Ureter cancer, technically known as upper tract urothelial carcinoma (UTUC), is a malignancy that develops in the lining of the ureters, which are the two narrow tubes that transport urine from the kidneys to the bladder. The inner surface of the ureter is lined with transitional cells, classifying this cancer as urothelial carcinoma. UTUC is rare compared to bladder cancer, accounting for only about 5 to 10 percent of all urothelial malignancies.
Causes and Risk Factors
The development of ureter cancer is driven by genetic changes within the urothelial cells, though the precise trigger is often linked to chronic exposure to carcinogens. The most significant risk factor is tobacco smoking, as toxic chemicals are filtered by the kidneys and concentrated in the urine, directly exposing the ureteral lining to damage.
Occupational exposure to certain chemicals also plays a significant role, particularly in industries involving dyes, rubber, and textiles. Specific aromatic amines are known carcinogens processed through the urinary system. Chronic irritation from recurrent kidney stones or long-standing kidney disease can also promote malignant transformation. Furthermore, a history of bladder cancer increases the risk, and inherited conditions like Lynch syndrome also predispose individuals to this malignancy.
Recognizing Common Symptoms
The most frequent sign is hematuria, or the presence of blood in the urine, which occurs in up to 90 percent of cases. This bleeding is often intermittent and painless, meaning the urine may appear pink, red, or cola-colored. This visible blood should always be evaluated by a medical professional.
Flank or back pain is another common symptom, typically presenting as a dull ache or discomfort between the ribs and the hip. This pain arises when the tumor partially or completely blocks the flow of urine down the ureter. The resulting backup causes swelling and pressure in the kidney, known as hydronephrosis. Less common symptoms include increased frequency, urgency, or a burning sensation during urination, which can mimic a urinary tract infection.
Diagnosis and Disease Staging
Diagnosis begins with non-invasive tests, including urine cytology, where a sample of urine is examined under a microscope for abnormal cells shed from the tumor. Blood tests are also performed to evaluate overall kidney function and liver health. Imaging studies are fundamental for visualizing the urinary collecting system, most commonly involving a Computed Tomography (CT) urogram. This scan uses an injected contrast dye to create detailed images of the kidneys, ureters, and bladder, helping to identify the tumor’s size and location.
The definitive diagnosis and determination of tumor grade require a direct visual examination and tissue sampling. This is achieved through ureteroscopy, where a thin, lighted scope is passed through the urethra and bladder into the ureter to visualize the tumor and perform a biopsy.
Once the cancer is confirmed, it is formally staged using the TNM (Tumor, Node, Metastasis) system to guide treatment planning. This staging classifies the tumor (T) based on how deeply it has invaded the ureteral wall, assesses if it has spread to nearby lymph nodes (N), and determines if it has spread to distant organs (M).
Staging Levels
- Stage I: Cancer is confined to the sub-epithelial connective tissue.
- Stage II: Cancer has invaded the muscle layer of the ureter.
- Stage III: Cancer has invaded the fat surrounding the ureter.
- Stage IV: Cancer signifies spread to adjacent organs or distant sites.
Treatment Approaches
The selection of a treatment approach depends on the tumor’s stage, grade (aggressiveness), location, and the patient’s overall kidney function. For high-grade or invasive disease, the standard surgical procedure is a radical nephroureterectomy. This operation involves the complete removal of the affected kidney, the entire ureter, and a small cuff of the bladder to ensure all cancerous tissue is excised.
In cases of low-grade, non-invasive tumors, or for patients with poor kidney function, a nephron-sparing approach is preferred to preserve renal capacity. These options include endoscopic resection or laser ablation, where the tumor is removed or destroyed using instruments passed through the ureteroscope. Segmental ureterectomy involves surgically removing only the affected portion of the ureter before reattaching the healthy ends.
Systemic treatments are incorporated for more advanced or high-risk cancers. Neoadjuvant chemotherapy, typically cisplatin-based, may be given before surgery for locally advanced disease to shrink the tumor and improve outcomes. Adjuvant chemotherapy is administered after surgery to eliminate any remaining cancer cells. Immunotherapy drugs, such as checkpoint inhibitors, are used for advanced or metastatic ureter cancer.