A Randomized Trial Comparing Concurrent versus Sequential Radiation and Endocrine Therapy in Early-Stage, Hormone-Responsive Breast Cancer.

Concerns exist regarding increased toxicities, including endocrine therapy toxicity, with concurrent radiation and endocrine therapy in early breast cancer (EBC). We present a pragmatic, randomized trial comparing concurrent versus sequential endocrine and radiotherapy in hormone-responsive EBC. In this multicenter trial, patients were randomized to receive adjuvant endocrine therapy concurrent with, or sequential to, radiotherapy. The primary outcome was change in endocrine therapy toxicity from baseline to 3 months post radiotherapy using the Functional Assessment of Cancer Therapy-Endocrine Symptom (FACT-ES) score. From September 2019 to January 2021, 133 patients were randomized to concurrent endocrine and radiotherapy, and 127 to sequential treatment. Most patients were post-menopausal (72.7%, 189/260) with stage 1 disease (65.8%, 171/260). Tamoxifen was the endocrine therapy of choice for 69.6% (181/260) of patients, and an aromatase inhibitor for the remainder. The median total radiation dose and fractions were 40.1 Gray (range 26-50) and 15 fractions (range 5-25), respectively. For the primary outcome of change in endocrine therapy toxicity per FACT-ES scores from baseline to 3 months post radiotherapy, no significant difference was found between the groups (median [range] = -4.9 (-82, 38.8) for concurrent and -5.1 (-42, 40) for sequential, p = 0.87). This is the first trial to investigate the impact of concurrent versus sequential adjuvant endocrine and radiotherapy on endocrine therapy-related toxicities. The findings provide further support to allow the optimal timing of radiation and endocrine therapy to be tailored for the individual patient.

Hemorrhage Risk Among Patients With Breast Cancer Receiving Concurrent Direct Oral Anticoagulants With Tamoxifen vs Aromatase Inhibitors.

Importance: Tamoxifen is commonly used as adjuvant therapy in breast cancer and is proposed to interfere with cytochrome P450 enzyme and P-glycoprotein pathways. Concurrent use with direct oral anticoagulants (DOACs) poses the threat of a potentially dangerous drug-drug interaction by leading to an increase in hemorrhage risk. Objective: To assess the risk of hemorrhage in patients with breast cancer coprescribed a DOAC and tamoxifen compared with a DOAC and an aromatase inhibitor (AI). Design, Setting, and Participants: This population-based, retrospective cohort study was conducted among adults aged 66 years or older who were prescribed tamoxifen (compared with an AI) concurrently with a DOAC in Ontario, Canada, between June 23, 2009, and November 30, 2020, and followed up until December 31, 2020. Interventions: Concurrent prescription of a DOAC and tamoxifen compared with a DOAC and an AI. Main Outcomes and Measures: The primary outcome was major hemorrhage requiring an emergency department visit or hospitalization after prescription. Overlap weighted Cox proportional hazards models, accounting for multiple covariates, were used to assess the association between hemorrhage and tamoxifen or AI use with a DOAC. Results: Among a total of 4753 patients (4679 [98.4%] women; mean [SD] age, 77.4 [7.4] years), 1179 (24.8%) were prescribed tamoxifen, and 3574 (75.2%) were prescribed an AI. Rivaroxaban (2530 [53.2%]) and apixaban (1665 [35.0%]) were the most frequently used DOACs. Patients taking AIs were younger than patients taking tamoxifen (mean [SD] age, 77.1 [7.3] vs 78.3 [7.6] years), with higher Charlson Comorbidity Index (mean [SD], 1.8 [2.4] vs 1.5 [2.2]) and more advanced cancer stage (stages III and IV, 569 [15.9%] vs 127 [10.8%]). During a median follow-up of 166 days (IQR, 111-527 days), tamoxifen was not associated with a higher risk of major hemorrhage (29 of 1179 [2.5%]) compared with an AI (119 of 3574 [3.3%]) when combined with a DOAC (absolute risk difference, -0.8%; weighted hazard ratio, 0.68 [95% CI, 0.44-1.06]). These results were similar in additional analyses using a more liberal definition of hemorrhage, accounting for kidney function, limiting follow-up to 90 days, stratifying by incident and prevalent DOAC users, and accounting for cancer duration and the competing risk of death. Conclusions and Relevance: In this cohort study, findings suggest that among DOAC users, the concurrent use of tamoxifen was not associated with a higher risk of hemorrhage compared with the concurrent use of an AI. These findings should directly inform prescribers regarding the apparent safety of concurrent DOAC and tamoxifen use.

A Randomized Trial Comparing 3- versus 4-Monthly Cardiac Monitoring in Patients Receiving Trastuzumab-Based Chemotherapy for Early Breast Cancer.

PURPOSE: The optimal frequency for cardiac monitoring of left ventricular ejection fraction (LVEF) in patients receiving trastuzumab-based therapy for early breast cancer (EBC) is unknown. We conducted a randomized controlled trial comparing 3- versus 4-monthly cardiac monitoring. PATIENTS AND METHOD: Patients scheduled to receive trastuzumab-containing cancer therapy for EBC with normal (>53%) baseline LVEF were randomized to undergo LVEF assessments every 3 or 4 months. The primary outcome was the change in LVEF from baseline. Secondary outcomes included the rate of cardiac dysfunction (defined as a decrease in the LVEF of ≥10 percentage points, to a value <53%), delays in or discontinuation of trastuzumab therapy, and cardiology referral. RESULTS: Of the 200 eligible and enrolled patients, 100 (50%) were randomized to 3-monthly and 100 (50%) to 4-monthly cardiac monitoring. Of these patients, 98 and 97 respectively underwent at least one cardiac scan. The estimated mean difference in LVEF from baseline was -0.94% (one-sided 95% lower bound: -2.14), which exceeded the pre-defined non-inferiority margin of -4%. There were also no significant differences between the two study arms for any of the secondary endpoints. The rate of detection of cardiac dysfunction was 16.3% (16/98) and 12.4% (12/97) in the 3- and 4-monthly arms, respectively (95% CI: 4.0 [-5.9, 13.8]). CONCLUSIONS: Cardiac monitoring every 4 months was deemed non-inferior to that every 3 months in patients with HER2-positive EBC being treated with trastuzumab-based therapy. Given its costs and inconvenience, cardiac monitoring every 4 months should be considered standard practice. Registration: NCT02696707, 18 February 2016.

Long-term impact of bone-modifying agents for the treatment of bone metastases: a systematic review.

PURPOSE: Bone-modifying agents (BMAs) for bone metastases are commonly prescribed for many years even though randomized clinical trials are only 1-2 years in duration. A systematic review on the risk-benefit of BMA use for > 2 years in breast cancer or castrate-resistant prostate cancer was conducted. METHODS: MEDLINE, Embase, and Cochrane databases were searched (1970-February 2019) for randomized and observational studies, and case series reporting on BMA efficacy (skeletal-related events and quality of life) and toxicity (osteonecrosis of the jaw, renal impairment, hypocalcemia, and atypical femoral fractures) beyond 2 years. RESULTS: Of 2107 citations, 64 studies were identified. Three prospective and 9 retrospective studies were eligible. Data beyond 2 years was limited to subgroup analyses in all studies. Only one study (n = 181) reported skeletal-related event rates based on bisphosphonate exposure, with decreased rates from 27.6% (0-24 months) to 15.5% (> 24 months). None reported on quality of life. All 12 studies (denosumab (n = 948), zoledronate (n = 1036), pamidronate (n = 163), pamidronate-zoledronate (n = 522), ibandronate (n = 118)) reported ≥ 1 toxicity outcome. Seven bisphosphonate studies (n = 1077) and one denosumab study (n = 948) reported on osteonecrosis of the jaw. Across three studies (n = 1236), osteonecrosis of the jaw incidence ranged from 1 to 4% in the first 2 years to 3.8-18% after 2 years. Clinically significant hypocalcemia ranged from 1 to 2%. Severe renal function decline was ≤ 3%. Atypical femoral fractures were rare. CONCLUSIONS: Evidence informing the use of BMA beyond 2 years is heterogeneous and based on retrospective analysis. Prospective randomized studies with greater emphasis on quality of life are needed. PROSPERO REGISTRATION NUMBER: CRD42019126813.

Optimal frequency of scans for patients on cancer therapies: A population kinetics assessment.

BACKGROUND: Optimal frequency of follow-up scans for patients receiving systemic therapies is poorly defined. Progression-free survival (PFS) generally follows first-order kinetics. We used exponential decay nonlinear regression analysis to calculate half-lives for 887 published PFS curves. METHOD: We used the Excel formula x = EXP(-tn *0.693/t1/2 ) to calculate proportion of residual patients remaining progression-free at different times, where tn is the interval in weeks between scans (eg, 6 weeks), * indicates multiplication, 0.693 is the natural logarithm of 2, and t1/2 is the PFS half-life in weeks. RESULTS: Proportion of residual patients predicted to remain progression-free at each subsequent scan varied with scan intervals and regimen PFS half-life. For example, with a 4-month half-life (17.3 weeks) and scans every 6 weeks, 21% of patients would progress by the first scan, 21% of the remaining patients would progress by the second scan at 12 weeks, etc With 2, 6- and 12-month half-lives (for example), the proportion of remaining patients progressing at each subsequent scan if repeated every 3 weeks would be 21%, 8% and 4%, respectively, while with scans every 12 weeks it would be 62%, 27% and 15%, respectively. Furthermore, optimal scan frequency can be calculated for populations comprised of distinct rapidly and slowly progressing subpopulations, as well as with convex curves arising from treatment breaks, where optimal scan frequency may differ during therapy administration vs during more rapid progression after therapy interruption. CONCLUSIONS: A population kinetics approach permits a regimen- and tumor-specific determination of optimal scan frequency for patients on systemic therapies.

Long-range transcriptional regulation by the p110 CUX1 homeodomain protein on the ENCODE array.

BACKGROUND: Overexpression of the Cut homeobox 1 gene, CUX1, inversely correlates with patient survival in breast cancers. Cell-based assays and molecular studies have revealed that transcriptional regulation by CUX1 involves mostly the proteolytically processed p110 isoform. As there is no antibody specific to p110 CUX1 only, an alternate strategy must be employed to identify its targets. RESULTS: We expressed physiological levels of a tagged-p110 CUX1 protein and performed chromatin affinity purification followed by hybridization on ENCODE and promoter arrays. Targets were validated by chromatin immunoprecipitation and transcriptional regulation by CUX1 was analyzed in expression profiling and RT-qPCR assays following CUX1 knockdown or p110 CUX1 overexpression. Approximately 47% and 14% of CUX1 binding sites were respectively mapped less than 4 Kbp, or more than 40 Kbp, away from a transcription start site. More genes exhibited changes in expression following CUX1 knockdown than p110 CUX1 overexpression. CUX1 directly activated or repressed 7.4% and 8.4% of putative targets identified on the ENCODE and promoter arrays respectively. This proportion increased to 11.2% for targets with 2 binding sites or more. Transcriptional repression was observed in a slightly higher proportion of target genes. The CUX1 consensus binding motif, ATCRAT, was found at 47.2% of the CUX1 binding sites, yet only 8.3% of the CUX1 consensus motifs present on the array were bound in vivo. The presence of a consensus binding motif did not have an impact on whether a target gene was repressed or activated. Interestingly, the distance between a binding site and a transcription start site did not significantly reduced the ability of CUX1 to regulate a target gene. Moreover, CUX1 not only was able to regulate the next adjacent gene, but also regulated the gene located beyond this one as well as the gene located further away in the opposite direction. CONCLUSION: Our results demonstrate that p110 CUX1 can activate or repress transcription when bound at a distance and can regulate more than one gene on certain genomic loci.