Tailored treatment investigations for premenopausal women with endocrine responsive (ER+ and/or PGR+) breast cancer: The SOFT, TEXT, and PERCHE trials

Impact of body mass index on the efficacy of endocrine therapy in premenopausal patients with breast cancer: an analysis of the prospective ABCSG-12 trial

PURPOSE

Aromatase inhibitors are effective as endocrine treatment for patients with hormone receptor-positive breast cancer. According to the hypothesis that overweight patients have higher levels of aromatase enzyme availability, we investigated the influence of body mass index (BMI) on the efficacy of adjuvant endocrine therapy in premenopausal patients in a retrospective analysis of the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 12 trial.

PATIENTS AND METHODS

ABCSG-12 examined the efficacy of ovarian suppression using goserelin (3.6 mg subcutaneously every 28 days) in combination with anastrozole or tamoxifen with or without zoledronic acid (4 mg intravenously every 6 months) in premenopausal women with endocrine-responsive breast cancer. BMI was calculated using the prospectively collected data on patients' height and weight at study entry. BMI categories have been differentiated according to the WHO definition.

RESULTS

Overweight patients treated with anastrozole had a 60% increase in the risk of disease recurrence (hazard ratio [HR], 1.60; 95% CI, 1.06 to 2.41; P = .02) and more than a doubling in the risk of death (HR, 2.14; 95% CI, 1.17 to 3.92; P = .01) compared with normal weight patients treated with anastrozole. In the overweight group, patients treated with anastrozole had a nearly 50% increase in the risk of disease recurrence (HR, 1.49; 95% CI, 0.93 to 2.38; P = .08) and a three-fold increase in the risk of death (HR, 3.03; 95% CI, 1.35 to 6.82; P = .004) compared with patients treated with tamoxifen.

CONCLUSION

BMI significantly impacts on the efficacy of anastrozole plus goserelin in premenopausal patients with breast cancer, probably through influencing aromatase availability and/or ovarian suppression by goserelin.

The clinical outcome of chemotherapy-induced amenorrhea in premenopausal young patients with breast cancer with long-term follow-up

BACKGROUND

We investigated the factors that predict chemotherapy-induced amenorrhea (CIA) and the prognostic significance of CIA after long-term follow-up.

METHODS

We reviewed data from 241 premenopausal patients with breast cancer who underwent adjuvant CMF or FAC chemotherapy after breast cancer surgery between January 1995 and December 2000.

RESULTS

The median follow-up duration was 109.8 (range, 16.6-193.1) months. The age of CIA patients was older than non-CIA patients (median, 44 (range, 28-53) years and 36 (range, 25-49) years, respectively; P < 0.001). The addition of tamoxifen to the chemotherapy increased the incidence of CIA from 48% to 63.6% (P = 0.015). The 10-year disease-free survival (DFS) rate was higher in the CIA group compared with the non-CIA group in hormonal receptor-positive patients (78.4% vs. 67%, respectively; P = 0.022), and the 10-year overall survival (OS) rate also was higher in the CIA group compared with the non-CIA group (90.8% vs. 79.7%, respectively; P = 0.041).

CONCLUSIONS

The most important predictors of CIA are age and the addition of tamoxifen to the chemotherapy. CIA is likely to have an influence on DFS and OS in premenopausal patients with breast cancer with a positive hormone receptor, and it might be used as a surrogate marker for effective chemotherapy in these young Asian patients.

Optimal adjuvant endocrine therapy for early breast cancer

Adjuvant endocrine therapy substantially reduces tumor recurrence and mortality in pre- and post-menopausal women with hormone receptor-positive early breast cancer but is ineffective in women with hormone receptor-negative tumors. Tamoxifen has been the standard adjuvant endocrine therapy for both pre- and post-menopausal women with hormone receptor-positive early breast cancer and remains the standard of care for premenopausal women. In addition to tamoxifen, ovarian ablation by surgery or radiotherapy remains an option for selected premenopausal women and trials are evaluating the role of ovarian function suppression using luteinizing hormone-releasing hormone agonists. For postmenopausal women, aromatase inhibitors are more effective than tamoxifen therapy and aromatase inhibitors and tamoxifen are regarded as standards of care. Prolonging adjuvant endocrine therapy in postmenopausal women by the sequencing of aromatase inhibitors and tamoxifen can improve outcomes further. Adjuvant endocrine therapy will probably be used for longer durations in selected postmenopausal women.

Phosphorylation of the oestrogen receptor alpha at serine 305 and prediction of tamoxifen resistance in breast cancer

Phosphorylation of oestrogen receptor alpha at serine 305 (ERalphaS305-P) induces tamoxifen resistance in experimental studies, but does not influence response to other endocrine agents, such as fulvestrant. We evaluated ERalphaS305-P using immunohistochemistry in 377 breast carcinomas from premenopausal participants of a randomized trial (n=248) and patients with advanced disease (n=129). Among the premenopausal patients, adjuvant tamoxifen improved recurrence-free survival (RFS) for ERalphaS305-P-negative tumours (multivariate HR=0.53, 95% CI 0.32-0.86, p=0.010), but not for ERalphaS305-P-positive tumours (multivariate HR=1.01, 95% CI 0.33-3.05, p=0.99) (interaction p=0.131). Notably, ERalphaS305-P was not significantly associated with RFS in patients not treated with tamoxifen (multivariate HR=0.64, 95% CI 0.30-1.37, p=0.248), indicating that ERalphaS305-P is a marker for treatment outcome rather than tumour progression. Given the direct experimental link between ERalphaS305-P and tamoxifen resistance and these first clinical data suggesting that premenopausal patients with ERalphaS305-P-positive breast cancer are resistant to adjuvant tamoxifen, further research is encouraged to study whether alternative endocrine treatment should be considered for this subgroup.

The role of endocrine therapies in reducing risk of recurrence in postmenopausal women with hormone receptor-positive breast cancer

Hormone receptor-positive breast cancer is increasingly considered a chronic disease, as there remains an ongoing risk of local and distant relapse for years after diagnosis. While early recurrence risk peaks 2-3 years post diagnosis, the majority of breast cancer recurrences and deaths occur following 5 years of adjuvant tamoxifen. Aromatase inhibitors have achieved greater relative reductions in recurrence risk than tamoxifen alone and are now widely recommended as adjuvant therapy for postmenopausal women with hormone-sensitive breast cancer. Although both anastrozole and letrozole have demonstrated superior disease-free survival compared with tamoxifen, letrozole to date offers the greatest significant reduction in the risk of distant metastases in patients with hormone-sensitive breast cancer. Anastrozole and exemestane also reduce local and distant recurrence risk in the "switch setting" following 2-3 years of tamoxifen. Extended adjuvant letrozole, given after 5 years of tamoxifen, significantly reduces local and distant recurrence as well as mortality in patients with node-positive disease. Specialist nurses and nurse practitioners facilitate informed choice for breast cancer patients through explaining treatment options and side effects; they thus need an understanding of which treatment strategies reduce recurrence risk, especially the risk of distant metastases.

Adjuvant endocrine treatment of early breast cancer

Endocrine therapy plays a pivotal role in the early treatment of estrogen receptor (ER)-positive breast cancer. Although evidence suggests that chemotherapy may work partly through ovarian ablation in young women who have ER-positive tumors, combined chemotherapy and endocrine therapy are generally advocated. In postmenopausal women, aromatase inhibition has become the new "gold standard" of treatment. More research is needed to define optimal regimens (aromatase inhibitor monotherapy versus tamoxifen sequential application), optimal duration of therapy and potential advantages of particular compounds. The optimal use of estrogen suppression (ovarian ablation with or without aromatase inhibition) and tamoxifen (administered sequentially or in concert with ovarian ablation) in premenopausal women has yet to be defined.

Use of luteinising-hormone-releasing hormone agonists as adjuvant treatment in premenopausal patients with hormone-receptor-positive breast cancer: a meta-analysis of individual patient data from randomised adjuvant trials

BACKGROUND

Several trials have been done to assess treatment of premenopausal breast cancer with luteinising-hormone-releasing hormone (LHRH) agonists, but results have been inconclusive, especially for patients with hormone-receptor-positive cancer.

METHODS

We collected individual patients' data from published trials and did analyses focused on women with tumours positive for oestrogen receptor, progesterone receptor, or both. The main endpoints were recurrence and death after recurrence.

FINDINGS

We obtained data for 11 906 premenopausal women with early breast cancer randomised in 16 trials. When used as the only systemic adjuvant treatment, LHRH agonists did not significantly reduce recurrence (28.4% relative reduction, 95% CI consistent with 50.5% reduction to 3.5% increase, p=0.08) or death after recurrence (17.8%, 52.8% reduction to 42.9% increase, p=0.49) in hormone-receptor-positive cancers. Addition of LHRH agonists to tamoxifen, chemotherapy, or both reduced recurrence by 12.7% (2.4-21.9, p=0.02); and death after recurrence by 15.1% (1.8-26.7, p=0.03). LHRH agonists showed similar efficacy to chemotherapy (recurrence 3.9% increase, 7.7% reduction to 17.0% increase; death after recurrence 6.7% reduction, 20.7% reduction to 9.6% increase; both not significant). No trials had assessed an LHRH agonist versus chemotherapy with tamoxifen in both arms. LHRH agonists were ineffective in hormone-receptor-negative tumours.

INTERPRETATION

LHRH agonists provide an additional class of agents for treatment of premenopausal women with hormone-receptor-positive breast cancer. Optimum duration of use is unknown.

The Rates of Chemotherapy-Induced Amenorrhea in Patients Treated With Adjuvant Doxorubicin and Cyclophosphamide Followed by a Taxane

OBJECTIVE

Adjuvant chemotherapy in premenopausal women with breast cancer may induce amenorrhea, which can affect fertility, choice of hormonal therapy, and increase the risk of late toxicity. The incidence of chemotherapy-induced amenorrhea (CIA) resulting from doxorubicin and cyclophosphamide (AC) followed by a taxane (T) is poorly characterized.

METHODS

We retrospectively surveyed women who were premenopausal and less than age 50 at initiation of chemotherapy to determine the rates of CIA in women receiving AC followed by T compared with AC alone.

RESULTS

One hundred ninety-one eligible women completed the survey. The rate of CIA in women who received AC followed by T was 64% (95% confidence interval [CI] = 55-72%) compared with 55% (95% CI = 43-66%) in AC alone. As expected, CIA rates were higher in older than younger women (82% vs. 55%, P = 0.004). Multivariate logistic regression analysis revealed that age >40 was associated with a 4.6-fold increased risk of CIA (95% CI = 1.7-12.1, P = 0.002). It also revealed that receiving T after AC was associated with an odds ratio of 1.9 for CIA as compared with receiving AC alone (95% CI = 1.0-3.5, P = 0.05). Despite > or =6 months of amenorrhea, many women < or =40 resumed menses (40%). CIA was more likely to be irreversible in those >40. The addition of taxanes did not alter the rate of reversibility for the group as a whole (P = 0.36).

CONCLUSIONS

Older age and the addition of taxane to AC increased the risk of CIA and the amenorrhea was more likely to be irreversible for women >40. Women < or =40 often resume menstruation even after 6 months of amenorrhea, and the addition of T does not play a role. Subsequent resumption of menstrual function must be considered when initiating appropriate hormonal therapy.

Tamoxifen after adjuvant chemotherapy for premenopausal women with lymph node-positive breast cancer: International Breast Cancer Study Group Trial 13-93

PURPOSE

The value of adjuvant tamoxifen after chemotherapy for premenopausal women with breast cancer has not been adequately assessed.

PATIENTS AND METHODS

Between 1993 and 1999, International Breast Cancer Study Group Trial 13-93 enrolled 1,246 assessable premenopausal women with axillary node-positive, operable breast cancer. All patients received chemotherapy (cyclophosphamide plus either doxorubicin or epirubicin for four courses followed by immediate or delayed classical cyclophosphamide, methotrexate, and fluorouracil for three courses), which was followed by either tamoxifen (20 mg daily) for 5 years or no further treatment. The primary end point was disease-free survival (DFS). Tumors were classified as estrogen receptor (ER) -positive (n = 735, 59%) if immunohistochemical (IHC) or ligand-binding assays (LBA) were clearly positive. The ER-negative group included all other tumors (n = 511, 41%). A subset of the ER-negative group was defined as ER absent (n = 108, 9%) if IHC staining was none or if the LBA result was 0 fmol/mg cytosol protein. The median follow-up time was 7 years.

RESULTS

Tamoxifen improved DFS in the ER-positive cohort (hazard ratio [HR] for tamoxifen v no tamoxifen = 0.59; 95% CI, 0.46 to 0.75; P < .0001) but not in the ER-negative cohort (HR = 1.02; 95% CI, 0.77 to 1.35; P = .89). Tamoxifen had a detrimental effect on patients with ER-absent tumors compared with no tamoxifen in an unplanned exploratory analysis (HR = 2.10; 95% CI, 1.03 to 4.29; P = .04). Patients with ER-positive tumors who achieved chemotherapy-induced amenorrhea had a significantly improved outcome (HR for amenorrhea v no amenorrhea = 0.61; 95% CI, 0.44 to 0.86; P = .004), whether or not they received tamoxifen.

CONCLUSION

Tamoxifen after adjuvant chemotherapy significantly improved treatment outcome in premenopausal patients with endocrine-responsive disease, but its use as adjuvant therapy for patients with ER-negative tumors is not recommended.

The choice of systemic adjuvant therapy in receptor-positive early breast cancer

Patients with endocrine-responsive breast cancer represent a distinct population for which tailored adjuvant treatments are needed. Endocrine therapy is mandatory for this population. For premenopausal patients, ovarian ablation or tamoxifen can be recommended; the combination of both, as well as the combination of ovarian ablation and aromatase inhibitors is under investigation. For postmenopausal patients, tamoxifen for 5 years is the 'standard of care'. Anastrozole can be recommended for patients with a contraindication to tamoxifen. The addition of 5 years of letrozole after 5 years of tamoxifen has yielded benefits in terms of disease-free survival. The sequential use of tamoxifen and exemestane was superior to tamoxifen for 5 years. However, in both studies, long-term toxicity is still not fully evaluated. The addition of chemotherapy to endocrine treatment can be recommended for patients at high risk of relapse and in young patients. Chemotherapy should consist of 3-6 cycles of cyclophosphamide, methotrexate, 5-fluorouracil or of an anthracycline-containing regimen. The addition of taxanes cannot be routinely recommended in this population. Endocrine treatment should start after completion of chemotherapy.

Tailoring adjuvant treatments for the individual breast cancer patient

BACKGROUND

Chemotherapy, tamoxifen and ovarian function suppression have all demonstrated their effectiveness for treating women with early breast cancer. Treatment selection for individual patients, however, requires estimates on the magnitude of treatment effects to be achieved from the application of each modality. Unfortunately, information currently available is insufficient to properly tailor adjuvant treatments.

METHODS

We consider predictive factors to improve our understanding about selection of adjuvant therapies, reassessment of data from previous clinical trials and design of future studies.

RESULTS

Estrogen receptor (ER) and progesterone receptor (PgR) are the primary measures available today to tailor adjuvant therapies. Patient age/menopausal status (ability to obtain treatment effects via ovarian function suppression), measures of the metastatic potential of the tumor (such as number of positive axillary lymph nodes), and concurrent use of chemotherapy and tamoxifen are other factors that modify the magnitude of relative effect associated with chemotherapy and endocrine therapies. The Subpopulation Treatment Effect Pattern Plots (STEPP) method displays the patterns of treatment effects within randomized clinical trials or datasets from meta-analyses to identify features that predict responsiveness to the treatments under study without relying on retrospective subset analysis. Confirmation of hypotheses using independent clinical trial databases is recommended.

DISCUSSION

All findings from clinical trials and meta-analyses should be presented primarily according to steroid hormone receptor status and patient age. Future studies should be designed as tailored treatment investigations, with endocrine therapies evaluated within populations of patients with endocrine responsive tumors, and chemotherapy questions focused within populations of patients with endocrine nonresponsive disease.