Course and predictors of excellent response to therapy in patients with differentiated thyroid cancer at long-term follow-up

Shaza A. Samargandy; Ghofran N. Qorban; Arwa K. Aljadani; Salihah S. Almufarji; Abdulrahman M. Azab; Mazin A. Merdad; Marwan R. Al-Hajeili; Saad J. Samargandy

doi:10.15537/smj.2024.45.2.20230596

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Figure 1
- Cancer-free survival probability among different initial American Thyroid Association risk groups.
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Figure 2
- Probability of cancer-free survival in differentiated thyroid cancer patients based on the risk. A) Low risk; B) intermediate risk; and C) high risk.

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Table 1

- Descriptive characteristics of the study participants overall and by initial risk status (N=230).

Variables	Total	Initial risk			P-values
Variables	Total	Low (n=104)	Intermediate (n=71)	High (n=55)	P-values
Age (years), mean±SD	41.33±14.53	41.14±12.19	38.44±15.40	45.40±16.64	0.03
Age
≤55 years	191 (83.0)	90 (86.5)	61 (85.9)	40 (72.7)	0.06
>55 years	39 (17.0)	14 (13.5)	10 (14.1)	15 (27.3)	0.06
Gender
Male	60 (26.1)	13 (12.5)	25 (35.2)	22 (40.0)	<0.0001
Female	170 (73.9)	91 (87.5)	46 (64.8)	33 (60.0)	<0.0001
Pathology
Papillary	213 (92.6)	99 (95.2)	65 (91.5)	49 (89.1)	0.29
Follicular or oncocytic	17 (7.4)	5 (4.8)	6 (8.5)	6 (10.9)	0.29
N
N0 or NX	156 (67.8)	100 (96.2)	28 (39.4)	28 (50.9)	<0.0001
N1	74 (32.2)	4 (3.8)	43 (60.6)	27 (49.1)	<0.0001
M
M0	210 (91.3)	104 (100)	71 (100)	35 (63.6)	<0.0001
M1	20 (8.7)	0 (0.0)	0 (0.0)	20 (36.4)	<0.0001
Vascular invasion	54 (26.5)	0 (0.0)	31 (50.8)	23 (48.9)	<0.0001
Margin involvement	41 (20.9)	6 (6.6)	17 (27.9)	18 (40.9)	<0.0001
Extrathyroidal extension	34 (15.7)	0 (0.0)	13 (19.04)	21 (42.0)	<0.0001
Variant
Non papillary	15 (8.1)	5 (5.8)	4 (7.3)	6 (13.6)	0.001
PTC-low risk variants	157 (84.9)	81 (94.2)	46 (83.6)	30 (68.2)
PTC-high risk variants	13 (7.0)	0 (0.0)	5 (9.1)	8 (18.2)
Multifocality	106 (49.5)	40 (40.4)	37 (55.2)	29 (60.4)	0.04
Size of the largest focus (cm), median (Q1, Q3)	2.3 (1.0, 4.0)	1.5 (0.8, 3.0)	3.0 (2.0, 4.0)	3.5 (1.5, 5.0)	<0.0001
Size of the largest focus
≤4 cm	164 (81.2)	83 (86.5)	50 (82.0)	31 (68.9)	0.04
>4 cm	38 (18.8)	13 (13.5)	11 (18.0)	14 (31.1)	0.04
Size of the largest focus
≤2.3 cm	104 (51.5)	65 (67.7)	21 (34.4)	18 (40.0)	<0.0001
>2.3 cm	98 (48.5)	31 (32.3)	40 (65.6)	27 (60.0)	<0.0001
Stage at diagnosis
1	202 (87.8)	104 (100.0)	65 (91.5)	33 (60.0)	<0.0001
2	18 (7.8)	0 (0.0)	6 (8.5)	12 (21.8)
3	5 (2.2)	0 (0.0)	0 (0.0)	5 (9.1)
4b	5 (2.2)	0 (0.0)	0 (0.0)	5 (9.1)
Type of surgery
Lobectomy/hemithyroidectomy	11 (4.8)	8 (7.7)	1 (1.4)	2 (3.6)	0.14
Total or subtotal thyroidectomy	219 (95.2)	96 (92.3)	70 (98.6)	53 (96.4)	0.14
Given at least one RAI, dose ≥30 mCi	183 (79.6)	67 (64.4)	67 (94.4)	49 (89.1)	<0.0001

Values are presented as numbers and precentages (%), mean ± standard deviation (SD), or median (first quartile [Q1], third quartile [Q3]).

PTC: papillary thyroid cancer, RAI: radioactive iodine

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Table 2

- Long-term outcomes based on initial risk (N=230).

Variables	Total	Initial risk			P-values
Variables	Total	Low (n=104)	Intermediate (n=71)	High (n=55)	P-values
Follow-up (years), median (Q1, Q3)	4.6 (2.7, 7.4)	5.2 (3.0, 8.0)	4.6 (2.3, 7.0)	3.5 (2.5, 5.1)	0.01
Outcome at last visit
Excellent response	142 (61.7)	81 (77.9)	47 (66.2)	14 (25.5)	<0.0001
Indetermined response	32 (13.9)	16 (15.4)	7 (9.9)	9 (16.4)
Biochemically incomplete	24 (10.4)	4 (3.8)	10 (14.1)	10 (18.2)
Structurally incomplete	32 (13.9)	3 (2.9)	7 (9.9)	22 (40.0)
Death related to thyroid cancer
Alive	222 (96.5)	103 (99.0)	71 (100)	48 (87.3)	0.0003
Yes	6 (2.6)	0 (0.0)	0 (0.0)	6 (10.9)
no	2 (0.9)	1 (1.0)	0 (0.0)	1 (1.8)

Values are presented as numbers and precentages (%) or median (first quartile [Q1], third quartile [Q3]).

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Table 3

- Odds ratios (95% confidence interval) for predictors of incomplete response (reference value of excellent and indeterminate responses).

Variables	Univariable		Multivariable
Variables	OR (95% CI)	P-values	OR (95% CI)	P-values
Age >55 years	4.5 (2.2-9.4)	<0.0001^*	5.0 (1.9-13.0)	0.001^*
Gender (male)	2.3 (1.2-4.4)	0.01^*	1.3 (0.6-3.2)	0.51
Pathology (others vs papillary)	0.9 (0.3-3.1)	0.94	-	-
Lymph node metastasis	3.8 (2.0-7.1)	<0.0001^*	3.4 (1.4-8.6)	0.01^*
Distant metastasis	24.8 (6.9-89.0)	<0.0001^*	29.0 (6.9-122.6)	<0.0001^*
Vascular invasion	3.4 (1.7-6.7)	0.001^*	1.8 (0.8-4.4)	0.18
Extrathyroidal extension	6.7 (3.1-14.7)	<0.0001^*	1.8 (0.6-5.0)	0.29
Multifocality	2.5 (1.3-4.9)	0.006^*	1.8 (0.7-4.3)	0.20
Tumor size >2.3 cm (median)	2.1 (1.1, 4.1)	0.03^*	1.6 (0.6, 3.9)	0.31
Received radioactive iodine	1.5 (0.7-3.2)	0.35	-	-