Upper Urinary Tract Urothelial Cell Carcinoma

4. STAGING AND CLASSIFICATION SYSTEMS

4.1. Classification

The classification and morphology of UTUC and BC are similar [1]. However, because of the difficulty in adequate sample acquisition, it is often difficult to distinguish between non-invasive papillary tumours [93], flat lesions (CIS), and invasive carcinoma in biopsies. Therefore, histological grade is often used for clinical decision-making as it is strongly associated with pathological stage [94].

4.2. Tumour, Node, Metastasis classification

Table 1 shows the TNM classification [95]. The regional LNs are the hilar and retroperitoneal nodes and, for the mid- and distal ureter, the pelvic nodes. Laterality does not affect N classification.

4.3. Tumour grade

In 2004 and 2022, the World Health Organization (WHO) published a new histological classification of UCs that provides a different patient stratification between individual categories compared to the older 1973 WHO classification [96-98]. These Guidelines are still based on both the 1973 and 2004/2016 WHO classifications since most published data use the 1973 classification [93].

Table 1: Tumour, Node, Metastasis classification 2025 for upper tract urothelial cell carcinoma [95]