DICER1 syndrome (DICER1), also known as DICER1 tumoura tissue mass that forms from groups of unhealthy cells predisposition syndrome, is a rare genetic disorder 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 commonly pleuropulmonary blastoma. It is caused by an alteration in the DICER gene, which is a type of tumour suppressor gene.
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.
DICER1 is generally diagnosed equally among the sexes, and is generally diagnosed before the age of 40. In many cases, it can be diagnosed in childhood and adolescence, however anyone can develop this disease.
DICER1 Syndrome Related Tumours
DICER1 is most commonly associated with the development of pleuropulmonary blastoma, however it has also been linked to other types of tumours. Some examples include:
- Pineal region tumours, most commonly pineoblastomas.
- Central nervous system sarcomas (rare).
- Benignnot cancerous, can grow but will not spread to other body parts tumours, potentially including:
-
- Pulmonary cystsabnormal growths that are usually filled with liquid or air.
-
- Cystic nephromas.
-
- Hamartomatous polyps.
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 cellsthe basic structural and functional unit of all living things 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 DICER1 will present with a unique disease behaviour, with varying tumour 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 DICER1 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.
- 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 DICER1 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 DICER1 may include:
- Annual physical examinations with family education surrounding signs and symptoms of disease and importance of prompt workup with imagingtests that create detailed images of areas inside the body for any concerning symptoms.
- Chest x-rays every 4-6 months until eight years old, then annually until age 12.
- Annual physical thyroid examination.
- Thyroid ultrasounds every 3-5 years.
- Pelvic ultrasounda type of medical imaging that uses sound waves to create detailed images of the organs and structures within the pelvis, including the uterus, ovaries, and surrounding tissues every 6-12 months for females beginning by age eight until at least 40 years old.
- Abdominal ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body every six months until eight years old, then annually until age 12.
- Annual eye examinations from age three until at least age 10.
Screening options for DICER1 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
DICER1 is caused by a genetic mutation in the DICER tumour suppressor gene, which acts to inhibit cell growth to prevent overproduction of cells and the development of tumours. It is an autosomal dominant disease, which means that you have a 50% chance of developing the condition if one of your parents carries the mutation.
Symptoms
The symptoms of DICER1 often vary by the type(s) of tumours present. General symptoms of DICER1 may include:
- Dyspneadifficulty breathing, shortness of breath.
- Unexplained weight loss/loss of appetite.
- Fevers.
- Abdominal pain.
- Abdominal distention.
- Abdominal massa growth of cells that come together to make a lump, may or may not be cancer.
- Menstrual irregularities.
- Amenorrhoeaabscense of menstrual periods.
- Precocious (early) puberty.
- Changes in vision, most commonly decreased vision.
- Headaches.
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 DICER1 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 examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Neurological examinationan assessment of sensory and motor functions, such as vision, balance and coordination.
- Pelvic examinationa physical exam of the external and internal female pelvic organs.
- Genetic testing.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Urine teststesting done to measure the levels of certain substances in the urine.
- Imaging tests, potentially including:
-
- Chest x-raya type of medical imaging that uses x-ray beams to create detailed images of the body .
-
- Ultrasound.
-
- 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.
- 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.