Ask the Experts: Winter 2023

Is a kidney cyst cancerous?

As a person ages, sacs filled with fluid, called cysts, can form in the kidneys. There are five different categories of kidney cyst. The majority are class I (simple cyst) and class II (minimally complex). Class I cysts are benign (not cancerous), with no risk of cancer. Although cancers have rarely been reported in class II cysts, the risk of cancer is close to zero.

Simple kidney cysts are fluid-filled round or oval sacs that form in the kidneys. They are usually small, with watery fluid in them. Some people have one cyst, while others have many. Cysts can be found in one kidney or both kidneys. The sacs can range in size from a pea to a softball. These cysts are generally harmless. They do not enlarge the kidneys or affect their function. Simple kidney cysts are more common in people over 50. They are more common in men than in women. It is not known what causes the cysts.

Most people with kidney cysts don’t even know they have them. Kidney cysts are usually found when a person has an imaging test (such as an ultrasound, CT scan or MRI) for another reason. If you are found to have a simple or minimally complex kidney cyst and it isn’t causing problems, your doctor will likely tell you that you don’t need more testing or treatment.

In rare cases, kidney cysts can become large enough to cause problems. If they do cause symptoms, these may include:

• Pain on your side between the ribs and the hip
• Pain in the back
• Fever
• Blood in the urine or dark urine

Complex kidney cysts (Classes III, IV and V) may be associated with cancer and will need to be either watched or treated. If you have symptoms from kidney cysts or complex cysts, your doctor will refer to you a urologist to discuss treatment options.

Dr. Khurshid Ghani, Professor and Director of the Michigan Urological Surgery Improvement Collaborative at University of Michigan, is an endourologist who specializes in the treatment of kidney stones and small kidney tumors.

Can I live with only one kidney?

The short answer is ‘Yes’. One healthy kidney can work as well as two, however it is of great value to stay as healthy as possible throughout your lifetime to protect the remaining kidney.

There are three main reasons why a person may have only one kidney:

1. A person may be born with only one kidney. This condition is called renal agenesis. Another condition, which is called kidney dysplasia, causes a person to be born with two kidneys, but only one of them works. Most people who are born without a kidney (or with only one working kidney) lead normal, healthy lives.
2. A person may have had one kidney removed during an operation to treat an injury or a disease like cancer.
3. A person may have donated one kidney to a person who needed a kidney transplant.

In general, most people with a single, healthy kidney have few problems. However, some long-term problems have been seen in some people.

In some people who are born with a single kidney or had a kidney removed during childhood, there is a chance of slight loss in kidney function later in life. This usually takes 25 years or more to happen. There may also be a chance of high blood pressure later in life. However, the loss in kidney function is usually very mild, and life span is normal. Most people with one kidney live healthy, normal lives with few problems.

Dr. Lindsey Herrel, a urologist at University of Michigan, specializes in kidney cancer, testis cancer, bladder cancer, adrenal cancers, penile and urethral cancer.

What is Upper Tract Urothelial Carcinoma (UTUC) and what is the standard of treatment?

Upper Tract Urothelial Carcinoma (UTUC) is a cancer that affects the inside lining (urothelium) of the kidney (the “collecting system” – where urine starts to drain after it is made by the kidney) and the ureter (the tube that carries urine from the kidney to the bladder). It is different from bladder cancer or the more common type of kidney cancer called renal cell carcinoma, which affects the “meat” of the kidney. UTUC is rare, with an estimated 7,000 new cases in the United States each year.

Men are two to three times more likely than women to get UTUC. It is most likely to occur in people age 70 or older. The biggest risk factor is smoking. Many people with UTUC do not have any symptoms.

They are often diagnosed when they have a urine test for another reason and the test detects blood in the urine that can only be seen under a microscope. If patients have side pain or blood in their urine, the doctor may order a special type of CT scan that focuses on the kidneys and ureter. If the scan suggests the presence of UTUC, the doctor may confirm the diagnosis with a procedure called ureteroscopy.

There are two types of UTUC that both have high rates of returning after treatment:

• Low-grade UTUC is less aggressive. It is less likely to invade deeper into the kidney or to spread to other parts of the body.
• High-grade UTUC is more likely to invade the kidney itself or other organs. It is more likely to spread to other parts of the body.

Low-grade UTUC is treated with:

• Ureteroscopy: This is a minor surgery in which a doctor uses a small camera and a laser, or electrocautery to destroy the tumor. For a larger tumor, the doctor may remove it with small instruments and cameras placed through a small incision in the patient’s side. Because UTUC often recurs, patients may have multiple ureteroscopies in the first year after they are diagnosed to see if the disease has returned.
• Nephroureterectomy: This surgery removes the whole kidney and ureter and a little piece of the bladder where the ureter connects to it.
• Ureterectomy: This surgery is when just a part of the ureter may be removed and the remaining, uninvolved parts of the ureter are sewn back to one another or back to the bladder.
• Medicine: For low-grade UTUC, there are a few medications that may be instilled in the kidney, ureter or bladder. One option is a therapy that combines chemotherapy that goes directly into the kidney using an innovative gel technology.

High-grade UTUC is treated with:

• Medicine and Surgery: One treatment option is four cycles of chemotherapy, followed by nephroureterectomy to remove the whole kidney and ureter and a little piece of
  the bladder. Some of the lymph nodes in the surrounding area of the belly may also be removed.

Dr. Eric Kauffman, a urologist and Associate Professor of Urology at Roswell Park Comprehensive Cancer Center, specializes in renal cell carcinoma (RCC).