Lymph node ratio (LNR) and the log odds of positive lymph nodes (LODDS) may be the most suitable lymph node classification systems for patients with medullary thyroid carcinoma (MTC), according to a new study published in the journal Endocrine Tumors.

“However, larger-scale studies are needed to further verify our findings,” the author said.

Researchers have proposed LNR and LODDS as alternative lymph node classification schemes. In the present study, a team of researchers led by Andreas Krieg, MD, of the Department of Surgery, Heinrich-Heine-University and University Hospital Düesseldorf in Germany retrospectively compared the predictive impact of different lymph node classification systems. Their aim was to identify the most appropriate set of cut-off values to accurately evaluate overall survival in MTC patients.

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To do so, they used data from 182 patients with the disease who were operated on between 1985 and 2018. They assessed the discriminative power of 28 LNRs and 28 LODDS using statistical analyses and compared it to that of the currently used N category.

They found that high LNR and LODDS were associated with advanced T category, distant metastasis, sporadic disease, and male gender. They also found that of the 56 alternative lymph classifications, only 1 LNR and 1 LODDS were independently associated with overall survival in medullary thyroid carcinoma. This was independent of the presence of metastasis. However, none of the lymph node classification systems were superior in predicting prognosis over the N category.

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“This work provides an important foundation for future research in the context of carefully designed larger scale clinical trials,” the authors concluded.

MTC represents 2 to 3% of all types of thyroid cancers. It can spread to the cervical lymph nodes and other parts of the body such as the bones, lungs, liver, and brain. The main factors affecting the prognosis of the disease are the stage at diagnosis and the extent of local disease.


Prassas D, Kounnamas A, Cupisti K, Schott M, Knoefel WT, Krieg A. Prognostic performance of alternative lymph node classification systems for patients with medullary thyroid cancer: a single center cohort study. Ann Surg Oncol. Published online December 10, 2021. doi:10.1245/s10434-021-11134-3