Paraneoplastic Syndrome: Specialists & Information

Various accompanying symptoms can occur in the context of cancer that are not caused by the tumor itself. This means, for example, that the symptoms are not due to tissue destruction caused by the tumor. Instead, they are triggered by signaling molecules—such as hormone-like substances—produced by the tumor cells.

Generally, a distinction can be made between general and specific paraneoplastic syndromes.

General paraneoplasias include, for example, severe fatigue and significant weight loss. In medicine, this is also referred to as tumor cachexia. General paraneoplasias occur in the majority of cancer patients.

Specific paraneoplasias, on the other hand, include tumor-specific accompanying symptoms. The specific symptoms present often allow for the identification of a particular tumor type. Paraneoplastic functional disorders are frequently an early sign of a malignant tumor.

This group of paraneoplasias includes endocrine paraneoplasias, such as bronchial carcinoma. It can produce the hormones erythropoietin or calcitonin.

The nature of the symptoms associated with specific paraneoplasias depends primarily on the signaling molecules produced by the tumor.

The most common endocrine paraneoplasia is bronchial carcinoma, which produces excess parathyroid hormone. Parathyroid hormone is normally produced in the parathyroid glands and is responsible for maintaining calcium balance in the blood. Increased production leads to bone loss and calcification of blood vessels.

If, on the other hand, the cancer cells produce the hormone TSH (thyrotropin), this leads to hyperthyroidism with symptoms such as

• hair loss,
• heart palpitations,
• nervousness, or
• diarrhea.

Low blood sugar (hypoglycemia) with symptoms such as

• trembling,
• nausea,
• restlessness,
• aggression, or
• dizziness

may be a sign of increased insulin production. Such hyperinsulinemia occurs, for example, in cases of cancer of the liver or pancreas.

Another type of paraneoplasia involves antibody-mediated reactions. In these cases, the immune system produces antibodies against the cancer. However, these antibodies also attack healthy tissue. Doctors refer to this as cross-reactivity. This cross-reactivity can lead, for example, to inflammation of the brain (encephalitis) in the context of a tumor, with the following symptoms:

• impaired consciousness,
• hallucinations,
• neurological deficits,
• seizures,
• disorientation,
• vomiting.

Antibody-mediated paraneoplasias also include

• aplastic anemia,
• dermatomyositis,
• Zollinger-Ellison syndrome, and
• Lambert-Eaton syndrome.

Fatigue can be a symptom of a general paraneoplastic syndrome © sebra | AdobeStock

Depending on the type of primary tumor, paraneoplastic symptoms can vary greatly. Often, these symptoms appear as early signs before the cancer has been detected. For example, antibody-mediated neurological paraneoplasia can precede the actual tumor disease by years.

This often makes diagnosis difficult. Therefore, whenever a symptom cannot be clearly explained by a specific disease, paraneoplasia should be considered.

If antibody-mediated paraneoplasia is suspected, the treating physician will test for antibodies in the blood—even if no tumor has been diagnosed yet. Various antibodies are associated with specific tumors. For example, Hu antibodies are found in prostate cancer, whereas ANNA-3 antibodies indicate lung cancer.

Evidence of hormone-mediated paraneoplastic syndrome can also be found in the blood. In such cases of endocrine paraneoplasia, levels of the corresponding hormone are elevated in the blood. However, such a hormonal imbalance can also have other causes. For this reason, endocrine paraneoplasia is often a diagnosis of exclusion.

If the doctor suspects paraneoplasia as the cause of the symptoms, a tumor search is always performed. Various diagnostic tools are used for this purpose, such as

• X-rays,
• MRI,
• CT, or
• ultrasound

are used. Other procedures in cancer diagnostics include:

• endoscopy,
• scintigraphy,
• positron emission tomography (PET),
• the collection (biopsy) and pathological examination of cell and tissue samples.

Treatment depends primarily on the type of tumor and its grade of malignancy. This grade describes the growth and differentiation of tumors and neoplasms. The term “neoplasm” is often used synonymously with a malignant tumor.

Paraneoplastic syndrome can only be successfully treated by addressing the primary tumor. The physician often achieves initial success simply by reducing the tumor’s size. Chemotherapy and radiation therapy are the primary treatments used for this purpose.

In most cases, surgical removal of the underlying tumor can completely eliminate the associated paraneoplastic symptoms. Antibody-mediated paraneoplasias are an exception to this rule. Even after the tumor has been removed, antibodies may remain in the blood and cause symptoms.

In addition to tumor-specific treatment strategies, doctors also employ nonspecific measures. Depending on the type and severity of the symptoms, patients are prescribed medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or opioids for pain relief.

The diagnosis and treatment of paraneoplastic syndrome fall within the field of oncology. Oncology is the medical specialty that deals with cancer. Oncology includes

• prevention,
• diagnosis,
• treatment, and
• follow-up care

of cancer and its associated symptoms.

Oncology is a complex field. For this reason, it is typically characterized by interdisciplinary collaboration. In oncology, for example,

• radiologists,
• pathologists, and
• pain management specialists.

To be licensed to practice in the field of oncology, a physician must complete further training to become a specialist in hematology and oncology after earning a medical degree. This training lasts a total of six years and covers, among other things, diagnostic and therapeutic procedures in hematology and oncology.