Incidence and predictors of ovarian function recovery (OFR) in breast cancer (BC) patients with chemotherapy-induced amenorrhea (CIA) who switched from tamoxifen to exemestane.

Annals of oncology : official journal of the European Society for Medical Oncology / ESMO

PubMedID: 23108951

Guerrero A, Gavilá J, Folkerd E, Ortiz B, Martínez F, García A, Climent MA, Guillem V, Ruíz A. Incidence and predictors of ovarian function recovery (OFR) in breast cancer (BC) patients with chemotherapy-induced amenorrhea (CIA) who switched from tamoxifen to exemestane. Ann Oncol. 2013;24(3):674-9.
BACKGROUND
Aromatase inhibitors (AIs) may promote ovarian function recovery (OFR). True incidence, predictors and impact on the outcome of OFR are unknown.

PATIENTS AND METHODS
We carried out a prospective study to assess ovarian function in estrogen receptor (ER)-positive BC patients on tamoxifen who had at least 2 years of chemotherapy-induced amenorrhea (CIA) and postmenopausal E2 levels. Patients switched to exemestane and underwent a series of investigations including vaginal ultrasound, antimullerian hormone, follicle stimulating hormone (FSH), and E2. E2 measurements were made using a clinical assay (direct) and a highly sensitive (indirect) immunoassay for comparison.

RESULTS
Both E2 assays (indirect versus direct) showed a similar incidence of OFR 32% (95% CI 19.5-44.5) versus 30% (95% CI 17.7-42.3) and median time to OFR 5.4 months (95% CI 1.2-9.6) versus 6.0 months (95% CI 4.8-7.1).On multivariate analysis, the mean age at the start of exemestane treatment was the only marker associated with probability of OFR (OR: 0.44, 0.24-0.78; P = 0.006). According to a receiver operating characteristic (ROC) analysis, age <48 years predicted for OFR (sensitivity: 59%; 1-specificity: 17%; AUC: 0.796; P = 0.001). Patients with OFR had higher mean E2 levels (43.6 versus 5.76 pmol/l; P = 0.001) and a reduced disease-free survival [DFS; HR 9.3 (95% CI 3.3-48.0; P = 0.04)] than those without it.

CONCLUSION
Even with a clinical and biochemical profile compatible with menopause, switching from tamoxifen to an AI should be avoided in patients <48 with CIA.