Table 2.
Results, Active Surveillance vs. Immediate Surgery
| Author | Methods for addressing confounders | Subsequent surgery | Tumor growth | Recurrence after surgery | All-cause mortality | Thyroid cancer mortality | Lymph node metastasis | Distant metastasis |
|---|---|---|---|---|---|---|---|---|
| Ito et al. (19) and Ito et al. (20) [longer-term follow-up from Ito et al. (21)] | None (for AS vs. immediate surgery comparison) | AS: 32% (109/340) at 5 years [Ito et al. (21)]; 16% (191/1194) at 10 years [Ito et al. (20)] Indication for surgery: Diagnosis of familial carcinoma (1), tumor enlargement (32), young age (1), suspicion of multicentricity (7), tumor location near dorsal surface (17), patients' choice (12), lymph node metastasis (5), other thyroid disease (10), unknown (25) |
AS: 7.8% (10/129) at 10 years [Ito et al. (20)] Young age associated with increased risk of size enlargement in AS group |
AS: 0% (0/109) Immediate surgery: 3.0% (32/1055) |
Not reported | AS: 0% (0/340) Immediate surgery: 0.2% (2/1055) |
AS: 1.2% (2/162) at 5 years [Ito et al. (21)]; 3.7% (5/136) at 10 years [Ito et al. (20)] Immediate surgery: 50% (300/594) at time of surgery; not reported at follow-up 102 [Ito et al. (21)] Young age associated with increased risk of lymph node metastasis in AS group |
AS: none reported Immediate surgery: 0% (0/626) [Ito et al. (21)] |
| Jeon et al. (34) | Adjusted for age, sex, and serum TSH level | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported |
| Moon et al. (31) [earlier cohort reported in Kong et al. (22) and protocol reported in Moon et al. (25)] | Unclear (generalized estimating equation analyses performed, but do not describe adjustment for confounders) | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported |
| Nakamura et al. (35) [potential overlap with Ito et al. (19) and Ito et al. (20)] | None | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported |
| Oda et al. (26) Sasaki et al. (33) (AS arm only) | None | AS: 8.0% (94/1179); 7.1% (162/2288) [Sasaki et al. (33)] Indication for surgery: Patient request (54%), tumor enlargement ≥3 mm (29%), lymph node metastasis (6.4%), enlargement of associated benign nodules (5.3%), unclear (5.3%) |
Increase ≥3 mm AS: 2.3% (27/1179); 1.8% (42/2288) [Sasaki et al. (33)] |
AS: 1.1% (1/94) Immediate surgery: 0.5% (5/974) |
AS: 0.3% (3/1179) Immediate surgery: 0.5% (5/974) |
AS: 0% (0/1179) Immediate surgery: 0% (0/974) |
AS: 0.1% (1/1179); 0.7% (15/2288) [Sasaki et al. (33)] Immediate surgery: 0.3% (3/974) |
AS: 0% (0/1179) Immediate surgery: 0% (0/974) |
| Rosario et al. (27) | None | AS: 4.3% (3/70) Tumor enlargement (1), other (2) |
AS: 1.4% (1/70) | Not reported | None reported | None reported | AS: None reported Immediate surgery: 5.6% (1/18) |
AS: 0% (0/70) Immediate surgery: 0% (0/18) |
| Sakai et al. (28) [longer-term follow-up from same T1a cohort as Sugitani et al. (29) adds T1b with surgical comparison group]; also, Fukuoka et al. (17) and Nagaoka et al. (32) (7.6 year follow-up, AS only) |
None | AS: 2.6% (11/421); 9.5% (54/571) in Nagaoka et al. (32) Indication for surgery: Patient request (45%), tumor enlargement (36%), lymph node metastasis (9.1%), extrathyroidal infiltration (9.1%) |
Increase ≥3 mm AS: 8% (29/360, T1a) and 7% (4/61, T1b); 7.5% (54/718) in Nagaoka et al. (32) Volume increase ≥50% AS: 21% (74/360, T1a), 11% (7/61, T1b); 19.8% (142/718) in Nagaoka et al. (32) Noncalcification pattern and rich vascularity associated with increased risk of growth |
AS: 0% (0/11) Immediate surgery: 2.4% (8/331); all occurred in patients with tumor ≥15 mm; 5-year disease free survival for tumor ≥15 mm 99% and 10-year disease-free survival 95% |
None reported | None reported | AS: 0.8% (3/360, T1a) and 3.3% (2/61, T1b); 1.4% (8/571) in Nagaoka et al. (32) Immediate surgery: 1.5% (5/331, T1b) Younger age associated with increased risk of lymph node metastasis in T1b AS patients |
AS: None reported; 0% (0/571) in Nagaoka et al. (32) Immediate surgery: 0.3% (1/331, T1b) |
TSH, thyrotropin.