The lymph node ratio is an independent prognostic factor for disease-free and overall survival in medullary thyroid carcinoma (MTC), according to a new study published in Peer J. Moreover, it also impacted the biochemical cure of the disease.
To assess the possible link between lymph node status (i.e. the number of lymph nodes that are resected during surgery, the number of metastatic lymph nodes, and the lymph node ratio) and the biochemical recurrence and disease-free and overall survival in MTC, a team of researchers from China conducted a study in 160 patients with the disease who were seen at Tianjin Medical University Cancer Institute and Hospital between 2011 and 2019.
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They identified prognostic factors influencing biochemical cure as being multifocality, levels of calcitonin before the operation, pathologic N stage, resected lymph nodes, metastatic lymph nodes, lymph node ratio, and clinical stage as defined by the American Joint Committee on Cancer.
Significant factors affecting disease-free survival were gross extrathyroidal extension, levels of calcitonin before surgery, pathologic T classification, pathologic N stage, resected lymph nodes, metastatic lymph nodes, lymph node ratio, clinical stage, and biochemical cure.
Statistical analyses revelated that the lymph node ratio was a predictor of disease-free survival, while tumor size, pathologic N stage, and lymph node ratio were predictors of overall survival.
The cut-off value of the lymph node ratio was 0.24, with the highest predictive performance.
“Further investigations are needed to determine the optimal cut-off value for predicting prognosis,” the researchers said.
MTC is a rare type of neuroendocrine tumor of the thyroid gland arising from the parafollicular cells and accounting for 2 to 4% of all cases of thyroid cancer. In localized cases, the 5-year survival rate of the disease is almost 100%, but it can be as low as 38% in case of metastasis.
Reference
Hao W, Zhao J, Guo F, et al. Value of lymph node ratio as a prognostic factor of recurrence in medullary thyroid cancer. PeerJ. Published online March 13, 2023. doi:10.7717/peerj.15025
