Kidney cancer drug Votrient may help some thyroid cancer
One recent phase II clinical trial reported in the medical journal The Lancet Oncology suggests the kidney cancer drug Pazopanib or Votrient, made by GlaxoSmithKline, may be used to treat a very aggressive thyroid cancer.
The trial results showed advanced differentiated thyroid cancer in about 49 percent of the patients responded well to Pazopanib, with more than two thirds having a response that lasted longer than one year.
The response rate does not seem too high, but it is considered high as no treatment has been available thus far to treat this particular thyroid cancer.
Most differentiated thyroid cancers can be treated with surgery and radioiodine to have a favorable outcome. But one out of 20 these patients end up having the aggressive form of the malignancy.
For the Phase II clinical trial, Keith Bible from the Mayo Clinic, Rochester and colleagues tested pazopanib in 37 patients with rapidly progressing thyroid cancer, which has not effective treatment to help patients survive longer.
The researchers found 18 patients or 49 percent of all the participants had their cancer mass shrunken. Among those with follicular thyroid cancer using the drug, 73 percent experienced tumor shrinkage compared with 33 percent of those with more common papillary thyroid cancer.
However, side effects were common, ranging from diarrhea, high blood pressure or hypertension, and high aminotransferase levels. The effects were so severe doctors had to lower the dosage for 15 patients. Two patients using the drug, who also had other conditions, died during the treatment.
Because of the side effects, the researchers did not recommend Pazopanib for patients who have slowly progressing thyroid cancer. More research is needed to examine the safety profile and the benefits of this drug.
Pazopanib targets certain receptors involved in the process of developing new blood vessels that tumors rely on to grow. The targeted receptors include those for vascular endothelial growth factor, platelet, derived growth factor, and c-kit, according to Medical News Today.
Thyroid cancer forms in the thyroid gland that helps make hormones that control the heart rate, blood pressure, body temperature, and body weight. The disease is expected to be diagnosed in 44,670 men and women and kill 1,690 in the United States in 2010.
One risk factor is radiation exposure. People exposed to radiation are more likely than others who are not to develop papillary or follocular thyroid cancer, two common thyroid cancers, Accoridng to the National Cancer Institute.
Radiation includes routine diagnostic x-rays and radioactive fallout from atomic weapon tests such as those conducted in the United States and elsewhere in the 1950s and 1960s.
The effect of one dietary factor, iodine, remains uncertain. Some studies suggest that lack of sufficient iodine can be a risk for thyroid cancer while others suggest too much iodine in the diet may boost the risk of papillary thyroid cancer.
One study published in the Sept 7 2010 issue of International Journal of Cancer suggests that dietary nitrate, which is used as a curing agent in processed meat and also found in small quantity in vegetables, may boost the risk of thyroid cancer.
The study led by Kilfoy B.A. and colleagues at the National Cancer Institute showed men who had their intake of nitrate in the highest quintile were more than twice as likely as those having the lowest quintile to develop thyroid cancer. But the association was not found in women.
On the other hand, nitrite was not found associated with increased risk of thyroid cancer either in men or women.
By Jimmy Downs
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