Addition of endocrine therapy to dual anti-HER2 targeted therapy in initial treatment of HER2 + /HR + metastatic breast cancer.

PURPOSE: Dual anti-HER2 targeted therapy and chemotherapy is the current first-line standard of care for HER2 + metastatic breast cancer (MBC), with endocrine therapy (ET) the backbone of treatment in hormone receptor positive (HR +) disease. The potential ET benefit in HER2 + /HR + patients is unknown as pivotal dual anti-HER2 clinical trials precluded ET use. METHODS: Real-world data from a multi-site registry of consecutive HER2 + MBC patients treated at clinician discretion were examined. Patients that were HR + (ER + and/or PR +) and had received first-line chemotherapy alongside trastuzumab and pertuzumab were explored. Of 362 patients in the registry, 215 were excluded due to being HR- (n = 210) or not receiving chemotherapy (n = 5). RESULTS: Of the 147 patients included, 91 (62%) received concurrent ET and 56 (38%) had not. Comparing the groups, there were no significant differences in age, performance status, metastatic sites, use of previous therapy and de novo metastatic disease. More patients with ER + PR + disease versus those with ER + PR- or ER-PR + received ET (73 vs 45%). The addition of ET was associated with significantly improved 5-year PFS (HR 0.58, CI 0.37-0.89, p = 0.014) and OS (HR 0.52, CI 0.31-0.90, p = 0.018), with no increase in adverse events noted. CONCLUSION: The addition of ET to first-line dual anti-HER2 therapy post chemotherapy in patients with HER2 + /HR + MBC was associated with major gains in PFS and OS with no safety concerns evident. Further studies of this combination are justified, along with studies of how best to integrate other agents that are active in this patient subset, including CDK4/6 inhibitors.

Telehealth in cancer care during the COVID-19 pandemic.

INTRODUCTION: The Victorian COVID-19 Cancer Network (VCCN) Telehealth Expert Working Group aimed to evaluate the telehealth (TH) experience for cancer patients, carers and clinicians with the rapid uptake of TH in early 2020 during the COVID-19 pandemic. METHODS: We conducted a prospective multi-centre cross-sectional survey involving eight Victorian regional and metropolitan cancer services and three consumer advocacy groups. Patients or their carers and clinicians who had TH consultations between 1 July 2020 and 31 December 2020 were invited to participate in patient and clinician surveys, respectively. These surveys were opened from September to December 2020. RESULTS: The acceptability of TH via both video (82.9%) and phone (70.4%) were high though acceptability appeared to decrease in older phone TH users. Video was associated with higher satisfaction compared to phone (87.1% vs 79.7%) even though phone was more commonly used. Various themes from the qualitative surveys highlighted barriers and enablers to rapid TH implementation. DISCUSSION: The high TH acceptability supports this as a safe and effective strategy for continued care and should persist beyond the pandemic environment, where patient preferences are considered and clinically appropriate. Ongoing support to health services for infrastructure and resources, as well as expansion of reimbursement eligibility criteria for patients and health professionals, including allied health and nursing, are crucial for sustainability.

Real-World Outcomes in Patients With Brain Metastases Secondary to HER2-Positive Breast Cancer: An Australian Multi-centre Registry-based Study.

BACKGROUND: The development of brain metastases occurs commonly in HER2-positive metastatic breast cancer and is associated with a poorer prognosis. The advent of HER2-targeted therapy has improved overall survival, but the benefit in patients with brain metastases is unclear, as these patients are often excluded from clinical trials. This study aimed to explore real-world outcomes in patients with brain metastases in HER2-positive MBC. MATERIALS & METHODS: Data was extracted from the TABITHA registry, which consists of patient data collected prospectively from 16 Australian sites from 24th February 2015 to 31st October 2021. Data analysed included characteristics of brain metastases, treatment received and survival outcomes. RESULTS: A total of 135 (37%) of 361 patients with HER2-positive MBC were diagnosed with brain metastases during their clinical course, including 45 (12%) with brain metastases at time of MBC diagnosis. 61 (45%) had ≥4 brain lesions. The most common local therapy given was whole brain radiation therapy (WBRT) (36%) followed by multi-modality treatment with both surgery and radiation therapy (27%). The majority of patients received first-line HER2-targeted treatment with trastuzumab and pertuzumab followed by second-line trastuzumab emtansine (T-DM1) but third-line therapy was heterogenous. The median overall survival in patients who developed brain metastases was significantly shorter than those who did not develop brain metastases (58.9 vs. 96.1 months, P = .02). CONCLUSION: Real-world patients diagnosed with brain metastases in HER2-positive MBC have a relatively poor prognosis, despite advances in HER2-targeted treatment. As the range of HER2-targeted treatment expands, it is important to pursue clinical trials that focus on patients with brain metastases.

Uptake of bone-modifying agents in patients with HER2+ metastatic breast cancer with bone metastases - prospective data from a multi-site Australian registry.

BACKGROUND: International practice guidelines recommend administration of bone-modifying agents (BMA) in metastatic breast cancer (MBC) patients with bone metastases to reduce skeletal-related events (SRE). Optimal delivery of BMA in routine clinical practice, including agent selection and prescribing intervals, remains unclear. AIM: To describe real-world practice of Australian breast oncologists. METHODS: Prospective data from February 2015 to July 2020 on BMA delivery to MBC patients with bone metastases was analysed from Treatment of Advanced Breast Cancer in the Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Australian Patient (TABITHA), a multi-site Australian HER2+ MBC registry. RESULTS: Of 333 HER2+ MBC patients, 171 (51%) had bone metastases at diagnosis, with a mean age of 58.1 years (range, 32-87). One hundred and thirty (76%) patients received a BMA, with 90 (69%) receiving denosumab and 40 (31%) receiving a bisphosphonate. Patients who received a BMA were more likely to have received concurrent first-line systemic anti-HER2 therapy (95% vs 83%; P = 0.04), to present with bone-only metastases at diagnosis (24% vs 7%; P = 0.02) and less likely to have visceral metastases (51% vs 71%; P = 0.03). Ten of 40 (25%) bisphosphonate patients and 45 of 90 (50%) denosumab patients received their BMA at the recommended 4-weekly interval. Prescribing intervals varied over time. Adverse events reported were consistent with clinical trial data. CONCLUSION: Three-quarters of Australian HER2+ MBC patients with bone metastases receive a BMA, often at different schedules than guidelines recommend. Further studies, including all MBC subtypes, are warranted to better understand clinicians' prescribing rationale and potential consequences of current prescribing practice on SRE incidence.

Impact of prior (neo)adjuvant trastuzumab (NAT) exposure on the efficacy of HER2-targeted therapy for metastatic breast cancer.

PURPOSE: Trastuzumab, pertuzumab, and docetaxel are the standard first-line therapy for HER2-positive (HER2+) metastatic breast cancer (MBC). However, only 10% of patients received neoadjuvant and/or adjuvant trastuzumab (NAT) in the registration trial (NCT00567190). In contemporary practice, the majority of recurrent HER2+ MBC patients had prior NAT. We explore any impact of prior therapy on the efficacy of dual HER2-targeted antibody with taxane therapy for metastatic disease. METHODS: Utilising a prospective national registry, clinico-pathological, treatment, and outcome data for HER2+ MBC patients diagnosed between October 2006 and January 2019 were collected. Survival was estimated by the Kaplan-Meier method and compared among groups by log-rank test. RESULTS: Of 287 HER2+ MBC patients, 222 (77%) received first-line trastuzumab, pertuzumab, and taxane therapy. There were 130 (45%) with de novo MBC. Of the recurrent MBC patients 107/157 (68%) had received NAT. The median progression-free survival (PFS) among patients who received NAT was 15.8 months compared with 24.3 months without prior NAT (hazard ratio [HR] 1.45, 95% CI 1.05-2.03, p = 0.03). The median overall survival (OS) was 42.7 months in patients who had NAT, and was not reached in those who did not (HR 1.80, 95% CI 1.12-2.90, p = 0.02). However, when excluding de novo MBC patients, prior NAT exposure was no longer significantly associated with survival (p = 0.11). De novo MBC patients had the longest median PFS (25.2 months) and OS (91.2 months). CONCLUSIONS: Prior receipt of NAT was associated with inferior median PFS following first-line HER2-based therapy in the metastatic setting. However, prior NAT exposure did not significantly impact OS, supporting the efficacy of taxane, trastuzumab, pertuzumab combination for first-line HER2+ MBC regardless of prior NAT exposure. Patients with de novo MBC had the longest survival, suggesting stratification for synchronous versus metachronous disease in prospective clinical trials of MBC should be considered.

Syndrome of inappropriate anti-diuretic hormone secretion secondary to carboplatin after docetaxel-carboplatin-trastuzumab combination for early stage HER-2 positive breast cancer.

Carboplatin is a platinum analogue, widely used in the treatment of numerous cancer types including lung, genitourinary and ovarian cancers. It is also used in the adjuvant treatment of human epidermal growth factor receptor 2 positive breast cancer, where a non-anthracycline regimen is preferred. It is considered generally to be less toxic though potentially less efficacious than cisplatin, another platinum compound. Cisplatin is well recognized as causing hyponatremia, through the mechanism of renal salt wasting. Conversely, carboplatin has only rarely been associated with hyponatremia. We report here a case of severe hyponatremia occurring 6 days after adjuvant treatment with a carboplatin-containing chemotherapy regimen for early stage breast cancer. The mechanism of hyponatremia was consistent with the syndrome of inappropriate anti-diuretic hormone secretion based on biochemical and clinical findings, and response to fluid restriction. With no previously reported cases of docetaxel-associated or trastuzumab-associated hyponatremia, the causative agent was considered to be carboplatin. Additionally there was no recurrence of hyponatremia on recommencement of docetaxel and trastuzumab therapy. Hyponatremia secondary to carboplatin has been rarely reported in the literature, with only three previously reported cases. Although it is rare, oncologists should be aware of the potential for carboplatin to cause hyponatremia and the need to monitor electrolytes throughout therapy.