Trastuzumab emtansine increases the risk of stereotactic radiosurgery-induced radionecrosis in HER2 + breast cancer

The dilemma of radiation necrosis from diagnosis to treatment in the management of brain metastases

Radiation therapy with stereotactic radiosurgery (SRS) or whole brain radiation therapy is a mainstay of treatment for patients with brain metastases. The use of SRS in the management of brain metastases is becoming increasingly common and provides excellent local control. Cerebral radiation necrosis (RN) is a late complication of radiation treatment that can be seen months to years following treatment and is often indistinguishable from tumor progression on conventional imaging. In this review article, we explore risk factors associated with the development of radiation necrosis, advanced imaging modalities used to aid in diagnosis, and potential treatment strategies to manage side effects.

International multidisciplinary consensus on the integration of radiotherapy with new systemic treatments for breast cancer: European Society for Radiotherapy and Oncology (ESTRO)-endorsed recommendations

Novel systemic therapies for breast cancer are being rapidly implemented into clinical practice. These drugs often have different mechanisms of action and side-effect profiles compared with traditional chemotherapy. Underpinning practice-changing clinical trials focused on the systemic therapies under investigation, thus there are sparse data available on radiotherapy. Integration of these new systemic therapies with radiotherapy is therefore challenging. Given this rapid, transformative change in breast cancer multimodal management, the multidisciplinary community must unite to ensure optimal, safe, and equitable treatment for all patients. The aim of this collaborative group of radiation, clinical, and medical oncologists, basic and translational scientists, and patient advocates was to: scope, synthesise, and summarise the literature on integrating novel drugs with radiotherapy for breast cancer; produce consensus statements on drug-radiotherapy integration, where specific evidence is lacking; and make best-practice recommendations for recording of radiotherapy data and quality assurance for subsequent studies testing novel drugs.

The promise and challenges of combination therapies with antibody-drug conjugates in solid tumors

Antibody-drug conjugates (ADCs) represent an important class of cancer therapies that have revolutionized the treatment paradigm of solid tumors. To date, many ongoing studies of ADC combinations with a variety of anticancer drugs, encompassing chemotherapy, molecularly targeted agents, and immunotherapy, are being rigorously conducted in both preclinical studies and clinical trial settings. Nevertheless, combination therapy does not always guarantee a synergistic or additive effect and may entail overlapping toxicity risks. Therefore, understanding the current status and underlying mechanisms of ADC combination therapy is urgently required. This comprehensive review analyzes existing evidence concerning the additive or synergistic effect of ADCs with other classes of oncology medicines. Here, we discuss the biological mechanisms of different ADC combination therapy strategies, provide prominent examples, and assess their benefits and challenges. Finally, we discuss future opportunities for ADC combination therapy in clinical practice.

A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

BACKGROUND

Trastuzumab deruxtecan (T-DXd) has demonstrated efficacy in patients with brain metastasis (BM), a group historically with poor outcomes. The prevalence of BMs in patients commencing T-DXd is currently unknown. No direct comparisons have been made of the activity of T-DXd in patients with active BM versus those with extracranial progression alone. This real-world study explored the prevalence of BMs in patients commencing T-DXd, the efficacy of T-DXd in active BM versus extracranial progression alone and the safety of T-DXd.

PATIENTS AND METHODS

Patients with human epidermal growth factor receptor 2-positive advanced breast cancer treated with T-DXd between June 2021 and February 2023 at our specialist cancer hospital were identified and notes reviewed. Clinicopathological information, prior treatment, the presence or absence of central nervous system (CNS) disease, outcomes and treatment-emergent adverse events (TEAEs) were recorded.

RESULTS

Twenty-nine female patients, with a median age of 52 years (interquartile range 44-62 years), were identified; the prevalence of BM was 41%. Median number of lines of prior therapy was 2 (range 2-6). At a median follow-up of 13.8 months, median progression-free survival (PFS) for the overall population was 13.9 months [95% confidence interval (CI) 12.4 months-not estimable (NE)], 16.1 months (95% CI 15.1 months-NE) for active BMs and 12.4 months (95% CI 8.3 months-NE) for progressive extracranial disease alone. The 12-month overall survival (OS) rate was 74% (95% CI 59% to 95%) in the overall population, and 83% (95% CI 58% to 100%) and 66% (95% CI 45% to 96%) for active BMs and extracranial disease only, respectively. Most common TEAEs were fatigue, alopecia, and constipation. In nine patients (31%, including two deaths), pneumonitis occurred.

CONCLUSION

In this real-world population, we demonstrate T-DXd to be effective in patients with active BMs and those with progressive extracranial disease alone. PFS and OS were numerically longer in those with active BMs. These data demonstrate that patients with active BM treated with T-DXd have at least comparable outcomes to those with extracranial disease alone. The high rate of pneumonitis warrants further consideration.

Safety profile of trastuzumab-emtansine (T-DM1) with concurrent radiation therapy: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

In recent years, the treatment landscape for breast cancer has undergone significant advancements, with the introduction of several new anticancer agents. One such agent is trastuzumab emtansine (T-DM1), an antibody drug conjugate that has shown improved outcomes in both early and advanced breast cancer. However, there is currently a lack of comprehensive evidence regarding the safety profile of combining T-DM1 with radiation therapy (RT). In this study, we aim to provide a summary of the available data on the safety of combining RT with T-DM1 in both early and metastatic breast cancer settings.

MATERIALS AND METHODS

This systematic review and meta-analysis project is part of the consensus recommendations by the European Society for Radiotherapy and Oncology (ESTRO) Guidelines Committee on integrating RT with targeted treatments for breast cancer. A thorough literature search was conducted using the PUBMED/MedLine, Embase, and Cochrane databases to identify original studies focusing on the safety profile of combining T-DM1 with RT.

RESULTS

After applying eligibility criteria, nine articles were included in the meta-analysis. Pooled data from these studies revealed a high incidence of grade 3 + radionecrosis (17%), while the rates of grade 3 + radiation-related pneumonitis (<1%) and skin toxicity (1%) were found to be very low.

CONCLUSION

Although there is some concern regarding a slight increase in pneumonitis when combining T-DM1 with postoperative RT, the safety profile of this combination was deemed acceptable for locoregional treatment in non-metastatic breast cancer. However, caution is advised when irradiating intracranial sites concurrently with T-DM1. There is a pressing need for international consensus guidelines regarding the safety considerations of combining T-DM1 and RT for breast cancer.

A Review of Advances in Radiotherapy in the Setting of Esophageal Cancers

Esophageal cancer is the eighth most common cancer worldwide and is the sixth most common cause of cancer-related mortality. The paradigm has shifted to include a multimodality approach with surgery, chemotherapy, targeted therapy (including immunotherapy), and radiation therapy. Advances in radiotherapy through techniques such as intensity modulated radiotherapy and proton beam therapy have allowed for the more dose homogeneity and improved organ sparing. In addition, recent studies of targeted therapies and predictive approaches in patients with locally advanced disease provide clinicians with new approaches to modify multimodality treatment to improve clinical outcomes.

Neurotoxicity from Old and New Radiation Treatments for Brain Tumors

Research regarding the mechanisms of brain damage following radiation treatments for brain tumors has increased over the years, thus providing a deeper insight into the pathobiological mechanisms and suggesting new approaches to minimize this damage. This review has discussed the different factors that are known to influence the risk of damage to the brain (mainly cognitive disturbances) from radiation. These include patient and tumor characteristics, the use of whole-brain radiotherapy versus particle therapy (protons, carbon ions), and stereotactic radiotherapy in various modalities. Additionally, biological mechanisms behind neuroprotection have been elucidated.

Radiotherapeutic Strategies to Overcome Resistance of Breast Cancer Brain Metastases by Considering Immunogenic Aspects of Cancer Stem Cells

Breast cancer is the most diagnosed cancer in women, and symptomatic brain metastases (BCBMs) occur in 15-20% of metastatic breast cancer cases. Despite technological advances in radiation therapy (RT), the prognosis of patients is limited. This has been attributed to radioresistant breast cancer stem cells (BCSCs), among other factors. The aim of this review article is to summarize the evidence of cancer-stem-cell-mediated radioresistance in brain metastases of breast cancer from radiobiologic and radiation oncologic perspectives to allow for the better interpretability of preclinical and clinical evidence and to facilitate its translation into new therapeutic strategies. To this end, the etiology of brain metastasis in breast cancer, its radiotherapeutic treatment options, resistance mechanisms in BCSCs, and effects of molecularly targeted therapies in combination with radiotherapy involving immune checkpoint inhibitors are described and classified. This is considered in the context of the central nervous system (CNS) as a particular metastatic niche involving the blood-brain barrier and the CNS immune system. The compilation of this existing knowledge serves to identify possible synergistic effects between systemic molecularly targeted therapies and ionizing radiation (IR) by considering both BCSCs' relevant resistance mechanisms and effects on normal tissue of the CNS.

Gamma knife icon based hypofractionated stereotactic radiosurgery (GKI-HSRS) for brain metastases: impact of dose and volume

OBJECTIVE

Gamma Knife Icon-based hypofractionated stereotactic radiosurgery (GKI-HSRS) is a novel technical paradigm in the treatment of brain metastases that allows for both the dosimetric benefits of the GKI stereotactic radiosurgery (SRS) platform as well as the biologic benefits of fractionation. We report mature local control and adverse radiation effect (ARE) outcomes following 5 fraction GKI-HSRS for intact brain metastases.

METHODS

Patients with intact brain metastases treated with 5-fraction GKI-HSRS were retrospectively reviewed. Survival, local control, and adverse radiation effect rates were determined. Univariable and multivariable regression (MVA) were performed on potential predictive factors.

RESULTS

Two hundred and ninety-nine metastases in 146 patients were identified. The median clinical follow-up was 10.7 months (range 0.5-47.6). The median total dose and prescription isodose was 27.5 Gy (range, 20-27.5) in 5 daily fractions and 52% (range, 45-93), respectively. The median overall survival (OS) was 12.7 months, and the 1-year local failure rate was 15.2%. MVA identified a total dose of 27.5 Gy vs. ≤ 25 Gy (hazard ratio [HR] 0.59, p = 0.042), and prior chemotherapy exposure (HR 1.99, p = 0.015), as significant predictors of LC. The 1-year ARE rate was 10.8% and the symptomatic ARE rate was 1.8%. MVA identified a gross tumor volume of ≥ 4.5 cc (HR 7.29, p < 0.001) as a significant predictor of symptomatic ARE.

CONCLUSION

Moderate total doses in 5 daily fractions of GKI-HSRS were associated with high rates of LC and a low incidence of symptomatic ARE.