Upper tract tumors develop in the renal pelvis (tissue in the kidneys that collects urine) and the ureters (tubes that carry urine from the kidneys to the bladder). Cancer that originates in the upper urinary tract accounts for less than 1% of cancers of the genitourinary system (reproductive and urinary systems). Upper tract tumors are often associated with bladder cancer.

Types

More than 90% of renal pelvis tumors develop in transitional epithelial cells (surface lining cells). This type is called transitional cell carcinoma (TCC). TCC often develops in multiple areas of the upper urinary tract.

Fewer than 10% of renal pelvis tumors are squamous cell carcinomas, which develop in flat surface cells that line the renal pelvis. Adenocarcinoma, which develops in glandular cells, is extremely rare. These types of renal pelvis tumors are associated with inflammation caused by chronic urinary tract infections and kidney stones.

Incidence and Prevalence

According to the American Cancer Society, incidence of upper tract tumors is about 1-2 cases per 100,000 people each year. Renal pelvis tumors are more common in men and in Caucasians. Peak incidence occurs in the 60- to 70-year age group. The highest incidence is in Balkan countries such as Bulgaria, Greece, Yugoslavia, and Romania.

Bilateral (occurring on both sides) upper tract tumors occur in less than 2% of cases.

Causes and Risk Factors

The cause of upper tract tumors is unknown. A personal history of bladder cancer is the primary risk factor. Smoking cigarettes is also a major risk factor. Smoking may contribute to as many as 60-80% of cases. Other risk factors include the following:

• Age
• Balkan descent
• Chronic urinary tract infections
• Family history of transitional cell carcinoma
• Genetic mutation of the p53 gene
• Overuse of analgesics that contain phenacetin
• Recurrent kidney stones
• Use of chemotherapy drugs cyclophosphamide and ifosfamide

People who work in chemical, petroleum, aniline dye, and plastics industries, and those exposed to coal, tar, and asphalt, also have an increased risk for upper tract tumors. Consuming more than seven cups of coffee a day may slightly increase the risk for the condition.

Signs and Symptoms