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 [83], flat lesions (carcinoma in situ [CIS]), and invasive carcinoma in biopsies. Therefore, histological grade is often used for clinical decision making as it is strongly associated with pathological stage [84].

4.2. Tumour Node Metastasis staging

The tumour, node, metastasis (TNM) classification is shown in Table 1 [85]. The regional lymph nodes (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 2016, the WHO and the International Society of Urological Pathology published a new histological classification of UCs which provides a different patient stratification between individual categories compared to the older 1973 WHO classification [86,87]. In 2022, an update of the 2004/2016 WHO grading classification was published without major changes [88]. These guidelines are still based on both the 1973 and 2004/2016 WHO classifications since most published data use the 1973 classification [83].

Table 1: TNM classification 2017 for upper tract urothelial cell carcinoma [85]

TNM = Tumour, Node, Metastasis (classification).