Paraneoplastic syndromes are rare conditions that can occur alongside cancerous tumors. Sometimes, tumors release substances that cause your body’s organs and body systems to behave abnormally. Or your body’s attempt to destroy a tumor can cause unintended damage to healthy tissue. The damage can cause the symptoms of a paraneoplastic syndrome.
A paraneoplastic syndrome is a set of signs and symptoms that can occur when you have cancer. The symptoms develop when a malignant tumor causes changes in your body that aren’t directly caused by the cancer itself. The tumor may secrete a hormone or protein that affects a particular body system. Often with paraneoplastic syndromes, your immune system releases antibodies to destroy the tumor. During this process, the antibodies also damage healthy cells (autoimmune response).
Paraneoplastic syndromes can affect multiple body systems and organs, including your nervous system, endocrine system (hormones), kidneys, bones, joints, skin and blood, etc.
Often, the symptoms of a paraneoplastic syndrome are the first signs of cancer.
You’re more likely to have a paraneoplastic syndrome if you’re middle-aged or older and you have lung, lymphatic, ovarian or breast cancer. The same factors that increase your cancer risk can increase your chances of developing a paraneoplastic syndrome.
About 8% to 20% of people with cancer develop paraneoplastic syndromes.
Anyone with a cancerous tumor can develop a paraneoplastic syndrome. The types of cancer most commonly associated with paraneoplastic syndromes are:
Some cancerous tumors secrete substances, like hormones or proteins, that cause certain organs in your body to work atypically. As a result, you may experience symptoms that wouldn’t occur without the tumor. These substances can permanently damage an organ or system without treatment.
Often, paraneoplastic syndromes occur because your body’s immune system mistakenly harms healthy tissue. Your immune system makes a substance called antibodies. Antibodies protect you from disease by identifying and destroying abnormal cells, like cancer cells. Sometimes, the signals get crossed, and antibodies attack healthy cells and tissue instead, causing symptoms associated with a paraneoplastic syndrome.
Symptoms of paraneoplastic syndromes vary depending on the organ systems affected. In more than half of cases (60%), people experience symptoms before receiving a cancer diagnosis. Identifying a paraneoplastic syndrome early can help your healthcare provider diagnose cancer in its early stages when it’s easiest to treat.
Common symptoms of a paraneoplastic syndrome include:
Paraneoplastic syndromes that affect particular organs or body systems may cause system-specific symptoms.
Paraneoplastic syndromes affecting your central nervous system (brain, spinal cord) and your peripheral nervous system (nerves outside of your brain and spinal cord) may cause:
Paraneoplastic syndromes affecting your endocrine system may cause:
Paraneoplastic syndromes affecting your joints, bones, muscles and connective tissue may cause:
Paraneoplastic syndromes affecting your skin may cause:
There are several paraneoplastic syndromes, including those that affect your nervous system, endocrine system, joints, blood, skin, kidneys, etc.
Paraneoplastic glomerulonephritis is a paraneoplastic syndrome that affects your kidneys.
Your healthcare provider will diagnose paraneoplastic syndromes with a medical history, physical exam and several tests.
Your healthcare provider will treat the underlying cancer that’s causing your symptoms. They’ll also work to manage your symptoms to decrease any damage to your body’s organs or systems.
Therapies used to manage paraneoplastic syndromes include:
Your prognosis mostly depends on your cancer. In some instances, paraneoplastic syndromes cause mild, temporary symptoms. In others, paraneoplastic syndromes cause severe symptoms that must be managed long-term.
Talk to your healthcare provider about how your stage of cancer and response to treatment will affect your prognosis.
You may experience a broad range of complications, some of which are minor and some that may be more serious or even life-threatening without treatment. Your healthcare provider will discuss potential complications and treatment options with you.
Contact your healthcare provider if you notice symptoms of a paraneoplastic syndrome that don’t have a clear cause. If you’re experiencing symptoms and you’ve been treated for cancer within the last five years, it’s a good idea to get re-screened. Re-screening can alert your provider that the cancer has returned.
Questions to ask your healthcare provider include:
A note from Cleveland Clinic
Cancerous tumors cause unexpected changes in your body, including (sometimes) the symptoms of a paraneoplastic syndrome. There are multiple syndromes, and the symptoms are varied. As a result, it may take time for your healthcare provider to recognize your symptoms as cancer-related. Once they confirm your diagnosis, they can recommend treatments to address your symptoms and, most importantly, treat the underlying tumor causing the problem. Receiving the most effective cancer treatments provides the best outlook for managing a paraneoplastic syndrome.
Last reviewed by a Cleveland Clinic medical professional on 09/06/2022.
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