Introduction:
De-intensification of cancer treatment in children and young adults has gathered considerable momentumas the long-term childhood cancer survivors are at an increased risk of serious health related issuesrelatedto treatment[1,2]. Since radiation is one of the major contributors to the late effects in children including growth defects, neuro-cognitive defects, endocrinopathies, cardiovascular effects, lymphedema and secondary malignant neoplasms (SMN) [3], there has been a widespread evaluation of radiation de-intensification in the last two decades for several haematological and solid tumors [4,5,6]. Radiation therapy however cannot be completely avoided in many clinical protocols and remain an integral component of management and the best possible conformal techniques of radiation should be employed in such situations.
Proton beam therapy (PBT) owing to its superior physical property results in significantly lower doses of radiation to the healthy normal structures thereby has a potential tomitigate both acute and late radiation related effects. This is especially impactful in children and young adults due to much larger tumor to body volumes (compared to adults) and also due to higher propensity to develop permanent radiation sequelae. Multiple prospective and retrospective studies have shown that the dosimetric benefit achieved results in favourable clinical outcomes[7-11].Despite the lack of randomized controlled trials demonstrating superiority of PBT over conformal photon-based techniques most collaborative group trials conducted in North America (Children’s Oncology group) and Europe allow patients to be treated with PBT [12, 13]. In fact, it is the preferred treatment modality for a majority of leading pediatric oncologists of the worldfor most solid tumors requiring radiation therapy[14]. The concerns related to safety of the older generation passive scattering proton therapy (PSPT) such as neutron contamination, higher rates of treatment related necrosis have been addressed sufficiently with the advent of contemporary pencil beam scanning (PBS) PBT with on-board volumetric imaging, modern planning algorithms and better understanding of biological uncertainties of PBT.
Our multi-room PBT facility with fully rotating gantries capable of delivering contemporary image guided PBS PBT is the first proton therapy centre in the Indian subcontinent. The patient treatments began in Jan 2019 [15,16] and since then our centre has been the only referral centre for PBT in this region. The patients and physicians of this region, which is home to nearly one quarter of the world’s population have diverse socio-economic, cultural and educational back grounds and very little is known regarding their preference and adoption of this relatively new and cost-intensive technology. We hereby report the demographic profile and our initial experience of treating children and young adults with image guided PBS PBT.