Hereditary paraganglioma-pheochromocytoma (PGL/PCC), also known as familial paraganglioma-pheochromocytoma syndrome, is a rare genetic condition that increases the riskthe possibility that something bad will happen of developing certain types of cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs, most notably paragangliomas and pheochromocytomas. Paragangliomas and pheochromocytomas are classified as neuroendocrine tumours (NETs).
NETS are a complex group of tumours that develop in the neuroendocrine system, which is responsible for regulating important bodily functions such as heart rate, bloodthe red bodily fluid that transports oxygen and other nutrients around the body pressure and metabolism. They most commonly develop in the gastro-intestinal tract, pancreasa long, flat organ that sits between the stomach and the spine that plays a key role in digestion and blood sugar regulation, and the lungs; however, they can develop anywhere in the body. These tumours develop from neuroendocrine cellsthe basic structural and functional unit of all living things, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response.
Familial cancer syndromes, also known as hereditary cancer syndromes, are rare conditions that cause an increased risk of cancer as the result of inherited genetic mutations in certain cancer-related genes. They can affect both adults and children, however they generally develop in people at a younger age than normal. While familial cancer syndromes are not classified as cancer, they are equally as severe and can be life-threatening as they are associated with the development of various tumours throughout the body. Having a familial cancer syndrome does not guarantee the development of cancer, however the risk of developing cancer is higher than those who do not have a familial cancer syndrome.
PGL/PCC tends to affect the sexes equally, and is often diagnosed in childhood. However, anyone can develop this disease.
PGL/PCC Related Tumours
PGL/PCC is most commonly associated with the development of paragangliomas and pheochromocytomas, however it has also been linked to other types of tumours. Some examples include:
- Paraganglioma.
- Pheochromocytoma.
- Gastrointestinal stromal tumours (GISTs).
- Renal cell carcinoma.
- Thyroid cancer.
- Pulmonary chondromas (benignnot cancerous, can grow but will not spread to other body parts).
Treatment
When cancers are detected, they are staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you. However, each patient with PGL/PCC will present with a unique disease behaviour, with varying tumoura tissue mass that forms from groups of unhealthy cells locations and symptoms. As such, there is no one treatment method that will work for everyone, and there is no standard staging system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:
- Type of tumours present.
- Whether the tumours are malignantcancerous, may grow and spread to other areas of the body (cancerous) or benign (non-cancerous).
- Tumour location.
- Whether or not malignant tumours have metastasised.
- Your age.
- General health.
- Your treatment preferences.
Your doctor may also recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment options for tumours associated with PGL/PCC may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence to remove as much of the tumour(s) as possible – these will vary based on tumour type and location.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Watch and waitthe close monitoring of a cancer without giving treatment until symptoms appear or worsen.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Cancer Screening
Once a diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results of PGL/PCC has been confirmed, implementing a targeted screeningtesting for cancer or conditions that can lead to cancer before symptoms appear, also known as cancer screening plan becomes essential due to the increased risk of developing certain cancers. The content of this plan will vary from person to person based on the genetic mutation involved, your family’s history of cancer and the types of cancers that may be present. It will also outline the routine tests you should have and how regularly you should have them. Some recommendations for PGL/PCC may include:
- Annual physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Serum or urine metanephrine tests every 1-2 years in children, then annually in adults.
- Whole body MRI every 2-3 years.
Screening options for PGL/PCC may evolve as new technologies are developed and our understanding of the condition grows. It is essential to discuss your individual circumstances with your healthcare team to determine the most appropriate screening plan for you.
Risk factors
In most cases, PGL/PCC is caused by genetic mutations of succinate dehydrogenase (SDH) genes, however other genes can also cause the disease. Some examples include:
- SDHA (succinate dehydrogenase complex flavoprotein subunit A, tumour suppressor gene).
- SDHB (succinate dehydrogenase complex iron-sulphur subunit B, tumour suppressor gene).
- SDHC (succinate dehydrogenase complex subunit C, tumour suppressor gene).
- SDHD (succinate dehydrogenase complex subunit D, tumour suppressor gene).
- SDHAF2 (succinate dehydrogenase complex assembly factor two, tumour suppressor gene).
- MAX (MYC-associated factor X, tumour suppressor gene).
- TMEM127 (transmembrane protein 127, tumour suppressor gene).
PGL/PCC is an autosomal dominant disease, which means that you have a 50% chance of developing the condition if one of your parents carries the genetic mutation.
Symptoms
The symptoms of PGL/PCC often vary by the type(s) of tumours present. General symptoms of PGL/PCC may include:
- Hypertensionhigh blood pressure.
- Headaches.
- Heart palpitations.
- Unexplainable sweating.
- Tachycardiaa rapid heart rate; clinically defined as a rate of more than 100 beats per minute.
- Anxiety.
- Being very pale.
- Nauseato feel sick or likely to vomit and/or vomiting.
- Unexplainable weight loss/loss of appetite.
- Abdominal pain and/or massa growth of cells that come together to make a lump, may or may not be cancer.
- Blood in stoolwaste product from the bowel sent to the anus for removal; also known as faeces or poo and/or vomit.
- Fatiguea state of extreme tiredness or exhaustion, can be physical or mental.
- Difficulties swallowing.
Symptoms related to specific tumours can be found on our knowledgebase.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have tumours associated with PGL/PCC, they may order some of the following tests to confirm the diagnosis and refer you to a specialist for treatment. The tests required for diagnosis will often vary based on the symptoms present, and where the tumour(s) are suspected to be located.
- Physical examination.
- Genetic testing.
- Endocrine studiesstudies that involve blood, urine and/or imaging tests to analyse hormone levels.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- MIBG scana type of medical imaging that uses radioactive tracers to detect overactive parathyroid glands or neuroendocrine tumours; also known as a MIBI or sestamibi scan.
- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
- Exploratory procedures, such as an endoscopya procedure that involves inserting a long, flexible tube with a light and small camera (endoscope) into the body to view internal organs.
- Biopsyremoval of a section of tissue to analyse for cancer cells.