Use of 3'-deoxy-3'-[18F]fluorothymidine PET/CT for evaluating response to cytotoxic chemotherapy in dogs with non-Hodgkin's lymphoma.

Abstract

Imaging and measurement of proliferation with computed tomography (CT) and positron emission tomography (PET) provide a noninvasive method for improved staging and monitoring of response to cancer treatment. We evaluated prospectively the proliferation marker 3'-deoxy-3'[18F] fluorothymidine (FLT) in the context of FLT-PET/CT for detection of early response, confirmation of posttreatment response, and prediction of relapse in dogs with non-Hodgkin's lymphoma. Nine dogs with non-Hodgkin's lymphoma who were scheduled to receive five cycles of an investigational cytotoxic chemotherapy agent were included. All dogs received baseline FLT-PET/CT imaging immediately before chemotherapy. Intent was to repeat imaging with FLT-PET/CT at various time points: group 1 (n = 4), 5 days after initiation of chemotherapy and 3 weeks following the last chemotherapy administration; group 2 (n = 5), before the fourth cycle of chemotherapy and 3 weeks following the last administration. Two dogs in group 2 did not undergo repeat PET/CT. Body mass standardized uptake values (SUV) for FLT were calculated for each dog. Eight dogs had initially increased FLT uptake (mean SUVmax = 9.8 [2.6-22.3]). Mean SUV decreased significantly for the seven dogs that underwent follow-up PET/CT following chemotherapy (mean SUVmax = 3.5 [1.1-7.9], P<0.016). Increased uptake preceded clinical and cytological evidence of relapse in two dogs. Ki-67 immunohistochemistry confirmed decreased proliferation corresponding to decreased SUV in three canine lymph node samples. FLT-PET/CT functional and anatomical imaging shows promise for the evaluation of response to cytotoxic chemotherapy in dogs with non-Hodgkin's lymphoma and for predicting relapse before standard clinical and clinicopathologic confirmation.

• Authors: Jessica Lawrence, Matthew Vanderhoek, David Barbee, Robert Jeraj, Daniel B Tumas, David M Vail
• Journal: Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association (Vet Radiol Ultrasound) 2009 Nov-Dec Vol. 50 Issue 6 Pg. 660-8 ISSN: 1058-8183 [Print] England
• PMID: 19999354 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dideoxynucleosides
• Radiopharmaceuticals
• alovudine

Topics

• Animals
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Clinical Trials as Topic
• Dideoxynucleosides
• Dog Diseases (diagnostic imaging, drug therapy)
• Dogs
• Immunohistochemistry (veterinary)
• Lymph Nodes (diagnostic imaging, drug effects)
• Lymphoma, Non-Hodgkin (diagnostic imaging, drug therapy, veterinary)
• Positron-Emission Tomography (veterinary)
• Radiopharmaceuticals
• Secondary Prevention
• Treatment Outcome