Transitional cell carcinoma (TCC) is the most common urinary tract tumor in dogs and research suggests that it may becoming more common.
Generally, TCC occurs in older dogs (mean age 11 years) and it occurs in females more frequently than in males. The increasing incidence of TCC may be related to pet obesity, use of topical pesticides for fleas/ticks, or environmental pollutants. (Mutsaers AJ, Widmer WR, Knapp DW. Transitional Cell Carcinoma. J Vet Intern Med 2003: 136-144).
Several drugs have been reported to alter thyroid function tests in dogs. These include glucocorticoids, potentiated sulfonamides and anticonvulsants, such as phenobarbital. Many other drugs have been reported to affect thyroid function in humans and other species.