Abstract

Elasmobranchs experience neoplastic disease in a variety of body systems, and prevalence of neoplasia in this taxon ranges from 0.5–4%.^1-9 It is suspected that rates are higher but have not been well-elucidated due to paucity of literature. Additionally, research on chemotherapeutic drug usage and dosing in aquatic animals is minimal in comparison to domestic species.¹⁰ Due to the potential narrow margins of safety, chemotherapeutic drugs are typically dosed in milligrams per square meter (mg/m²), requiring body surface area (BSA), a calculated measure based on a pre-determined K constant. The objective of this study was to use BSA obtained via computed tomography (CT) to calculate the K constant and provide a formula for BSA based on morphometric measurements (i.e., weight) in Atlantic stingrays (Dasyatis sabina). Six deceased Atlantic stingrays of unknown age and a range of sizes collected during a natural mortality event were utilized—three males, three females. All animals were physically examined, and morphometric measurements (mean±SD; range) obtained including thawed body weight (1743.33±1482.47; 390–4540 grams) and disc width (33.42±8.19; 23–47 cm). All animals appeared to be in appropriate body condition. Animals then received a CT scan, and a 3D surface model was reconstructed from imaging data to measure BSA (Mimics Innovation Suite, Materialise NV, Leuven, Belgium). Non-linear regression analysis of BSA versus thawed body weight was performed, and a species-specific formula derived. A two-sample t-test of pooled variance and t-distribution was used to compare K constant between sexes. Mean±SD; range BSA was 2015.01±1115.02; 844.2–4043.12 cm². The calculated K constant was 14.9 for the six Atlantic stingrays, and the CT-derived BSA formula was as follows: BSA in cm² = 14.9 × (body weight in grams)^⅔. There was no significant difference between K constant when comparing male versus female. These results provide a minimally invasive method to calculate BSA in this species, and this information could be used for allometric dosing of chemotherapeutic agents in Atlantic stingrays and other similarly shaped species.

Acknowledgments

Authors thank Nick Dannemiller for ideation of the project, park ranger Benjamin Fleming and all staff at Fort Macon State Park that assisted with cadaver collection, and the Exotic Species Cancer Research Alliance (ESCRA) for their support that made this research possible.

*Presenting author
+Student presenter

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