Urothelial carcinomas are the sixth most common tumours in developed countries. They can be localised in the lower (bladder and urethra) and/or the upper (pyelocaliceal cavities and ureter) urinary tract. Bladder tumours account for 90–95% of UCs and are the most common urinary tract malignancy.
Upper urinary tract UCs are uncommon and account for only 5–10% of UCs with an estimated annual incidence in Western countries of almost two cases per 100,000 inhabitants. This rate has risen in the past few decades as a result of improved detection and improved bladder cancer (BC) survival.
Pyelocaliceal tumours are approximately twice as common as ureteral tumours and multifocal tumours are found in approximately 10–20% of cases. The presence of concomitant carcinoma in situ of the upper tract is between 11% and 36%. In 17% of cases, concurrent BC is present whilst a prior history of BC is found in 41% of American men but in only 4% of Chinese men.
This, along with genetic and epigenetic factors, may explain why Asian patients present with more advanced and higher-grade disease compared to other ethnic groups. Following treatment, recurrence in the bladder occurs in 22–47% of UTUC patients, depending on initial tumour grade compared with 2–5% in the contralateral upper tract.
A retrospective international registry including data from 2,380 patients from 2014 to 2019 (101 centres in 29 countries) confirmed that UTUC patients were predominantly male (70.5%) and 53.3% were past or present smokers. The majority of patients (58.1%) were evaluated because of symptoms, mainly visible haematuria.
The latter was confirmed by a meta-analysis pooling 44 studies and showing a pooled incidence rate for UTUC of 0.75% for visible haematuria and 0.17% for nonvisible haematuria. With regards to UTUC occurring following an initial diagnosis of BC, a series of 82 patients treated with bacillus Calmette-Guérin (BCG) who had regular upper tract imaging between years 1 and 3 showed a 8 UPPER URINARY TRACT UROTHELIAL CARCINOMA – LIMITED UPDATE MARCH 2023 13% incidence of UTUC, all of which were asymptomatic, whilst in another series of 307 patients without routine upper tract imaging the incidence was 25%.
A multicentre cohort study (n = 402) with a 50 month follow-up demonstrated a UTUC incidence of 7.5% in NMIBC patients receiving BCG with predictors being intravesical recurrence and non-papillary tumour at transurethral resection of the bladder (TURB). Following radical cystectomy for MIBC, 3–5% of patients develop a metachronous UTUC.