Your mother will do well, and you do not need to worry much.
Thyroid cancer, like many cancers is rare. Also like other cancers, it comes in a variety of different types depending on the underlying tissue: Papillary thyroid carcinoma, follicular thyroid carcinoma, medullary thyroid carcinoma, anaplastic thyroid carcinoma.
Some thyroid cancers (namely medullary thyroid carcinoma aka MTC) have underlying genetic syndromes associated with them. In this case, it is very important to have genetic testing done, and in many cases preventive thyroid surgery. The other thyroid cancers have some genetic component but no available commercial genetic testing.
However, if you're like many, the most common is papillary thyroid carcinoma (PTC). This is potentially curable by thyroid removal and depending on the extent of cell spread can be treated with radioactive iodine.
The biggest risk factors for thyroid cancers are exposure to radiation in the neck area (ie: treatment for other cancers like lymphoma, etc).
To protect yourself, I would recommend becoming familiar with the thyroid by looking and feeling it in the mirror. Doing a daily (or at least weekly) thyroid neck exam on yourself is a nice preventive tool. Much like doing a self breast exam, this would note any new lumps/bumps or changes day to day. Should you notice a change, then an ultrasound could be done to confirm an abnormality.
Routine ultrasound screening is generally not recommended given how common thyroid nodules are. Less than 5% are cancerous.
I value people knowing their body and in your case, becoming familiar with your thyroid and neck area is the best method of protecting yourself.
Let me know if you have other questions!
A thorough annual exam, including neck exam is recommended for everyone, with or without a family history of thyroid cancer. Self-examinations are explained in pamphlets offered by the American Association of Clinical Endocrinologists.
Thyroid cancer may develop in patients with a normal, over and under functioning thyroid gland. There is no routine lab that can screen for thyroid cancer. If a neck lump is felt, your healthcare provider should order a neck ultrasound. There are no vitamins, herbs, or supplements that can lower your risk of thyroid cancer.
Enjoy an active and healthy lifestyle. Know that most patients with thyroid cancer do very well. Keep a close professional relationship with your doctor(s), ask them questions, and follow their advice.
From the standpoint of Naturopathic Medicine it is advisable to take regular Iodine Supplements because the Iodized Salt is not enough for the requirement of many people.