Present developments in reaching an international consensus for a model-based approach to particle beam therapy

Abstract

Particle beam therapy (PBT), including proton and carbon ion therapy, is an emerging innovative treatment for cancer patients. Due to the high cost of and limited access to treatment, meticulous selection of patients who would benefit most from PBT, when compared with standard X-ray therapy (XRT), is necessary. Due to the cost and labor involved in randomized controlled trials, the model-based approach (MBA) is used as an alternative means of establishing scientific evidence in medicine, and it can be improved continuously. Good databases and reasonable models are crucial for the reliability of this approach. The tumor control probability and normal tissue complication probability models are good illustrations of the advantages of PBT, but pre-existing NTCP models have been derived from historical patient treatments from the XRT era. This highlights the necessity of prospectively analyzing specific treatment-related toxicities in order to develop PBT-compatible models. An international consensus has been reached at the Global Institution for Collaborative Research and Education (GI-CoRE) joint symposium, concluding that a systematically developed model is required for model accuracy and performance. Six important steps that need to be observed in these considerations include patient selection, treatment planning, beam delivery, dose verification, response assessment, and data analysis. Advanced technologies in radiotherapy and computer science can be integrated to improve the efficacy of a treatment. Model validation and appropriately defined thresholds in a cost-effectiveness centered manner, together with quality assurance in the treatment planning, have to be achieved prior to clinical implementation.

Current practice in proton therapy delivery in adult cancer patients across Europe

“…Of these, two thirds evaluated DDose rather than DNTCP. This might be explained by the lack of high quality NTCP-models for several tumour types [32]. The model-based approach has been adopted in the Netherlands, Denmark, France, Germany, Italy, and Spain for a number of tumour sites including GI, breast and HNC.…”

Comparison of intensity modulated proton therapy beam configurations for treating thoracic esophageal cancer

“…The NTCP model is a valuable tool to translate the dosimetric advantage of IMPT into a clinical benefit. The NTCP model-based approach has been used as a strategy to select patients who will potentially benefit from PBT [32] , [33] , [34] . Our results confirmed the clinical benefit of IMPT because there was a significant reduction in NTCP for the heart and lungs, which was consistent with previous studies [11] , [25] .…”

NTCP Modeling of Late Effects for Head and Neck Cancer: A Systematic Review

“…It has been previously shown that NTCP models developed for photon therapy did retain discriminatory properties for proton therapy and could hence be used to select patients [ 60 ]. Furthermore, the conformality afforded by proton therapy decreases concerns such that an NTCP model can reliably score a radiation plan for both photons and protons [ 61 , 62 ].…”