For people living with neuroendocrine tumors (NETs), it’s common to experience symptoms that change over time, like fatigue, shortness of breath, or reduced stamina, all of which may seem like an expected part of living with cancer or receiving treatment. But in some cases, these symptoms may point to a different condition altogether: carcinoid heart disease.
Carcinoid heart disease is a serious but treatable complication that can occur in some people with carcinoid syndrome. While it is relatively uncommon, recognizing the warning signs early and monitoring heart health can help prevent permanent valve damage and improve long-term outcomes.
Here’s what every patient and caregiver should know.
What Is Carcinoid Heart Disease?
Carcinoid heart disease occurs when hormones released by certain neuroendocrine tumors, particularly serotonin, damage the heart valves over time. Unlike many forms of heart disease that affect the heart muscle or arteries, carcinoid heart disease primarily affects the valves that regulate blood flow through the heart. As these hormones circulate over many years, they can cause the valves to become thickened, stiff, and unable to open and close normally.
The condition most often affects the tricuspid and pulmonary valves on the right side of the heart because blood carrying these hormones reaches the right side first before traveling to the lungs, where many of the hormones are broken down.
Who Is Most at Risk?
Not everyone with a neuroendocrine tumor will develop carcinoid heart disease. The condition is most often seen in patients with carcinoid syndrome, particularly those who have persistently elevated serotonin levels or high urine 5-HIAA measurements over time, but patients with hormone-producing metastatic tumors may also have a higher risk.
The good news is that advances in NET treatment have improved hormone control, reducing the number of patients who develop severe carcinoid heart disease compared with previous decades.
Symptoms Can Be Easy to Miss
One of the biggest challenges is that the symptoms often develop slowly and can easily be mistaken for other causes.
Common symptoms include:
- Shortness of breath during activity
- Fatigue
- Difficulty climbing stairs
- Reduced exercise tolerance
- Swelling in the legs or ankles
- Abdominal swelling caused by fluid buildup
Many patients assume these symptoms are simply part of living with cancer, getting older, or becoming less active. As a result, heart valve disease may progress before it is recognized.
If symptoms become worse over time or begin interfering with daily activities, it’s important to discuss them with your healthcare team rather than assuming they are expected.
A Patient’s Story: “I Really Feel Like I Got My Life Back.”
Jill Sampson understands how easily carcinoid heart disease can be overlooked.
Before receiving her diagnosis, she visited numerous physicians searching for an explanation for her worsening symptoms. Walking uphill became difficult. Climbing stairs left her breathless. Activities she once enjoyed gradually became impossible.
It wasn’t until she met with her NET specialist that cardiac testing revealed severe carcinoid heart disease affecting two of her heart valves.
After undergoing valve replacement surgery, Jill slowly recovered and was able to return to many of the activities she had missed.
As she shared during our FLaNET Carcinoid Heart Disease educational webinar:
“I really feel like I got my life back.”
Her story is an important reminder that worsening symptoms deserve attention and that effective treatment is available.
How Is Carcinoid Heart Disease Diagnosed?
The primary screening tool is an echocardiogram, an ultrasound that allows physicians to evaluate how well the heart valves are functioning.
Depending on an individual’s situation, additional evaluation may include:
- Urine 5-HIAA testing
- Blood tests that assess cardiac stress
- Transesophageal echocardiography (TEE)
- Other cardiac imaging when appropriate
Patients with carcinoid syndrome or persistently elevated serotonin levels may benefit from routine heart monitoring, even before symptoms develop.
Why Early Detection Matters
Heart valve damage often progresses gradually, but once significant damage occurs, it cannot be reversed with medication alone.
Fortunately, valve replacement surgery has become highly successful for appropriately selected patients. Combined with ongoing management of the underlying neuroendocrine tumor, many patients experience meaningful improvements in symptoms and quality of life.
Because of this, experts encourage patients and providers to monitor for signs of carcinoid heart disease before symptoms become severe.
Questions to Ask Your Healthcare Team
If you have carcinoid syndrome or hormone-producing NETs, consider asking your care team:
- Am I at risk for carcinoid heart disease?
- Should I have regular echocardiograms?
- How often should my urine 5-HIAA levels be checked?
- Could my fatigue or shortness of breath be related to my heart?
- Should I see a cardiologist familiar with neuroendocrine tumors?
Staying Informed Through FLaNET
Understanding the potential complications of neuroendocrine tumors empowers patients to recognize symptoms earlier and have informed conversations with their healthcare team.
At FLaNET, we’re committed to providing trusted educational resources that help patients and caregivers better understand every stage of the NET journey. Explore our webinars, educational guides, and community resources to stay informed about the latest advances in neuroendocrine tumor care. You’re not in this alone.