More permissive parameters for active surveillance eligibility is potentially possible in slow-growing thyroid cancers

by Kassandra McFarlane, Sze Wah Samuel Chan

Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Patients in the active surveillance group who had forgone surgery had no difference in survival compared to patients who underwent surgery

2. Patients receiving immediate surgery for thyroid cancer have increased anxiety as compared to patients receiving active surveillance only.

Evidence Rating Level: 2 (Good)

Study Rundown:

Active surveillance has been recommended by the American Thyroid Association for the management of thyroid tumours identified as very low risk. This study aimed to determine whether widened parameters for active surveillance is suitable and also to compare anxiety levels between patients receiving immediate surgery and those receivimageing active surveillance for their tumours. The primary outcome of interest was cumulative incidence of tumour growth and secondary outcomes included anxiety levels. Tumour growth of greater than 5 mm represented the cutoff for recommending surgery and was noted in 3.6% patients receiving active surveillance. Two year cumulative incidence of more than 5 mm of tumour growth was 1.2%. Five year cumulative incidence of greater than 5 mm growth was 10.8%. Despite this, a majority of patients continued with active surveillance for management of their slow-growing thyroid tumours and overall survival rates were 100% for all patients in either arm of the study at the time of study follow-up. Anxiety levels in the immediate surgery group were significantly higher than levels in the active surveillance group and remained that way even at 4 years follow up. Limitations to this study include that it was a non-randomized study and so the results may be affected by confounders. Additionally, the sample size was relatively small and future studies would benefit from recruiting increased numbers of patients. Overall, the results from this study suggest that expanding the eligibility parameters for active surveillance is a potentially viable option to investigate for larger, slow-growing thyroid cancer tumours.

In-Depth [prospective cohort]:

This non-randomized, prospective trial was completed out of a single healthcare centre in the United States. The study enrolled 222 adult patients with Bethesda 5 or 6 thyroid nodules less than 20 mm in size who elected to receive either active surveillance (112 patients) or immediate surgery (110 patients). Previous studies employed stricter inclusion criteria for active surveillance eligibility (i.e. tumour size less than 1 cm). The cumulative incidence at 2 years for tumour growth greater than 5 mm was 1.2% (95% confidence interval (CI), 0.1-5.8%) and at 5 years it was 10.8% (95% CI, 3.0-24.2%). Baseline anxiety levels in the group receiving immediate surgery were higher than those of the group receiving active surveillance (estimated difference in anxiety scores, 0.39; 95% confidence interval (CI), 0.22-0.55). Additionally, anxiety scores in the immediate surgery group remained elevated, whereas the active surveillance group anxiety scores exhibited a declining trend (estimated difference at 4 years of follow up, 0.50; 95% CI, 0.21 – 0.79).

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