Urothelial carcinoma of the renal pelvis — a cancer inside the kidney that is not kidney cancer

The renal pelvis is the funnel-shaped chamber inside each kidney where urine collects before it drains away down the ureter. It is lined by urothelium, the same lining that continues along the ureter and covers the inside of the bladder. A cancer that begins in that lining is a urothelial carcinoma, and when it starts in the renal pelvis it is called upper tract urothelial carcinoma. Older reports may call it transitional cell carcinoma, which is the same thing under an earlier name. It sits inside the kidney, so scans and records file it under kidney cancer, but it is a different disease from renal cell carcinoma, which begins in the filtering tissue of the kidney itself.

Only in the sense that it grows inside the kidney. Renal cell carcinoma, which accounts for most kidney cancers, starts in the tiny filtering tubes of the kidney. Urothelial carcinoma of the renal pelvis starts in the lining of the urine-collecting system, and that lining runs on into the ureter and the bladder without a break. Because the cell of origin is the same one that gives rise to bladder cancer, the tests used, the way the tumour is graded, the operation usually recommended and the systemic treatment pathway all follow urothelial practice rather than renal cell practice. If your report says urothelial or transitional cell carcinoma, material written about renal cell carcinoma will not describe your situation accurately.

Most often it begins with blood in the urine, either visible or found on a routine test. CT urography is the main imaging study, because it shows the collecting system filling with contrast and can reveal the filling defect where a tumour sits. Urine cytology looks for abnormal urothelial cells shed into the urine and is more informative for high-grade disease than for low-grade. The diagnosis is usually confirmed at ureteroscopy, where a fine telescope is passed up to inspect the lining directly and take a biopsy. CT, MRI, ultrasound, urine cytology and blood work are delivered in-house at CION; ureteroscopy is coordinated with specialist urology partners.

For a high-grade, invasive or bulky tumour the long-standing standard is removing the kidney together with the whole ureter and a cuff of bladder around the point where the ureter joins it, because any of that lining left behind is where the tumour tends to return. Selected small, low-grade, single tumours can sometimes be treated through the ureteroscope instead, keeping the kidney. Kidney and ureter surgery, robotic surgery and endoscopic procedures are not in-house CION services: we coordinate them with specialist urology and uro-oncology partners, where they may also be billed. Chemotherapy, immunotherapy and radiation, where they are needed, are delivered in-house and planned along NCCN lines.

Because the same lining runs from the renal pelvis all the way down into the bladder, and a tumour in one stretch of it is a signal that the rest of the lining is at risk. Recurrence in the bladder after treatment for an upper tract tumour is common enough that scheduled cystoscopy, a look inside the bladder with a telescope, becomes a routine part of follow-up for years, alongside imaging of the remaining kidney and its ureter. Cystoscopic surveillance is coordinated with our specialist urology partners; the imaging, blood tests and survivorship care around it are in-house. Skipping surveillance because you feel well is the main avoidable risk.

Sometimes. Kidney-sparing treatment is considered when the tumour is low-grade, small, confined to one spot and reachable in full through a ureteroscope. It is also weighed up when the other kidney is missing or already working poorly, or when kidney function would fall too far after removal, because preserving function can matter more than the higher chance of the tumour coming back in the same tract. The trade-off is a demanding follow-up schedule of repeated endoscopic checks. This is a decision for a tumour board that has seen your grade, your imaging and your kidney function, not for a rule of thumb, and NCCN sets out the pathway it is argued along.