Volumetric tumor response assessment is inefficient without overt clinical benefit compared to conventional, manual veterinary response assessment in canine nasal tumors

Abstract

Accurate assessment of tumor response to therapy is critical in guiding management of veterinary oncology patients and is most commonly performed using response evaluation criteria in solid tumors criteria. This process can be time consuming and have high intra‐ and interobserver variability. The primary aim of this serial measurements, secondary analysis study was to compare manual linear tumor response assessment to semi‐automated, contoured response assessment in canine nasal tumors. The secondary objective was to determine if tumor measurements or clinical characteristics, such as stage, would correlate to progression‐free interval. Three investigators evaluated paired CT scans of skulls of 22 dogs with nasal tumors obtained prior to and following radiation therapy. The automatically generated tumor volumes were not useful for canine nasal tumors in this study, characterized by poor intraobserver agreement between automatically generated contours and hand‐adjusted contours. The radiologist's manual linear method of determining response evaluation criteria in solid tumors categorization and tumor volume is significantly faster (P < .0001) but significantly underestimates nasal tumor volume (P < .05) when compared to a contour‐based method. Interobserver agreement was greater for volume determination using the contour‐based method when compared to response evaluation criteria in solid tumors categorization utilizing the same method. However, response evaluation criteria in solid tumors categorization and percentage volume change were strongly correlated, providing validity to response evaluation criteria in solid tumors as a rapid method of tumor response assessment for canine nasal tumors. No clinical characteristics or tumor measurements were significantly associated with progression‐free interval.

Computed tomography radiomic features hold prognostic utility for canine lung tumors: An analytical study

“…There was very strong correlation between contoured volumes and maximum axial diameter and those measurements obtained from the radiologist’s assessment. This result is contrary to a recent study that showed poor consistency between manual volume or maximum diameter measurements determined by a radiologist and automatically generated measurements from segmented canine nasal tumor contours [ 37 ]. In that study, manual radiologist-generated measurements significantly underestimated tumor volume and maximum diameter compared to those obtained following segmentation [ 37 ].…”

“…This result is contrary to a recent study that showed poor consistency between manual volume or maximum diameter measurements determined by a radiologist and automatically generated measurements from segmented canine nasal tumor contours [ 37 ]. In that study, manual radiologist-generated measurements significantly underestimated tumor volume and maximum diameter compared to those obtained following segmentation [ 37 ]. One possible explanation for this difference is nasal tumors are irregular in shape and can be difficult to differentiate from surrounding nasal secretions and inflammation in comparison to lung tumors, which tend to be well delineated ( Table 2 ).…”

“…Volumetric tumor measurements from segmented volumes were considered most accurate and were used for our statistical analyses. However, contouring of tumors can be time-consuming and requires additional software [ 37 ]. There was very strong correlation between contoured volumes and maximum axial diameter and those measurements obtained from the radiologist’s assessment.…”

Dose‐escalated simultaneously integrated boost radiation protocol fails to result in a survival advantage for sinonasal tumors in dogs

“…The contour‐based volume response determination by Nell et al. was used 23 . Recheck CT was recommended 6 and 12 months after the end of radiation therapy.…”

“…Descriptive statistics such as absolute/relative frequencies and mean/median and standard deviation/IQR were computed. PFS was defined as the interval between first RT and either recurrence of clinical nasal signs or imaging PD (whichever occurred first) or death 23 . Dogs alive and free of progression at the time of data evaluation were censored.…”