Preoperative endocrine therapy for older women with breast cancer: renewed interest in an old idea

Delays in operative management of early-stage, estrogen receptor-positive breast cancer during the COVID-19 pandemic: A multi-institutional matched historical cohort study

Background

During the COVID-19 pandemic, guidelines recommended that breast cancer centers delay estrogen receptor–positive breast cancer surgeries with neoadjuvant endocrine therapy. We aimed to evaluate pathologic upstaging of breast cancer patients affected by these guidelines.

Methods

Female patients with stage I/II breast cancer receiving neoadjuvant endocrine therapy were prospectively identified and were matched to a historical cohort of stage I/II estrogen receptor–positive breast cancer patients treated with upfront surgery ≤35 days. Primary outcomes were pathologic T and N upstaging versus clinical staging.

Results

After matching, 28 neoadjuvant endocrine therapy and 48 control patients remained. Median age in each group was 65 (P = .68). Most patients (78.6% and 79.2%) had invasive ductal carcinoma with a clinical tumor size of 0.9 cm vs 1.7 cm (P = .056). Time to surgery was 68 days in the neoadjuvant endocrine therapy group and 26.5 days in the control (P < .001). A total of 23 neoadjuvant endocrine therapy patients (82.1%) had the same or lower pT-stage compared with 31 (64.5%) control patients (P = .115). Only 3 (10.7%) neoadjuvant endocrine therapy patients had increased pN-stage vs 14 (29.2%) control patients (P = .063).

Conclusion

Despite 2.5-times longer delays, patients with early-stage estrogen receptor–positive breast cancer receiving neoadjuvant endocrine therapy did not experience pathologic upstaging during the COVID-19 pandemic. These findings may support the use of neoadjuvant endocrine therapy in similar patients if delays to surgery are projected.

Primary Hormone Therapy in Elderly Women with Hormone-Sensitive Locoregional Breast Cancer: Endocrine Therapy Alone Is a Reasonable Alternative in Selected Patients

BACKGROUND

Treatment with aromatase inhibitors (AIs) followed by surgery is often recommended for women with locoregional hormone-sensitive breast cancer. However, no study has compared the efficacy of AIs alone versus AIs followed by surgery.

METHODS

33 postmenopausal breast cancer patients were treated with primary hormone therapy. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor type 2 receptor (HER2) expression levels were analyzed by immunohistochemistry. After hormone therapy, eligible patients underwent surgery, and those who were not candidates for surgery continued on hormone therapy. We retrospectively analyzed time to progression, overall survival, response, and impact of surgery on outcome.

RESULTS

All patients were ER+. HER2 was successfully analyzed in 30 patients, all of whom were HER2-. The median time to progression was 94 months, and the median overall survival was not reached, while the mean overall survival was 123 months. The overall response rate was 63.6%, with 9.1% complete responses. No significant differences in time to progression or survival were observed between patients who underwent surgery and those who did not.

CONCLUSIONS

Primary hormone therapy with AIs is effective in elderly breast cancer patients with high levels of hormone receptors and may provide a feasible and tolerable alternative to surgery in selected hormone-sensitive breast cancer patients.

Surgical considerations in patients receiving neoadjuvant systemic therapy

Neoadjuvant chemotherapy is being increasingly used in the treatment of patients presenting with early-stage, operable breast cancer. Neoadjuvant chemotherapy downsizes most tumors, allowing appropriately selected patients to undergo breast-conserving therapy. Management of the axilla in patients receiving neoadjuvant chemotherapy is dictated by whether patients present with clinically node-negative or node-positive disease. Patients with clinically node-negative disease can undergo sentinel lymph node dissection after neoadjuvant chemotherapy, with axillary lymph node dissection reserved for patients with a positive sentinel lymph node. For patients with clinically node-positive disease at presentation, the current standard of care is axillary lymph node dissection. An ongoing cooperative group trial is investigating the utility of sentinel lymph node surgery in the clinically node-positive population.

Improved surgical outcomes for breast cancer patients receiving neoadjuvant aromatase inhibitor therapy: results from a multicenter phase II trial

BACKGROUND

Neoadjuvant aromatase inhibitor therapy has been reported to improve surgical outcomes for postmenopausal women with clinical stage II or III hormone receptor-positive breast cancer. A multicenter phase II clinical trial was conducted to investigate the value of this approach for US surgical practice.

STUDY DESIGN

One hundred fifteen postmenopausal women with >2 cm, estrogen receptor (ER) or progesterone receptor (PgR)-positive breast cancer were enrolled in a trial of 16 to 24 weeks of letrozole 2.5 mg daily before operation.

RESULTS

One hundred six patients were eligible for primary analysis, 96 underwent operations, 7 received chemotherapy after progressive disease, and 3 did not undergo an operation. Baseline surgical status was marginal for breast-conserving surgery (BCS) in 48 (45%), 47 were definitely ineligible for BCS (44%), and 11 were inoperable by standard mastectomy (10%). Overall Response Evaluation Criteria In Solid Tumors clinical response rate in the breast was 62%, with 12% experiencing progressive disease. Fifty percent underwent BCS, including 30 of 46 (65%) patients who were initially marginal for BCS and 15 of 39 (38%) patients who were initially ineligible for BCS. All 11 inoperable patients successfully underwent operations, including 3 (27%) who had BCS. Nineteen percent of patients undergoing mastectomy had a pathologic T1 tumor, suggesting that some highly responsive tumors were overtreated surgically.

CONCLUSIONS

Neoadjuvant aromatase inhibitor improves operability and facilitates BCS, but there was considerable variability in responsiveness. Better techniques to predict response, determine residual tumor burden before operation, and greater willingness to attempt BCS in responsive patients could additionally improve the rate of successful BCS.

Aromatase inhibitors in early breast cancer therapy: a variety of treatment strategies

Until recently, standard endocrine therapy for estrogen receptor-positive early breast cancer in the preoperative neoadjuvant and postoperative adjuvant settings was the selective estrogen receptor modulator tamoxifen. An alternate therapeutic approach is to suppress total-body estrogen synthesis using an aromatase inhibitor. The highly potent and specific third-generation aromatase inhibitors (anastrozole, exemestane and letrozole) have consistently demonstrated improved efficacy over tamoxifen in large randomised neoadjuvant and adjuvant clinical trials. As neoadjuvant therapy, compared with tamoxifen, all three aromatase inhibitors significantly improved breast-conserving surgery rates, but only letrozole achieved a significantly higher overall response rate. These agents have also been evaluated in three adjuvant strategies: instead of tamoxifen for 5 years, sequenced after 2-3 years of tamoxifen, or as extended adjuvant therapy following a full 5-year course of tamoxifen. In all cases, the aromatase inhibitor was significantly more effective in reducing the risk of recurrence, compared with tamoxifen in the first two approaches and with placebo or no treatment as extended therapy. Long-term aromatase inhibitor treatment is associated with less endometrial cancer, thromboembolic events and strokes than tamoxifen, but more musculoskeletal disorders and bone loss. Further investigation is focusing on identification of the patient subgroups most likely to benefit from each of these adjuvant therapy options.

Comparison of anastrozole versus tamoxifen as preoperative therapy in postmenopausal women with hormone receptor-positive breast cancer: the Pre-Operative "Arimidex" Compared to Tamoxifen (PROACT) trial

BACKGROUND

The Pre-Operative "Arimidex" Compared to Tamoxifen (PROACT) study was a randomized, multicenter study comparing anastrozole with tamoxifen as a preoperative treatment of postmenopausal women with large, operable (T2/3, N0-2, M0), or potentially operable (T4b, N0-2, M0) breast cancer. The effect of preoperative endocrine therapy in patients scheduled for mastectomy or with inoperable tumors at baseline was also investigated.

METHODS

Patients with hormone receptor-positive breast cancer received anastrozole (n = 228) or tamoxifen (n = 223) with or without chemotherapy for 12 weeks before primary surgery.

RESULTS

Objective responses for anastrozole and tamoxifen occurred in 39.5% and 35.4% of patients, respectively (ultrasound measurements), and 50.0% and 46.2% of patients, respectively (caliper measurements). In hormonal therapy-only patients (n = 314), feasible surgery at baseline improved after 3 months in 43.0% of patients receiving anastrozole and 30.8% receiving tamoxifen (P = .04). In the intent-to-treat population, improvement in feasible surgery at baseline to actual surgery at 3 months was found to be numerically higher in the anastrozole group compared with the tamoxifen group, although this difference did not reach significance. Drug-related adverse events were reported in 20.2% and 18.1% of patients, respectively, in the anastrozole and tamoxifen groups.

CONCLUSIONS

Anastrozole is an effective and well-tolerated preoperative therapy, producing clinically beneficial tumor downstaging and reductions in tumor volume. These effects enable more minimal surgical interventions in patients scheduled for mastectomy, and mastectomy in patients with previously inoperable tumors. Anastrozole appears to be at least as effective as tamoxifen in this setting, and more effective than tamoxifen in certain clinically relevant subgroups. Cancer 2006. (c) 2006 American Cancer Society.

Antiestrogens, aromatase inhibitors, and apoptosis in breast cancer

Antiestrogens have been the therapeutic agents of choice for breast cancer patients whose tumors express estrogen receptors, regardless of menopausal status. Unfortunately, many patients will eventually develop resistance to these drugs. Antiestrogens primarily act by preventing endogenous estrogen from activating estrogen receptors and promoting cell growth, which can ultimately lead to tumor cell death. Understanding the mechanisms by which antiestrogens cause cell death or apoptosis is critical to our efforts to develop ways to circumvent resistance. This article focuses on antiestrogen-induced apoptosis both in vitro and in vivo. We review the clinical utility of both antiestrogens and aromatase inhibitors and their apoptogenic mechanisms in cell culture models. Among the key signaling components discussed are the roles of Bcl-2 family members, several cytokines, and their receptors, p53, nuclear factor kappa B (NFkappaB), IRF-1, phosphatidylinositol 3-kinase (PI3K)/Akt, and specific caspases. Finally, we discuss the evidence supporting a role for apoptotic defects in acquired and de novo antiestrogen resistance.

Current limits of knowledge in adjuvant and neoadjuvant endocrine therapy of breast cancer: the need for more clinical research

Adjuvant endocrine therapy following surgical resection of early, endocrine sensitive breast cancer has proven benefits in reducing risk of recurrence and death, as demonstrated in many mature well controlled clinical trials. The introduction of new endocrine therapies as potential alternatives to tamoxifen or ovarian ablation and the incorporation of neoadjuvant endocrine therapy into the overall management strategy continue to provide exciting challenges for clinical research. In this article the focus is on as yet unanswered questions pertinent to adjuvant or neoadjuvant endocrine therapy for breast cancer. In the process, we broadly outline the current limits of knowledge as we understand it. Many relevant and current clinical trials are ongoing and a list of these with contact details or references are provided. Definitive data is urgently needed in many areas and, when available, will provide important evidence on which the management of breast cancer patients in future can be based. Participation in relevant clinical trials is vital for future progress.

A roundtable discussion of aromatase inhibitors as therapy for breast cancer

This article summarizes the conclusions of a meeting of diverse breast cancer experts who discussed issues, controversies, and new clinical trial results relevant to the use of aromatase inhibitors for treating postmenopausal women with breast cancer. The new generation of aromatase inhibitors (anastrozole, letrozole, exemestane) have largely replaced megestrol acetate as a second-line therapy in postmenopausal women with hormone-responsive advanced breast cancer. In addition, anastrozole and letrozole have been shown to be superior to tamoxifen for first-line therapy. Finally, recent results suggest that anastrozole may be superior to tamoxifen as adjuvant therapy for early stage disease in postmenopausal women with hormone-responsive disease.

Role of antiestrogens and aromatase inhibitors in breast cancer treatment

This review explores the recent experience with, and the basis for, the use of selective estrogen receptor modulators to treat and prevent breast cancer. As new agents are unveiled, they will continue to be tested against tamoxifen. A number of new selective estrogen receptor modulators are in clinical development in an attempt to decrease the unwanted effects of tamoxifen. Raloxifene holds the promise of treating osteoporosis with the beneficial side effect of breast cancer prevention. Additionally, two different classes of hormonal agents, the aromatase inhibitors and estrogen receptor down-regulators, which have no estrogen-like properties at any site, appear to be promising new treatments for advanced breast cancer.

Letrozole is more effective neoadjuvant endocrine therapy than tamoxifen for ErbB-1- and/or ErbB-2-positive, estrogen receptor-positive primary breast cancer: evidence from a phase III randomized trial

PURPOSE

Expression of ErbB-1 and ErbB-2 (epidermal growth factor receptor and HER2/neu) in breast cancer may cause tamoxifen resistance, but not all studies concur. Additionally, the relationship between ErbB-1 and ErbB-2 expression and response to selective aromatase inhibitors is unknown. A neoadjuvant study for primary breast cancer that randomized treatment between letrozole and tamoxifen provided a context within which these issues could be addressed prospectively.

PATIENTS AND METHODS

Postmenopausal patients with estrogen- and/or progesterone receptor-positive (ER+ and/or PgR+) primary breast cancer ineligible for breast-conserving surgery were randomly assigned to 4 months of neoadjuvant letrozole 2.5 mg daily or tamoxifen 20 mg daily in a double-blinded study. Immunohistochemistry (IHC) for ER and PgR was conducted on pretreatment biopsies and assessed by the Allred score. ErbB-1 and ErbB-2 IHC were assessed by intensity and completeness of membranous staining according to published criteria.

RESULTS

For study biopsy-confirmed ER+ and/or PgR+ cases that received letrozole, 60% responded and 48% underwent successful breast-conserving surgery. The response to tamoxifen was inferior (41%, P =.004), and fewer patients underwent breast conservation (36%, P =.036). Differences in response rates between letrozole and tamoxifen were most marked for tumors that were positive for ErbB-1 and/or ErbB-2 and ER (88% v 21%, P =.0004).

CONCLUSION

ER+, ErbB-1+, and/or ErbB-2+ primary breast cancer responded well to letrozole, but responses to tamoxifen were infrequent. This suggests that ErbB-1 and ErbB-2 signaling through ER is ligand-dependent and that the growth-promoting effects of these receptor tyrosine kinases on ER+ breast cancer can be inhibited by potent estrogen deprivation therapy.