Thyroidectomy in dogs with thyroid tumors: Survival analysis in 144 cases (1994‐2018)

Abstract Background Few studies have assessed predictors of outcome in dogs with thyroid tumors undergoing thyroidectomy. Objective To estimate the survival and identify prognostic factors in dogs with thyroid tumors treated by thyroidectomy. Animals A total of 144 client‐owned dogs with thyroid neoplasia that underwent thyroidectomy. Methods Retrospective study. Data for analysis included hospital attended and year of surgery, signalment, thyroxine concentration, thyroid tumor features (lobe involvement, size, invasiveness, histopathological type), thrombosis, metastasis, additional surgery and therapy, administration of adjuvant chemotherapy. The association of predictors with survival (time from surgery to death) were assessed by calculating cause‐specific hazard ratios (HRcs) and 95% confidence intervals (CI). Causes of death were classified as thyroid‐related or because of other cause. Results Overall median survival time was 802 days (CI95% = 723‐1015 days); 89 dogs (77.4%) survived >500 days. Metastases were identified at admission in 12 (8.3%) dogs and were associated with higher thyroid cancer‐related fatality (HR = 5.83, CI95% = 1.56‐21.78; P = .009). Thrombosis occurred in 40 dogs and was associated with increased risk of death because of other cause (HR = 2.73, CI95% = 1.18‐6.35; P = .019). Nonfollicular carcinoma (HR = 4.17, CI95% = 1.27‐13.69; P = .018) and administration of chemotherapy (HR = 3.45, CI95% = 1.35‐8.82; P = .01) were associated with higher risk of thyroid cancer‐related death. Conclusions and Clinical Importance Dogs with thyroid tumors undergoing thyroidectomy have a long life expectancy. Despite the rare presence of nonfollicular carcinoma and metastases, thyroidectomy should still be considered in some of these dogs

Immunohistochemical study of STAT3 expression in feline injection-site fibrosarcomas

STAT3 (signal transducer and activator of transcription 3) is a cytoplasmic transcription factor that plays a role in the G1 to S phase cell-cycle transition and is induced by cytokines and growth factors. In the present study, the relation between histological grade and anti-STAT3 immunoreactivity was evaluated in 39 feline injection-site sarcomas treated surgically, 24 of the cats having received preoperative treatment with doxorubicin. Anti-STAT3 immunoreactivity was significantly lower in cases receiving preoperative doxorubicin, specifically with regard to nuclear localization. Moreover, STAT3 expression (intranuclear) was significantly correlated with mitotic activity in the animals that did not receive doxorubicin (P=0.019), and with differentiation score (P=0.009). STAT3 expression was correlated with the histological grade in both doxorubicin-treated and -untreated cats; in the treated cats, however, this correlation applied only to cytoplasmic STAT3 (P=0.018). Doxorubicin treatment induced a significant decrease in STAT3 expression (nuclear, P=0.0001; cytoplasmic, P=0.033) as compared with cases treated by surgery alone. These findings support existing evidence from human and experimental pathology on the potential role of STAT3 in oncogenesis and tumour progression