A new study has demonstrated that patients with high-grade medullary thyroid carcinoma (MTC) often have a calcitonin doubling time of less than 2 years, which is associated with poorer outcomes and tumor recurrence. The study, published in Thyroid, found significantly slower calcitonin doubling times among patients with low-grade tumors.
“In this study, our object was to determine how calcitonin doubling times were different in high- vs low-grade MTC,” the authors wrote. “We hypothesized that high-grade patients would have more rapid observed calcitonin doubling times compared to low-grade patients after surgery. In addition, high-grade patients with rapid calcitonin doubling times would consequently be associated with worse tumor-specific outcomes.”
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The research team conducted a retrospective cohort study of 117 patients with MTC at a single center between 1986 and 2017. Ninety-five patients had low-grade tumors and 22 had high-grade tumors.
In addition to significantly faster calcitonin doubling times among patients with high-grade tumors compared to those of patients with low-grade tumors, 70% of patients with high-grade tumors had a calcitonin doubling time of less than 2 years, which is a previously validated cutoff point predicting poorer outcomes. Specifically, patients with high-grade tumors had poorer overall survival, locoregional relapse-free survival, and distant metastasis-free survival than patients with low-grade tumors.
Furthermore, the team found that the short calcitonin doubling times among patients with high-grade tumors predicted recurrence and were also an indicator of more aggressive disease.
The use of tumor grade and marker surveillance are clearly important components of stratifying patients with MTC, such that those with low-grade tumors could have longer follow-up intervals after surgery than patients with high-grade tumors. The authors recommend routine determination of tumor grade and calcitonin doubling times postoperatively and close monitoring of those with high-grade tumors.
Nigam A, Xu B, Spanheimer P, et al. Tumor grade predicts for calcitonin doubling times and disease-specific outcomes after resection of medullary thyroid carcinoma. Thyroid. Published online August 11, 2022. doi:10.1089/thy.2022.0217