The systemic immunostimulatory effects of radiation therapy producing overall tumor control through the abscopal effect

Sharing Mono-Institutional Experience of Treating Pancreatic Cancer with Stereotactic Body Radiation Therapy (SBRT)

BACKGROUND

Stereotactic body radiotherapy (SBRT) is an evolving treatment for the local management of pancreatic cancer (PC). The main purpose of this study is to report our initial experience in terms of local control (LC) and toxicity for PC patients treated with SBRT.

METHODS

We conducted a retrospective review of patients treated with SBRT using abdominal compression (AC) or an end-expiratory breath-holding (EEBH) technique. The median prescribed dose was 35 Gy, delivered in five fractions. Toxicities were recorded using Common Terminology Criteria for Adverse Events (CTCAE) v5.0, and survival was estimated using the Kaplan-Meier method.

RESULTS

From 2017 to 2023, 17 PC patients were offered SBRT. Their median age was 69 years. The median follow-up from the date of diagnosis was 22.37 months. The overall survival (OS) was 94% at 1 year and 60.9% at 2 years. The progression-free survival (PFS) was 63.1% at 6 months and 56.1% at 9 months. The median OS was 26.3 months, and the median PFS was 20.6 months. The 6-month and 1-year LC rates were 71% and 50.8%, respectively.

CONCLUSION

We are successful in implementing the SBRT program at our centre. SBRT appears to be a promising treatment option for achieving LC with limited acute toxicities.

Lutetium-177 Labelled Anti-PSMA Monoclonal Antibody (Lu-TLX591) Therapy for Metastatic Prostate Cancer: Treatment Toxicity and Outcomes

INTRODUCTION

Whilst prostate cancer is the fourth most common cancer globally, effective therapies for patients with advanced disease are lacking. In recent years, interest in using theranostic agents to treat castrate-resistant prostate cancer (CRPC) and metastatic prostate cancer has emerged. Lu-TLX591 monoclonal antibody is a potential agent of significance; however, to date, reports on its toxicity and efficacy have been limited to small clinical trials in heavily pretreated patients. This retrospective study describes the real-world toxicity and efficacy profile of Lu-TLX591.

METHODS

Eighteen patients received Lu-TLX591 at two private oncology centres in Australia. Patients were eligible if they had CRPC or metastatic prostate cancer and prostate-specific membrane antigen (PSMA)-avid disease confirmed by PSMA-positron emission tomography (PET). Patients received two cycles of Lu-TLX591 monoclonal antibody (177 Lu-DOTA-rosopatamab) each dosed from 1.01-2.85 GBq, 14 days apart. Patient side effects, blood test results and radiology reports were recorded on the patient's electronic medical record (eMR).

RESULTS

Prominent side effects included fatigue (55.6%), anorexia (16.7%), nausea (11.1%), and transfusion reactions (11.1%). All-grade haematological toxicities included lymphopenia (61.1%), anaemia (22.2%), leukopenia (27.8%), neutropenia (27.8%), and thrombocytopenia (27.8%). Grade 4 toxicity included lymphopenia (6.7%) and thrombocytopenia (6.7%). Patients' prostate-specific antigen (PSA) responses were as follows; ≥ 30% PSA decline (27.8%), ≥ 50% PSA decline (11.4%) and any PSA decline (38.9%). Follow-up radiology revealed 54.5% stable disease, 45.4% disease progression and 9.1% disease regression.

CONCLUSION

Lu-TLX591 was safely administered at acceptable toxicity and its efficacy reflects previous clinical trials. Larger studies are required and are underway (NCT04786847; NCT05146973; NCT04876651) to determine Lu-TLX591 effectiveness amongst different prostate cancer populations and compare its efficacy against peptide-based radiopharmaceutical agents.

Radiation Therapy for Primary Cutaneous Gamma Delta Lymphoma Prior to Stem Cell Transplantation

We present a patient with widespread PCGD-TCL of the bilateral arms and legs, who underwent radiotherapy with 34 Gy in 17 fractions using circumferential VMAT and 3-D printed bolus to the four extremities prior to planned stem cell transplant, who was then found to have progression in the liver, lung, and skin, followed by drastic regression of all in and out-of-field lesions on imaging 1.5 months later. The cause of regression may be related to a radiation-induced abscopal effect from the immunomodulatory effects of radiation, or related to immune reactivation in the setting of cessation of systemic immunosuppressive agents.

International consensus on radiotherapy in metastatic non-small cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer-related death worldwide, with non-small cell lung cancer (NSCLC) accounting for most cases. While radiotherapy has historically served as a palliative modality in metastatic NSCLC, considerable advances in its technology and the continuous development of cutting-edge therapeutic agents, such as targeted therapy and immune checkpoint inhibitors (ICIs), are increasing its role in the multi-disciplinary management of the disease.

METHODS

International radiotherapy experts were convened to consider and reach consensuses on the clinical utilities of radiotherapy in metastatic NSCLC, with the aim to provide patient-focused, up to date, evidence-based, recommendations to assist cancer specialists in the management of patients with metastatic NSCLC worldwide.

RESULTS

Timely radiotherapy can offer rapid symptom alleviation and allow subsequent aggressive treatment approaches in patients with heavy tumor burden and/or oncologic emergencies. In addition, appropriate incorporation of radiotherapy as concurrent, consolidation, or salvage therapy makes it possible to achieve long-term survival, or even cure, for patients with oligo-metastatic disease. Cranial radiotherapy plays an important role in the management of brain metastasis, potentially augmenting the response and prolonging survival associated with targeted agents and ICIs. However, key questions remain, such as the appropriate choice of radiation techniques, optimal sequence of systemic therapies and radiotherapy, and optimal patient selection for such combination strategies. Although a strong rationale for combining radiotherapy and ICIs exists, its optimal parameters in this setting remain to be established.

CONCLUSIONS

In the modern era, radiotherapy serves not only as a palliative tool in metastatic NSCLC, but also plays active roles in patients with oligo-focal disease, CNS metastasis and receiving ICIs.

Cell-Derived Biogenetic Gold Nanoparticles for Sensitizing Radiotherapy and Boosting Immune Response against Cancer

The biosynthesis of nanomedicine has gained enormous attention and exhibited promising prospects, while the underlying mechanism and advantage remain not fully understood. Here, a cell-reactor based on tumor cells is developed to obtain biogenetic gold nanoparticles (Au@MC38) for sensitizing radiotherapy and boosting immune responses. It demonstrates that the intracellular biomineralization and exocytosis process of Au@MC38 can be regulated by the cellular metabolites level and other factors, such as glutathione and reactive oxygen species (ROS), autophagy, and UV irradiation. The elucidation of mechanisms may promote the understanding of interaction principles between nanoparticles and biosystems in the process of biosynthesis. Combined with radiotherapy, Au@MC38 strengthens the radiation-induced DNA damage and ROS generation, thus aggravating cell apoptosis and necrosis. Benefiting from homologous targeting and transcytosis effect, Au@MC38 demonstrates good tumor distribution. Local radiation-induced immunogenic cell death initiates an effective immune response. Especially, CD8a⁺ dendritic cells are significantly increased in mice that received combinatorial treatment. This radio-sensitization strategy has demonstrated the effective inhibition on primary and metastatic tumors, and achieved satisfactory survival benefit in combinatorial with immune checkpoint blockade. Thus, this bio-inspired synthetic strategy may impulse the development of biosynthesis and its therapeutic applications, contributing to a non-invasive and efficient modality for nanomedicine exploitation.

True abscopal effect in a patient with metastatic non-small cell lung cancer

Background

Systemic response to local anticancer treatment is a phenomenon called ‘abscopal effect’. The immune system is thought to play a pivotal role in its occurrence. To date, several cases have been reported, particularly in patients receiving combined local treatment and immune checkpoint inhibitors. In such cases, it is impossible to discriminate between the effects of local and systemic treatment. Only a few cases of abscopal effect have been described with radiotherapy alone.

Case presentation

Here, we report on the case of an 81-year-old woman with recurrent metastatic squamous cell carcinoma of the lung with mediastinal tumor bulk, lymph node and bone metastases. The patient refused to undergo systemic treatment, and palliative stereotactic radiotherapy of the mediastinal tumor was performed. At restaging with FDG-PET/CT, the patient presented with a decrease in size and FDG-avidity both of the irradiated site and of the lymph node and bone metastases (which did not receive radiotherapy). At 25 months after radiotherapy, the patient is still in remission at all sites.

Conclusions

This is a rare case of an abscopal effect after radiotherapy as monotherapy. It is one of the few hitherto reported for lung cancer. Several ongoing studies with a combination of radiotherapy and immunotherapy are seeking to exploit a potential synergy to induce abscopal effects.

Brain Radiation Induced Extracranial Abscopal Effects in Metastatic Melanoma

Historically, the brain has been viewed as a specialized neurovascular inert organ with a distinctive immune privilege. Therefore, radiation-induced extracranial abscopal effects would be considered an unusual phenomenon due to the difficulty of the immunogenic signaling molecules to travel across the blood-brain barrier (BBB). However, it is now possible that localized central nervous system radiation has the ability to disrupt the structural integrity of the BBB and increase its endothelial permeability allowing the free passage of immunogenic responses between the intracranial and extracranial compartments. Thus, the nascent tumor-associated antigens produced by localized brain radiation can travel across the BBB into the rest of the body to modulate the immune system and induce extracranial abscopal effects. In clinical practice, localized brain radiation therapy-induced extracranial abscopal effects are a rarely seen phenomenon in metastatic melanoma and other advanced cancers. In this article, we provide a detailed overview of the current state of knowledge and clinical experience of central nervous system radiation-induced extracranial abscopal effects in patients with malignant melanoma. Emerging data from a small number of case reports and cohort studies of various malignancies has significantly altered our earlier understanding of this process by revealing that the brain is neither isolated nor passive in its interactions with the body's immune system. In addition, these studies provide clinical evidence that the brain is capable of interacting actively with the extracranial peripheral immune system. Thus, localized radiation treatment to 1 or more locations of brain metastases can induce extracranial abscopal responses. Collectively, these findings clearly demonstrate that localized brain radiation therapy-induced abscopal effects traverses the BBB and trigger tumor regression in the nonirradiated extracranial locations.