Abstract
Purpose: The aim of our study was to report on patterns of failure using detailed information from follow-up positron emission tomography-computed tomography (PET/CT) scans for patients with laryngeal squamous cell carcinoma (SCCA) treated with definitive radiation therapy using intensity-modulated radiation therapy (IMRT).Methods: One hundred and sixty-eight patients with laryngeal SCCA treated with definitive IMRT using a simultaneous integrated boost were included. The point of recurrence origin on follow-up PET/CT was determined using two separate data-driven methods. The first method, the mathematical epicenter point of origin (POEpi), calculated the mathematical focal epicenter point for which the maximum distance to the surface of the surrounding volume was smaller than for any other point. The second method, maximum standardized uptake value point of origin (POMax), calculated the voxel with maximum standardized uptake value (SUV) uptake within the recurrence volume. The failure pattern was then determined by whether the point of recurrence origin fell within the low, intermediate, or high-risk target volumes in the original treatment planning CT.Results: Thirty-five primary/nodal recurrences in 33 patients were included in the analysis. In the POEpi method, 94% (33/35) of all recurrences originated either within the high-risk gross tumor volume (GTVHigh-risk) or within an average of 0.9 ± 1.3 mm from it. In the POMax method, 91% (32/35) of all recurrences originated either within the GTVHigh-risk or within an average of 1.8 ± 1.7 mm from it. There were no recurrences outside the low-risk planning target volume (PTVLow-risk) for the POEpi method but there was one for the POMax method, which was 19.8 mm away from the edge of the gross tumor volume receiving 70 Gy (GTV70). Increasing distance between the two different origin points was strongly correlated with the size of the recurrence volume.Conclusion: The majority of recurrences for laryngeal cancer patients treated with definitive IMRT originated from within the high-dose treatment region. This can have implications for reducing clinical target volumes while using a risk-adaptive treatment approach to both constrain dose to critical areas and further escalate the dose to the gross tumor to improve locoregional control rates.
Highlights
Definitive radiation therapy delivered using intensity-modulated radiation therapy (IMRT) has been established as the standard of care treatment for many head and neck cancers, including laryngeal cancer, where the aim is to preserve the larynx function [1,2,3]
There were no recurrences outside the low-risk planning target volume (PTVLow-risk) for the POEpi method but there was one for the POMax method, which was 19.8 mm away from the edge of the gross tumor volume receiving 70 Gy (GTV70)
We present an in-depth pattern of failure analysis focused on laryngeal cancer patients treated with definitive IMRT with locoregional recurrence origin determined from positron emission tomography/computed tomography (PET/CT) follow-up imaging
Summary
Definitive radiation therapy delivered using intensity-modulated radiation therapy (IMRT) has been established as the standard of care treatment for many head and neck cancers, including laryngeal cancer, where the aim is to preserve the larynx function [1,2,3]. Previous studies have examined failure patterns for head and neck cancers in general, typically showing a higher rate of recurrence within the high-dose treatment area [1, 3, 5, 13,14,15,16]. How to cite this article Kabarriti R, Brodin N, Ahmed S, et al (January 08, 2019) Origin of Locoregional Recurrences After Definitive Intensity-modulated Radiation Therapy (IMRT) for Laryngeal Cancer Determined Based on Follow-up PET/CT Imaging.
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