or to switch to Aromasin after 2-3 years of Nolvadex.
- Over the course of two years, there were no notable differences in overall quality of life between women who switched to Aromasin and women who remained on Nolvadex.
- Hot flashes were the most commonly reported symptom in both groups. Hot flashes were reported by 46% of women who switched to Aromasin and 45% of women who remained on Nolvadex. The frequency of hot flashes declined over time in both groups.
- Lack of energy and loss of libido were also common and affected both groups similarly. Lack of energy was reported by 38% of women who switched to Aromasin and 34% of women who remained on Nolvadex. Loss of libido was reported by 41% of women who switched to Aromasin and 45% of patients who remained on Nolvadex.
- Vaginal discharge was less common in women who switched to Aromasin than in women who remained on Nolvadex.
The researchers conclude that the previously reported benefits of switching to Aromasin after Nolvadex appear to be obtained without decreasing quality of life or increasing symptoms.
 Coombes R, Hall E, Gibson L, et al. A randomized trial of exemestane after two to three years of tamoxifen therapy in postmenopausal women with primary breast cancer. New EnglandJournal of Medicine.2004;350:1081-1092.
 Fallowfield LJ, Bliss JM, Porter LS et al. Quality of Life in the Intergroup Exemestane Study: A Randomized Trial of Exemestane Versus Continued Tamoxifen After 2 to 3 Years of Tamoxifen in Postmenopausal Women with Primary Breast Cancer. Journal of Clinical Oncology. 2006;24:910-917.