A new test increases the odds by 30 percent that people with thyroid cancer will undergo the correct initial surgery.
“Before this test, about one in five potential thyroid cancer cases couldn’t be diagnosed without an operation to remove a portion of the thyroid,” says Linwah Yip, assistant professor of surgery in the University of Pittsburgh School of Medicine.
Yip says without the test a second surgery to remove the thyroid was often required if the portion removed during the first surgery came back positive for cancer.
“The molecular testing panel now bypasses that initial surgery, allowing us to go right to fully removing the cancer with one initial surgery. This reduces risk and stress to the patient, as well as recovery time and costs,” adds Yip, lead author of the study published in the Annals of Surgery.
Cancer in the thyroid, which is located in the “Adam’s apple” area of the neck, is now the fifth most common cancer diagnosed in women. Thyroid cancer is one of the few cancers that continues to increase in incidence, although the five-year survival rate is 97 percent.
Previously, the most accurate form of testing for thyroid cancer was a fine-needle aspiration biopsy, where a doctor guides a thin needle to the thyroid and removes a small tissue sample for testing. However, in 20 percent of these biopsies, cancer cannot be ruled out.
A lobectomy, which is a surgical operation to remove half of the thyroid, is then needed to diagnose or rule-out thyroid cancer. In the case of a postoperative cancer diagnosis, a second surgery is required to remove the rest of the thyroid.
Researchers have identified certain gene mutations that are indicative of an increased likelihood of thyroid cancer, and the new molecular testing panel can be run using the sample collected through the initial, minimally invasive biopsy, rather than a lobectomy. When the panel shows these mutations, a total thyroidectomy is advised.
Yip and her colleagues followed 671 patients with suspicious thyroid nodes who received biopsies. Approximately half the biopsy samples were run through the panel, and the other half were not. Patients whose tissue samples were not tested with the panel had a 2.5-fold higher statistically significant likelihood of having an initial lobectomy and then requiring a second operation.
“We’re currently refining the panel by adding tests for more genetic mutations, thereby making it even more accurate,” says coauthor Yuri Nikiforov, a professor in the pathology department. “Thyroid cancer is usually very curable, and we are getting closer to quickly and efficiently identifying and treating all cases of thyroid cancer.”
A grant from UPMC funded the study.
Source: University of Pittsburgh