The Effects of Radioiodine Therapy on the Recovery of Parathyroid Function in Patients with Protracted Hypoparathyroidism after Total Thyroidectomy for Papillary Thyroid Carcinoma

Figures & data

Table 1. Demographic and clinicopathological characteristics of the 260 patients who developed protracted HypoPT with or without 131I treatment.

	Control group (n = 94) (%)	131I group (n = 166) (%)	p
PTC with Hashimoto thyroiditis	26(27.66)	48(28.92)	0.79
PTC with Nodular goiter	45(47.87)	93(56.02)	0.18
Surgical approach			0.00*
TT + iCND	28(29.79)	25(15.06)
TT + bCND	57(60.64)	73(43.98)
TT + bCND + iLND	8(8.51)	53(31.93)
TT + bCND + bLND	1(1.06)	15(9.04)
T stage			0.04*
T1 /T2 /≥T3	57(60.64) /2(2.13) /35(37.23)	76(45.78) /11(6.63) /79(47.59)
N stage			0.00*
N0/ N1a/ N1b	70(74.47)/ 17(18.09)/ 7(7.45)	45(27.11)/ 59(35.54)/ 62(37.35)
M stage			0.63
M1	1(1.06)	3(1.81)
Total number of PG			0.25
0/ 1/ 2/ 3/ 4/ 5	0(0)/ 4(4.26)/ 7(7.45)/ 14(14.89)/ 69(73.4)/ 0(0)	1(0.6)/ 4(2.41)/ 18(10.84)/ 35(21.08)/ 104(62.65)/ 4(2.41)
All PG left in situ
NO/ YES	67(71.28)/ 27(36.49)	130(78.31)/ 36(21.69)	0.16
PGRIS			0.29
0/ 1 ∼ 2/ 3 ∼ 4	7(7.45)/ 37(39.36)/ 51(54.26)	12(7.23)/ 81(48.8)/ 73(43.98)
Proportion of PG retained in situ			0.29
0–1/3	41(43.62)	57(34.34)
1/3–2/3	21(22.34)	43(25.9)
2/3–1	32(34.04)	66(39.76)
Accidental parathyroidectomy			0.13
0/ 1/ 2	83(88.3)/ 10(10.64)/ 1(1.06)	148(89.16)/ 10(6.02)/ 8(4.82)
Times of 131Itreatment			0.00*
0/ 1/ 2/ 3	40(42.55)/ 0(0)/ 0(0)/ 0(0)	0(0)/ 158(95.18)/ 6(3.61)/ 2(1.2)
Persistent hypoPT			0.02*
NO/ YES	71(75.53)/ 24(25.53)	101(60.84)/ 65(39.16)
PTH (pmol/L)
Pre-op	5.46 ± 1.8	6.01 ± 2.41	0.16
Post-op 1 day	1.01 ± 0.74	1.1 ± 1.45	0.56
3day	1.08 ± 1.39	1.03 ± 1.42	0.2
1 mo	2.51 ± 2.45	2.71 ± 2.31	0.36
6 mo	2.8 ± 1.68	3.62 ± 4.25	0.14
12 mo	3.42 ± 3.54	3.3 ± 2.96	0.67
Last mo	2.88 ± 1.6	3.56 ± 4.11	0.81
Ca (mmol/L)
Pre-op	2.31 ± 0.1	2.31 ± 0.1	0.65
Post-op 1 day	2.02 ± 0.17	2.03 ± 0.18	0.59
3day	1.99 ± 0.19	1.93 ± 0.26	0.22
1 mo	2.08 ± 0.22	2.08 ± 0.23	1
6 mo	2.13 ± 0.18	2.09 ± 0.17	0.19
12 mo	2.13 ± 0.18	2.13 ± 0.22	0.56
Last mo	2.09 ± 0.19	2.06 ± 0.18	0.48

* , significantly statistical differences.

PTC: papillary thyroid carcinoma; TT: Total thyroidectomy; CND: Central lymph node dissection; LND: Lateral lymph node dissection; Pre-op: preoperative; post-op: postoperative; mo: month; PG: parathyroid gland; PTH: parathormone; PGRIS: number of parathyroid glands remaining in situ.

Figure 1. The changes of PTH (A) and Ca (B) levels following 131I treatment.

Table 2. Demographic and clinicopathological characteristics of the 260 patients who recovered from protracted HypoPT or developed persistent HypoPT.

	Persistent HypoPT (n = 88) (%)	Recovered (n = 172) (%)	p
Hashimoto thyroiditis	24(27.27)	50(29.07)	0.76
Nodular goiter	43(48.86)	95(55.23)	0.33
Surgical approach			0.15
TT + iCND	17(19.32)	36(20.93)
TT + bCND	46(52.27)	84(48.84)
TT + bCND + iLND	16(18.18)	45(26.16)
TT + bCND + bLND	9(10.23)	7(4.07)
T stage			0.31
T1 /T2 ≥ T3	41(46.59) /3(3.41)44(50)	92(53.49) /10(5.81)70(40.7)
N stage			0.97
N0/ N1a/ N1b	39(44.32)/ 25(28.41)/ 24(27.27)	76(44.19)/ 51(29.65)/ 45(26.16)
M stage			0.71
M1	1(1.14)	3(1.74)
Total number of PG			0.02*
0/ 1/ 2/ 3/ 4/ 5	1(1.14)/ 6(6.82)/ 12(13.64)/ 16(18.18)/ 53(60.23)/ 0(0)	0(0)/ 2(1.16)/ 13(7.56)/ 33(19.19)/ 120(69.77)/ 4(2.33)
All PG left in situ
NO/ YES	68(77.27)/ 20(22.73)	128(74.42)/ 44(25.58)	0.61
PGRIS			0.03*
0/ 1 ∼ 2/ 3 ∼ 4	11(12.5)/ 40(45.45)/ 37(42.05)	7(4.07)/ 78(45.35)/ 87(50.58)
Proportion of PG retained in situ			0.65
0–1/3	33(37.5)	65(37.79)
1/3–2/3	19(21.59)	45(26.16)
2/3–1	36(40.91)	62(36.05)
Accidental parathyroidectomy			0.93
0/ 1/ 2	79(89.77)/ 6(6.82)/ 3(3.41)	152(88.37)/ 14(8.14)/ 6(3.49)
131 I treatment			0.02*
NO/ YES	23(26.14)/ 65(73.86)	71(41.28)/ 101(58.72)
Times of 131Itreatment			0.13
0/ 1/ 2/ 3/ 4	23(26.14)/ 59(67.05)/ 4(4.55)/ 2(2.27)/ 0(0)	71(41.28)/ 94(54.65)/ 4(2.33)/ 2(1.16)/ 1(0.58)
Dosages of 131 I (mCi)			0.76
30/ 50/ 60/ 80/ 100/ 150/ 200	1(1.14)/ 0(0)/ 0(0)/ 0(0)/ 53(60.23)/ 8(9.09)/ 3(3.41)	5(2.91)/ 1(0.58)/ 1(0.58)/ 1(0.58)/ 77(44.77)/ 12(6.98)/ 4(2.33)
Intervals of 131I treatment from surgery(days)			0.13
<60	21(23.86)	30(17.44)
≤60 < 180	44(50)	65(37.79)
≥180	0(0)	6(3.49)
PTH (pmol/L)
Pre-op	6.12 ± 2.56	5.65 ± 2.01	0.34
Post-op 1 day	1.07 ± 1.42	1.06 ± 1.13	0.4
3day	1.17 ± 1.56	0.98 ± 1.31	0.96
1 mo	2.63 ± 3.43	2.64 ± 1.57	0.01*
6 mo	2.57 ± 2.06	3.83 ± 4.23	0.00*
12 mo	3.59 ± 5.23	3.25 ± 1.91	0.01*
Last mo	3.59 ± 5.5	3.15 ± 1.25	0.02*
Ca (mmol/L)
Pre-op	2.31 ± 0.11	2.31 ± 0.1	0.68
Post-op 1 day	2.01 ± 0.18	2.03 ± 0.17	0.54
3day	1.93 ± 0.24	1.96 ± 0.24	0.24
1 mo	2.06 ± 0.23	2.09 ± 0.23	0.37
6 mo	2 ± 0.18	2.17 ± 0.13	0.00*
12 mo	1.99 ± 0.14	2.2 ± 0.2	0.00*
Last mo	1.91 ± 0.19	2.16 ± 0.1	0.00*

* , significantly statistical differences.

TT: Total thyroidectomy; CND: Central lymph node dissection; LND: Lateral lymph node dissection; Pre-op: preoperative; post-op: postoperative; mo: month; PG: parathyroid gland; PTH: parathormone; PGRIS: number of parathyroid glands remaining in situ.

Table 3. Multivariate analysis for persistent HypoPT vs. recovery from protracted HypoPT.

	P	OR	CI
I 131 treatment	0.02*	1.98	1.11 ∼ 3.51
PGRIS	0.05*
1 ∼ 2	0.03*	3.19	1.13 ∼ 8.99
3 ∼ 4	0.02*	3.62	1.29 ∼ 10.2

* significantly statistical differences.

PGRIS: number of parathyroid glands remaining in situ.

Table 4. Demographic variables of 172 patients who recovered from protracted hypoPT within six months, after six months, and/or twelve months after surgery.

	<6 months(n = 100) (%)	6 ≥ months > 12(n = 49) (%)	≥12 months(n = 23) (%)	p
Hashimoto thyroiditis	26(26)	18(36.73)	6(26.09)	0.38
Nodular goiter	55(55)	28(57.14)	12(52.17)	0.92
Surgical approach				0.31
TT + iCND	23(23)	6(12.24)	7(30.43)
TT + bCND	49(49)	24(48.98)	11(47.83)
TT + bCND + iLND	26(26)	15(30.61)	4(17.39)
TT + bCND + bLND	2(2)	4(8.16)	1(4.35)
T stage				0.91
T1 /T2 /≥T3	53(53) /5(5) /42(42)	28(57.14) /3(6.12) /18(36.73)	11(47.83) /2(8.7) /10(43.48)
N stage				0.01*
N0/ N1a/ N1b	50(50)/ 24(24)/ 26(26)	21(42.86)/ 13(26.53)/ 15(30.61)	5(21.74)/ 14(60.87)/ 4(17.39)
M stage
M1	2(2)	0(0)	1(4.35)	0.4
Total number of PG				0.31
0/ 1/ 2/ 3/ 4/ 5	2(2)/ 7(7)/ 19(19)/ 71(71)/ 1(1)/ 0(0)	0(0)/ 3(6.12)/ 8(16.33)/ 37(75.51)/ 1(2.04)/ 0(0)	0(0)/ 3(13.04)/ 6(26.09)/ 12(52.17)/ 2(8.7)/ 0(0)
All PG left in situ				0.47
NO/ YES	71(71)/ 29(29)	39(80)/ 10(20)	18(78)/ 5(22)
PGRIS				0.28
0/ 1 ∼ 2/ 3 ∼ 4	2(2)/ 43(43)/ 55(55)	3(6.12)/ 26(53.06)/ 20(40.82)	2(8.7)/ 9(39.13)/ 12(52.17)
Proportion of PG retained in situ				0.35
0–1/3	40(40)	17(34.69)	8(34.78)
1/3–2/3	22(22)	18(36.73)	5(21.74)
2/3–1	38(38)	14(28.57)	10(43.48)
Accidental parathyroidectomy				0.95
0/ 1/ 2	88(88)/ 9(9)/ 3(3)	43(87.76)/ 4(8.16)/ 2(4.08)	21(91.3)/ 1(4.35)/ 1(4.35)
131 I treatment†				0.02*
NO/ YES	50(50)/ 50(50)	15(30.61)/ 34(69.39)	6(26.09)/ 17(73.91)
Times of 131Itreatment†				0.00*
0/ 1/ 2/ 3/ 4	50(50)/ 46(46)/ 3(3)/ 0(0)/ 1(1)	15(30.61)/ 34(69.39)/ 0(0)/ 0(0)/ 0(0)	6(26.09)/ 14(60.87)/ 1(4.35)/ 2(8.7)/ 0(0)
Dose of 131 I (mCi)†				0.37
30/ 50/ 60/ 80/ 100/ 150/ 200	3(3)/ 1(1)/ 0(0)/ 0(0)/ 39(39)/ 6(6)/ 1(1)	2(4.08)/ 0(0)/ 1(2.04)/ 0(0)/ 25(51.02)/ 5(10.2)/ 1(2.04)	0(0)/ 0(0)/ 0(0)/ 1(4.35)/ 13(56.52)/ 1(4.35)/ 2(8.7)
Intervals of 131I treatment from surgery(days)†				0.05
<60	19(19)	4(8.16)	7(30.43)
≤60 < 180	29(29)	28(57.14)	8(34.78)
≥180	2(2)	2(4.08)	2(8.7)
PTH (pmol/L)
Pre-op	5.74 ± 1.98	5.68 ± 1.95	5.2 ± 2.27	0.46
Post-op 1 day	1.01 ± 0.68	0.96 ± 0.62	1.52 ± 2.61	0.53
3day	0.92 ± 1.28	1.33 ± 1.75	0.73 ± 0.4	0.21
1 mo	2.75 ± 1.69	2.56 ± 1.43	2.33 ± 1.25	0.71
6 mo	4.24 ± 5.14	3.73 ± 3.84	2.91 ± 1.19	0.37
12 mo	3.4 ± 2.08	3.09 ± 2.22	3.17 ± 0.96	0.29
Last mo	3.2 ± 1.13	2.51 ± 1.01	3.73 ± 1.35	0.12
Ca (mmol/L)
Pre-op	2.31 ± 0.1	2.32 ± 0.09	2.31 ± 0.09	0.88
Post-op 1 day	2.03 ± 0.19	2.03 ± 0.13	1.99 ± 0.2	0.78
3day	1.98 ± 0.27	1.87 ± 0.2	2.01 ± 0.2	0.05
1 mo	2.07 ± 0.25	2.07 ± 0.16	2.22 ± 0.21	0.01*
6 mo	2.19 ± 0.15	2.17 ± 0.12	2.15 ± 0.13	0.61
12 mo	2.25 ± 0.25	2.15 ± 0.12	2.17 ± 0.17	0.17
Last mo	2.16 ± 0.11	2.11 ± 0.08	2.21 ± 0.07	0.01*

* significantly statistical differences. ^†Including 101 patients who received 131Itreatment.

TT: Total thyroidectomy; CND: Central lymph node dissection; LND: Lateral lymph node dissection; Pre-op: preoperative; post-op: postoperative; mo: month; PG: parathyroid gland; PTH: parathormone; PGRIS: number of parathyroid glands remaining in situ.

Figure 2. Time to recovery of the parathyroid function (RPF) in patients with protracted hypoparathyroidism. (A) Time to RPF for the whole cohort (n = 260). (B) RPF in patients with or without 131I treatment (p = 0.00). (C) RPF in patients with N0 vs. N1a vs. N1b stage (p = 0.05). (D) RPF according to PGRIS (parathyroid glands remaining in situ) (p = 0.22). Horizontal axis expressed in the logarithmic scale (months); hypoPT: hypoparathyroidism; p-values are from the log-rank (Mantel-Cox) test.

Figure 3. Time to recovery of parathyroid function (RPF) in patients with protected hypoPT who received 131I treatment. (A) RPF in patients with intervals of 131I treatment <60 days and ≥ 60 days (p = 0.40). (B) RPF in patients treated with 131I once vs. ≥2 times (p = 0.08). The horizontal axis is in the logarithmic scale (months); hypoPT: hypoparathyroidism; p-values are from the log-rank (Mantel-Cox) test.

Data sharing statement

Not applicable.