Vol 10, No 2 (2007)
Review paper
Published online: 2007-05-23
Distant metastases of differentiated thyroid cancer: diagnosis, treatment and outcome
Nucl. Med. Rev 2007;10(2):106-109.
Abstract
The remarkably good prognosis and long-term survival in differentiated
thyroid cancer (DTC) are significantly reduced in
patients with distant metastasis (DM). Multi-site metastases are
associated with a high mortality rate reaching 92% at 5 years
necessitating early diagnosis and treatment. The most common
site of metastases are the lungs, followed by the bone,
with the former having better prognosis than the latter due to
late detection. A number of factors contribute to the development
of DM including large and multifocal primary tumour, extrathyroidal
extension, aggressive histology and advanced age.
In patients with good 131I uptake, 131I therapy appears highly
effective and should be offered up to a cumulative activity of 22
GBq. Other measures such as surgery, radiotherapy, arterial
embolisation and cementoplasty may be required.
If there is low or no 131I uptake, FDG-PET should be obtained due to its prognostic impact. It may help in selecting patients for other modalities such as cytotoxic chemotherapy and redifferentiation therapy by 13-cis retinoic acid. The development of tyrosine kinase inhibitors has raised hopes in providing alternative therapy for bone metastasis, especially in older age groups with poorly differentiated tumours with no 131I uptake but good uptake of FDG.
If there is low or no 131I uptake, FDG-PET should be obtained due to its prognostic impact. It may help in selecting patients for other modalities such as cytotoxic chemotherapy and redifferentiation therapy by 13-cis retinoic acid. The development of tyrosine kinase inhibitors has raised hopes in providing alternative therapy for bone metastasis, especially in older age groups with poorly differentiated tumours with no 131I uptake but good uptake of FDG.
Keywords: metastatesdifferentiated thyroid cancerdiagnosistreatment