Thyroid cancer that has spread throughout the body can dramatically worsen a patient's prognosis, but new research suggests that in the case of bone metastases, radioactive iodine (I-131) therapy may be a reliable treatment.
A report appearing in the Journal of Clinical Endocrinology and Metabolism (JCEM) determined that intravenous I-131 injections were able to halt or even reverse the apparent growth of bone tumors among three quarters of participants with differentiated thyroid cancer.
The authors, a group of nuclear medicine specialists from China's Shanghai Jiao Tong University, said that overall survival was relatively good.
At the five-year mark, the survival rate among patients with bone metastases was 86 percent. After a full decade, 58 percent of participants were still alive.
Compare these figure to those collected by the National Cancer Institute's Surveillance Epidemiology and End Results Program. For distant thyroid cancer - in other words, a carcinoma that has metastasized far beyond the head and neck - the five-year survival rate is listed as 56 percent.
In general, distant metastasis of thyroid carcinomas (DMTC) is fairly uncommon. Data appearing in the Journal of Nuclear Medicine (JNM) indicated that no mote than 15 percent of thyroid cancer patients are diagnosed with distant tumors.
A study published in the journal Clinical Endocrinology found that in more than 60 years, the UK's Royal Marsden Hospital treated only 111 patients for such extensive thyroid carcinoma. The report noted that skeletal tumors are the second most common form of DMTC, following lung metastases.
Both this study and the new JCEM report agree that the outlook is better for patients with DMTC in the skeleton alone, compared to those with metastases in multiple organ systems. Furthermore, the Chinese team noted that having a single bone tumor improved the post-I-131 prognosis, as did having had bone surgery prior to the iodine-based treatment.
Researchers discovered that I-131 treatment also acted as a palliative, reducing pain levels for more than one third of all participants.
They concluded that this form of therapy is a viable method for stopping or reversing the expansion of skeletal DMTC, as well as for relieving pain and discomfort caused by the condition.
Much ink has already been spilt in the discussion of using I-131 for thyroid cancer's bone metastases. The JNM report emphasized that the benefits of I-131 are most apparent when it is used as early as possible.