Hurthle cell thyroid cancer, or oncocytic thyroid cancer, is a type of follicular thyroid cancer. This is an unusual type of tumor that’s less common than follicular cancer, making up only 4 percent of all thyroid cancers. Most people who develop Hurthle cell thyroid cancer are in their midﬁ fties and older—about ten years older than those with the follicular type. Hurthle cell cancer doesn’t tend to spread to the lymph nodes, but it can sprout again in the same place or spread to the lungs or bones. It may take years for Hurthle cell cancers to grow and do much damage. The cure rate relates, as with follicular cancers, to the staging.
Uncommon Types of Thyroid Cancer
There are some less common types of thyroid cancer that I will discuss only brieﬂy here.
Medullary Thyroid Cancer
Medullary thyroid cancer (MTC), which accounts for fewer than one out of ten cases of thyroid cancer found in the United States each year, can be spontaneous or inherited. Medullary thyroid cancer involves the parafollicular cell (C cell), which does not make thyroid hormone or take up iodine.
Therefore, radioactive iodine cannot be used as a treatment for this aggressive type of cancer. Surgery is the main treatment for this cancer, although experimental trials may be used when the cancer is advanced.
The best way to treat MTC is through prevention. If you are diagnosed with MTC, you should have the genetic test to see if you have the inherited form; if so, your children, siblings, and other family members should be tested too. If they have the mutation, then they have a virtually 100 percent chance of developing this cancer at some point; a prophylactic thyrodectomy can prevent this cancer from developing or from spreading if caught early.
Unresponsive Aggressive Thyroid Cancer Tumors
Anaplastic thyroid cancer is a wildly undifferentiated cancer that accounts for only about three hundred cases of thyroid cancer per year in the United States. Papillary or follicular thyroid cancers may become anaplastic—a very aggressive, untreatable form of thyroid cancer—if they are not treated. There are also cases where papillary or follicular thyroid cancers are unresponsive to treatment and can become aggressive tumors.
Staging and Spreading
While people can be diagnosed with the same kind of thyroid cancer, their treatments will depend on the stage, or phase, of the cancer.
Staging systems are not useful in predicting the outcomes of individual cases of thyroid cancer; they’re mainly used as a way to predict general trends in thyroid cancer in large groups of patients. Most thyroid cancers have four stage classiﬁcations that basically answer the question, “Where has it spread?”
For papillary cancer, Stage I means that the cancer is conﬁ ned to the thyroid gland in either one lobe or both lobes. Stage II in people under forty-ﬁve years means the cancer has spread beyond the thyroid; in people over forty-ﬁve, it means that the cancer may still be conﬁ ned to the thyroid, but is larger than 0.5 in. Stage III means the cancer has spread beyond the thyroid to surrounding lymph nodes but has not gone beyond the neck. If you’re younger than forty-ﬁ ve, you won’t get to Stage III. Stage IV is also only seen in people over forty-ﬁve years and means the cancer has spread to distant organs, such as the lungs or the bones.
For follicular thyroid cancer, Stage I means the cancer is conﬁ ned to the thyroid, in either one lobe or both. Stage II in people under fortyﬁve means the cancer has spread beyond the thyroid gland; in people over forty-ﬁ ve it means a larger tumor, about 0.5 in., conﬁ ned to the thyroid. Stage III is seen only in people over forty-ﬁve and means the cancer has spread outside the thyroid, possibly to the lymph nodes, but not beyond the neck. Stage IV, also seen only in people over forty-ﬁ ve, means the cancer has spread to distant organs, such as the lungs or bones.