No abstract

Sentinel lymph node evaluation is widely used in human medicine to evaluate the first lymph node(s) to which a tumor drains. Sentinel lymph node biopsy allows avoidance of extensive lymphadenectomies in cases where the sentinel lymph node is negative for metastasis, thereby reducing patient morbidity. It has been shown that regional lymph nodes are not always the sentinel lymph node, thus identification and sampling of sentinel lymph nodes allows for more accurate staging, which is critical for treatment and prognostication in dogs with cancer. The objective of this prospective, pilot study was to determine if indirect computed tomography (CT) lymphangiography with aqueous contrast agent would successfully allow identification of sentinel lymph nodes in dogs with masses on the head. Eighteen dogs underwent CT lymphangiography. The sentinel lymph node was successfully identified within 3 min of contrast injection in 16 dogs (89%). Compression of lymphatic vessels from endotracheal tube ties and/or the patient's own body weight delayed or prevented identification of sentinel lymph nodes in two dogs (11%). Computed tomography lymphangiography with aqueous contrast can be used successfully to rapidly identify sentinel lymph nodes in dogs with masses on the head.

A 14-year-old spayed female domestic shorthair cat presented with an interscapular mass. A computed tomography scan, biopsy, and histological examination revealed a fibrosarcoma adjacent to a pet identification microchip. Because the cat was previously vaccinated at this site, it is not possible to establish definitive causation of the fibrosarcoma, but this is the first report of a tumor in the vicinity of a microchip in a cat. Microchip-associated tumors have been reported in rodents and dogs. Veterinarians should be aware that because inflammation may predispose felines to tumor formation, separation and observation of vaccination and implantation sites are indicated. Adherence to American Association of Feline Practitioners (AAFP) vaccination guidelines and monitoring of microchip implantation sites are recommended.

Background: The combination of lomustine, L-asparaginase, and prednisone (LAP) is an effective rescue treatment for canine lymphoma (LSA). In a previous study, we reported that remission was typically lost around the time L-asparaginase was discontinued.Hypothesis: Use of L-asparaginase with each lomustine treatment will be well tolerated and efficacious as a rescue therapy for canine LSA.Animals: Forty-eight client-owned dogs with cytologically confirmed multicentric LSA whose disease had relapsed after a cyclophosphamide, doxorubicin, vincristine, and prednisone-based chemotherapy protocol were included.Methods: Lomustine was administered orally at 3-week intervals, concurrently with subcutaneous or intramuscular L-asparaginase for a total of 5 doses or until disease progression. Prednisone was administered at a tapering dose for the duration of the protocol.Results: The overall response rate (ORR) for dogs treated with this protocol was 77%, with 65% achieving a complete response (CR). The median time to progression (TTP) was 70 days. Based on loose comparison, these findings are not significantly different from our previously reported historical control. The actual CCNU dosage administered did not affect response rate or remission duration.Conclusions/Clinical Importance: These findings support previous data concluding that the LAP protocol is a viable rescue treatment option for dogs with LSA. However, results from this study suggest that continued use of L-asparaginase with each lomustine treatment does not significantly increase remission duration and toxicity appears greater.