Re‑Irradiation In Practice: Streamlining Assessment In a Regional Cancer Centre
Abstract
Purpose
To guide practice for Re-Irradiation (RI) assessment at a regional cancer centre in Ontario.
Methods
A retrospective review of RI cases over a four-month period was conducted. Current practice was evaluated including treatment intent, time efficiency, documentation completeness and challenges encountered. Process was improved including standardize local practice based on these findings.
Results
Of 1,900 radiotherapy cases treated between May and September 2024, 17.5% were flagged for potential overlap with prior treatments; among this, 27 cases (1.4%) underwent the local RI assessment process. The main reasons for by-passing the RI process were clinically non-significant previous dose to current OARs and emergency palliation with short life expectancy. Among the 27 assessed cases, 26% were treated with radical intent while the rest were palliative. Most radical RI cases were associated with lung or breast primary histology, whereas palliative cases were predominantly breast cancer. Assessment complexity varied widely, requiring review of 1-27 previous plans, of which 0-7 were deemed consequential. Intervals between previous and current treatments ranged from 1 month to over 40 years. Key challenges included effective case identification, accurate anatomical evaluation of cumulative doses, consensus on EQD2 calculation parameters and time efficiency. Common dose limiting structures were the spinal canal, great vessels and esophagus in that order. When OAR constraints could not be met, mitigation strategies included technique modification, target coverage compromise, adjustment of dose fractionation (3 cases) and treatment abandonment (1 case). Local process improvements included documenting reasons to skip the RI process, integrating RI assessment considerations at multiple workflow points, escalating complex cases to a multidisciplinary team (accuracy and time improvement), establishing local consensus on calculation parameters, and enhancing documentation completeness and accessibility.
Conclusion
This review highlights the complexity and variability of RI planning, the challenges involved and the need for a multidisciplinary approach to streamline the process.