Clinical and computed tomography tumour dimension assessments for planning wide excision of injection site sarcomas in cats: how strong is the agreement?

Abstract

In injection site sarcoma (ISS) in cats lateral as well as deep margins should be correctly planned for a successful surgical outcome. The discrepancy between clinical and computed tomography (CT) measurements of dimension in resectable tumour has led to possible bias that affects the subsequent surgical dose. The aim of this study was to prospectively investigate the agreement between clinical and CT measurements of dimension in newly diagnosed ISS in cats. Fifty-three client-owned cats that underwent both clinical and CT measurements of the length and width of ISS were included. CT measurements showed a tendency towards being larger than clinical dimensions, and this difference increased with increasing tumour size. Based on our results, in further studies focusing on ISS in cats, the kind of assessment used to define tumour dimensions (CT versus clinic) should be declared and specified to properly consider surgical results and prognostic impact of this variable.

Quantification of surgical margin length changes after excision of feline injection site sarcomas—A pilot study

“…Post‐fixation GNSM measurements were an average of 3 mm larger than CT‐derived measurements (data not shown). Although relatively small, this is consistent with recent literature indicating that CT overestimates FISS tumor size and therefore would underestimate lateral margin length . The net effect of this potential discrepancy is that the influence of formalin‐fixation on lateral margin length decrease may be even smaller than reported here.…”

Current knowledge on feline injection-site sarcoma treatment

“…Thoracic radiography is performed to exclude metastases to the lungs, which occur in 10–24% of FISS cases. CT has proven useful not only in planning peripheral excision margins [ 16 , 21 , 24 ] but also for the patient following surgical excision because it can provide information about the area that needs to be re-excised or included in the radiation treatment field [ 25 ].…”

Dynamic tomographic studies of interscapular feline injection-site sarcoma: essential or useless practice?

“…The assessment of tumour dimensions using a clinical calliper has shown wide limits of agreement compared with CT, with increased variability for neoplasms with increased size. 10 Both CT and MRI were described as useful tools for the investigation of FISS; [7][8][9] however, CT is commonly used because of its ability to characterise and stage a tumour within the same scan. [8][9][10] Moreover, multiplanar reconstructions represent an important advantage for the correct estimation of tumour volume, reducing the gap between tomographic volumetric measurements and histopathology.…”

“…1 CT is commonly applied to achieve a better understanding of the relationship with the adjacent musculoskeletal structures and for assessment of the deep margins. 8,10 There are few published studies concerning new imaging strategies for specifically defining the anatomy of the region, 11 and consequently its margins, or for computing the real volume of the neoplasm, which increase the agreement with histopathological measurements. 10,12 Moreover, the effects of formalin fixation on the assessment of tumour volume were investigated by comparing CT measurements with histopathology.…”