18F-FDG—PET/CT in Canine Mammary Gland Tumors

Abstract

Medical imaging techniques play a central role in clinical oncology, helping to obtain important information about the extent of disease, and plan treatment. Advanced imaging modalities such as Positron Emission Tomography–Computed Tomography (PET/CT), may help in the whole-body staging in a single procedure, although the lesions should be carefully interpreted. PET/CT is becoming commonly used in canine cancer patients, but there is still limited information available on specific tumors such as mammary cancer. We evaluated the utility of fluorine-18 fluorodeoxyglucose ( 18 F-FDG)-PET/CT to detect malignant lesions in eight female dogs with naturally occurring mammary tumors. A whole-body scan was performed prior to surgery, and mammary and non-mammary lesions detected either on PET/CT or during pre-surgical physical exam were resected when possible and submitted for histopathological examination. Multiple mammary lesions involving different mammary glands were detected in 5/8 dogs, for a total of 23 lesions; there were 11 non-mammary-located lesions in 6/8 dogs, three of these were lung or lymph node metastasis. A total of 34 lesions were analyzed: 22 malignant (19 mammary tumors and three metastatic lesions), and 12 benign (four mammary lesions and eight of non-mammary tissues). Glucose uptake by maximum standardized uptake value (SUVmax) was analyzed and correlated with tumor size, and benign vs. malignant pathology. We found that the minimum tumor size needed to distinguish malignant lesions according to the SUVmax was 1.5 cm; benign and malignant lesions <1.5 cm did not differ in glucose uptake (mean SUVmax = 1.1). In addition, a SUVmax value >2 was 100% sensitive for malignancy. Combining these data, lesions >1.5 cm with a SUVmax >2 had a positive predictive value of 100%. Finally, we did not find an association between SUVmax and histologic subtype or grade, which may be present in a larger sample. Thus, 18 F-FDG PET/CT is useful for distinguishing malignant from benign lesion but further imaging of dogs with diverse tumors, should establish characteristic SUV value cutoffs for detecting primary and metastatic disease, and distinguishing them from benign lesions.

Evaluation of a dog with inflammatory mammary carcinoma using 18F‐2‐deoxy‐2‐fluoro‐d‐glucose positron emission tomography/computed tomography

“…In humans with IMC, an 18 F‐FDG‐PET/CT pattern of multiple scattered highlighted foci, particularly at the site of cutaneous lesions, is observed; this pattern was also observed in this dog (Baslaim et al., 2003). A previous report of 18 F‐FDG PET/CT in dogs with mammary carcinoma recommended a maximum SUV cut‐off for mammary carcinoma of 2 and maximum SUV range for metastatic lymph nodes of 0.56–2.14 (Sánchez et al., 2019). In this dog, the maximum SUV of the right first mammary gland was 3.62, and mammary carcinoma was therefore suspected.…”

Modern Imaging Techniques in the Study and Disease Diagnosis of the Mammary Glands of Animals

“…Anatomical features, structures or physiological processes can be assessed by employing different imaging methods [ 6 , 7 ]. The main methods used in the imaging of mammary glands of animals include computed tomography, positron emission tomography, magnetic resonance imaging, and ultrasonographic techniques (e.g., B-mode ultrasonography, Doppler ultrasonography, contrast-enchased ultrasonography, three-dimensional ultrasonography, and elastography) [ 2 , 4 , 5 , 8 ].…”

Staging canine patients with appendicular osteosarcoma utilizing fluorine‐18 fluorodeoxyglucose positron emission tomography/computed tomography compared to whole body computed tomography

“…4,9,10 In veterinary medicine, 18 F-FDG-PET/CT has been shown to be an effective staging tool for patients with several different neoplasms, including lymphoma, mast cell tumour, mammary carcinoma, primary lung tumour, histiocytic sarcoma, Sertoli cell tumour and splenic hemangiosarcoma. 7,[11][12][13][14][15] Initial research has also shown that 18 F-FDG-PET/CT is effective for identifying both osseous and soft tissue lesions in dogs afflicted with appendicular osteosarcoma 4 and that the SUV max of the primary lesion is significantly associated with survival time. 10 However, the efficacy of 18 F-FDG-PET/CT has yet to be directly compared to other staging modalities.…”