Abstract
We have created an Excel-based dose calculation template specifically for reirradiation in cases of locally recurrent and unresectable head and neck carcinoma, as well as for second primary tumors in these regions. This calculation tool is primarily based on international guidelines for reirradiation using intensity-modulated radiation therapy for locally recurrent nasopharyngeal carcinoma, as outlined by Ng et al. 1 This tool is designed to calculate the remaining allowable dose for organs-at-risk (OARs) during reirradiation. It also computes the cumulative biologically effective dose (BED) and the equivalent dose in 2 Gy fractions (EQD2). For these calculations, we have used an α/β ratio of 2.5 for neural structures and 3 for other OARs. Additionally, we have implemented dose constraints for the mandible as specified by Dionisi et al. 2
This template is designed to be user-friendly and saves time on repeated calculations while allowing for easy documentation and verification. It effectively provides calculations for EQD2 and BED, even when the dose per fraction varies between the initial course of treatment and the reirradiation course (e.g., doses ranging from 1.8-2.12 Gy). In addition to the reporting of OARs suggested by Ng et al. for nasopharyngeal carcinomas, we recommend that clinicians document cumulative dose calculations for other OARs related to late toxicity. These include the mandible, structures associated with dysphagia and aspiration, larynx, cochlea, and cervical esophagus. Additionally, tracking the gross target volume is important to monitor local control. This approach will be beneficial for monitoring outcomes in cases of reirradiation. It is essential to document the following information: age, gender, comorbidities, time interval between courses, concurrent chemotherapy usage, clinical target volumes from both courses, and any pre-existing late toxicities from previous treatments.
We hope that these suggestions will support the ongoing efforts to improve and optimize reirradiation practices. By incorporating this Excel-based tool for dose calculation, we can enhance the accuracy and consistency of reporting doses to OAR. This improvement will aid in monitoring the occurrence of late toxicities.
Link for Excel-based dose calculation template is available as a supplementary file to assist with this documentation on reirradiation in head and neck cancer.
Footnotes
Authors’ Contribution
Pooja Sethi helped in conceptualization and drafting of manuscript.
Pooja and Avinash contributed for Excel development.
Bhargav, Ananth, and Gunaseelan helped in verification of Excel-based template.
Manuscript has been read and approved by all the authors and that each author believes that the manuscript represents honest work.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
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References
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