Cancer cells have the potential to spread from the thyroid to other parts of the body where they can grow into new tumours. This process is called metastasis. The tumours are also called metastasis (singular) or metastases (plural). Metastases are also called secondary tumours.
Understanding the usual progression of cancer helps the doctor to predict its probable course, plan treatment and anticipate further care.
The most common sites where thyroid cancer spreads depend on the type of thyroid cancer.
Papillary thyroid cancer is usually slow growing and tends to spread regionally (locally) rather than distantly.
Follicular thyroid cancer is slightly more aggressive than papillary thyroid cancer, although it is still considered a slow growing, well-differentiated cancer.
Most cases of anaplastic thyroid cancer have distant metastasis at the time of diagnosis because of the rapid growth and aggressive nature of this type of cancer.
Medullary thyroid cancer commonly spreads to the regional lymph nodes in the neck.
A clinical trial led by the Society’s NCIC Clinical Trials group found that men with prostate cancer who are treated with intermittent courses of hormone therapy live as long as those receiving continuous therapy.