Compensation for radiotherapy treatment interruptions due to a cyberattack: An isoeffective DVH‐based dose compensation decision tool

Abstract

Unscheduled interruptions to radiotherapy treatments lead to decreased tumor control probability (TCP). Rapid cell repopulation in the tumor increases due to the absence of radiation dose, resulting in the loss of TCP. Compensation for this loss is required to prevent or reduce an extension of the patient's overall treatment time and regain the original TCP. The cyberattack on the Irish public health service in May 2021 prevented radiotherapy treatment delivery resulting in treatment interruptions of up to 12 days. Current standards for treatment gap calculations are performed using the Royal College of Radiologists (RCR) methodology, using a point-dose for planning target volume (PTV) and the organs at risk (OAR). An in-house tool, named EQD 2 VH, was created in Python to perform treatment gap calculations using the dose-volume histogram (DVH) information in DICOM data extracted from commercial treatment planning system plans. The physical dose in each dose bin was converted into equivalent dose in 2-Gy fractions (EQD 2 ), accounting for tumor cell repopulation. This EQD 2 -based DVH provides a 2D representation of the impact of treatment gap compensation strategies on both PTV and OAR dose distributions compared to the intended prescribed treatment plan. This additional information can aid clinicians' choice of compensation options. EQD 2 VH was evaluated using five high-priority patients experiencing a treatment interruption when the cyberattack occurred. Compensation plans were created using the RCR methodology to evaluate EQD 2 VH as a decision-making tool. The EQD 2 VH method demonstrated that the comparison of compensated treatment plans alongside the original intended treatment plans using isoeffective DVH analysis can be achieved. It enabled a visual and quantitative comparison between treatment plan options and provided an individual analysis of each structure in a patient's plan. It demonstrated potential to be a useful decision-making tool for finding a balance between optimizing dose to PTV while protecting OARs.

Effect of radiotherapy interruption on nasopharyngeal cancer

“…A short postoperative interval to OS: overall survival; LRFS: local relapse-free survival; NRFS: nodal relapse-free survival; DMFS: distant metastasis-free survival; DFS: disease-free survival; TLI: radiation-induced temporal lobe injury; LRRFS: loco-regional relapse-free survival; PFS: progression-free survival; DSS: disease-specific survival. adjuvant radiotherapy was found to be beneficial in improving patient survival, and this interval was usually considered optimal to be controlled at 6 weeks or less (61)(62)(63). Table 2 summarized realworld data on the impact of radiotherapy interruptions.…”

“…Tumor tissue regenerates at a faster rate than normal tissue, and the onset of rapid cell regeneration in tumor tissue during the treatment interval results in a lower radiobiologic dose to the planned target volume (PTV) ( 64 ). Radiotherapy interruption for nearly a full workweek and reduction in radiation service utilization may compromise the therapeutic benefit for patients because of the reduction in biological activity, which can lead to sublethal loss of repair ( 65 ).…”

“…Increase the number of daily radiotherapy sessions, such as splitting twice a day; c. Increase the dose of a single radiotherapy session without extending the total treatment time; and d. Extend the total treatment time ( 80 ). However, regimen b increases the probability of normal tissue complications due to incomplete repair of normal tissue between divisions, resulting in increased sublethal damage to normal tissue ( 64 ). Regimens c and d either result in reduced local control rates or excessive late adverse effects ( 80 ).…”

“…It provides radiobiological dose-volume histograms that explain inhomogeneous dose distributions, as well as direct visual and quantitative comparisons between the plan being studied and the expected plan. Key dose-volume histogram statistics are provided for each plan to help monitor dose and compare with dose limits ( 64 ).…”

Image Guided Radiotherapy (IGRT) and Delta (Δ) Radiomics—An Urgent Alliance for the Front Line of the War against Head and Neck Cancers

“…An equivalent dose in 2Gy fractions (EQD2), based on the linear quadratic model (LQ), is widely used to compensate for breaks during the radiotherapy treatment, but the differences in cell repopulation from one case to another make this strategy imprecise. Another method of compensating radiotherapy treatment gaps is the administration of two daily doses at an interval of at least 6 h. Both strategies could create an increase in the risk of toxicities by escalating doses received by organs at risk (OARs) [ 11 , 12 , 13 , 14 ].…”