An active surveillance management approach to low-risk thyroid cancer has been pioneered and effectively implemented in Japan. Now, researchers say it may be time to do the same thing in the United States.
Researchers from Memorial Sloan Kettering Cancer Center in New York reported at the 86th Annual Meeting of the American Thyroid Association (ATA) that an active surveillance management approach to low-risk thyroid cancer could safely and effectively be employed in the US population.
The researchers looked at a series of nearly 300 patients who had fine needle aspiration biopsy results and were either definite or suspicious for papillary thyroid cancer, with sizes ranging from 3 mm to about 15 mm. The patients elected to be followed with observation rather than immediate surgery.
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“After a follow-up of nearly 2 years, only 6 patients demonstrated an increase in the size of their tumor (about 2% to3%) and no patient developed lymph node metastases. Importantly, surgery was curative at the time of disease progression in the patients who initially chose an observational management approach,” said study investigator R. Michael Tuttle, MD, clinical director of the endocrinology service at Memorial Sloan Kettering Cancer Center.
An active surveillance management approach for low-risk thyroid cancer has been shown to be both safe and effective in Japan, the researchers noted. However, it remains uncertain whether this type of monitoring would be accepted and successful in the United States.
Dr Tuttle and colleagues employed careful risk stratiﬁcation, and the thyroid cancer disease management team at Dr Tuttle’s institution has offered an observational management approach to selected patients with low-risk papillary thyroid cancer for many years. It has set up a protocol that calls for an ultrasound every 6 months for 2 years, then yearly without levothyroxine suppression.
As of August 2016, 278 low-risk patients were being followed with an active surveillance management approach, noted Dr Tuttle. Among these patients, 84% (n=234) had Bethesda VI and 16% (n=44) had Bethesda V cytology. The cohort was predominantly composed of women (75%) and the median age at diagnosis was 52 years. The median tumor size was 8 mm (range: 3–22 mm) and the median follow-up was 20 months.
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The team has been pleasantly surprised with the overall findings at the follow-up, according to Dr Tuttle. As of August 2016, 96% (n=267) continue on active surveillance without evidence of structural disease progression. He also said 2.2% of the patients (n=6) experienced an increase in the size of the primary tumor greater than 3mm. Among these 6 patients, the median diameter increased from 9.5 mm to 11.5 mm during 23 months of observation. In this cohort, 1.1% of the patients (n=3) elected to have surgery without evidence for structural disease progression and 0.7% of the patients (n=2) transferred their care back to the community.
In this cohort, no patient developed lymph node metastases. The investigators also found that neither the size of the primary tumor nor gender predicted tumor growth. The same was true for the duration of follow-up. Dr Tuttle said what did stand out was that the patients showing an increase in tumor size during observation tended to be younger than those with stable disease, but nonetheless were effectively treated with surgery if they did demonstrate an increase in the size of the primary tumor.
“An observational management approach (serial neck ultrasounds every 6 to12 months) is a very reasonable option for thyroid nodules less than 1 cm that either appear to be thyroid cancer based on ultrasound features or are biopsy-proven papillary thyroid cancer,” Dr Tuttle told Endocrinology Advisor. “Obviously, an observational management approach is not appropriate or preferable for all patients. But since this can be safely done in many patients, clinicians should consider observation rather than immediate surgery for very low-risk thyroid cancers.”