As with other types of cancer, a person's thyroid cancer prognosis usually depends on the stage at which the cancer is diagnosed and when treatment begins. In most cases, a patient's prognosis is best when the cancer is caught at an early stage and before it has spread to other parts of the body. Other factors play a role in the prognosis as well. For example, a person's prognosis may depend on the treatment method his doctors choose as well as his overall health aside from the cancer. Cancer cell appearance and aggressiveness make a difference as well, and an individual's age may also play a role.

One of the most important factors in a thyroid cancer prognosis is the stage at which doctors discover and treat the cancer. Cancer is most treatable when it is diagnosed during an early stage. This means before the cancer has grown large or spread to other parts of the body. A person can usually expect to have a much lower chance of survival when thyroid cancer is discovered and treated after it has spread to other parts of the body.

An individual's thyroid cancer prognosis is often specifically related to age and overall health. For example, individuals who are younger than 40 generally have the best prognosis when it comes to thyroid cancer, and this is particularly true when the cancer has not spread to other parts of the body. Likewise, an individual who is in good health may prove more likely to be strong enough to fight the cancer and withstand the often-harmful effects of the cancer treatments.

The appearance and aggressiveness of the cancer cells also has a good deal of effect on a person's thyroid cancer prognosis. For example, the more abnormal the thyroid cancer cells appear, the worse a person's prognosis may prove. The same goes for the aggressiveness of the thyroid cancer cells. Those that are more aggressive are likely to spread faster, which often results in a poor prognosis.

The treatments that are used, as well as a patient's response to treatment, also affect thyroid cancer prognosis. Some of the treatments a doctor may recommend are surgery to remove the thyroid or lymph nodes, chemotherapy, and radiation therapy. Doctors may also recommend thyroid hormone therapy or the ingestion of radioactive iodine as treatment. The effectiveness of the treatment may depend on the stage and aggressiveness of the cancer as well as on the individual's unique response to treatment.