Improving Access to Proton Treatment in Canada Via a Proton Plan Consultation Service: A Use Case Example

Abstract

Aim: To provide an overview of the Proton Plan Consultation Service offered at our cancer centre and to demonstrate how that service triggered a reversal in the decision that would have denied a patient access to a treatment not currently offered in Canada. Process: The Proton Consultation Service is a multidisciplinary team comprised of a Radiation Oncologist, two Medical Physicists and two Medical Dosimertists. A referring physician can request a proton plan by completing the online referral form and sending the patients planning CT and photon treatment plan including targets and clinical goals. A 14 yo male with an orbital rhabdomyosarcoma was referred to the Proton Plan Consultation Service from a cancer centre in Montreal. The patient had recently been denied referral to a U.S. Proton Centre for treatment. A proton plan was generated by the consultation service and exported back to the Montreal referring Radiation Oncologist. After reviewing this comparative proton plan against the original photon plan an approval committee for the Quebec government reversed their initial decision and supported sending the child to a U.S. Proton Centre for treatment. Benefits/Challenges: Proton plans allow for reduced normal tissue dose to surrounding structures when compared to photon plans. To highlight with a few examples from this case, the pituitary mean dose was reduced from 1137 cGy in the photon plan to 73 cGy in the proton plan. Brainstem max dose to 0.1 cc was reduced from 1086 cGy to 3 cGy. Finally, right hippocampus max dose to 0.1cc was reduced from 803 cGy to 25 cGy. As radiotherapy can cause neurocognition changes, these dose reductions for normal brain structures may have long-term benefits for this child. The challenges encountered are based around educating the dosimetry staff around best practices for proton planning and expediting the proton plan for the referring centre so the patient experiences limited delay in start of treatment. Impact/Outcomes: This use case demonstrates how the Proton Consultation Service can be used to ensure Canadians have appropriate access to proton treatment. It also serves as an education tool for oncology staff across Canada, highlighting the benefits of proton treatment as a valuable tool for the treatment of cancer in difficult sites.