Poirier VJ, Koh ESY, Darko J, Fleck A, Pinard C, Vail DM. Patterns of local residual disease and local failure after intensity modulated/image guided radiation therapy for sinonasal tumors in dogs.
J Vet Intern Med 2021;
35:1062-1072. [PMID:
33660342 PMCID:
PMC7995431 DOI:
10.1111/jvim.16076]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND
Most dogs with sinonasal tumors (SNT) treated with radiation therapy (RT) died because of local disease progression.
HYPOTHESIS/OBJECTIVES
Our hypothesis is that the majority of local failure and residual disease would occur within the radiation field.
ANIMALS
Twenty-two dogs with SNT treated with RT.
METHODS
Retrospective cohort study.
INCLUSION CRITERIA
dogs with SNT receiving 10 daily fractions of 4.2 Gy with intensity modulated radiation therapy (IMRT)/image guided radiation therapy (IGRT) and follow-up cone beam computed tomography (CBCT). Each CBCT was registered with the original radiation planning CT and the gross tumor volume (GTV) contoured. The GTV was classified as residual (GTVr) or a failure (GTVf). The dose statistic for each GTV was calculated with the original IMRT plan. For GTVf, failures were classified as "in-field," "marginal," or "out-field" if at least 95, 20-95, or less than 20% of the volume of failure was within 95% (D95) of the total prescription dose, respectively.
RESULTS
There were 52 follow-up CBCT/CTs. Overall there was a GTVr for 20 dogs and GTVf for 16 dogs. The majority of GTVr volume was within the original GTV. GTVf analysis showed that 75% (12/16) were "in-field," 19% (3/16) were "marginal" and 6% (1/16) were "out-field."
CONCLUSION AND CLINICAL IMPORTANCE
In-field failures are the main pattern for local recurrence, and there is evidence of radioresistant subvolumes within the GTV.
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