Thyroid Cancer Cases Climb as Treatment Advances

February 05, 2008
Overall, cancer rates are declining in the United States, but some cancers are on the rise. Among these, thyroid cancer rates are climbing the fastest. Diagnosed cases in the United States now number more than 30,000 each year. The population's risk for the disease doubled from 1974 to 2004, according to the National Cancer Institute. Each year, about 1,500 people now die as a result of thyroid cancer. Many more women than men are stricken. Scientists who study disease trends suspect that better detection may be responsible for much of the rapid rise in thyroid cancer diagnosis. Others point to radiation or other environmental threats. Some evidence also suggests that being overweight is associated with a higher risk of certain forms of thyroid cancer. The trend toward growing numbers of overweight people in the United States is decades-long. Treatment Advances Whatever the causes of thyroid cancer, physicians at UCSF aim to cure or at least control it with appropriate treatment. On the other hand, they want to avoid hormone imbalances, harm to vocal cords or other side effects that diminish quality of life. Research shows that thyroid cancer patients fare best when treated by the most experienced surgeons - and the five endocrine surgeons who treat thyroid cancer at UCSF are among the most experienced. Orlo H. Clark, MD, former chief of surgery at UCSF Medical Center at Mount Zion, has been an early user of improved techniques and equipment throughout his 30-year career as a specialist in endocrine tumors. Early on, he created a stir by being among the first to advocate total removal of the thyroid in most cases of thyroid cancer. He justified the now generally accepted approach by showing that side effects of the surgery could be reduced, while at the same time cutting the chances of the cancer returning. Replacing thyroid hormone normally is not difficult. Clark and his fellow UCSF endocrine surgeons also were among the first to save the function of the neighboring parathyroid gland during thyroidectomy - by transplanting a portion to the arm - in cases where the blood supply to the parathyroid was compromised. More recently, UCSF thyroid surgeons have become experts in minimally invasive and endoscopic procedures to remove thyroid and parathyroid tumors. Search for Molecules That Predict Cancer Growth The most common and curable form of thyroid cancer is called papillary thyroid cancer. It accounts for 80 percent of cases. About 7 percent of patients die of papillary thyroid cancer within 10 years of diagnosis. A less common form, medullary thyroid cancer, arises in a different part of the gland. It is about four times as deadly. Unfortunately, growth of individual tumors or a recurrence of cancer after treatment is not always predicted by size, location or how cancer cells look to a pathologist. These factors are not much of a guide in deciding how aggressively to treat patients with thyroid cancer. Clark notes that over the past decade, blood thyroid hormone markers, use of radioactive iodine, and improvement in ultrasound, CT, MRI and PET imaging have dramatically increased the detection of residual thyroid tumor tissue in lymph nodes and elsewhere following surgery. In many cases, this detectable tumor tissue does not grow aggressively. Clark and surgeons Electron Kebebew, MD, Quan-Yang Duh, MD, Wen T. Shen, MD, and Jessica Gosnell, MD, are leading efforts to identify molecular markers in biopsy tissue. These markers should help distinguish aggressive cancer - requiring additional surgery, radiation or chemotherapy - from tumor tissue that only requires monitoring because the markers indicate it is unlikely to grow in a threatening way. "Our job is to think of new ways of doing it better," Clark says.