Epidemiology and risk factors
Unlike bladder cancer, which predominates in the structure of urothelial tumors (90–95%), upper tract involvement is much less common—approximately 1–2 cases per 100,000 population per year. The disease is more commonly diagnosed in men aged 70–80 years.
The main causes and risk factors include:
- Smoking — the primary risk factor.
- Occupational hazards — exposure to aromatic amines (e.g., benzidine, β-naphthylamine). The latency period can reach 20 years, and about 7 years of exposure are sufficient for tumor development.
- Medications — use of the analgesic phenacetin (banned in the 1970s).
- Endemic factors — Balkan endemic nephropathy and ingestion of aristolochic acid, which causes rapidly progressive renal fibrosis and urothelial damage.
- Heredity — association with Lynch syndrome (HNPCC).
Clinical Course and Prognosis
Most such carcinomas are diagnosed at advanced stages and have a high histological grade (high grade). About 60% of tumors are already invasive at the time of diagnosis.
Prognosis depends primarily on the stage and tumor grade.
- Factors worsening the prognosis include advanced age, ureteral localization, multifocal growth, delay in resection exceeding 12 weeks, high ASA score, and high BMI.
- Independent predictors of survival include lymphovascular invasion and lymph node metastases.
TNM Classification (Summary)
| Grade | Description |
|---|---|
| Ta/Tis | Non-invasive papillary carcinoma / Carcinoma in situ |
| T1 | Invasion into subepithelial connective tissue |
| T2 | Invasion into the muscular layer |
| T3 | Extension beyond the muscular layer (into peripelvic/periureteral adipose tissue or renal parenchyma) |
| T4 | Invasion into adjacent organs or paranephric adipose tissue |
Lymph node involvement (N) is categorized as no regional lymph node metastases (N0), metastasis in a single lymph node <2 cm in greatest dimension (N1), and metastasis in a lymph node >2 cm or multiple lymph nodes (N2).
Diagnostic radiology
The primary complaint of patients is hematuria. To evaluate it and detect the tumor, the following imaging modalities are used:
- CT urography (CTU) — the gold standard. It has high sensitivity (67–100%) and specificity (93–99%).
- MR urography (MRU) — used when CT is contraindicated (iodine allergy, renal failure, need to avoid ionizing radiation).
Various CT urography protocols exist:
- Single-bolus (non-contrast, nephrographic, and excretory phases) — provides superior enhancement.
- Split-bolus — combines the nephrographic and excretory phases to reduce radiation dose, although image quality may be slightly lower.
Treatment approaches
Management tactics depend on risk stratification:
- Gold standard — open radical nephroureterectomy with excision of a bladder cuff. Resection of the distal ureter is mandatory due to the risk of recurrence.
- Laparoscopic approaches reduce blood loss and accelerate recovery, but may be less effective in T3/T4 stages or high-grade tumors.
- Endoscopic management (via ureteroscopy) is feasible in solitary kidneys, bilateral tumors, or small low-grade lesions under strict surveillance.
Briefly: answers to topical questions
What specific radiological and CT features are observed in urothelial cancer of the renal pelvis and ureter?
Urothelial cancer of the renal pelvis and ureter presents as contrast-enhancing mass lesions and filling defects.
- Mass lesion (enhancing mass) — enhances following contrast administration, and may cause dilation of the ureter and pelvicalyceal system proximal to the site of obstruction.
- Filling defect (abrupt filling defect) — fixed, smooth or irregular, solitary or multiple. On antegrade pyelography, it yields the "amputation" or abrupt cutoff sign of contrast medium.
- Focal wall thickening — localized alteration of the collecting system wall.
- Phantom calyx sign (phantom calyx) — occurs due to tumor obstruction of a renal calyx infundibulum (infundibulum).
What diagnostic imaging methods are used to assess distant metastases (M staging) in urothelial cancer?
PET/CT is indicated for assessing distant metastases in urothelial carcinoma. It is utilized when metastasis is suspected based on equivocal CT or MRI findings, as well as when planning radical treatment for oligometastatic disease.
What specific physical methods are used for endoscopic destruction of upper tract urothelial tumors?
Electroneosurgical resection and laser ablation are used for endoscopic destruction of upper tract urothelial tumors.
- Endoscopic electroresection — used as the method of choice for tumors of the renal pelvis as well as the middle and upper caliceal groups utilizing a flexible ureteroscope.
- Laser ablation — is also a method of choice for the destruction of tumors in these locations.
- Percutaneous electroresection/ablation — used for tumors of the renal pelvis and lower calyx when they cannot be removed pyeloscopically; however, this access route carries a higher risk of tumor dissemination.
Class and exam questions
How does its histological grade differ from that of bladder cancer?
Upper tract urothelial cancer frequently exhibits a high grade and invasive behavior even at initial diagnosis.
Which imaging modality is the primary one?
Multiphasic CT urography enables not only the detection of ureteral or pelvic tumors, but also the exclusion of other causes of macroscopic and microscopic hematuria.
Why is a part of the urinary bladder removed during nephroureterectomy?
Excision of the ipsilateral bladder cuff around the ureteral orifice is necessary due to the high risk of tumor recurrence in this region.
What else to study on this topic
- Criteria for patient stratification into low- and high-risk groups
- Optimization of CT urography protocols (single-bolus vs. split-bolus)
- The role of topical therapy (BCG, mitomycin C) following resection
- Challenges of upper urinary tract biopsy (staging underestimation)
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