Spotlight on capecitabine for the treatment of unresectable or metastatic carcinoma of various origin: A retrospective study of 25 dogs.

Capecitabine, the oral prodrug of 5-fluorouracil, is indicated in people to treat various malignant epithelial cancers. In dogs, capecitabine has not been extensively evaluated. The aim of this retrospective study was to investigate toxicity and preliminary efficacy of single agent capecitabine in dogs with advanced malignant epithelial cancers of any site, for which no effective therapy existed, conventional treatment failed or was declined. Capecitabine was administered orally at 750 mg/m2 from day 1 to 14, followed by 1-week rest period, given as 3-week cycles. Safety evaluation was performed after 2 cycles, and every 2-3 cycles thereafter. Tumour response was determined every 2-3 cycles. Twenty-five dogs with hepatocellular carcinoma (n = 6), lung papillary carcinoma (n = 4), anal sac adenocarcinoma (n = 3), colic adenocarcinoma (n = 2), and other individually represented epithelial cancers (n = 10) were included. Dogs received a median of 4 cycles (range, 2-43) for a median of 84 days (range, 42-913). Toxicity occurred in 17 (68.0%) dogs; the most frequent adverse events were gastrointestinal, with the majority being self-resolving and of mild grade. Of the 22 dogs with macroscopic disease, 3 (13.6%) achieved partial remission, 16 (72.7%) were stable and 3 (13.6%) progressed; overall clinical benefit rate was 86.4%. Median progression-free interval was 93 days (95% CI 42-154; range, 1-521) and median tumour-specific survival was 273 days (95% CI 116-482; range 45-913). These findings suggest that capecitabine is an attractive option for the treatment of several types of carcinomas in dogs. Prospective studies are warranted to optimize the scheduling of capecitabine and confirm its efficacy.

A Retrospective Clinico-Pathologic Study of 35 Dogs with Urethral Transitional Cell Carcinoma Undergoing Treatment.

Chemotherapy and cyclooxygenase inhibitors (COXi) are primary treatments for canine urethral transitional cell carcinoma (uTCC), a tumor known for its aggressiveness and poor prognosis. This retrospective study aimed to evaluate the clinico-pathological characteristics, treatment modalities, and prognostic factors of 35 dogs with confirmed uTCC that received chemotherapy and COXi. Upon admission, urethral obstruction (UO) and urinary tract infection (UTI) were observed in seven (20%) dogs each. Gemcitabine (n = 20; 57.1%) and vinblastine (n = 10; 28.6%) were commonly used as first-line therapies, with four dogs also receiving radiation therapy. Based on RECIST, one (2.9%) dog achieved complete remission, nine (25.7%) partial remission, 20 (57.14%) showed stable disease, and five (14.3%) progressed. Among dogs with UO, six (85.7%) showed resolution or improvement after the first chemotherapy dose. The median time to local progression was 171 days (range: 107-235), and the median survival time was 333 days (range: 158-508). Dogs with UO upon admission had a higher risk of local progression, while both UO and UTI were associated with an increased risk of overall disease progression and tumor-related death. Additionally, gemcitabine significantly improved metastatic control. This study identified UO and UTI as negative prognostic factors, highlighting the importance of a multimodal approach in managing uTCC.

Longitudinal lymph node step-sectioning for the identification of metastatic disease in canine mast cell tumor.

Lymph node (LN) metastasis in canine mast cell tumor (MCT) can affect prognosis and postsurgical treatment recommendations; however, routine histological single-section examination may underestimate the incidence of metastases. This prospective study aimed at determining whether longitudinal step-sectioning of the entire LN allows for a more reliable detection of metastases. Dogs with MCT undergoing resection of the primary tumor and regional lymphadenectomy were enrolled. Formalin-fixed LNs were bisected longitudinally, both halves were embedded in paraffin and histological sections prepared at 200 µm steps. The nodal mast cells were classified according to the Weishaar classification. First-section evaluation (FSE; ie, examination of the first section obtained from the blocks) and whole LN step-section evaluation (SSE) were compared. Fifty-eight LNs were included. The median number of sections per LN was 6 (range, 3-28). FSE with toluidine blue (TB) revealed 27 (47%) nonmetastatic (HN0), 14 (24%) premetastatic (HN1), 9 (15%) early metastatic (HN2), and 8 (14%) overtly metastatic (HN3) LNs. SSE with TB resulted in upgrading the LN status in 2 cases (HN2 to HN3; HN0 to HN1). Evaluation of the first section plus an additional step-section resulted in 100% accuracy. Compared with SSE with TB, the accuracy of FSE with HE was 98% for HN3 LNs and 74% for HN2 LNs. FSE appears to reliably allow for the detection of LN metastasis in MCT, although examination of a further parallel section at a 200 µm step may increase the accuracy. A metachromatic stain is recommended for the identification of early metastases.