Assessing potential impact of 2015 American Thyroid Association guidelines on community standard practice for I-131 treatment of low-risk differentiated thyroid cancer: case study of Jordan.

OBJECTIVES: The 2015 American Thyroid Association (ATA) guidelines called for significantly more selective 131I therapy in patients with low-risk differentiated thyroid cancer (DTC). We hypothesized that application of these guidelines would significantly reduce the 131I activity utilized by an academic tertiary hospital in Jordan. METHODS: All DTC patients managed at Jordan University Hospital (JUH) between 1/2009 and 6/2019 were classified according to the 2015 ATA risk category and 131I activity was assigned accordingly. The actual 131I activity administered was compared with that recommended by the 2015 ATA guidelines. RESULTS: In total, 135/182 DTC patients (74.2%) managed at JUH underwent 131I therapy. Of those, 58 (43%) had ATA low-, 58 (43%) intermediate-, and 19 (14%) high-risk disease. The low-, intermediate-, and high-risk DTC patients received an average (±SD) initial 131I activity of 3.53 ± 0.95, 4.40 ± 1.49, and 5.06 ± 2.52 GBq, respectively. Withholding 131I therapy altogether in the 2015 ATA low-risk patients would result in decreasing the 131I activity in the overall patient population by 37%. Withholding 131I therapy only in low-risk papillary thyroid microcarcinomas while administering 1.11 GBq of 131I to other low-risk patients would result in 28% reduction of 131I. CONCLUSION: This study demonstrates a significant reduction in 131I therapeutic activity that would be given to DTC patients in an academic tertiary setting in Jordan, following acceptance of the 2015 ATA recommendations. Institutions that adopted the 2015 ATA guidance should measure outcomes in comparison to their historical controls and report those findings, while long-term results of randomized controlled trials are forthcoming.

Transient ischemic dilatation with adenosine 99mTc-sestamibi stress: prognostic significance in patients with normal myocardial perfusion.

OBJECTIVE: To determine the significance of transient ischemic dilatation (TID) in patients with normal perfusion on adenosine stress/rest. METHODS: We analyzed 430 consecutive patients with normal perfusion on 2-day adenosine stress/rest 99mTc-sestamibi. A group of 70 patients with Framingham 10-year coronary heart disease risk < 10% was used to derive abnormal TID thresholds (derivation group). The significance of TID at these thresholds was validated in the remaining 360 patients (validation group) followed for cardiac events for 31.2 ± 9.7 (mean ± SD) months. RESULTS: Transient ischemic dilatation in the derivation group was 1.05 ± 0.13. Three definitions of an abnormal TID were used: > mean + 2SD (TID ≥ 1.32), > mean + 1SD (TID ≥ 1.19) and a TID in the group's highest quartile (TID ≥ 1.15). Of the 360 validation group patients, 12 (3.3%), 48 (13.3%) and 70 (19.4%) had TID ≥ 1.32, 1.19 and 1.15, respectively. Age, gender, family history of coronary artery disease (CAD), known CAD, smoking, hypertension, diabetes, dyslipidemia, rest LVEF, post-stress LVEF, ΔLVEF, ≥ 5% or 10% decrease in LVEF did not predict TID ≥ 1.32. However, TID ≥ 1.19 was predicted by rest LVEF and ≥ 5% decrease in LVEF (P = 0.04 and 0.02, respectively) and TID ≥ 1.15 was predicted by ≥ 5% decrease in LVEF (P = 0.02). Cardiac event-free survivals were similar in patients with a TID ≥ and < 1.32 (P = 0.68), ≥ and < 1.19 (P = 0.40) and ≥ and < 1.15 (P = 0.79). CONCLUSIONS: Transient ischemic dilatation does not confer adverse prognosis in patients with normal perfusion on adenosine stress/rest 99mTc-sestamibi irrespective of the threshold used for its definition.