Familial Medullary Thyroid Cancer (Familial MTC)
Familial medullary thyroid cancer (familial MTC) is an inherited condition that increases the risk of developing medullary thyroid cancer, a type of thyroid cancer that arises from C-cells in the thyroid.
Overview
Familial medullary thyroid cancer (familial MTC) is an inherited condition that increases the risk of developing medullary thyroid cancer, a type of thyroid cancer that arises from C-cells in the thyroid. Familial MTC is part of the spectrum of RET-related conditions and is closely related to MEN2. In familial MTC, the main feature is medullary thyroid cancer, without the other typical MEN2 features in some families.
Causes and Genetics
Familial MTC is usually caused by changes (mutations) in the RET gene. It is inherited in an autosomal dominant pattern, meaning a person only needs one altered copy of the gene to be at increased risk. Each child of an affected person has a 50% chance of inheriting the mutation. Different RET mutations are linked to different levels of risk and influence the recommended timing of screening and surgery.
Symptoms and Features
Many people are diagnosed through family screening before symptoms develop.
Characteristic Symptoms and Features
- A lump in the neck
- Swelling in the neck
- Hoarse voice
- Difficulty swallowing
- Enlarged lymph nodes
Other Associated Symptoms and Features
- Some people may have diarrhoea or flushing if the tumour produces higher levels of hormones, but this is not always present
Treatment
Regular follow-up is important, including monitoring calcitonin and other tests to check for recurrence.
Research and Future Directions
Research continues to refine risk-based management using specific RET mutations and biomarkers to guide the timing of surgery and follow-up. Targeted treatments that block RET signalling are also improving options for advanced medullary thyroid cancer in selected cases.