Impact of the menstrual cycle on commercial prognostic gene signatures in oestrogen receptor-positive primary breast cancer.

PURPOSE: Changes occur in the expression of oestrogen-regulated and proliferation-associated genes in oestrogen receptor (ER)-positive breast tumours during the menstrual cycle. We investigated if Oncotype® DX recurrence score (RS), Prosigna® (ROR) and EndoPredict® (EP/EPclin) prognostic tests, which include some of these genes, vary according to the time in the menstrual cycle when they are measured. METHODS: Pairs of test scores were derived from 30 ER-positive/human epidermal growth factor receptor-2-negative tumours sampled at two different points of the menstrual cycle. Menstrual cycle windows were prospectively defined as either W1 (days 1-6 and 27-35; low oestrogen and low progesterone) or W2 (days 7-26; high oestrogen and high or low progesterone). RESULTS: The invasion module score of RS was lower (- 10.9%; p = 0.098), whereas the ER (+ 16.6%; p = 0.046) and proliferation (+ 7.3%; p = 0.13) module scores were higher in W2. PGR expression was significantly increased in W2 (+ 81.4%; p = 0.0029). Despite this, mean scores were not significantly different between W1 and W2 for any of the tests and the two measurements showed high correlation (r = 0.72-0.93). However, variability between the two measurements led to tumours being assigned to different risk categories in the following proportion of cases: RS 22.7%, ROR 27.3%, EP 13.6% and EPclin 13.6%. CONCLUSION: There are significant changes during the menstrual cycle in the expression of some of the genes and gene module scores comprising the RS, ROR and EP/EPclin scores. These did not affect any of the prognostic scores in a systematic fashion, but there was substantial variability in paired measurements.

Timing of adjuvant surgical oophorectomy in the menstrual cycle and disease-free and overall survival in premenopausal women with operable breast cancer.

BACKGROUND: For women with hormone receptor-positive, operable breast cancer, surgical oophorectomy plus tamoxifen is an effective adjuvant therapy. We conducted a phase III randomized clinical trial to test the hypothesis that oophorectomy surgery performed during the luteal phase of the menstrual cycle was associated with better outcomes. METHODS: Seven hundred forty premenopausal women entered a clinical trial in which those women estimated not to be in the luteal phase of their menstrual cycle for the next one to six days (n = 509) were randomly assigned to receive treatment with surgical oophorectomy either delayed to be during a five-day window in the history-estimated midluteal phase of the menstrual cycles, or in the next one to six days. Women who were estimated to be in the luteal phase of the menstrual cycle for the next one to six days (n = 231) were excluded from random assignment and received immediate surgical treatments. All patients began tamoxifen within 6 days of surgery and continued this for 5 years. Kaplan-Meier methods, the log-rank test, and multivariable Cox regression models were used to assess differences in five-year disease-free survival (DFS) between the groups. All statistical tests were two-sided. RESULTS: The randomized midluteal phase surgery group had a five-year DFS of 64%, compared with 71% for the immediate surgery random assignment group (hazard ratio [HR] = 1.24, 95% confidence interval [CI] = 0.91 to 1.68, P = .18). Multivariable Cox regression models, which included important prognostic variables, gave similar results (aHR = 1.28, 95% CI = 0.94 to 1.76, P = .12). For overall survival, the univariate hazard ratio was 1.33 (95% CI = 0.94 to 1.89, P = .11) and the multivariable aHR was 1.43 (95% CI = 1.00 to 2.06, P = .05). Better DFS for follicular phase surgery, which was unanticipated, proved consistent across multiple exploratory analyses. CONCLUSIONS: The hypothesized benefit of adjuvant luteal phase oophorectomy was not shown in this large trial.

Bone mineral density following surgical oophorectomy and tamoxifen adjuvant therapy for breast cancer.

BACKGROUND: In premenopausal women treated for breast cancer, loss of bone mineral density (BMD) follows from menopause induced by chemotherapy or loss of ovarian function biochemically or by surgical oophorectomy. The impact on BMD of surgical oophorectomy plus tamoxifen therapy has not been described. METHODS: In 270 Filipino and Vietnamese premenopausal patients participating in a clinical trial assessing the impact of the timing in the menstrual cycle of adjuvant surgical oophorectomy on breast cancer outcomes, BMD was measured at the lumbar spine and femoral neck before this treatment, and at 6, 12, and 24 months after surgical and tamoxifen therapies. RESULTS: In women with a pretreatment BMD assessment and at least 1 other subsequent BMD assessment, no significant change in femoral neck BMD was observed over the 2-year period (-0.006 g/cm2 , -0.8%, P = .19), whereas in the lumbar spine, BMD fell by 0.045 g/cm2 (4.7%) in the first 12 months (P < .0001) and then began to stabilize. CONCLUSIONS: Surgically induced menopause with tamoxifen treatment is associated with loss of BMD at a rate that lessens over 2 years in the lumbar spine and no significant change of BMD in the femoral neck.

CYP2D6 genotypes, endoxifen levels, and disease recurrence in 224 Filipino and Vietnamese women receiving adjuvant tamoxifen for operable breast cancer.

BACKGROUND: While tamoxifen activity is mainly due to endoxifen and the concentration of this active metabolite is, in part, controlled by CYP2D6 metabolic status, clinical correlative studies have produced mixed results. FINDINGS: In an exploratory study, we determined the CYP2D6 metabolic status and plasma concentrations of endoxifen among 224 Filipino and Vietnamese women participating in a clinical trial of adjuvant hormonal therapy for operable breast cancer. We further conducted a nested-case-control study among 48 women (half with recurrent disease, half without) investigating the relationship of endoxifen concentrations and recurrence of disease. We found a significant association of reduced endoxifen plasma concentrations with functionally important CYP2D6 genotypes. High endoxifen concentrations were associated with higher risk of recurrence; with a quadratic trend fitted to a stratified Cox proportional hazards regression model, the likelihood ratio p-value was 0.002. The trend also showed that in 8 out of 9 pairs with low endoxifen concentrations, the recurrent case had lower endoxifen levels than the matched control. CONCLUSIONS: This exploratory analysis suggests that there is an optimal range for endoxifen concentrations to achieve favorable effects as adjuvant therapy. In particular, at higher concentrations (>70 ng.ml), endoxifen may promote recurrence.

Survival after adjuvant oophorectomy and tamoxifen in operable breast cancer in premenopausal women.

PURPOSE: Worldwide, approximately 750,000 new cases of breast cancer are diagnosed annually in premenopausal women with limited economic resources. Longer-term survival benefits from adjuvant therapies in such women with operable breast cancer are unknown. PATIENTS AND METHODS: From 1993 to 1999, we recruited 709 premenopausal women with operable breast cancer to a multisite randomized clinical trial of adjuvant oophorectomy and tamoxifen for 5 years or observation and this combined hormonal therapy on recurrence. RESULTS: With a median follow-up of 7.0 years, disease-free and overall survival were significantly improved with the adjuvant treatment (log-rank P = .0003 and .0002, respectively). Five year disease-free survival (DFS) probabilities of 74% and 61% (95% CI for difference, 7% to 21%) and overall survival (OS) rates of 78% and 71% (95% CI for difference, 1% to 21%) were observed in the adjuvant and observation groups. Ten-year DFS probabilities of 62% and 51% (95% CI for difference, 4% to 22%) and OS probabilities of 70% and 52% (95% CI for difference, 6% to 34%) between adjuvant and observation groups, respectively, were observed. In the subset of estrogen receptor-positive patients, 5-year DFS probabilities were 83% and 61%, and 10-year DFS probabilities were 66% and 47%, while 5-year OS probabilities were 88% and 74%, and 10-year OS probabilities were 82% and 49% in the adjuvant and observation groups, respectively. CONCLUSION: In premenopausal women with operable breast cancer not selected for estrogen receptor status or with estrogen receptor-positive tumors, 5- and 10-year DFS and OS rates are significantly improved following adjuvant oophorectomy and tamoxifen.