DEAR DR. ROACH: No parent should ever outlive their children. A couple of years ago, my son, who is now approaching 54 years young, was diagnosed with what I am told is an extremely rare illness called primary sclerosing cholangitis (PSC). Since he required special bile duct tubes to be installed and repeatedly changed out, he had been waiting for a proper liver transplant.

When this was finally about to happen, the disease apparently morphed into abdominal cancer, thus rendering the (long-awaited) liver transplant no longer viable. I had never heard of this illness before, but recently, a guest on a talk show commented to the host about her mom who was also confronting this incurable condition.

Dr. Roach, having lost my wife (of over 50 years) to breast cancer a few years ago, I am now at an emotional loss. What do you know about PSC, and is it as unusual as all of the treating physicians have indicated?

• J.B.

ANSWER: I am very sorry for this devastating news. PSC is a rare disorder; about 1-2 people per 100,000 will be diagnosed with it in their lifetime in the United States. It is strongly associated with inflammatory bowel disease, especially ulcerative colitis. Because I trained in a program with a very large referral population of IBD, as well as a large and early liver transplant center, I did see many patients with PSC during my training.

PSC is characterized by inflammation in the liver and bile ducts. The underlying mechanism isn’t exactly known but may involve an immune reaction to the bile ducts. Without the movement of bile, there can be additional damage to the liver and bile ducts.

As your experience with your son shows, one goal of treatment is to open up the bile ducts that were damaged by the disease and use a stent to keep them open. Medication therapy, such as ursodeoxycholic acid, can have some benefits but doesn’t improve survival or reduce the need for definitive treatment, which is a liver transplant. A liver transplant is the treatment of choice when people have advanced liver disease.

Unfortunately, there is another problem with PSC, which is its association with cancers. People with PSC are at a higher risk for bile duct (cholangiocarcinoma) and gallbladder cancers, and they should be screened. Once liver disease becomes advanced (cirrhosis), there is also a risk for liver (hepatocellular) cancer.

The lifetime risk for cholangiocarcinoma in people with PSC is approximately 10% to 20%. Another 2.4% of people with PSC will develop hepatocellular carcinoma, almost all of which cases occur in people with cirrhosis. Gallbladder cancer has about a 2% lifetime risk.