Proton Beam Therapy 

Proton Beam Therapy - PBT

Precise targeting by radiotherapy is crucial to maximize therapeutic ratio of this integral treatment modality. NCCS has therefore incorporated a Proton Beam Therapy (PBT) clinical programme in its new Centre, along with a comprehensive translational research framework to understand the physical and biological advantages of PBT leading up to this clinical implementation.

For some background, the clinical use of PBT is motivated primarily by their inverted depth-dose profile compared to photons, which is uniquely characterized by the Bragg peak (Fig. 1). PBT is thus able to offer a physical dosimetric advantage over photons by avoiding unnecessary irradiation of adjacent normal tissues. PBT is also thought to demonstrate an enhanced cell killing. This is due to the increased Linear Energy Transfer (LET) compared with photons when proton particles approach Bragg peak. High LET values are indicative of localized energy deposition resulting in the induction of enhanced, irreparable biological damage. The increased effectiveness of protons compared to photons may be quantified by Relative Biological Effectiveness (RBE), which is 1.1 in favor of PBT. However, despite the evidence from in vitro studies modelling the 1.1-fold increased efficacy of PBT over photon X-irradiation, the mechanisms underpinning the increased tissue responses are unclear.

On this note, we have thus assembled a multidisciplinary research team to conduct research from bench to bedside, encompassing fundamental research in cancer cells, translational research using animal models of cancers, and clinical research in PBT treated cancer patients. Our programme is led by two clinician-scientists – Professor SOO Khee Chee and Dr. Melvin CHUA Lee Kiang; and it encompasses eight research teams across institutes and universities that are specialized in physics, cancer molecular and stem cell biology, cancer genomics and epigenomics, pharmacology, radio-resistance, in vivo tumor models for N = 1 novel radiosensitiser drug trials, and radiotherapy technological innovation. The members and scope of their work are as outlined in Figure 2.