The metastatic lymph node ratio can be used to predict disease-free survival in medullary thyroid carcinoma (MTC), a new study published in the journal Cancers suggests.

It can therefore help in risk stratification for recurrence and ensure that patients are followed and treated as necessary.

The metastatic lymph node ratio is already used as a prognostic predictor in many other cancer types including differentiated thyroid cancer. However, its value in medullary thyroid carcinoma is not well documented.

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Here, a team of researchers from Korea evaluated metastatic lymph node ratio as a risk factor for structural recurrence in medullary thyroid carcinoma patients. They retrospectively reviewed the medical records of 132 patients, mean age 49.7, treated for MTC between 1995 and 2017. Of these, 39 patients had structural recurrence. 

Read more about medullary thyroid carcinoma treatment.

Significant predictors of structural recurrence were identified, including gross extrathyroidal extension, N stage, levels of serum calcitonin and carcinoembryonic antigen levels following surgery, and metastatic lymph node ratio. 

Predictors of disease-free survival were calcitonin and carcinoembryonic antigen in the serum following surgery, as well as metastatic lymph node ratio.  

“[Metastatic lymph node ratio] can potentially predict structural recurrence as a quantitative evaluation tool for lymph node metastasis in patients with MTC,” the researchers concluded.

Metastatic lymph node ratio is the ratio of metastasized lymph nodes to the total number of evaluated lymph nodes. Recurrence-free survival was defined as the time from the date of total thyroidectomy to recurrence or last follow-up.

MTC represents 2% to 4% of all types of thyroid cancer. Because it consists of thyroid parafollicular cells, which do not have thyroid-stimulating hormone receptors, the disease does not respond to thyroid-stimulating hormone suppression like other thyroid cancers. It also does not respond well to radioactive iodine therapy. Surgery involving total thyroidectomy is the only curative option.


Kim J, Park J, Park H, et al. Metastatic lymph node ratio for predicting recurrence in medullary thyroid cancer. Cancers (Basel). 2021;21;13(22):5842. doi:10.3390/cancers13225842