Table 1

World Health Organization clinical staging of canine urinary bladder tumors

T: primary tumor
 Tis Carcinoma in situ
 T0 No evidence of tumor
 T1 Superficial papillary tumor
 T2 Tumor invading the bladder wall with induration
 T3 Tumor invading neighboring organs
N: regional node (RLN)
 N0 No evidence of RLN involvement
 N1 RLN involved
 N2 RLN and juxta RLN involved
M: distant metastasis
 M0 No evidence of distant metastasis
 M1 Distant metastasis detected