This year, the American Society of Clinical Oncology (ASCO) celebrates the 50th anniversary of its founding. ASCO’s 2014 annual meeting acknowledged the society’s role in the advances made against cancer and presented the latest research and educational information about prevention, detection, and treatment of cancer. This year’s meeting was well attended and provided a wealth of learning opportunities. Below are some highlights of the many ASCO presentations. These news briefs touch upon the harmful effects of obesity and the beneficial effects of weight loss on parameters of body composition and sex hormones, preservation of fertility in premenopausal breast cancer survivors, and a study that shows that loratadine is not effective in treating pegfilgrastim-induced bone pain.
Exemestane Plus Ovarian Suppression a Valid Option in Premenopausal Early Breast Cancer
The aromatase inhibitor exemestane was superior to tamoxifen when combined with ovarian function suppression (OFS) in preventing recurrence in premenopausal women with hormone-sensitive breast cancers. These were the findings of a joint analysis of 2 important phase 3 clinical trials, TEXT (Tamoxifen and Exemestane Trial) and SOFT (Suppression of Ovarian Function Trial), that were presented at the American Society of Clinical Oncology 2014 annual meeting and published simultaneously in the New England Journal of Medicine.1,2
Lead author, Olivia Pagani, MD, explained that up until now exemestane has been used only in postmenopausal women. “This analysis demonstrates that an aromatase inhibitor is effective adjuvant therapy for premenopausal women when combined with ovarian suppression. Exemestane [plus OFS] is a valid alternative to tamoxifen [plus OFS] in young women with hormone-sensitive disease. It is a new adjuvant treatment option that reduces recurrence in this setting,” she stated. Pagani is clinical director of the Breast Unit at the Oncology Institute of Southern Switzerland in Bellinzona.
OFS is used more frequently in Europe than in the United States to achieve low estrogen levels in patients with hormone-sensitive breast cancer. Tamoxifen is considered the standard of care in this setting, and adjuvant chemotherapy is sometimes used depending on the judgment of the oncologist and patient preference.
Both SOFT and TEXT compared 5 years of tamoxifen plus OFS versus 5 years of exemestane plus OFS. SOFT was a 3-arm trial comparing both of those treatment approaches versus tamoxifen alone; results of the tamoxifen-alone arm have not yet been analyzed, so it is currently not possible to determine if tamoxifen alone is superior, equal, or inferior to hormonal therapy plus OFS.
The joint analysis of SOFT and TEXT included 4690 patients from both trials enrolled in the OFS-containing arms.
Chemotherapy was given at the discretion of the treating physician, and 42.6% did not receive chemotherapy. About 28% of the women who did not get chemotherapy had tumors larger than 2 cm and some positive nodes. In a separate interview, Pagani said that the study suggests that exemestane plus OFS could replace chemotherapy in some patients.
“Our study suggests that for hormone-sensitive tumors, go for exemestane and OFS and you can avoid chemotherapy,” Pagani stated.
At a median follow-up of 68 months, 5-year disease-free survival was 91.1% with exemestane plus OFS versus 87.3% in the tamoxifen plus OFS group (P < .001). The 5-year rate of freedom from breast cancer was 92.8% in the exemestane-treated patients compared with 88% in those who received tamoxifen (P < .001). Among patients who did not receive chemotherapy and were treated with exemestane plus OFS, 97.6% of those in the TEXT population and 97.5% of those in the SOFT population were free of breast cancer at 5 years.
The 5-year rate of freedom from recurrence at a distant site was 93.8% in the exemestane plus OFS group compared with 92% in the tamoxifen plus OFS group. At 5 years, overall survival was 95.9% in the exemestane group and 96.9% in the tamoxifen group. However, it is premature to determine survival, Pagani said.
Side effects of both drugs were as expected. Adverse events that were more frequent with exemestane included fractures, musculoskeletal symptoms, vaginal dryness, decreased libido, and dyspareunia; those more frequently reported with tamoxifen included thromboembolic events, hot flushes, night sweats, and urinary incontinence. Gynecologic cancers were reported in 7 exemestane-treated patients and in 9 patients in the tamoxifen group; endometrial cancers occurred in 2 and 5 patients, respectively. About 30% of patients in both arms experienced grade 3 or 4 adverse events.
Experts said that they were awaiting results of the tamoxifen-alone arm of the TEXT trial to see whether these findings would be practice changing.
- Pagani O, Regan MM, Walley B, et al. Randomized comparison of adjuvant aromatase inhibitor (AI) with exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): joint analysis of IBCSG TEXT and SOFT trials. Presented at: 50th Annual Meeting of the American Society of Clinical Oncology; May 30-June 3, 2014; Chicago, IL. Abstract LBA1.
- Pagani O, Regan MM, Walley BA, et al; the TEXT and SOFT Investigators and the International Breast Cancer Study Group. Adjuvant exemestane with ovarian suppression in premenopausal breast cancer.
N Engl J Med. 2014;371(2):107-118.