Table 3.

Overall Incidence of Unfavorable Events in Patients Who Chose Active Surveillance and in Those Who Underwent Immediate Surgery

Variables	AS group (N = 2896)		IS group (N = 1739)		p
	No. of events	% [CI]	No. of events	% [CI]
Surgery	242	8.4 [7.4–9.4]	1739	100. [100–100]	<0.001
Levothyroxine administration after diagnosisa	729	25.2 [23.6–26.8]	1134	65.2 [63.0–67.5]	<0.001
Postoperative hematoma requiring reoperation	1	0.0 [0.0–0.2]	13	0.7 [0.4–1.3]	<0.001
Transient vocal cord paralysis	26	0.9 [0.6–1.3]	151	8.7 [7.5–10.1]	<0.001
Permanent vocal cord paralysis caused byb	0	0.0 [0–NaN]	15	0.9 [0.5–1.4]	<0.001
Accidental transection or injury			4	0.2 [0.1–0.6]
Surgery for tumor invasion			11	0.6 [0.4–1.1]
Transient hypoparathyroidism	60	2.1 [1.6–2.7]	362	20.8 [19.0–22.8]	<0.001
Permanent hypoparathyroidismc	5	0.2 [0.1–0.4]	24	1.4 [0.9–2.1]	<0.001
Recurrence in the neck	1	0.0 [0.0–0.2]	9	0.5 [0.3–1.0]	<0.001
Contralateral lobe	0	0.0 [0–NaN]	6	0.3 [0.2–0.8]	0.002
Lymph node	1	0.0 [0.0–0.2]	3	0.2 [0.1–0.5]	0.121
Distant metastasis	0	0.0 [0–NaN]	0	0.0 [0–NaN]	N/A
Death from thyroid cancer	0	0.0 [0–NaN]	0	0.0 [0–NaN]	N/A

^a Patients who were administered levothyroxine before diagnosis were not included.

^b Persistent vocal code paralysis on laryngoscopy one year after surgery or longer.

^c Administration of vitamin D and/or calcium preparation one year after surgery or longer.

AS, active surveillance; N/A, not available.