Anaplastic thyroid carcinoma is an aggressive form of cancer of the thyroid gland. It is one of the fastest growing tumors in humans. Unlike other forms of thyroid cancer (papillary, follicular, medullary, and their variants) it spreads quickly to other organs. It does not respond to the radioiodine therapy or TSH suppression with thyroxine used for some of the other types of thyroid cancer.
Only about 1% of thyroid cancers are of the anaplastic type.
ATC occurs most often in people over age 60. It is a very rare disease. About 600 new cases are diagnosed in the USA every year (with a median age of 67).
The cause of ATC is unknown. It sometimes arises within a preexisting thyroid cancer that has been less aggressive, such as a papillary thyroid cancer.Symptoms
From the National Library of Medicine:
- Lower neck mass, often noted to be enlarging
- Hoarseness or changing voice
- Coughing up blood
- Difficulty swallowing
- Loud breathing
Also, something called “stridor” can occur. Stridor is harsh-sounding breathing caused by a restricted airway.
Thyroid function tests are usually normal.Progression
ATC can progress in different individuals in different ways. Here is a typical scenario.
A patient, or a family member, notices a lump in the neck and some hoarseness in the voice. The patient goes to see the doctor.
The doctor feels a tumor in the thyroid and refers the patient to an endocrinologist or an oncologist. The endocrinologist or oncologist determines whether the tumor is malignant or benign, and, if malignant, the cancer type. This can usually be done with a fine needle aspiration (FNA) or with a core needle biopsy, but sometimes a surgical biopsy is done. The tumor tissue is examined by a pathologist experienced in the identification of thyroid tumors.
The tumor may grow to the point that it compresses the airway, or trachea, and causes difficulty in breathing.
If airway compression occurs, a tracheostomy is often done to place a plastic tube in the airway below the tumor. This is usually done by an endocrine surgeon; an ear, nose, and throat (ENT) surgeon; or a general surgeon experienced in this procedure.
The surgeon also evaluates the patient to determine if the tumor can be safely resected. Unlike the situation with most other thyroid cancers, surgical removal is often inadvisable because of the potential complications and the low likelihood that the tumor can be completely removed.
Sometimes the tumor also compresses the food pipe (esophagus), interfering with the patient's ability to swallow. This situation requires a feeding tube to be inserted into the stomach through the wall of the stomach or intestine.
Then, a team of physicians recommends a course of treatment. This team typically consisting of a surgeon, a chemotherapy oncologist (cancer doctor who specializes in using drugs to treat cancer), an endocrinologist, and a radiotherapy oncologist (cancer doctor who specializes in using radiation to treat cancer).
In about half of patients with ATC, the cancer has already spread to other organs at the time of diagnosis, usually to the lungs and/or bones.
In all ATC cases, speed and a sense of urgency in treatment are important because of the extremely fast tumor growth rate. For more thoughts on this, see the section titled ATC Treatment Urgency.Survival Statistics
The survival statistics are grim, but there are long-term survivors of ATC.
The problem with statistics is that while they are valid for a group, they say nothing about what will actually happen to any one person. Be sure to read the section titled Survivor Stories before getting too discouraged.
Many believe that the survival statistics can become a self-fulfilling prophecy, and that if doctors and patients aggressively pursue treatment despite the statistics, the survival statistics will improve.
- A recent study showed the following statistics for a group of 30 patients. The study was published in 2004 and is titled "Combined Treatment of Anaplastic Thyroid Carcinoma with Surgery, Chemotherapy, and Hyperfractionated Accelerated External Radiotherapy" (DeCrevoisier, et. al. International Journal of Radiation Oncology Biological Physics, Vol. 60, No. 4, pp. 1137-1143, 2004)
- 6 patients had metastasis at the time of diagnosis. Half died within 6 months of diagnosis, and all died by 16 months.
- 24 patients had no metastasis at the time of diagnosis. Half died within 12 months of diagnosis, and 6 were still alive after 60 months.
- The Mayo Clinic study cited below studied 134 cases from 1949-1999. The median survival was 3 months from diagnosis, and 13 patients survived longer than 1 year.
- The study of statistics from the National Cancer Institute’s SEER Program (cited below and published in 2005) summarized information from 516 patients seen in USA hospitals between 1973 and 2000. Almost one in 5 (a total of 19 percent) survived longer than 1 year.
Overall, not much is known about the cause of ATC. It does not appear to be hereditary. It is associated with goiter, and some believe that it is a mutation from another form of thyroid cancer. However, the exact cause has not been determined. The current thoughts are that it results from a chain of genetic mutations, but it isn't clear what triggers these mutations.
The question "why did this happen to me?" usually follows the question "will I survive this?"
It is natural to blame the ATC on various things that happened in the past of someone diagnosed with ATC, but it is unlikely that any of the things we think of were actually the cause. Still, we all wish we "knew" what caused it.Why Is Most ATC Diagnosed In a Late Stage?
Comments from ATC Survivors and Caregivers
There is usually a feeling among ATC patients and their families of "if only the ATC was diagnosed earlier, things would be OK now." While in hindsight this may seem clear, the fact is that ATC is so deadly because it is so hard to detect early and progresses so rapidly. Even when detected early, patients in the overwhelming majority of instances go on to develop distant (metastatic) disease.
Therefore, almost everyone with ATC is in the same boat of being diagnosed "late." So, people with ATC or their families should not spend too much time feeling guilty about not seeking care earlier. We also need to recognize that early diagnosis of ATC may have been difficult or impossible for one’s doctors, too.
The following points are not intended to excuse uninformed medical care, but they do highlight the need for the development of techniques for earlier detection. Here are some facts about ATC that show why it is so hard to diagnose.
- ATC hits about 600 Americans each year, which means the odds of any of us getting it in a year are about 1 in a million (worse odds if you are older, better if you are younger). So, symptoms of hoarseness or neck swelling are far more likely to be due to much simpler and less deadly causes.
- Many doctors, even endocrinologists, endocrine surgeons, and ear, nose, and throat (ENT) specialists, have never seen a case of ATC.
- Most thyroid tumors are not cancerous and most cancerous thyroid tumors are not ATC (only about 1% are ATC) and the non-ATC tumors are typically highly treatable. And, there is usually no "rush" to treat the non-ATC tumors.
- ATC can be difficult to diagnose, even with a biopsy. Because of this, specialized treatment centers typically have a pathologist who is expert in determining whether or not a thyroid tumor is ATC. To make things worse, sometimes there are a mix of cancer types in the thyroid, so when the biopsy is done, it might miss the ATC cells and then conclude it is a different type of thyroid cancer.
- ATC tumors can grow very rapidly.
- ATC patients often have perfectly normal thyroid hormone function.
- There is no known cause for ATC, so you can't predict who will get it. It appears to be associated with goiter, the risk increases with age, and it may mutate from another form of thyroid cancer.
Consequently, ATC is difficult to diagnose early, so let go of the guilt.
Last updated: May 13, 2022