Nodules and Thyroid Cancer
Remember those abnormal lumps of tissue called thyroid nodules? It turns out they’re very common as we get older. While only about five per cent will have a lump that’s detectable by feel, “if you do a thyroid ultrasound on people 50 years of age, about half will have a nodule,” Opgenorth says. Typically, these are found by accident when someone undergoes a scan for some other reason—for example, an ultrasound to check for narrowing of the carotid artery.
About 95 per cent of such growths are benign, but since some are indeed cancerous, this discovery is usually followed by an ultrasound to check for worrying traits. “If someone has a suspicious nodule based on imaging characteristics or history,” Opgenorth says, the next step is usually to take a sample of cells with a small needle under ultrasound guidance. “If it looks malignant, or it’s not possible to tell whether it’s benign or not, then it’s treated with surgery,” she adds. (In about 20 to 25 per cent of cases, it’s not possible to tell whether a nodule is malignant simply by looking at cells under the microscope.) If cancer is present, the next question is how aggressively to treat it.
Currently, that decision is made based on factors such as the size of the tumour and the patient’s age. For example, for tumours smaller than one centimetre, “one option for management is observation,” explains Dr. Sam Wiseman, a surgeon and researcher specializing in the treatment of thyroid disease and cancer at St. Paul’s Hospital and an associate professor of surgery at the University of British Columbia in Vancouver. “For tumours that are considered to have a good prognosis, in some patients you don’t even necessarily have to take out the entire thyroid gland; you can take out the half that has the tumour in it.”
On the other hand, since the prognosis with the most common forms of thyroid cancer tends to be poorer in people over 45, “treatment of older people tends to be more aggressive in terms of surgery, as well as additional treatment after surgery, which is the use of radioactive iodine treatment,” Wiseman explains.
However, because we don’t yet have better ways to tell which thyroid cancers could eventually go on to become life-threatening, “I think we overtreat a lot of patients, and maybe we even undertreat some,” says Dr. Todd McMullen, an associate professor of surgery at the University of Alberta.
“The prognosis for the vast majority of people with thyroid cancer is excellent,” Wiseman says. “What we need are new tests that tell us not only whether a thyroid nodule is cancer, but how aggressive it will be. Such tests are being developed in my own and other research labs worldwide and will eventually allow for more tailored treatment of people diagnosed with thyroid nodules and cancer.”