Every year, about 60,000 Americans receive a diagnosis of thyroid cancer. The kinase inhibitor Nexavar (sorafenib), already approved for kidney and liver cancers, has been shown to keep thyroid cancer from progressing for five months, according to results of a phase 3 study presented at ASCO's annual meeting.Although thyroid cancer is highly curable with surgery and radioactive iodine treatment, the disease becomes resistant to therapies in about 10 percent of patients, often metastasizing to the lymph nodes, lungs, bones and other sites. For nearly four decades, the only approved treatment for patients whose disease had progressed was doxorubicin, which was avoided because it was ineffective and highly toxic.The multicenter, international DECISION trial included 417 participants with advanced differentiated thyroid cancer that had progressed within the prior 14 months on radioactive iodine. Participants were randomized to take Nexavar or a placebo. Those in the Nexavar group experienced greater tumor shrinkage (12 percent versus 0.5 percent), a higher rate of stable disease (42 percent versus 33 percent at six months), and a longer period of time to disease progression (10.8 versus 5.8 months).Side effects were similar to those experienced by patients taking Nexavar for liver and kidney cancers: rash, fatigue, weight loss, hair loss, hypertension and diarrhea.Of the four types of thyroid cancer (papillary, follicular, medullary and anaplastic), the vast majority (80 to 90 percent) of cases are papillary and follicular--the types Nexavar targets. Affecting more women than men, thyroid cancer is the fastest-increasing cancer in the U.S.