Thyroidectomy in dogs with thyroid tumors: survival analysis in 144 cases
The objective of this study was to estimate the survival and identify prognostic factors in dogs with thyroid tumors treated by thyroidectomy.
Thyroid tumors in dogs have a prevalence of 1-4% among all neoplasms and represent the most common tumor of the neuroendocrine system. Older dogs are affected more frequently, and the beagle, boxer and golden retriever breeds are overrepresented.
Carcinomas are the most frequent thyroid tumors in dogs and, among them, 70% arise from follicular cells (i.e, follicular thyroid carcinomas) and 30% from parafollicular cells (i.e., medullary thyroid carcinomas), both are invasive. Adenomas, on the other hand, are rare in dogs. In dogs, follicular thyroid carcinomas are histologically classified as well-differentiated (i.e., follicular, compact, follicular-compact and papillary), poorly differentiated, undifferentiated and carcinosarcoma (malignant mixed thyroid tumor).
Researchers included a total of 144 client-owned dogs with thyroid neoplasia that underwent thyroidectomy in the 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 (HRs) and 95% confidence intervals (CI). Causes of death were classified as thyroid-related or because of other cause.
Overall median survival time was 802 days (CI95% = 723-1015 days). In addition,
- 89 dogs (77.4%) survived >500 days.
- Metastases were identified by the team 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.
In conclusion, the authors said that 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.
Daniela Enache, et al. “Thyroidectomy in dogs with thyroid tumors: Survival analysis in 144 cases (1994-2018).” J Vet Intern Med. 2023 Feb 27. doi: 10.1111/jvim.16644.
Comments
Related Articles
Copyright © 2025 - All Rights Reserved
ISSN 2768-198X
List
Add
Please enter a comment