BACKGROUND
Thyroid cancer has been one of the fastest rising cancers over the past few years. One of the causes of this increase has been the increase in detection of small, low risk cancers, most often papillary thyroid cancer. These cancers that are <1 cm are called papillary thyroid microcarcinomas. Most of the time, the next step after diagnosis of cancer is surgery to remove the thyroid. However, ~30 years ago, the concept of monitoring these small cancers with ultrasound instead of opting for immediate surgery, called active surveillance, was introduced in Japan. For those patients in active surveillance, if their cancer were to grow over time or spread to lymph nodes in the neck, surgery would be recommended. The option of active surveillance for small thyroid cancers was included in the American Thyroid Association’s 2015 thyroid cancer management guidelines as an alternative to surgery. Research data on long-term outcomes, however, is scant. This study reports on the long-term experience with active surveillance for papillary thyroid microcarcinoma in Japan.

THE FULL ARTICLE TITLE
Miyauchi A et al 2023 Long-term outcomes of active surveillance and immediate surgery for adult patients with low-risk papillary thyroid microcarcinoma: 30-year experience. Thyroid. Epub 2023 May 29. PMID: 37166389.

SUMMARY OF THE STUDY
Data from the largest available database worldwide of patients with papillary thyroid microcarcinoma in Kuma Hospital in Japan was used to identify patients. A total of 5646 were enrolled in the study between October 1993 and December 2019 and offered the option of either active surveillance or immediate surgery. Of the 5646 patients with papillary thyroid microcarcinoma,

57.1% underwent active surveillance for a year or longer, while 42.9% underwent surgery within 1 year of their diagnosis. The average duration of active surveillance was 7.3 years, while the surgery group was followed for an average of 11.9 years after thyroid surgery. About 12.2% (394) patients that were in the active surveillance group eventually did have surgery for various reasons, mostly due to patient or physician preference. Less than 1/3 of these patients actually had a change of their cancer. The extent of surgery and lymph node removal were similar between the immediate surgery and the later surgery groups.

Very few patients under active surveillance had significant cancer growth, spread to the lymph nodes or new cancer nodules on their thyroid gland. Of all 5,646 patients, only 1 had spread of the cancer to the lungs in the active surveillance group and 1 in the immediate surgery group, both of whom are alive over 18 years after the initial diagnosis. Death from thyroid cancer was 0% in both groups.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
In this review of nearly 30 years follow-up of a study on active surveillance in patients with papillary thyroid microcarcinoma, the cancer-related outcomes of patients followed by surveillance did not differ from those of patients who had surgery within 1 year after diagnosis. No patient died of thyroid cancer in either group. This study strongly supports that surveillance is a viable (and many times, better) initial management option for many patients with low-risk papillary thyroid microcarcinomas. This data suggests that physicians should consider offering active surveillance as a reasonable, safe strategy in appropriate patients with low-risk papillary thyroid microcarcinomas.

— Maria Brito, MD

Table of Contents | PDF File for Saving and Printing