The 16th St. Gallen International Breast Cancer Conference 2019 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer.
Treatments were ...assessed in light of their intensity, duration and side-effects, estimating the magnitude of clinical benefit according to stage and biology of the disease. The Panel acknowledged that for many patients, the impact of adjuvant therapy or the adherence to specific guidelines may have modest impact on the risk of breast cancer recurrence or overall survival. For that reason, the Panel explicitly encouraged clinicians and patients to routinely discuss the magnitude of benefit for interventions as part of the development of the treatment plan.
The guidelines focus on common ductal and lobular breast cancer histologies arising in generally healthy women. Special breast cancer histologies may need different considerations, as do individual patients with other substantial health considerations. The panelists’ opinions reflect different interpretation of available data and expert opinion where is lack of evidence and sociocultural factors in their environment such as availability of and access to medical service, economic resources and reimbursement issues. Panelists encourage patient participation in well-designed clinical studies whenever available.
With these caveats in mind, the St. Gallen Consensus Conference seeks to provide guidance to clinicians on appropriate treatments for early-stage breast cancer and guidance for weighing the realistic tradeoffs between treatment and toxicity so that patients and clinical teams can make well-informed decisions on the basis of an honest reckoning of the magnitude of clinical benefit.
Bone-targeted treatments with bisphosphonates and denosumab, which reduce bone resorption, are known to reduce the risk of skeletal complications and prevent treatment-induced bone loss in patients ...with malignant bone disease. Additionally, these drugs may modify the course of bone destruction via inhibitory effects on the "vicious cycle" of growth factor and cytokine signaling between tumor and bone cells within the bone marrow microenvironment. Effects of the drugs on the stem cell niche, direct effects on the cancer cells, and immune modulation may also contribute. In early-stage (stages I, II, and III) breast cancer, treatment with the bisphosphonate zoledronic acid has shown improvements in disease-free and overall survival. Improved survival was particularly notable in women with established menopause at diagnosis and in premenopausal women with endocrine-responsive disease who received treatment with goserelin, which suppresses ovarian function by inhibiting the production of ovarian hormones. Additionally, in castrate-resistant prostate cancer, treatment with denosumab delays the development of bone metastases. These results strongly support the adjuvant use of bone-targeted treatments but suggest that reproductive hormones are an important treatment modifier to take into account. In advanced-stage (stage IV, ie, metastatic) cancers, survival benefits have been observed in patients with multiple myeloma and in patients with other solid tumors with rapid rates of bone destruction who received treatment with zoledronic acid. Here, we have critically reviewed the increasing evidence to support a disease-modifying effect of bone-targeted treatment and discussed the impact on clinical management.
These final results from ABCSG-12 confirm that twice-yearly ZOL safely enhances the efficacy of adjuvant endocrine therapy. Tamoxifen together with Goserelin for now remains the endocrine standard of ...care. In general, overall survival of more than 95% at 8 years' median follow-up supports the efficacy of endocrine-only regimens in this premenopausal patient population.
Zoledronic acid (ZOL) plus adjuvant endocrine therapy significantly improved disease-free survival (DFS) at 48- and 62-month follow-up in the ABCSG-12 trial. We present efficacy results of a final additional analysis after 94.4 months.
Patients were premenopausal women who had undergone primary surgery for stage I/II estrogen-receptor-positive and/or progesterone-receptor-positive breast cancer with <10 positive lymph nodes, and were scheduled for standard goserelin therapy. All 1803 patients received goserelin (3.6 mg every 28 days) and were randomized to tamoxifen (20 mg/days) or anastrozole (1 mg/days), both with or without ZOL (4 mg every 6 months) for 3 years. The primary end point was DFS; recurrence-free survival and overall survival (OS) were secondary end points.
After 94.4-month median follow-up (range, 0–114 months), relative risks of disease progression hazard ratio (HR) = 0.77; 95% confidence interval (CI) 0.60–0.99; P = 0.042 and of death (HR = 0.66; 95% CI 0.43–1.02; P = 0.064) are still reduced by ZOL although no longer significant at the predefined significance level. Overall, 251 DFS events and 86 deaths were reported. Absolute risk reductions with ZOL were 3.4% for DFS and 2.2% for OS. There was no DFS difference between tamoxifen alone versus anastrozole alone, but there was a pronounced higher risk of death for anastrozole-treated patients (HR = 1.63; 95% CI 1.05–1.45; P = 0.030). Treatments were generally well tolerated, with no reports of renal failure or osteonecrosis of the jaw.
These final results from ABCSG 12 suggest that twice-yearly ZOL enhances the efficacy of adjuvant endocrine treatment, and this benefit is maintained long-term.
NCT00295646 (http://www.clinicaltrials.gov/ct2/results?term=00295646).
Bisphosphonates are the standard of care for preventing skeletal morbidity and treating hypercalcemia of malignancy in patients with bone metastases. Zoledronic acid (intravenous; 4 mg monthly) is ...approved to prevent skeletal-related events (SREs) in patients with bone metastases from several tumor types, and can improve survival in some subsets of patients with skeletal metastases and high baseline bone turnover. In the adjuvant setting, bisphosphonates have shown clinical efficacy for preventing cancer treatment-induced bone loss and promise for reducing disease recurrence. For example, early studies of clodronate showed the potential for bisphosphonates to prevent bone metastases and prolong survival, but results with clodronate have been inconsistent. Recently, the more active bisphosphonate zoledronic acid (4 mg every 6 months) prevented bone loss and significantly reduced the risk of disease-free survival events by 36% (P = .01) compared with adjuvant endocrine therapy alone in a large phase III trial (N = 1,803) in premenopausal women with early breast cancer. Notably, these benefits were not limited to bone, because the addition of zoledronic acid reduced disease recurrence at all sites. Similarly, twice-yearly zoledronic acid has reduced disease recurrence in large phase III trials in more than 1,600 postmenopausal women with early breast cancer. Several ongoing trials (involving more than 20,000 patients altogether) are evaluating the efficacy of bisphosphonates for prevention of metastases in breast, prostate, and lung cancers; and multiple myeloma. Results from these studies are likely to expand the role of bisphosphonates, especially zoledronic acid, in the adjuvant therapy setting.
In early estrogen receptor (ER)-positive/HER2-negative breast cancer, the decision to administer chemotherapy is largely based on prognostic criteria. The combined molecular/clinical EndoPredict test ...(EPclin) has been validated to accurately assess prognosis in this population. In this study, the clinical relevance of EPclin in relation to well-established clinical guidelines is assessed.
We assigned risk groups to 1702 ER-positive/HER2-negative postmenopausal women from two large phase III trials treated only with endocrine therapy. Prognosis was assigned according to National Comprehensive Cancer Center Network-, German S3-, St Gallen guidelines and the EPclin. Prognostic groups were compared using the Kaplan–Meier survival analysis.
After 10 years, absolute risk reductions (ARR) between the high- and low-risk groups ranged from 6.9% to 11.2% if assigned according to guidelines. It was at 18.7% for EPclin. EPclin reassigned 58%–61% of women classified as high-/intermediate-risk (according to clinical guidelines) to low risk. Women reclassified to low risk showed a 5% rate of distant metastasis at 10 years.
The EPclin score is able to predict favorable prognosis in a majority of patients that clinical guidelines would assign to intermediate or high risk. EPclin may reduce the indications for chemotherapy in ER-positive postmenopausal women with a limited number of clinical risk factors.
The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with ...hormone-receptor-positive (HR+), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.
BOLERO-2 is a phase III, double-blind, randomized international trial comparing EVE 10 mg/day plus EXE 25 mg/day versus placebo (PBO) + EXE 25 mg/day in postmenopausal women with HR+ advanced breast cancer with prior exposure to NSAIs. The primary end point was PFS by local investigator assessment; OS was a key secondary end point.
At the time of data cutoff (3 October 2013), 410 deaths had occurred and 13 patients remained on treatment. Median OS in patients receiving EVE + EXE was 31.0 months 95% confidence interval (CI) 28.0–34.6 months compared with 26.6 months (95% CI 22.6–33.1 months) in patients receiving PBO + EXE (hazard ratio = 0.89; 95% CI 0.73–1.10; log-rank P = 0.14). Poststudy treatments were received by 84% of patients in the EVE + EXE arm versus 90% of patients in the PBO + EXE arm. Types of poststudy therapies were balanced across arms, except for chemotherapy (53% EVE + EXE versus 63% PBO + EXE). No new safety concerns were identified.
In BOLERO-2, adding EVE to EXE did not confer a statistically significant improvement in the secondary end point OS despite producing a clinically meaningful and statistically significant improvement in the primary end point, PFS (4.6-months prolongation in median PFS; P < 0.0001). Ongoing translational research should further refine the benefit of mTOR inhibition and related pathways in this treatment setting.
NCT00863655.
PAM50 is a 50-gene test that is designed to identify intrinsic breast cancer subtypes and generate a Risk of Recurrence (ROR) score. It has been developed to be carried out in qualified routine ...hospital pathology laboratories.
One thousand four hundred seventy-eight postmenopausal women with estrogen receptor (ER)+ early breast cancer (EBC) treated with tamoxifen or tamoxifen followed by anastrozole from the prospective randomized ABCSG-8 trial were entered into this study. Patients did not receive adjuvant chemotherapy. RNA was extracted from paraffin blocks and analyzed using the PAM50 test. Both intrinsic subtype (luminal A/B, HER2-enriched, basal-like) and ROR score were calculated. The primary analysis was designed to test whether the continuous ROR score adds prognostic value in predicting distant recurrence (DR) over and above standard clinical variables.
In all tested subgroups, ROR score significantly adds prognostic information to the clinical predictor (P < 0.0001). PAM50 assigns an intrinsic subtype to all cases, and the luminal A cohort had a significantly lower ROR at 10 years compared with Luminal B (P < 0.0001). Significant and clinically relevant discrimination between low- and high-risk groups occurred also within all tested subgroups.
The results of the primary analysis, in combination with recently published results from the ATAC trial, constitute Level 1 evidence for clinical validity of the PAM50 test for predicting the risk of DR in postmenopausal women with ER+ EBC. A 10-year metastasis risk of <3.5% in the ROR low category makes it unlikely that additional chemotherapy would improve this outcome—this finding could help to avoid unwarranted overtreatment.
ABCSG 8: NCT00291759.
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