Masterclass 11 - Personalised and High Precision Radiotherapy-Clinical Applications

Bone metastases occur commonly in patients with advance stage of malignancies, either as de novo at diagnosis or during the course of the disease. The presence of bone metastases not only cause debilitating symptoms like pain to patients, but also could significantly impact the neurological status and hence worsen their quality of life. External beam radiotherapy (EBRT) is the standard of care in symptomatic bone metastases to provide pain relief with minimal toxicities. The rapid evolution of systemic anti-cancer treatment landscape now led to longer survival of cancer patients, limited disease progression over bone may occur and warrant a more aggressive management approach with hope to offer a better symptom and disease control. Theoretically, a higher radiation dose to tumor could potentially lead to greater proportion of tumor cell kill and hence better treatment outcomes. However, this remained challenging by external beam radiotherapy due to the radiation tolerance of critical structures nearby. With the advancement in technology, radiation therapy could now be delivered by highly conformal techniques that target the tumor more precisely while sparing surrounding normal organs. Stereotactic body radiotherapy (SBRT) is one of the advancements in this aspect that had gained interest over the past years and increasing being studied in various case series and randomized controlled trials. In this presentation, the current evidence about the efficacy and toxicities of SBRT to bone metastases, either as primary treatment or re-irradiation setting, will be reviewed. Practical factors including technical issues and patient selections will also be discussed to provide insights when consider implementation of SBRT to bone metastases in daily practice.

Brain metastasis occurs in up to 20-40% of patients with advanced malignancy, and its incidence is further rising as result of increased accessibility of more sensitive neuroimaging. 


Historically, brain metastasis is regarded an ‘end-of-life event’, associated with very poor prognosis and limited treatment options. For decades, whole brain radiotherapy (WBRT) has been considered a standard of care, despite lack of benefit in overall survival or quality of life across clinical trials. On the other hand, it is associated with negative impact on long term neurocognitive function. 


In recent years, there has been rapid evolution in the treatment landscape of systemic therapy, with emergence of novel biomarker-directed treatment options, allowing improvement in disease control and survival for patients with brain metastasis. As patients survive longer, they are also vulnerable to treatment toxicity. In the modern era of anti-cancer treatment, personalised care to maximise the therapeutic ratio to improve intracranial control and minimise treatment-related toxicity and maintain neurocognitive function is paramount. 


Radiotherapy treatment paradigm has shifted to modern techniques such as stereotactic radiosurgery (SRS), producing excellent local tumour control and superior neurocognitive preservation and quality of life compared to WBRT, and has gained popularity in clinical practice in the past decade. Furthermore, emerging clinical evidence and advancement in radiotherapy technology support SRS treatment for suitable patients with more extensive intracranial disease. Other neurocognitive protection strategies such as WBRT with hippocampal avoidance and memantine also produce encouraging treatment results.  


In real-world practice, advanced radiotherapy treatment requires careful case selection, and calls for high precision in the process of radiotherapy treatment planning, quality assurance and image guidance, under the concerted effort of a multidisciplinary team. Here, we discuss on the available evidence for modern radiotherapy treatment strategies for brain metastasis, highlight on the procedures in radiotherapy planning, and share on local treatment experience.