Masterclass 2 - Advanced Radiation Therapy for Cancer Service in Hong Kong

Prostate cancer ranks the third most common male cancer in Hong Kong. Majority of patients present as localised disease and are amendable to cure, and radiotherapy is a standard of care in the definitive treatment of these patients. For many decades, external beam radiotherapy involved conventional fractionation delivered over eight weeks, and cancer survivors at significant risk of developing long term radiotherapy-related toxicities. In the recent two decades, with increased disease understanding and evolution in radiotherapy technology and image guidance to allow improved treatment precision, paradigm has shifted to the adoption of hypofractionated treatment schedules. Various randomized trials have demonstrated non-inferior clinical outcomes in patients treated with hypofractionated radiotherapy. Furthermore, harnessing on the radiobiological advantages, growing evidence support the efficacy and safety of ultra-hypofractionation, or stereotactic body radiotherapy, as standard of care for selected patients with localised prostate cancer. 
While advancements in radiotherapy techniques have improved precision, they have also increased treatment complexity, and demand for the concerted effort of a dedicated multidisciplinary team. This session will provide an overview of the clinical evidence on hypofractionation and stereotactic body radiotherapy for prostate cancer, discuss on practical considerations in radiotherapy treatment planning, and share on local experience in hypofractionation and multidisciplinary care.

Paediatric cancers often require radiotherapy as part of a multi-modality treatment approach. These patients achieve excellent long-term survival rates, exceeding 80% after initial cancer treatment. However, late effects, including cardiac, endocrine, and pulmonary complications, as well as secondary malignancies, are not uncommon. For central nervous system (CNS) tumours, radiotherapy inevitably results in varying degrees of neuro-cognitive impairment, which can significantly impact the quality of life in growing children.
Advancements in radiotherapy techniques, particularly Proton Beam Therapy (PBT), now enable the delivery of more precise radiation to tumour targets while minimizing harm to surrounding healthy tissues. In the past, families often had to travel overseas to access PBT for their children, facing significant challenges such as safety concerns for acute oncology conditions, limitations on concurrent chemotherapy, reduced access to comprehensive oncological care, and immense financial and psychosocial stress.
The introduction of local PBT services in 2023 has transformed care for children with newly diagnosed cancers, allowing them to access advanced radiotherapy closer to home. This development reduces the burden on families while ensuring comprehensive oncological support. However, the implementation of this service comes with funding and logistical challenges, particularly within the context of a public-private partnership program.
This session will explore the clinical, economic, and logistical benefits of local PBT, along with strategies to address the challenges of equitable access and sustainable program implementation.

Radiotherapy is effective in increasing local control in pediatric tumors, but it is often associated with severe late effects, including secondary malignancy and neuro-cognitive impairment. The physical advantages of protons, compared with conventional photons, decrease radiation dose to healthy tissues and allow dose escalation, and has translated into significant clinical benefits in multiple clinical studies. This better toxicity profile could substantially have positive impact on the survivors' quality of life. Proton radiation has been used safely and effectively for medulloblastoma, craniopharyngioma, ependymoma, germ cell intracranial tumors, low-grade glioma, retinoblastoma, chordoma, soft tissue sarcomas, lymphoma and neuroblastoma. Patients might not be able to obtain the benefits of protons because of the shortage of proton facilities. The spread of more proton centers in the near future will make this technology easily accessible to pediatric patients. Specialized teams of radiation oncologists, medical physicists, radiation therapists, anesthesiologists and nurses are needed. New protocols should be designed to investigate the benefits on late toxicity and quality of life. This presentation will give an overview of the state of the art proton therapy in the treatment of pediatric malignancies.

Spatially Fractionated Radiotherapy (SFRT), as characterized by its heterogeneous dose distribution within the tumor target, represents a novel approach in radiation therapy approach. 
Our institution pioneered the use of GRID and LATTICE techniques within Hong Kong and the Greater Bay Area in the treatment of large, bulky and/or radioresistant tumors. These tumors confer poor prognoses, have limited treatment options and represent unmet treatment needs. Contrasting with the conventional external beam radiation therapy (EBRT), which typically involves uniform dose administration across the target treatment area, the GRID therapy employs a physical GRID block to create high-dose "spots" while sparing areas in between beamlets. Such heterogeneous dose delivery potentially enhances therapeutic effects and mitigates treatment toxicities. On the other hand, deep-seated tumors with surrounding critical organs-at-risk could be treated with the LATTICE technique using multi-leaf collimators and volumetric modulated arc technologies to allow better individualization and treatment adaptation.
While the exact radiobiologic mechanism of SFRT remains partially understood, its unique therapeutic profile was postulated through an initiation of radiation-induced bystander signaling, tumor microvasculature damage and immunomodulatory effects. This Masterclass outlines the origins and principles of SFRT, and discusses the potential underlying mechanism, treatment planning processes, and clinical application. We share our local experience with case highlights on the promising outcomes of SFRT demonstrating effective tumor regression and favorable toxicities in the treatment of challenging clinical scenarios. Further clinical research and standardized guidelines are warranted to refine novel strategies and expand access to innovative cancer treatment modalities.