MAF Amplification and Adjuvant Clodronate Outcomes in Early-Stage Breast Cancer in NSABP B-34 and Potential Impact on Clinical Practice

Background

The Adjuvant Zoledronic Acid (ZA) study in early breast cancer (AZURE) showed correlation between a nonamplified MAF gene in the primary tumor and benefit from adjuvant ZA. Adverse ZA outcomes occurred in MAF-amplified patients. NSABP B-34 is a validation study.

Methods

A retrospective analysis of MAF gene status in NSABP B-34 was performed. Eligible patients were randomly assigned to standard adjuvant systemic treatment plus 3 years oral clodronate (1600 mg/daily) or placebo. Tumors were tested for MAF gene amplification and analyzed for their relationship to clodronate for disease-free survival (DFS) and overall survival (OS) in MAF nonamplified patients. All statistical tests were 2-sided .

Results

MAF status was assessed in 2533 available primary tumor samples from 3311 patients. Of these, 37 withdrew consent; in 77 samples, no tumor was found; 536 assays did not meet quality standards, leaving 1883 (77.8%) evaluable for MAF assay by fluorescence in situ hybridization (947 from placebo and 936 from clodronate arms). At 5 years, in MAF nonamplified patients receiving clodronate, DFS improved by 30% (hazard ratio = 0.70, 95% confidence interval = 0.51 to 0.94; P = .02). OS improved at 5 years (hazard ratio = 0.59, 95% confidence interval = 0.37 to 0.93; P = .02) remaining statistically significant for clodronate throughout study follow-up. Conversely, adjuvant clodronate in women with MAF-amplified tumors was not associated with benefit but rather possible harm in some subgroups. Association between MAF status and menopausal status was not seen.

Conclusions

Nonamplified MAF showed statistically significant benefits (DFS and OS) with oral clodronate, supporting validation of the AZURE study.

Phase III Randomized Trial of Bisphosphonates as Adjuvant Therapy in Breast Cancer: S0307

BACKGROUND

Adjuvant bisphosphonates, when given in a low-estrogen environment, can decrease breast cancer recurrence and death. Treatment guidelines include recommendations for adjuvant bisphosphonates in postmenopausal patients. SWOG/Alliance/Canadian Cancer Trials Group/ECOG-ACRIN/NRG Oncology study S0307 compared the efficacy of three bisphosphonates in early-stage breast cancer.

METHODS

Patients with stage I-III breast cancer were randomly assigned to 3 years of intravenous zoledronic acid, oral clodronate, or oral ibandronate. The primary endpoint was disease-free survival (DFS) with overall survival as a secondary outcome. All statistical tests were two-sided.

RESULTS

A total of 6097 patients enrolled. Median age was 52.7 years. Prior to being randomly assigned, 73.2% patients indicated preference for oral vs intravenous formulation. DFS did not differ across arms in a log-rank test (P = .49); 5-year DFS was 88.3% (zoledronic acid: 95% confidence interval [CI] = 86.9% to 89.6%), 87.6% (clodronate: 95% CI = 86.1% to 88.9%), and 87.4% (ibandronate: 95% CI = 85.6% to 88.9%). Additionally, 5-year overall survival did not differ between arms (log rank P = .50) and was 92.6% (zoledronic acid: 95% CI = 91.4% to 93.6%), 92.4% (clodronate: 95% CI = 91.2% to 93.5%), and 92.9% (ibandronate: 95% CI = 91.5% to 94.1%). Bone as first site of recurrence did not differ between arms (P = .93). Analyses based on age and tumor subtypes showed no treatment differences. Grade 3/4 toxicity was 8.8% (zoledronic acid), 8.3% (clodronate), and 10.5% (ibandronate). Osteonecrosis of the jaw was highest for zoledronic acid (1.26%) compared with clodronate (0.36%) and ibandronate (0.77%).

CONCLUSIONS

We found no evidence of differences in efficacy by type of bisphosphonate, either in overall analysis or subgroups. Despite an increased rate of osteonecrosis of the jaw with zoledronic acid, overall toxicity grade differed little across arms. Given that patients expressed preference for oral formulation, efforts to make oral agents available in the United States should be considered.

Validation of MAF biomarker for response prediction to adjuvant bisphosphonates in 2 clinical trials: AZURE and NSABP-B34

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Background: An Early Breast Cancer Trialists' Collaborative Group (EBCTCG) meta-analysis indicates that adjuvant bisphosphonates increase time to bone recurrence and survival in postmenopausal breast cancer patients, but results of individual trials have been inconclusive. Retrospective analyses of AZURE, a trial of adjuvant zoledronic acid, showed MAF (a transcription factor of the AP-1 family) amplification status predicted bisphosphonate benefit independently of menopause for invasive disease-free survival (IDFS) and overall survival (OS). Validation of MAF amplification status as a potential companion diagnostic for adjuvant bisphosphonates was confirmed using NSABP-B34 specimens. Methods: The randomized, placebo-controlled NSABP B-34 study of women with stage 1-3 breast cancer were assigned to adjuvant systemic therapy plus oral clodronate 1600 mg daily or placebo for 3 years. The primary endpoint was disease-free survival (DFS) with overall survival (OS) as a secondary outcome. MAF amplification was assessed by fluorescence in-situ hybridization on anonymized sections of breast tumor tissue in all patients with tumor samples and performed in a laboratory blind to treatment assignment. Protocol and analysis plans were pre-specified. Disease outcomes were analysed using intention to treat principles. Results: 2496 B-34 patients contributed tumor samples (from 2001-2004), of whom 1883 (75%) were evaluable (947 placebo and 936 clodronate). 1515 (80%) tumors were MAF negative (766 placebo and 749 clodronate) and 368 were MAF positive. At median follow-up of 108 months, MAF was prognostic for DFS, OS and bone-metastasis-free survival in the control group (MAF-positive vs MAF-negative: HRDFS=1·39, 95%CI 1·01-1·92; p=0.045; HROS=1·59, 95%CI 1·08-2·33; p=0.018; HRBM=2·03, 95%CI 1·13-3·68; p=0.016). In patients with MAF-negative tumors, clodronate gave higher DFS and OS than controls at 60 months (HRDFS=0·70, 95%CI 0·51-0·94; p=0.020 and HROS=0·59, 95%CI 0·37-0·93; p=0.024), the latter maintained through follow-up (HROS=0·74, 95%CI 0·54-1.00; p=0.047), but not in patients with MAF-positive tumors - consistent with previous AZURE results. Conclusions: MAF benefit prediction from adjuvant bisphosphonates was confirmed using specimens from 2 randomized clinical trials (AZURE and NSABP-B-34) conducted and analyzed in similar manner using the same validated tests and clinical endpoints. These results are evidence towards introducing MAF testing into clinical practice.

Factors associated with osteonecrosis of the jaw in women with breast cancer receiving high-dose bisphosphonates to prevent breast cancer metastases as part of the SWOG 0307 trial

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Background: Bisphosphonates reduce the risk of bone metastases in postmenopausal women with early-stage breast cancer but carry the risk of osteonecrosis of the jaw (ONJ). We used the data collected in the S0307 trial to describe factors associated with provoked and unprovoked ONJ. Methods: In S0307, 6097 patients with Stage I-III breast cancer who had surgery were randomized to receive zoledronic acid (ZA) 4mg IV monthly for 6 months, then every 3 months, clodronate (CL) 1600mg daily, or ibandronate (IB) 50mg daily for three years, with no difference in bone metastases or disease-free survival. Patients completed dental procedures prior to and had a dental exam at enrollment. Pearson’s Chi-squared and Student’s T-test were used to test differences in categorical and continuous variables, respectively; logistic regression was used test independent association. Results: Of 5836 evaluable women, 48 developed ONJ, which was associated with bisphosphonate type (28/2124 (1.26%) for ZA, 8/2185 (0.36%) for CL and 12/1527 (0.77%) for IB (p = 0.002). Median time to onset of ONJ was 24.9 (1.4-66.6) for ZA, 41.2 months (range 33.8-67.4) for CL, 23.9 (2.1-75.3) for IB (p = 0.0447). Infection was present in 21 (43.8%) and absent in 20. ONJ was considered unprovoked in 20 (41.7%) and provoked by dental extraction in 20 (41.7%), periodontal disease in 14 (29.2%), denture trauma in 6 (12.5%), other dental surgery in 3 (6.3%). ONJ was associated with dental calculus (OR 2.03 (95% CI: 1.08-3.81), gingivitis (OR 2.11, 95% CI: 1.12-3.98), and periodontal disease (OR 2.87, 95% CI 1.45-5.53) that were moderate/severe and > 4mm periodontitis (OR 2.20, 95% CI 1.18-4.08). Patients with provoked and unprovoked ONJ had similar amounts of dental disease and lesion location. ONJ was not associated with dentures, plaque, chemotherapy, corticosteroids or renal adverse events. In multivariate analysis (limited by small sample), only bisphosphonate type was associated with ONJ. Conclusions: ONJ prevalence was low, likely due to patients completing dental procedures before enrollment. ZA carried a higher risk of ONJ (though current adjuvant dosing interval recommendations are less frequent), with time to onset similar to IB. Oral CL and IB (not currently available in the United States) are thus likely more appropriate for patients with poor dental health. Clinical trial information: NCT00127205.

Efficacy of Chemotherapy for ER-Negative and ER-Positive Isolated Locoregional Recurrence of Breast Cancer: Final Analysis of the CALOR Trial

Purpose Isolated locoregional recurrence (ILRR) predicts a high risk of developing breast cancer distant metastases and death. The Chemotherapy as Adjuvant for LOcally Recurrent breast cancer (CALOR) trial investigated the effectiveness of chemotherapy (CT) after local therapy for ILRR. A report at 5 years of median follow-up showed significant benefit of CT for estrogen receptor (ER)-negative ILRR, but additional follow-up was required in ER-positive ILRR. Patients and Methods CALOR was an open-label, randomized trial for patients with completely excised ILRR after unilateral breast cancer. Eligible patients were randomly assigned to receive CT or no CT and stratified by prior CT, hormone receptor status, and location of ILRR. Patients with hormone receptor-positive ILRR received adjuvant endocrine therapy. Radiation therapy was mandated for patients with microscopically involved margins, and anti-human epidermal growth factor receptor 2 therapy was optional. End points were disease-free survival (DFS), overall survival, and breast cancer-free interval. Results From August 2003 to January 2010, 162 patients were enrolled: 58 with ER-negative and 104 with ER-positive ILRR. At 9 years of median follow-up, 27 DFS events were observed in the ER-negative group and 40 in the ER-positive group. The hazard ratios (HR) of a DFS event were 0.29 (95% CI, 0.13 to 0.67; 10-year DFS, 70% v 34%, CT v no CT, respectively) in patients with ER-negative ILRR and 1.07 (95% CI, 0.57 to 2.00; 10-year DFS, 50% v 59%, respectively) in patients with ER-positive ILRR ( Pinteraction = .013). HRs were 0.29 (95% CI, 0.13 to 0.67) and 0.94 (95% CI, 0.47 to 1.85), respectively, for breast cancer-free interval ( Pinteraction = .034) and 0.48 (95% CI, 0.19 to 1.20) and 0.70 (95% CI, 0.32 to 1.55), respectively, for overall survival ( Pinteraction = .53). Results for the three end points were consistent in multivariable analyses adjusting for location of ILRR, prior CT, and interval from primary surgery. Conclusion The final analysis of CALOR confirms that CT benefits patients with resected ER-negative ILRR and does not support the use of CT for ER-positive ILRR.

Chemotherapy (CT) for isolated locoregional recurrence (ILRR) of breast cancer in ER-positive (ER+) and ER-negative (ER-) cohorts: Final analysis of the CALOR trial

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Background: ILRR is associated with a high risk of developing breast cancer distant metastases and death. The CALOR trial (NCT00074152) investigated the effectiveness of CT following local therapy for ILRR. Previously reported results at 5-yrs median follow-up (MFU) showed significant benefit of CT for ER- ILRR, but further follow-up was required in ER+ ILRR. This report presents results at 8.8 yrs MFU within ER status cohorts. Methods: CALOR is an open-label, randomized trial for patients with completely excised ILRR after unilateral breast cancer. Eligible patients were randomized to CT (selected by the investigator; multidrug for at least 3 months recommended) or No-CT, and stratified by prior CT, hormone-receptor (ER, PR) status, and location of ILRR. Patients with ER and/or PR positive ILRR received adjuvant endocrine therapy. Radiation therapy was mandated for patients with microscopically involved margins, and anti-HER2 therapy was optional. Endpoints are disease-free survival (DFS), overall survival (OS) and breast cancer-free interval (BCFI). Results: From August 2003 to January 2010, 162 patients were enrolled: 104 ER+ and 58 ER-. The results at 8.8 years MFU in ER status cohorts are summarized in the Table (40 and 27 DFS events, respectively). The reduction in the hazard of an event associated with CT for the ER- ILRR cohort was sustained, but no benefit was observed for the ER+ cohort; interactions were significant for DFS and BCFI. The reduction in the hazard of an event seen in the ER- cohort was not apparent in ER+, with significant interactions for DFS and BCFI. Results for the 3 endpoints were consistent in multi-variable analyses adjusting for location of ILRR, prior chemotherapy, and interval from primary surgery. Conclusions: The final analysis of CALOR confirms that CT benefits patients with resected ER- ILRR. Long-term CALOR trial results do not support the use of CT for ER+ ILRR. Clinical trial information: NCT00074152. [Table: see text]

Abstract P6-09-20: Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival

Introduction:

Hormone receptors ER and PgR are routinely assessed by pathologists using immunohistochemical (IHC) assays to guide treatment decisions. Patients who are hormone receptor positive are offered hormonal therapy, such as tamoxifen, which improves survival. Although both ER and PgR are evaluated, ER is primarily utilized for patient management as the clinical utility of PgR has not been clearly established according to CAP/ASCO guidelines. Notably, a meta-analysis by the Early Breast Cancer Trialists' Collaborative Group reported that PgR status was not significantly predictive of response to adjuvant tamoxifen, suggesting that PgR may not have a role in breast cancer management. More recently, the level of PgR expression has been hypothesized to be important in predicting response to endocrine therapy, where high PgR levels are more indicative of estrogen-dependent tumors, and thus more sensitive to hormonal treatment.

In this study, we evaluate PgR expression using the current cut-point (Allred>2), as well as an optimized cut-point (Allred>5 to identify PgR high tumors), with regards to 15yr disease-free survival (DFS) and disease-specific overall survival (DSOS) using three commercially available ready-to-use (RTU) IHC assays from Dako, Leica and Ventana in an ER+ cohort.

Methods:

The Calgary tamoxifen breast cancer cohort (Calgary cohort) is a TMA series that includes 532 patients diagnosed with primary breast cancer (1985-2000) who received tamoxifen treatment regardless of hormone receptor status. All RTU assays followed vendor recommended protocols. Specific details regarding the cohort and IHC assays have been previously described (Kornaga et al. Mod Path 2016). All analyses were performed using Stata 12, and multivariate models were adjusted for age, grade, size, lymph node and HER2 status. ER status was defined by the corresponding vendor specific IHC assay.

Results:

Multivariate models looking at DFS are presented in Table 1. None of the assays were significant when the clinical cut-point was used; however, when the optimized cut-point was investigated, all assays found high expression of PgR was significantly associated with improved DFS. Table 2 presents the multivariate models looking at DSOS. Similarly, PgR was not found to be associated with improved DSOS using the current cut-point. When the optimized cut-point was examined, Dako and Leica assays were significantly associated with improved DSOS: The Ventana assay did not reach significance.

Table 1 PgR15YR DFS CutpointHR95% CIp-valueDako>20.830.40-1.730.624Dako>50.560.35-0.910.020Leica>21.130.45-2.830.792Leica>50.520.30-0.890.017Ventana>20.730.32-1.670.460Ventana>50.570.34-0.970.037

Table 2 PgR15YR DSOS CutpointHR95% CIp-valueDako>20.740.33-1.650.464Dako>50.550.32-0.950.031Leica>20.880.35-2.220.780Leica>50.440.24-0.790.006Ventana>20.590.25-1.370.218Ventana>50.630.35-1.150.134

Conclusions:

High PgR expression (Allred>5) is associated with improved 15yr DFS and DSOS in a tamoxifen-treated cohort, where PgR positivity defined using current guidelines is not associated with improved DFS or DSOS. Additionally, differences were noted between the vendor RTU assays with regards to DSOS.

Citation Format: Kornaga EN, Paterson AHG, Feng X, Morris DG, Magliocco AM, Klimowicz AC. Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-20.

Poor Prognosis After Second Locoregional Recurrences in the CALOR Trial

BACKGROUND

Isolated locoregional recurrences (ILRRs) of breast cancer confer a significant risk for the development of distant metastasis. Management practices and second ILRR events in the Chemotherapy as Adjuvant for LOcally Recurrent breast cancer (CALOR) trial were investigated.

METHODS

In this study, 162 patients with ILRR were randomly assigned to receive postoperative chemotherapy or no chemotherapy. Descriptive statistics characterize outcomes according to local therapy and the influence of hormone receptor status on subsequent recurrences. Competing risk regression models, Kaplan-Meier estimates, and Cox proportional hazards models were used to evaluate associations between treatment, site of second recurrence, and outcome.

RESULTS

The median follow-up period was 4.9 years. Of the 98 patients who received breast-conserving primary surgery 89 had an ipsilateral-breast tumor recurrence. Salvage mastectomy was performed for 73 patients and repeat lumpectomy for 16 patients. Another eight patients had nodal ILRR, and one patient had chest wall ILRR. Among 64 patients whose primary surgery was mastectomy, 52 had chest wall/skin ILRR, and 12 had nodal ILRR. For 15 patients, a second ILRR developed a median of 1.6 years (range 0.08-4.8 years) after ILRR. All second ILRRs occurred for patients with progesterone receptor-negative ILRR. Death occurred for 7 (47 %) of 15 patients with a second ILRR and 19 (51 %) of 37 patients with a distant recurrence. As shown in the multivariable analysis, the significant predictors of survival after either a second ILRR or distant recurrence were chemotherapy for the primary cancer (hazard ratio [HR], 3.55; 95 % confidence interval [CI], 1.15-10.9; p = 0.03) and the interval (continuous) from the primary surgery (HR, 0.87; 95 % CI, 0.75-1.00; p = 0.05).

CONCLUSIONS

Second ILRRs represented about one third of all recurrence events after ILRR, and all were PR-negative. These second ILRRs and distant metastases portend an unfavorable outcome.

Body Mass Index at Diagnosis and Breast Cancer Survival Prognosis in Clinical Trial Populations from NRG Oncology/NSABP B-30, B-31, B-34, and B-38

BACKGROUND

Body mass index (BMI) has been associated with breast cancer outcomes. However, few studies used clinical trial settings where treatments and outcomes are consistently evaluated and documented. There are also limited data assessing how patient/disease characteristics and treatment may alter the BMI-breast cancer association.

METHODS

We evaluated 15,538 breast cancer participants from four NSABP protocols. B-34 studied early-stage breast cancer patients (N = 3,311); B-30 and B-38 included node-positive breast cancer patients (N = 5,265 and 4,860); and B-31 studied node-positive and HER2-positive breast cancer patients (N = 2,102). We used Cox proportional hazards regression to calculate adjusted hazards ratios (HR) for risk of death and recurrence, and conducted separate analyses by estrogen receptor (ER) status and treatment group.

RESULTS

In B-30, increased BMI was significantly related to survival. Compared with BMI < 25, HRs were 1.04 for BMI 25 to 29.9 and 1.18 for BMI ≥ 30 (P = 0.02). Separate analyses indicated the significant relationship was only in ER-positive disease (P = 0.002) and the subgroup treated with doxorubicin/cyclophosphamide (P = 0.005). There were no significant trends across BMI for the other three trials. Similar results were found for recurrence. Increased BMI was significantly related to recurrence in B-30 (P = 0.03); and the significant relationship was only in ER-positive breast cancers (P = 0.001). Recurrence was also significant among ER-positive disease in B-38 (P = 0.03).

CONCLUSIONS

In our investigation, we did not find a consistent relationship between BMI at diagnosis and breast cancer recurrence or death.

IMPACT

This work demonstrates that the heterogeneity of breast cancer between different breast cancer populations and the different therapies used to treat them may modify any association that exists between BMI and breast cancer outcome.

The Breast Cancer to Bone (B2B) Metastases Research Program: a multi-disciplinary investigation of bone metastases from breast cancer

Background

Bone is the most common site of breast cancer distant metastasis, affecting 50–70 % of patients who develop metastatic disease. Despite decades of informative research, the effective prevention, prediction and treatment of these lesions remains elusive. The Breast Cancer to Bone (B2B) Metastases Research Program consists of a prospective cohort of incident breast cancer patients and four sub-projects that are investigating priority areas in breast cancer bone metastases. These include the impact of lifestyle factors and inflammation on risk of bone metastases, the gene expression features of the primary tumour, the potential role for metabolomics in early detection of bone metastatic disease and the signalling pathways that drive the metastatic lesions in the bone.

Methods/Design

The B2B Research Program is enrolling a prospective cohort of 600 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a five year period. At baseline, pre-treatment/surgery blood samples are collected and detailed epidemiologic data is collected by in-person interview and self-administered questionnaires. Additional self-administered questionnaires and blood samples are completed at specified follow-up intervals (24, 48 and 72 months). Vital status is obtained prior to each follow-up through record linkages with the Alberta Cancer Registry. Recurrences are identified through medical chart abstractions. Each of the four projects applies specific methods and analyses to assess the impact of serum vitamin D and cytokine concentrations, tumour transcript and protein expression, serum metabolomic profiles and in vitro cell signalling on breast cancer bone metastases.

Discussion

The B2B Research Program will address key issues in breast cancer bone metastases including the association between lifestyle factors (particularly a comprehensive assessment of vitamin D status) inflammation and bone metastases, the significance or primary tumour gene expression in tissue tropism, the potential of metabolomic profiles for risk assessment and early detection and the signalling pathways controlling the metastatic tumour microenvironment. There is substantial synergy between the four projects and it is hoped that this integrated program of research will advance our understanding of key aspects of bone metastases from breast cancer to improve the prevention, prediction, detection, and treatment of these lesions.

Chemotherapy for isolated locoregional recurrence of breast cancer (CALOR): a randomised trial

BACKGROUND

Patients with isolated locoregional recurrences (ILRR) of breast cancer have a high risk of distant metastasis and death from breast cancer. We aimed to establish whether adjuvant chemotherapy improves the outcome of such patients.

METHODS

The CALOR trial was a pragmatic, open-label, randomised trial that accrued patients with histologically proven and completely excised ILRR after unilateral breast cancer who had undergone a mastectomy or lumpectomy with clear surgical margins. Eligible patients were enrolled from hospitals worldwide and were centrally randomised (1:1) to chemotherapy (type selected by the investigator; multidrug for at least four courses recommended) or no chemotherapy, using permuted blocks, and stratified by previous chemotherapy, oestrogen-receptor and progesterone-receptor status, and location of ILRR. Patients with oestrogen-receptor-positive ILRR received adjuvant endocrine therapy, radiation therapy was mandated for patients with microscopically involved surgical margins, and anti-HER2 therapy was optional. The primary endpoint was disease-free survival. All analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00074152.

FINDINGS

From Aug 22, 2003, to Jan 31, 2010, 85 patients were randomly assigned to receive chemotherapy and 77 were assigned to no chemotherapy. At a median follow-up of 4·9 years (IQR 3·6-6 ·0), 24 (28%) patients had disease-free survival events in the chemotherapy group compared with 34 (44%) in the no chemotherapy group. 5-year disease-free survival was 69% (95% CI 56-79) with chemotherapy versus 57% (44-67) without chemotherapy (hazard ratio 0·59 [95% CI 0·35-0·99]; p=0·046). Adjuvant chemotherapy was significantly more effective for women with oestrogen-receptor-negative ILRR (pinteraction=0·046), but analyses of disease-free survival according to the oestrogen-receptor status of the primary tumour were not statistically significant (pinteraction=0·43). Of the 81 patients who received chemotherapy, 12 (15%) had serious adverse events. The most common adverse events were neutropenia, febrile neutropenia, and intestinal infection.

INTERPRETATION

Adjuvant chemotherapy should be recommended for patients with completely resected ILRR of breast cancer, especially if the recurrence is oestrogen-receptor negative.

FUNDING

US Department of Health and Human Services, Swiss Group for Clinical Cancer Research (SAKK), Frontier Science and Technology Research Foundation, Australian and New Zealand Breast Cancer Trials Group, Swedish Cancer Society, Oncosuisse, Cancer Association of South Africa, Foundation for Clinical Research of Eastern Switzerland (OSKK), Grupo Español de Investigación en Cáncer de Mama (GEICAM), and the Dutch Breast Cancer Trialists' Group (BOOG).

Bone-targeted agents and skeletal-related events in breast cancer patients with bone metastases: the state of the art

Most women with advanced breast cancer will develop bone metastases, which are associated with the development of skeletal-related events (sres) such as pathologic fractures and spinal cord compression. This article reviews the evolving definition and incidence of sres, the pathophysiology of bone metastases, and the key evidence for the safety and efficacy of the currently available systemic treatment options for preventing and delaying sres in the setting of breast cancer with bone metastases.The bisphosphonates are structural analogues of endogenous pyrophosphate; three of them (clodronate, pamidronate, and zoledronate) are currently approved for use in Canada in the setting of breast cancer with bone metastases. Denosumab is a fully human immunoglobulin G2 monoclonal antibody that binds to human rankl (receptor activator of nuclear factor κB ligand), thereby preventing osteoclast formation, function, and survival, and reducing cancer-induced destruction of bone. Denosumab has recently been approved in Canada for reducing the risk of sres from the bone metastases associated with a variety of malignancies, including breast cancer. How to predict the patients that will benefit most from prophylactic treatment, the agents to select and the timing of switches between agents, the dosing schedules and durations of treatment to choose, the potential utility of the agents in the adjuvant setting, and the utility of additional endpoints such as markers of bone resorption are among the outstanding questions with respect to the optimal use of antiresorptive agents for patients with breast cancer and bone metastases.

Bone-related complications and quality of life in advanced breast cancer: results from a randomized phase III trial of denosumab versus zoledronic acid

PURPOSE

Denosumab was shown to be superior to zoledronic acid in preventing skeletal related events (SRE) in patients with breast cancer and bone metastases in a randomized, double-blind phase III study. We evaluated further results from this study related to skeletal complications and health-related quality of life (HRQoL).

EXPERIMENTAL DESIGN

Patients were randomized 1:1 to receive subcutaneous denosumab 120 mg (n = 1,026) and intravenous placebo, or intravenous zoledronic acid 4 mg (n = 1,020) and subcutaneous placebo every 4 weeks. Analyses reported here include the proportion of patients with one or multiple on-study SREs, time to first radiation to bone, time to first SRE or hypercalcemia of malignancy, and change in HRQoL (functional assessment of cancer therapy-general).

RESULTS

Fewer patients receiving denosumab than zoledronic acid had an on-study SRE (31% vs. 36%, P = 0.006). The incidence of first radiation to bone was 12% (n = 123) with denosumab versus 16% (n = 162) with zoledronic acid. Denosumab prolonged the time to first radiation to bone by 26% versus zoledronic acid (HR, 0.74; 95% confidence interval [CI], 0.59-0.94, P = 0.012) and prolonged the time to first SRE or hypercalcemia of malignancy by 18% (HR, 0.82; 95% CI, 0.70-0.95; P = 0.007). Ten percent more patients had a clinically meaningful improvement in HRQoL with denosumab relative to zoledronic acid, regardless of baseline pain levels.

CONCLUSIONS

Denosumab was superior to zoledronic acid in reducing bone-related complications of metastatic breast cancer and maintained HRQoL, providing an efficacious, well-tolerated treatment option for patients with bone metastases from breast cancer.

Controlling angiogenesis in breast cancer: a systematic review of anti-angiogenic trials

PURPOSE

Angiogenesis is critical for tumor growth and a promising therapeutic target. This review will summarize and analyze data from clinical trials of anti-angiogenic agents in the treatment of breast cancer (BC).

DESIGN

A systematic search of PubMed and conference databases was performed to identify reports of randomized clinical trials investigating specific anti-angiogenic agents in the treatment of BC.

RESULTS AND DISCUSSION

Phase III trials in advanced BC have demonstrated a reduction in the risk of disease progression (22-52%), improved response rates and net improvements in progression-free survival of 1.2 to 5.5 months, but no significant improvements in overall survival with the addition of bevacizumab to chemotherapy. Results of phase III trials in early breast cancer have been inconsistent. Bevacizumab-containing regimens have also been associated with higher overall adverse event rates compared to chemotherapy alone. Phase III trials of the tyrosine kinase inhibitor sunitinib were negative, while randomized phase II trials of sorafenib and pazopanib have improved some outcomes when combined with chemotherapy or targeted therapy compared to controls. In addition to expected vascular class safety signals, tyrosine kinase inhibitors show "off-target" side effects. Ongoing clinical trials evaluating combinatorial strategies based on biological synergies and translational studies identifying biological predictors of response will be crucial to establish meaningful clinical benefits in selected BC populations.

CONCLUSION

Most trials of anti-angiogenic agents in BC have reported improved response rate and progression-free survival but no increase in overall survival compared to chemotherapy alone. Optimizing the therapeutic indices of these agents is a focus of ongoing research and will be critical to their future development.

A teaching model for aromatase inhibitors after tamoxifen

Breast cancer is the most common cancer diagnosed in women. The present study evaluated the family physicians' (FPs) understanding of adjuvant hormonal therapies for an early breast cancer. FPs were invited to attend teaching workshops on this topic, which utilized a pretest, didactic and interactive teaching, and posttest format. FPs (n = 23) showed an improvement (p < 0.001) in pretest to posttest score. It is clear that, with a targeted teaching, FPs can quickly become more knowledgeable on the topic of hormonal therapies in breast cancer, with the potential of applying this information in their own practice.

Guidance on the use of bisphosphonates in solid tumours: recommendations of an international expert panel

Bisphosphonates (BP) prevent, reduce, and delay cancer-related skeletal complications in patients, and have substantially decreased the prevalence of such events since their introduction. Today, a broad range of BP with differences in potency, efficacy, dosing, and administration as well as approved indications is available. In addition, results of clinical trials investigating the efficacy of BP in cancer treatment-induced bone loss (CTIBL) have been recently published. The purpose of this paper is to review the current evidence on the use of BP in solid tumours and provide clinical recommendations. An interdisciplinary expert panel of clinical oncologists and of specialists in metabolic bone diseases assessed the widespread evidence and information on the efficacy of BP in the metastatic and nonmetastatic setting, as well as ongoing research on the adjuvant use of BP. Based on available evidence, the panel recommends amino-bisphosphonates for patients with metastatic bone disease from breast cancer and zoledronic acid for patients with other solid tumours as primary disease. Dosing of BP should follow approved indications with adjustments if necessary. While i.v. administration is most often preferable, oral administration (clodronate, IBA) may be considered for breast cancer patients who cannot or do not need to attend regular hospital care. Early-stage cancer patients at risk of developing CTIBL should be considered for preventative BP treatment. The strongest evidence in this setting is now available for ZOL. Overall, BP are well-tolerated, and most common adverse events are influenza-like syndrome, arthralgia, and when used orally, gastrointestinal symptoms. The dose of BP may need to be adapted to renal function and initial creatinine clearance calculation is mandatory according to the panel for use of any BP. Subsequent monitoring is recommended for ZOL and PAM, as described by the regulatory authority guidelines. Patients scheduled to receive BP (mainly every 3-4 weeks i.v.) should have a dental examination and be advised on appropriate measures for reducing the risk of jaw osteonecrosis. BP are well established as supportive therapy to reduce the frequency and severity of skeletal complications in patients with bone metastases from different cancers.

Randomized active-controlled phase II study of denosumab efficacy and safety in patients with breast cancer-related bone metastases

PURPOSE

Denosumab, a fully human monoclonal antibody to receptor activator of nuclear factor-kappaB ligand, suppresses bone resorption. In this study, we evaluated the efficacy and safety of five dosing regimens of denosumab in patients with breast cancer-related bone metastases not previously treated with intravenous bisphosphonates (IV BPs).

PATIENTS AND METHODS

Eligible women (n = 255) with breast cancer-related bone metastases were stratified by type of antineoplastic therapy received and randomly assigned to one of six cohorts (five denosumab cohorts [blinded to dose and frequency]; one open-label IV BP cohort). Denosumab was administered subcutaneously every 4 weeks (30, 120, or 180 mg) or every 12 weeks (60 or 180 mg). The primary end point was percentage of change in the bone turnover marker urine N-telopeptide corrected for urine creatinine (uNTx/Cr) from baseline to study week 13. The percentage of patients achieving more than 65% uNTx/Cr reduction, time to more than 65% uNTx/Cr reduction, patients experiencing one or more on-study skeletal-related events (SRE), and safety were also evaluated.

RESULTS

At study week 13, the median percent reduction in uNTx/Cr was 71% for the pooled denosumab groups and 79% for the IV BP group. Overall, 74% of denosumab-treated patients (157 of 211) achieved a more than 65% reduction in uNTx/Cr compared with 63% of bisphosphonate-treated patients (27 of 43). On-study SREs were experienced by 9% of denosumab-treated patients (20 of 211) versus 16% of bisphosphonate-treated patients (seven of 43). No serious or fatal adverse events related to denosumab occurred.

CONCLUSION

Subcutaneous denosumab may be similar to IV BPs in suppressing bone turnover and reducing SRE risk. The safety profile was consistent with an advanced breast cancer population receiving systemic therapy.

The role of bisphosphonates in early breast cancer

Clinical trials are investigating the use of bisphosphonates in patients with early (nonmetastatic) breast cancer. Results from trials of clodronate are generally encouraging but somewhat contradictory. Of the three trials published to date, two reported that clodronate had beneficial effects on both bone metastases and survival. In contrast, the third trial reported that clodronate had no effect on metastases and a negative effect on survival. Small studies of adjuvant pamidronate and zoledronic acid also produced promising data, but these need to be reproduced in a large-scale, randomized trial setting before clinically meaningful conclusions can be drawn. A number of adjuvant trials are in progress to further evaluate the role of oral clodronate and i.v. zoledronic acid and to examine the effects of the newer bisphosphonate, ibandronate (oral formulation), in this setting. One of these trials is the joint Southwest Oncology Group/Intergroup/National Surgical Adjuvant Breast and Bowel Project trial, which is designed to compare the efficacy and safety of all three of these bisphosphonates in approximately 6,000 women with early breast cancer. Patient preference for oral or i.v. therapy will also be assessed.

High-dose mitoxantrone–vinblastine–cyclophosphamide and autologous stem cell transplantation for stage III breast cancer: final results of a prospective multicentre study

BACKGROUND

Stage III breast cancer patients continue to suffer high relapse and death rates despite standard chemotherapy regimens. High-dose alkylator chemotherapy does not further improve outcome. This phase II study evaluated a novel high-dose chemotherapy regimen which combined active breast cancer agents with differing mechanisms of action.

PATIENTS AND METHODS

Eligibility included at least seven involved axillary nodes (AxLNs) for tumours <5 cm, at least four AxLNs for tumours >5 cm or locally advanced breast cancer (LABC). Patients received four cycles of fluorouracil-adriamycin-cyclophosphamide (FAC) followed by one cycle of mitoxantrone 63 mg/m(2)-vinblastine 12.5 mg/m(2)-cyclophosphamide 6 g/m(2) (MVC) with autologous blood stem cell transplantation (ASCT).

RESULTS

Between April 1995 and December 1998, 92 patients aged 21-65 years (median 45 years) were enrolled, of whom 25 were treated preoperatively for LABC and 67 were treated postoperatively. Although there was no early treatment-related mortality, one late death occurred from secondary acute myeloid leukaemia. The 7-year event-free and overall survival rates were 53% (95% confidence interval 42-64%) and 62% (95% CI 52-73%), respectively, with no significant difference between pre- and postoperative groups.

CONCLUSION

FAC followed by MVC-ASCT is feasible and reasonably well tolerated, but does not result in improved survival rates compared with other conventional or high-dose regimens for stage III breast cancer.

Evaluating Bone Mass and Bone Quality in Patients with Breast Cancer

Bone remodeling is a process by which bone renews itself focally in distinct areas on cancellous (ie, trabecular) bone and/or in the Haversian systems of cortical (or compact) bone. Normal bone turnover involves the ordered metabolism of bone-resorbing cells (osteoclasts) and bone-forming cells (osteoblasts). Estrogen exerts a multitude of actions on bone tissues and is integral to bone health, and estrogen deprivation leads to accelerated bone loss. Bone strength reflects the integration of bone density and bone quality. Methods to assess bone strength fall into 3 categories: radiologic (ie, bone mineral density [BMD]), biochemical (ie, markers of bone turnover), and histologic (ie, bone biopsies for histomorphometry). The beneficial effect of aromatase inhibitors (AIs) and inactivators on breast cancer depends on reducing levels of circulating estrogens in the peripheral blood. There appears to be variability in the effects of AIs on bone in experimental animals, and this variability may not be the same in humans. In general, bone loss is an expected side effect of the AIs. For postmenopausal women receiving adjuvant anastrozole or other AIs, a BMD measurement using dual-energy x-ray absorptiometry is recommended, to be repeated every 1-2 years. Regular physical exercise is advised together with added calcium 1500 mg and vitamin D 800 U daily. If the T-score reaches a level of >2.5, or if it is between -1.5 and -2.5 in the presence of a fragility fracture or vertebral compression fracture, or if height loss > 2 cm occurs or BMD decreases > 3% in 1 year at the lumbar spine or > 5% at the femoral neck, bisphosphonate therapy should be considered.

Bisphosphonates: biological response modifiers in breast cancer

Bone recurrence constitutes one third of initial sites of relapse and one half of distant sites of relapse at 10 years from diagnosis of breast cancer. Bone pain, fracture (including vertebral fracture resulting from increased bone resorption following chemotherapy-induced menopause), and hypercalcemia are components of skeletal morbidity. The pathophysiology of malignant osteopathy occurs because of the secretion of substances (such as parathyroid hormone-related peptide), by the malignant cell, which stimulate osteoclast function; this in turn feeds further growth, which causes a vicious cycle. Interruption of this cycle by bisphosphonates may inhibit the growth of malignant cells. Bisphosphonates are drugs that inhibit bone turnover by decreasing bone resorption. Side effects of bisphosphonates include upper gastrointestinal symptoms (in oral nitrogen-containing bisphosphonates) and diarrhea (in oral non-nitrogen-containing bisphosphonates) and an acute phase-like reaction with intravenous (I.V.) pamidronate. Bisphosphonates have different molecular mechanisms of action: Nitrogen-containing bisphosphonates (eg, pamidronate and alendronate) inhibit the mevalonate-signaling pathway while the non-nitrogen-containing drugs (eg, clodronate) incorporate into adenosine triphosphate analogues. There is in vitro evidence that these drugs also possess anticancer properties. In hypercalcemia patients, treatment with pamidronate and zoledronate produce prompt and efficient normocalcemia. Intravenous pamidronate and zoledronate, oral clodronate, and ibandronate reduce skeletal complications in patients with bone metastases; I.V. pamidronate and clodronate are useful for bone pain relief. Three adjuvant bisphosphonate trials are discussed herein: 2 small open-label studies giving conflicting results and a large placebo-controlled trial of oral clodronate. This latter trial shows a reduction in the incidence of skeletal metastases (while the patients are on therapy) and an improved survival at 5 years.