A long-term follow-up study found most benign thyroid modules showed little growth, and rarely turned into thyroid cancer.

The detection of these types of nodules has been on the rise because of improved clinical screening methods, but a clear consensus has not been reached on what must be done after these nodules have been spotted, JAMA reported.  Current guidelines recommend serial ultrasound examinations and repeat cytology exams if growth is observed in the nodule, but the incidence rates of nodule growth have remained unclear.

Some follow-up options include: "cytologically (analysis of aspirated cells) proven benign lesions and sonographically (an imaging technique using ultrasonic waves) nonsuspicious nodules," the researchers reported.

"One of the goals of surveillance is the prompt detection and treatment of thyroid cancers that arise during follow-up or have been missed on the initial assessment. In the population we studied, these events were rare," the authors wrote.

A team of researchers looked at 992 patients who had between one and four "asymptomatic, sonographically or cytologically benign" thyroid nodules, and performed a five-year follow-up. Nodule growth was observed in 15.4 percent of the study participants, but the nodules shrank in 18.5 percent of the individuals. Thyroid cancer was diagnosed in only five of the original nodules, only two of which had grown; new nodules occurred in 9.3 percent of the patients.

"These data suggest that the American Thyroid Association's recommendation for indication for repeat cytology should be revised. Clinical and sonographic findings should probably play larger roles in the decision-making process," the researchers concluded.

The findings were published in recent edition of the journal JAMA.