BACKGROUND
Medullary thyroid cancer (MTC) is a rare form of cancer that can develop in the thyroid gland, a butterfly- shaped organ located in the front of the neck that regulates how the body uses energy (metabolism). Like all cancers, MTC can spread out of the thyroid gland to other parts of the body, a process called metastasis. When MTC does this, the first place it spreads to are the lymph nodes in the neck next to thyroid gland. If enough time passes without treatment, MTC may spread further, reaching more distant sites, such as the lungs or the liver. In general, the further a cancer spreads, the more dangerous it is.

Surgery is the most effective treatment for MTC, usually involving surgery to remove the thyroid (called a total thyroidectomy), and often the neighboring neck lymph nodes (called a neck dissection). There are two types of neck dissection: central neck dissection, which removes the lymph nodes in the front of the neck, immediately next to the thyroid gland, and lateral neck dissection, which removes the lymph nodes in the side of the neck, farther away from the thyroid gland. The possible risks associated with central and, in particular, lateral, neck dissections are greater than those associated with total thyroidectomy alone. These include risk of injury to nerves controlling muscles of the mouth and tongue, the vocal cords, the shoulder/neck and the diaphragm (a muscle involved in normal breathing). Because of these increased risks, knowing if a person diagnosed with MTC could avoid a neck dissection would be very useful in making the risk of surgery as low as possible.

The authors of this study were interested in knowing if blood testing before surgery and/or doing a thyroid biopsy during total thyroidectomy in people diagnosed with MTC might predict which of these patients need a neck dissection and which of them do not. This information would be very helpful, as this would allow a thyroid surgeon to avoid performing a neck dissection, and thus avoid the risks that come with neck dissection, in people who do not need lymph node removal during total thyroidectomy for MTC.

THE FULL ARTICLE TITLE
Niederle MB, et al. Tailored surgery for medullary thyroid cancer (MTC) based on pretherapeutic basal calcitonin and intraoperative diagnosis of desmoplastic stroma reaction: A proposal for a new surgical concept. Ann Surg Oncol 2025;32:4742–4753.

SUMMARY OF THE STUDY
For this study, the authors looked at the medical records of more than 300 people who had surgery for MTC. In particular, they collected two pieces of information in each case. First, before surgery, they evaluated the blood level of a hormone called calcitonin, which is made by MTC cells (the higher this level is, the higher the chances are that cancer cells have spread out of the thyroid). Second, the authors looked for evidence that the MTC removed in each case showed a particular pattern when evaluated by a pathologist using a microscope (a pattern called desmoplastic stroma reaction). The researchers wanted to see if these two factors were linked to whether the cancer had spread out of the thyroid to neighboring lymph nodes and also to how likely it was that the cancer would come back after surgery.

The authors found that people diagnosed with MTC for whom the blood calcitonin level was low prior to surgery were unlikely to have cancer spread to their neck lymph nodes and had excellent cure rates after surgery (98.2% were free of cancer following surgery). In addition, if the desmoplastic stroma reaction was not present, cancer was never found in the surrounding neck lymph nodes and 100% of these patients appeared to be cured after surgery. On the other hand, when the desmoplastic stroma reaction was present, about half of patients had cancer in their neck lymph nodes (51.1%). Moreover, high blood calcitonin levels were present for all people in whom cancer had spread to the neck lymph nodes in the sides of the neck.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
These findings suggest that neck dissection at the time of total thyroidectomy for treatment of MTC may be avoided if the pre-surgery blood calcitonin levels are low and if the desmoplastic stroma reaction is not present. This approach would allow many patients diagnosed with MTC to avoid larger, riskier surgeries while still effectively treating their thyroid cancer.

— Gaby Cordero, MD, and Jason D. Prescott, MD PhD

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