The leading causes of death in medullary thyroid carcinoma (MTC) are complications related to airway obstruction due to tracheal invasion, the progression of distant metastasis, and complications from chemotherapy. Clinical characteristics of the disease are not different according to the timing of distant metastasis.
These are the findings of a study published in Cancers that aimed to elucidate the long-term outcomes and causes of death among MTC patients with distant metastases.
It was already known that distant metastasis is a poor prognostic factor in MTC. However, the effect of the site of distant metastasis on prognosis was not clear.
Read more about MTC prognosis
Here, a team of researchers from Korea compared the clinical characteristics of MTC patients with distant metastasis based on the timing of the detection of distant metastasis. “We identified 46 MTC patients with distant metastasis between 1994 and 2019,” the researchers wrote. They also evaluated survival rates following the detection of distant metastasis to evaluate the clinical significance of metastatic site.
They found that 32.6% of patients (15 of 45) had synchronous distant metastasis, while 67.4% (31 of 45) had metachronous distant metastasis. There was no clinical difference between these patients apart from initial surgical extent.
The most common site of metastasis was the lungs, observed in 52.2% of patients. This was followed by the bones (28.3%), mediastinum (19.6%), and liver (17.4%). Metastasis to the adrenal glands and brain was noted in 4.3% of patients, while metastasis to the kidneys and pancreas was seen in 2.2% of patients.
The researchers found that the prognosis was significantly worse in patients with bone and multisite metastasis than in those with lung metastasis.
Medullary thyroid carcinoma is a rare type of neuroendocrine tumor of the thyroid gland. In half of patients, the disease presents with locoregional metastasis, while 10% to 15% of patients already have distant metastasis at the time of diagnosis.
Park H, Yang H, Heo J, Kim TH, Kim SW, Chung JH. Long-term outcomes and causes of death among medullary thyroid carcinoma patients with distant metastases. Cancers (Basel). 2021;13(18):4670. doi:10.3390/cancers13184670