Elsevier Global Medical News
Author – MG Sullivan

PARIS (EGMN) – Patients with a non-decisive fine-needle aspiration for large non-diagnostic thyroid nodules or lesions of undetermined significance should be considered for surgery because more than half of these large nodules can be malignant.

In a review of 156 patients with non-decisive fine-needle aspirations (FNAs), nodule size was a major determinant in surgical referral, Dr. Susana Mascarell said at the International Thyroid Congress. “Nodules of this size were associated with a malignancy rate of up to 60%,” said Dr. Mascarell of the John H. Stroger Jr. Hospital of Cook County, Chicago.

FNA is considered the main diagnostic tool in deciding which patient to refer to surgery. “However,” Dr. Mascarell said, “the FNA results may not be helpful when the cytology specimen is non-diagnostic or qualifies as a follicular lesion of undetermined significance – both classifications that are part of the new six-level FNA classification system suggested by the National Cancer Institute.”

When an FNA comes back as non-decisive on such specimens, the clinician must choose between surgery and clinical follow-up as the next step. Unfortunately, said Dr. Mascarell, there are no hard-and-fast rules about which management path to choose.

Molecular markers are becoming more important in the decision, but can’t be relied upon in every patient, she said. “When these markers are present in high concentrations, they are up to 99% accurate in identifying malignant nodules and so are a very helpful tool. But only 40% of nodules are positive for these risk markers, so we still have an unmet need of what to do with many other patients.”

Dr. Mascarell and her colleagues reviewed all thyroid FNAs performed at the hospital from 2004 to 2007. Out of nearly 500 tests, 156 were non-decisive. Of these specimens, 90 (58%) were classified as follicular lesions of undetermined significance (FLUS) and 66 (42%) as non-diagnostic.

Overall, 104 patients had a thyroidectomy (77% of the FLUS group and 52% of the non-diagnostic group). The rest were followed clinically. The rate of malignancy was 41% in the FLUS patients and 32% in the non-diagnostic patients.

Among those with FLUS who had surgery, 50% had no other clinical indication for surgery except the non-decisive FNA, Dr. Mascarell said. “The most common documented indication was a nodule size of 3 cm or larger in 29%.” Other indications – each of which accounted for less than 5% – were male gender, a family history of thyroid cancer, exposure to radiation, and a suspicious ultrasound exam.

“In the non-diagnostic group, all of those who went for surgery had other indications [besides the FNA result]. The most common one was a cold thyroid scan in 31%. Other indications were nodule size (20%), microcalcifications on ultrasound (16%), and a history of radiation exposure (15%).” Indications that Dr. Mascarell did not specify accounted for the remaining 18%.

Half of all patients for whom nodule size was the documented surgical indication had clinically significant thyroid cancer. “When we compared the surgical and clinical follow-up groups, we found that 60% of the surgical group had a lesion 3 cm or larger, compared with 29% of the follow-up group, so clearly, when clinicians found a large lesion, most of them referred to surgery,” Dr. Mascarell said.

Dr. Mascarell said she had no potential conflicts of interest.