July 3, 1995
Media Contact: John Cramer
Phone: (410) 955-1534
A test routinely performed during thyroid surgery to check growths for signs of cancer is largely useless, misleading, costly and prolongs the operation, according to Johns Hopkins researchers.
Frozen section evaluation could be dropped until a better diagnostic guide becomes available for follicular thyroid lesions, the study recommends. Instead, surgeons should simply remove the lobe of the thyroid with the nodule and rely on tissue analysis after surgery to determine if it is malignant, the study finds. Further surgery can then be done to remove the entire gland.
"We recommend that routine frozen section evaluation be omitted in the surgical management of follicular thyroid lesions," says Robert Udelsman, M.D., the study's senior author and director of endocrine surgery at The Johns Hopkins Medical Institutions. "Frozen section evaluation is of minimal diagnostic value, rendering no additional information 87 percent of the time, prolongs the operation, increases costs and leads to misguided interventions."
Results of the study are published in the July issue of Annals of Surgery.
Frozen section evaluation can reliably diagnose most malignant growths in the thyroid, but it is less accurate with follicular thyroid lesions, according to the study.
Four to 7 percent of the U.S. population has thyroid nodules. About 5 percent are malignant. The thyroid, a butterfly-shaped gland in the neck, regulates tissue and organ function throughout the body by secreting hormones into the blood.
Investigators looked at 125 consecutive patients with follicular thyroid lesions who underwent surgery from May 1984 to January 1994 at Hopkins. In 87 percent of cases, frozen section evaluation during surgery rendered no useful information and final treatment was determined through tissue analysis after surgery. In 5 percent of the cases, frozen section evaluation yielded incorrect results and misled the surgeon. In 3.3 percent of the cases, frozen section evaluation yielded information that was confirmed as accurate on final review of the tissue.
Total cost for a frozen section evaluation ranges from $500 to $800 per patient -- including $400 to $600 per specimen and the 10-30 minute additional operating room time required while the specimen is evaluated, results showed. Based on the above calculations that the procedure is useful only 3.3 percent of the time, each useful evaluation costs $15,000 to $24,000.
Udelsman notes that frozen section evaluation is used routinely during surgery because preoperative biopsies are unreliable for follicular thyroid nodules. In frozen section evaluation, the lesion is removed and quickly frozen for microscopic analysis to try to determine if it is malignant. The results are forwarded to the surgeon who is waiting for guidance before continuing the operation.
Current research seeking a reliable preoperative guide is focusing on molecular techniques to detect genes that cause cancer and mutations in genes linked to follicular cancers.
Other researchers in the study were lead author Herbert Chen, M.D., and Theresa L. Nicol, M.D.