Thyroid cancer occurs in the thyroid gland, a part of your endocrine system that helps manage the hormones responsible for your bodily functions.
Thyroid cancer can metastasize, which means the cancer cells spread from the thyroid gland to surrounding or distant areas. According to the American Thyroid Association, around 30% of people with thyroid cancer have metastatic cancer.
The most common areas that thyroid cancer spreads to are:
- the lymph nodes
- lungs
- bone
Metastatic thyroid cancer may not cause any different or new symptoms. However, when symptoms do appear, they can vary depending on the location of the cancer.
Specific symptoms to look out for include:
Fatigue
If cancer spreads from the thyroid gland, you may start to notice more generalized symptoms.
Symptoms include fatigue and lethargy. You may also notice that you feel physically and mentally exhausted, even if you are sleeping well.
Advanced cancer causes fatigue because when cancer cells grow, they require energy that your body usually uses to function. It may not be evident unless cancer spreads to a part of the body responsible for metabolism, like bone marrow.
Bone pain
While rare, thyroid cancer can spread to your bones. Between 2% and 13% of people with thyroid cancer develop metastases in their bones.
Up to 84% of people with advanced thyroid cancers in the bone experience bone pain.
Bone pain from advanced cancer can feel:
- dull
- continuous
- intense, in episodes mainly after movement
Weight loss
Unusual weight loss is a symptom of advanced metastatic thyroid cancer. Sometimes, you may lose weight due to a loss in appetite or as a side effect of a treatment such as chemotherapy. It might also be because your body is using up more energy to help fight the cancer rather than storing it.
A 2022 study notes how cancer that develops in the neck area, like thyroid cancer, is more likely to cause weight loss, as it can make eating and digestion more difficult.
Nausea
Cancer Research UK indicates that 7 out of 10 people with advanced cancers experience nausea and sickness.
If you experience any changes to your symptoms, new symptoms, or increasing severity of existing ones, speak with a doctor as soon as possible. They will perform scans and tests to determine if cancer spread is the cause.
Treatment
Treatment for thyroid cancer depends on the stage when a doctor diagnoses it and how you respond to previous treatments.
If thyroid cancer spreads, it can be either local or distant. Local metastasis means the cancer has spread to your lymph nodes and tissues. Distant metastasis means the cancer has spread to more distant areas, such as the bones.
If you have slow-growing thyroid cancer, doctors may recommend watchful waiting. Typically, this means you will not require treatment until symptoms appear.
However, sometimes, a doctor may suggest treatment, including:
Surgery
Surgery is an effective treatment for early-stage or local thyroid cancer, where tumors are under 4 centimeters. If nearby lymph nodes are affected, doctors may remove them at the same time.
Distant metastatic thyroid cancer can be incurable. However, depending on your circumstance, doctors may recommend surgery to remove tumors from distant sites.
If your condition is severe and the cancer is aggressive, treatment aims to improve your quality of life and reduce symptoms.
Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy radiation to kill or prevent cancer cells from growing.
Postsurgery radiation therapy can also help kill any cancer cells left over from surgery.
Chemotherapy
This technique uses high-strength drugs to stop cancer cells from growing. They are available as injections or in tablet form.
Examples include cyclophosphamide (Cytoxan) and fluorouracil (Adrucil).
Chemotherapy for thyroid cancer is rare. However, doctors may recommend it for people with anaplastic thyroid cancer or medullary thyroid cancer.
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