2017 Section 7 Green Book

PROPHYLACTIC CND DID NOT SIGNIFICANTLY LOWER LRR

Forest plot for overall morbidity after excluding temporary hypocalcemia.

FIG. 4.

test and Egger’s regression test, it is worth nothing that there was one particular large recent study that could have had a profound impact on the overall IRR (29). In fact, its number of person-years in groups A and B were almost two to three times of that of the next largest study (25). Nevertheless, on the funnel plot (data not shown), this particular study was just on the margin of the funnel, and therefore it was not excluded from the final meta-analysis. Despite this important positive finding, we remain cautious in our conclusions, as there are a number of potential limita- tions. First, the mean follow-up period was relatively short in one study, having a mean follow-up period of only 10 months. In fact, the overall mean follow-up duration for groups A and B was only 45.2 and 50.8 months, respectively, and hence both groups had a mean follow-up of less than five years. Given the fact that PTC is a relatively slow-growing, indolent tumor, patients may not develop detectable LRR until many years

and B were 598.9 and 662.3, respectively. Group A had sig- nificantly lower LRR than group B (75/1592 (4.7%) vs. 149/ 1739 (8.6%); IRR = 0.65 [CI = 0.48–0.86]). The potential publi- cation bias was not significant, as confirmed by Begg analysis (Kendall’s tau = - 0.1677, p = 0.4268) and the Egger regression test ( z = 0.0984, p = 0.9216).

Discussion

To our knowledge, this is to date one of the largest meta- analyses evaluating the impact of pCND on LRR in patients with clinically nodal negative PTC or cN0. With significantly more patients being included than in previous meta-analyses, our data suggest that those who undergo TT + pCND have a 35% reduction in risk of LRR than those who undergo TT alone. Although no significant publication bias was found in our meta-analysis, as shown by the Begg’s rank correlation

Table 3. Comparison of Locoregional Recurrence Rate Between Total Thyroidectomy + Prophylactic Central Neck Dissection (Group A) and Total Thyroidectomy Alone (Group B)

Number of LRR (%)

Mean follow-up (months)

Number of person-years

Incidence rate ratio [CI]

First author

A

B

A

B

A

B

Roh (17) Choi (18) Bardet (19) Perrino (20) Costa (21) Zuniga (22)

0 (0.0) 1 (2.1) 4 (11.1) 5 (5.4) 8 (6.3) 19 (14.0) 2 (4.4) 2 (2.6) 13 (5.0) 2 (1.7) 3 (3.7) 0 (0.0) 1 (0.8) 15 (5.8)

3 (4.1) 2 (3.8) 6 (3.7)

51

53

170

322 108

0.27 [0.01–5.25] 0.55 [0.05–6.09]

24.4 na a 69.2

24.4 na a 69.2

98

—

—

—

22 (13.8)

531 494 832 140 124 691 443 193

917 629

0.39 [0.15–1.04] 1.13 [0.44–2.94] 0.91 [0.50–1.64] 0.27 [0.05–1.32] 1.20 [0.17–8.52] 0.94 [0.49–1.81] 0.48 [0.09–2.63] 1.42 [0.29–7.04] 0.76 [0.01–38.06] 1.53 [0.06–37.56] 0.33 [0.18–0.59] 0.65 [0.18–0.86]

9 (7.6)

47

62

26 (20.0) 6 (16.7) 2 (3.1) 29 (8.4) 4 (3.5) 3 (2.9) 0 (0.0) 0 (0.0) 37 (13.1)

73.44

95.52

1035

Moo (23)

37.2 19.1

37.2 27.5

112 149

Hughes (24) Popadich (25)

32

50

1446

So (26)

44.7 28.2

45.4 31.9

428 274

Lang (7)

Wang (27)

10

10

41

31

Raffaelli (28)

25.0

25.5

258

132

Barczynski (29)

126.4

128.8

3771

3027

Overall

75

149

45.2

50.8

598.9

662.3

a Only medians were provided and therefore incidence rate ratio could not be calculated. LRR, locoregional recurrence.

85