Decline in Radioiodine Use But Not Total Thyroidectomy in Thyroid Cancer Patients Treated in United Arab Emirates- A Retrospective Study
Conditions: Thyroid, Cancer
Sponsor: Tawam Hospital

 
Dr. Khaled M. Aldahmani 
Endocrine Department, 
Tawam Hospital,  
Al-Ain, United Arab Emirates  
 
February 17, 2021 
 
Dear Authority,  
Please find enclosed our manuscript entitled: 
Decline in Radioiodine use but not total thyroidectomy in thyroid cancer patients treated in 
United Arab Emirates- A Retrospective Study 
In the United Arab Emirates (UAE), Thyroid Cancer represents the third most common 
malignancy in the population mostly occurring in the 3rd-4th decades of life and presenting as a 
localized disease. The management of Thyroid Cancer (TC) has significantly changed in the last 
decade with several guidelines around the world. These changes resulted in lower rates of total 
Thyroidectomy and Radioiodine administration in some parts of the world. But very little is known 
about the trend in Thyroid Cancer management in Middle East and North Africa (MENA) region.  
In this study we aim to analyze the trends of TC characteristics and treatment modalities in 
patients presenting to the largest oncology center in the UAE over the last decade. In addition, we 
evaluate factors associated with the extent of surgery and RAI therapy. 
We believe that this manuscript would be well-suited to be published as a case-controlled 
study. In submitting this manuscript for publication, we hope to highlight the evaluation of 
clinicopathological features and treatment modalities in Thyroid Cancer patients in the UAE. The 
significance of Nationality and Lymph Node Factor involvement in Surgery and RAI use. Most 
patients were diagnosed with localized Papillary Thyroid Cancer with no significant change in the 
extent of surgical approach but a substantial decline in RAI therapy administration over time.  
We confirm that this manuscript has not been submitted elsewhere for publication. There was no 
financial support for this work and authors will cover publication fees when study is accepted for 
publication. All authors contributed to the writing of this manuscript, revised it critically for 
important intellectual content, and approve its submission. The authors have no actual or potential 
conflicts of interest to declare. Please address all correspondence concerning this manuscript to 
me at kmdahmani@seha.ae 
Thank you for your consideration for this manuscript. 

 
Sincerely, 
Dr. Khaled M. Aldahmani 
Endocrine Department, 
Tawam Hospital,  
Al-Ain, United Arab Emirates  
kmdahmani@seha.ae 
 
 
 
 

 
1 
 
Decline in Radioiodine use but not total thyroidectomy in thyroid cancer 
1 
patients treated in United Arab Emirates- A Retrospective Study  
2 
Abstract 
3 
Background:  
4 
Objectives:  
5 
To assess the trend of clinicopathological features and treatment modalities in patients with 
6 
thyroid cancer (TC) in the largest oncology center in the United Arab Emirates (UAE). 
7 
Methods:  
8 
A retrospective analysis of patients with TC presenting to a tertiary care hospital in Al Ain, 
9 
UAE between September 2008 and December 2018 identified using ICD 9 & 10 codes was 
10 
performed. Data on demographics, histopathology, surgical extent, and use of Radioiodine 
11 
(RAI) were extracted. Exact logistic and ordinal logistic regressions were performed to analyze 
12 
the annual trend in features and management of TC, and logistic regression analysis was 
13 
performed to identify predictors of total thyroidectomy and RAI use. 
14 
Results:   
15 
A total of 762 patients were included in the analysis (mean age: 39.6 ±12.6 years, 45 (60%) 
16 
women). The majority (92.2%) were diagnosed with papillary thyroid cancer (PTC) and 83.9% 
17 
had tumor size of < 4 cm. All patients underwent surgery (93.8% total thyroidectomy, 6.2% 
18 
lobectomy) and 77.4% received RAI therapy overall with a significant (p<0.001) decline from 
19 
100% in 2008 to 60% in 2018. In multivariate analysis, nationality, and lymph node (LN) 
20 
involvement were significant predictors of total thyroidectomy, while nationality, LNs, year of 
21 
diagnosis, and tumor size significantly predicted RAI use.  
22 
Conclusion:  
23 
Most patients in our cohort were diagnosed with localized PTC with no significant change in 
24 
the extent of surgical approach but a substantial decline in RAI therapy administration over 
25 
time. Nationality and LN involvement were significant predictors of surgical extent and RAI 
26 
use.  
27 

 
2 
 
Introduction 
28 
Management of thyroid cancer (TC) has significantly changed in the last decade with several 
29 
guidelines advocating for a conservative approach in the majority of patients [1-2]. While these 
30 
changes resulted in lower rates of total thyroidectomy and radioiodine administration in some 
31 
parts of the world [3-4], data on TC from the Middle East and North Africa (MENA) region 
32 
has largely focused on incidence, characteristics, and treatment outcomes with recent 
33 
exploration of TC genetics [5-12]. Little is known about the trend in TC management in this 
34 
region. 
35 
It is difficult to predict if management of TC in the MENA region would follow similar trends 
36 
compared to other parts of the world. For example, it is unknown if patients or even physicians 
37 
are willing to observe micro papillary TC (MPTC) rather than offering surgery, at least 
38 
lobectomy. Similarly, attitudes toward the extent of surgery and use of RAI in localized TC 
39 
following the publication of the guidelines from the United Kingdom (UK) in 2014 and the 
40 
2015 American Thyroid Association (ATA) has not been well reported in the MENA region. 
41 
Furthermore, ethnicity has been shown to influence the incidence and outcomes of TC in some 
42 
studies [13-14]. Whether ethnicity impacts management of TC patients in our region remains 
43 
unclear.  
44 
In the United Arab Emirates (UAE), TC represents the third most common malignancy in the 
45 
population mostly occurring in the 3rd-4th decades of life and presenting as a localized disease 
46 
[15]. We aimed to study trends of TC characteristics and treatment modalities in patients 
47 
presenting to the largest oncology center in the UAE over the last decade. In addition, we 
48 
evaluated factors associated with the extent of surgery and RAI therapy.   
49 
 
50 
Materials and Methods 
51 
Study setting 
52 
This study was conducted in Tawam hospital (TWM), which provides tertiary care services to 
53 
patients in the UAE. It is the only center delivering radioactive iodine (RAI) therapy and 
54 
radiotherapy in Al Ain city. Most TC patients are followed in designated TC clinics within the 
55 
endocrinology division or less commonly through other clinics (surgery, radiation, or medical 
56 
oncology). The hospital runs monthly multidisciplinary team-based discussions on patients with 
57 
TC, wherein decisions regarding RAI treatment and dose selection are determined jointly by 
58 
nuclear medicine physicians and endocrinologists. 
59 

 
3 
 
Study Design and participants 
60 
We retrospectively evaluated all patients with TC presenting to TWM during the period of 
61 
September 2008 and December 2018. The beginning of data collection (September 2008) 
62 
reflects the inception time of electronic medical records (EMRs) use in the hospital. Cases of 
63 
TC were extracted from the EMRs using the International Classification of Disease 9 & 10 
64 
codes (193 & c73). Other variables were demographic information, year of diagnosis, type of 
65 
TC, histopathological subtype, lymph node (LN) involvement, type of thyroid surgery, use of 
66 
RAI treatment, and radiation therapy. The extent of surgery, the exact details of histopathology, 
67 
and the RAI dose were retrieved from the respective specialty reports. Tumor staging was 
68 
reported according to the 8th edition of the American joint committee on cancer (AJCC)/TNM 
69 
staging system [16]. Those with incorrect pathological diagnosis, incomplete data, or 
70 
noninvasive follicular type PTC were excluded. 
71 
Ethical considerations 
72 
The study was approved by Al Ain Medical District Human Research Ethical Committee and 
73 
consent was waved. 
74 
 
75 
STROCSS Compliance 
76 
This work has been reported in line with the STROCSS criteria [17].  
77 
Statistical Analysis 
78 
The data were extracted using Microsoft Excel 2015 and imported into Stata 16.0 for statistical 
79 
analysis. Continuous variables were described using means and standard deviations (±SD). 
80 
Categorical variables were described as frequency distributions. Variables of clinical features 
81 
and management were cross tabulated with the year of diagnosis and exact logistic and ordinal 
82 
logistic regressions were performed to analyze the annual trend in features and management of 
83 
TC as appropriate. The results of relative trend were reported as odds ratio (OR) with an overall 
84 
ptrend. The OR=1 indicated no change over years, OR <1 indicated a decline, while OR >1 
85 
indicated an increase over years. Simple and multiple logistic regression analysis were 
86 
performed to assess the unadjusted and adjusted association of management of TC (RAI, 
87 
surgical management) with age, gender, nationality, year of diagnosis, tumor subtype, and other 
88 
co-variates. The results of simple and multiple logistic regression were reported as odd ratios 
89 

 
4 
 
(OR) and adjusted odds ratios (AOR) respectively with their corresponding 95% confidence 
90 
intervals (CI) and p-values. 
91 
 
92 
Results 
93 
Overall patients’ demographics 
94 
A total of 762 patients were included in the analysis (Table 1). The mean age at the diagnosis 
95 
was 39.7 (12.6) and 583 (76.5%) were women. The vast majority of patients (92.1%) were 
96 
diagnosed with PTC. Of those, the histology subtype was available for 555 patients with the 
97 
two most common being classical (73.5%) and invasive follicular variant (22.3%). About 
98 
83.8% of the patients (N=555) had a tumor size of <4cm at diagnosis. The stage of TC was 
99 
documented in 590 patients. Of those, 523 (88.6%) patients were stage I while 23 (3.9%) were 
100 
stage IV. All patients underwent surgery with the majority receiving (93.8%) total 
101 
thyroidectomy and 566 (77.4%) RAI therapy.  
102 
 
103 
 
104 
Table 1: Characteristics of thyroid cancer patients (n=762) 
105 
 
106 
Demographics 
N (%) / Mean (SD) 
Age – years (n=762) 
39.7 (12.6) 
Gender (n=762) 
 
Female  
583 (76.5) 
Male 
179 (23.5) 
Nationality 
 
UAE 
349 (45.8) 
Others  
413 (54.2) 
Tumor size (n=551) 
 
1 cm 
147 (26.7) 
1.1 – 1.9 cm 
188 (34.1) 
2 – 3.9 cm 
127 (23.1) 
4 cm 
89 (16.1) 
Tumor Type (n=762) 
 
PTC 
702 (92.1) 
FTC 
35 (4.6) 
MTC 
19 (2.5) 
Anaplastic 
6 (0.8) 
PTC Subtype (n=555) 
 
Classical 
408 (73.5) 
Follicular 
124 (22.3) 
Others 
23 (4.1) 
Stage (n=590) 
 
I 
523 (88.6) 

 
5 
 
II 
35 (5.9) 
III 
9 (1.5) 
IV 
23 (3.9) 
Type of surgery (n=754) 
 
Hemithyroidectomy 
47 (6.2) 
Total thyroidectomy 
707 (93.8) 
RAI ablation (n= 731) 
 
Yes 
566 (77.4) 
No 
165 (22.6) 
Radiotherapy use (n=762) 
10 (1.3) 
MTC: Medullary Thyroid Cancer, FTC: Follicular Thyroid Cancer, 
PTC: Papillary Thyroid Cancer, RAI: Radioactive Iodine, UAE: 
United Arab Emirates 
N does not always make up to 762 due to missing data for some 
variables 
 
107 
 
108 
 
109 
Thyroid cancer characteristics over 10 years   
110 
The annual number of TC patients substantially increased during the study period from 25 cases 
111 
in 2008 to 106 cases in 2018. Compared to men, the increment was significantly higher in 
112 
women (Fig. 1). PTC was the most common type with a gradual increase (p=0.674) from 88% 
113 
in 2008 to 95% in 2018 (Table 2). Stage 1 Tumors represented the majority of TC patients in 
114 
2008 and also showed an insignificant (p=0.267) increase till 2018. During the study period, 
115 
compared to non-PTC types, the proportion of patients with PTC increased by 11% on average 
116 
(p=0.021). In contrast, patients presenting with advanced TC relatively decreased by 10% 
117 
(p=0.022) compared to stage 1 cancer. 
118 
 
119 
Figure 1: Incident cases of thyroid cancer between 2008 and 2018, overall and by gender 
120 
 
121 

 
6 
 
 
122 
 
123 
Trend in surgery and RAI treatment 
124 
Total thyroidectomy showed a modest decline (p=0.409) from 100% in 2008 to 90.1% in 2018. 
125 
The RAI treatment showed a significant decline (<0.001) from 100.0% in 2008 to 60.4% in 
126 
2018 (Table 2). 
127 
 
128 
Table 2: TC cases over years, overall and by characteristics 
129 
 
2008 
2009 
2010 
2011 
2012 
2013 
2014 
2015 
2016 
2017 
2018 
OR  
(Ptrend) 
Overall 
25 
(3.3) 
48 
(6.3) 
36 
(4.7) 
46 
(6.0) 
80 
(10.5) 
82 
(10.8) 
83 
(10.9) 
83 
(10.9) 
82 
(10.8) 
91 
(11.9) 
106 
(13.9) 
-- 
 
 
 
 
 
 
 
 
 
 
 
 
 
Gender 
 
 
 
 
 
 
 
 
 
 
 
 
Female  
17 
(68.0) 
37 
(77.1) 
23 
(63.9) 
39 
(84.8) 
64 
(80.0) 
61 
(74.4) 
63 
(75.9) 
67 
(80.7) 
66 
(80.5) 
65 
(71.4) 
81 
(76.4) 
0.99  
(0.777) 
Male 
8 
(32.0) 
11 
(22.9) 
13 
(36.1) 
7 
(15.2) 
16 
(20.0) 
21 
(25.6) 
20 
(24.1) 
16 
(19.3) 
16 
(19.5) 
26 
(28.6) 
25 
(23.6) 
 
 
 
 
 
 
 
 
 
 
 
 
 
Nationality 
 
 
 
 
 
 
 
 
 
 
 
 
UAE 
10 
(40.0) 
16 
(33.3) 
11 
(30.6) 
23 
(50.0) 
36 
(45.0) 
43 
(52.4) 
40 
(48.2) 
44 
(53.0) 
33 
(40.2) 
43 
(47.3) 
50 
(47.2) 
0.96 
(0.155) 
Others 
15 
(60.0) 
32 
(66.7) 
25 
(69.4) 
23 
(50.0) 
44 
(55.0) 
39 
(47.6) 
43 
(51.8) 
39 
(47.0) 
49 
(59.8) 
48 
(52.7) 
56 
(52.8) 
 
 
 
 
 
 
 
 
 
 
 
 
 
Stages 
 
 
 
 
 
 
 
 
 
 
 
 
I 
6 
(75.0) 
27 
(81.8) 
24 
(85.7) 
28 
(80.0) 
40 
(87.0) 
53 
(88.3) 
57 
(89.1) 
66 
(91.7) 
72 
(93.5) 
73 
(89.0) 
77 
(90.6) 
0.90 
(0.022) 
 
II 
0 
(0.0) 
4 
(12.1) 
3 
(10.7) 
1 
(2.9) 
3 
(6.5) 
3 
(5.0) 
4 
(6.3) 
5 
(6.9) 
4 
(5.2) 
5 
(6.1) 
3 
(3.5) 
III-IV 
2 
(25.0) 
2 
(6.1) 
1 
(3.6) 
6 
(17.1) 
3 
(6.5) 
4 
(6.7) 
3 
(4.6) 
1 
(1.4) 
1 
(1.3) 
4 
(4.9) 
5 
(5.9) 
0
20
40
60
80
100
120
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
Number of Cases
Year (2008 - 2018)
Female
Male
All

 
7 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Tumor size 
 
 
 
 
 
 
 
 
 
 
 
 
<1 cm 
3 
(50.0) 
6 
(20.7) 
2 
(8.0) 
11 
(32.3) 
13 
(30.2) 
23 
(41.8) 
22 
(37.3) 
34 
(49.3) 
29 
(38.7) 
27 
(34.6) 
20 
(25.6) 
0.96 
(0.142) 
1.1-1.9 cm 
1 
(16.7) 
6 
(20.7) 
10 
(40.0) 
5 
(14.7) 
6 
(13.9) 
8 
(14.5) 
8 
(13.6) 
17 
(24.6) 
13 
(17.3) 
20 
(25.6) 
20 
(25.6) 
2.0-3.9 cm 
2 
(33.3) 
11 
(37.9) 
4 
(16.0) 
15 
(44.1) 
16 
(37.2) 
15 
(27.3) 
18 
(30.5) 
11 
(15.9) 
21 
(28.0) 
19 
(24.4) 
26 
(33.3) 
4.0 cm 
0 
(0.0) 
6 
(20.7) 
9 
(36.0) 
3 
(8.8) 
8 
(18.6) 
9 
(16.4) 
11 
(18.6) 
7 
(10.1) 
12 
(16.0) 
12 
(15.4) 
12 
(15.4) 
 
 
 
 
 
 
 
 
 
 
 
 
 
Tumor type 
 
 
 
 
 
 
 
 
 
 
 
 
PTC 
22 
(88.0) 
45 
(93.7) 
32  
(88.9) 
38  
(82.6) 
70 
(87.5) 
75 
(91.5) 
78 
(94.0) 
78 
(94.0) 
79 
(96.3) 
84 
(92.3) 
101  
(95.3) 
1.11 
(0.021) 
Other 
3 
(12.0) 
3 
(6.3) 
4 
(11.1) 
8 
(17.4) 
10 
(12.5) 
7 
(8.5) 
5 
(6.0) 
5 
(6.0) 
3 
(3.7) 
7 
(7.7) 
5 
(4.7) 
 
 
 
 
 
 
 
 
 
 
 
 
 
PTC subtype 
 
 
 
 
 
 
 
 
 
 
 
 
Classical 
13 
(61.9) 
29 
(69.1) 
28 
(93.3) 
27 
(77.1) 
54 
(84.4) 
38 
(62.3) 
40 
(71.4) 
34 
(66.7) 
43 
(68.3) 
57 
(80.3) 
45 
(73.8) 
1.01 
(0.962) 
Follicular 
7 
(33.3) 
11 
(26.2) 
2 
(6.7) 
7 
(20.0) 
8 
(12.5) 
21 
(34.4) 
13 
(23.2) 
15 
(29.4) 
16 
(25.4) 
10 
(14.1) 
14 
(22.9) 
 
 
 
 
 
 
 
 
 
 
 
 
 
RAI use 
 
 
 
 
 
 
 
 
 
 
 
 
No 
0 
(0.0) 
2 
(4.4) 
1 
(2.78) 
6 
(13.3) 
8 
(10.1) 
12 
(15.0) 
17 
(21.5) 
22 
(28.9) 
27 
(34.6) 
30 
(34.5) 
40 
(39.6) 
0.75 
(<0.001) 
Yes 
25 
(100.0) 
43 
(95.6) 
35 
(97.2) 
39 
(86.7) 
71 
(89.9) 
68 
(85.0) 
62 
(78.5) 
54 
(71.1) 
51 
(65.4) 
57 
(65.5) 
61 
(60.4) 
 
 
 
 
 
 
 
 
 
 
 
 
 
Surgical 
management 
 
 
 
 
 
 
 
 
 
 
 
 
Hemithyroidectomy 
0  
(0.0) 
1  
(2.1) 
0  
(0.0) 
0  
(0.0) 
2  
(2.5) 
4  
(4.9) 
6  
(7.2) 
7  
(8.4) 
3  
(3.7) 
3  
(3.3) 
10  
(9.5) 
0.89  
(0.054) 
Thyroidectomy 
25  
(100.0) 
47  
(97.9) 
36  
(100.0) 
46  
(100.0) 
78  
(97.5) 
78  
(95.1) 
77  
(92.8) 
76  
(91.6) 
79  
(96.3) 
88  
(96.7) 
95  
(90.5) 
OR: Odds Ratio, RAI: Radioactive Iodine 
P-values are estimated for Exact logistic regression and ordinal logistic regression 
 
130 
 
131 
 
132 
 
133 
Correlates of Surgery and RAI treatment 
134 
In multiple logistic regression, non-UAE national patients were more likely to require total 
135 
thyroidectomy (OR: 2.46 [CI: 1.21 - 4.94]). No other significant correlates of surgical extent 
136 
were identified (Table 3). 
137 
 
138 
Table 3. Simple and multiple logistic regression analysis of surgical management of 
139 
thyroid cancer with selected variables. 
140 
 
141 
Variables 
With Total 
Thyroidectomy 
 
Unadjusted Analysis 
 
Adjusted Analysis 
n (%) 
 
OR (95% CI) 
P-value 
 
AOR (95% CI) 
P-value 
Year 
 
 
 
 
 
 
 
2008-2010 
107 (98.2) 
 
Reference 
 
 
Reference 
 
2011-2013 
195 (93.7) 
 
0.28 (0.06 - 1.26) 
0.098 
 
1.06 (0.10 - 10.93) 
0.962 
2014-2016 
230 (92.7) 
 
0.24 (0.05 - 1.05) 
0.058 
 
0.33 (0.04 - 2.83) 
0.314 

 
8 
 
2017-2018 
175 (92.6) 
 
0.23 (0.05 - 1.05) 
0.058 
 
0.40 (0.05 - 3.48) 
0.407 
Age – Mean SD 
39.5 12.3 
 
0.99 (0.97 - 1.02) 
0.612 
 
1.01 (0.97 - 1.05) 
0.653 
Sex 
 
 
 
 
 
 
 
Female 
542 (93.6) 
 
Reference 
 
 
Reference 
 
Male 
165 (94.3) 
 
1.13 (0.55 - 2.31) 
0.746 
 
0.60 (0.19 - 1.89) 
0.386 
Nationality 
 
 
 
 
 
 
 
UAE   
315 (90.5) 
 
Reference 
 
 
Reference 
 
Others 
392 (96.5) 
 
2.93 (1.54 - 5.58) 
0.001 
 
5.82 (1.85 - 18.30) 
0.003 
PTC Subtype 
 
 
 
 
 
 
 
Other 
22 (95.7) 
 
Reference 
 
 
Reference 
 
Classical 
388 (95.6) 
 
0.98 (0.13 - 7.68) 
0.985 
 
1.14 (0.13 - 10.45) 
0.907 
Follicular 
117 (94.3) 
 
0.76 (0.09 - 6.49) 
0.802 
 
1.01 (0.10 - 9.88) 
0.992 
Tumour size 
 
 
 
 
 
 
 
 1.0 cm 
166 (88.8) 
 
Reference 
 
 
Reference 
 
1.1-1.9 cm 
111 (95.7) 
 
2.81 (1.03 - 7.66) 
0.044 
 
2.05 (0.55 - 7.69) 
0.285 
2.0-3.9 cm 
148 (94.3) 
 
2.08 (0.92 - 4.68) 
0.077 
 
1.43 (0.45 - 4.51) 
0.540 
 4.0 cm 
85 (95.5) 
 
2.69 (0.89 - 8.08) 
0.078 
 
1.99 (0.45 - 8.75) 
0.362 
Lymph node 
 
 
 
 
 
 
 
No 
384 (91.4) 
 
Reference 
 
 
Reference 
 
Yes 
156 (97.5) 
 
3.66 (1.28 - 10.44) 
0.015 
 
2.74 (0.74 - 10.15) 
0.131 
AOR: Adjusted Odds Ratio, CI: Confidence Interval, OR: Odds Ratio, PTC: Papillary Thyroid Cancer, RAI: Radioactive 
Iodine, SD: Standard Deviation, UAE: United Arab Emirates 
 
 
 
142 
 
143 
 
144 
 
145 
 
146 
Multiple logistic regression analysis showed that compared to 2008-2010, the likelihood of 
147 
receiving RAI was 58% less in 2011-2013, 84% less in 2014-2016, and 92% less in 2017-2018. 
148 
In addition, non-UAE nationals, those with larger tumor sizes, and LN involvement were more 
149 
likely to receive RAI treatment (Table 4). 
150 
Table 4. Simple and multiple logistic regression analysis of RAI with selected co-
151 
variates. 
152 
 
153 
Variables 
With RAI 
 
Unadjusted Analysis 
 
Adjusted Analysis 
n (%) 
 
OR (95% CI) 
P-value 
 
AOR (95% CI) 
P-value 
Year 
 
 
 
 
 
 
 
2008-2010 
103 (97.2) 
 
Reference 
 
 
Reference 
 
2011-2013 
178 (87.3) 
 
0.20 (0.06 - 0.67) 
0.010 
 
0.42 (0.11 - 1.52) 
0.187 
2014-2016 
167 (71.7) 
 
0.07 (0.10 - 0.24) 
<0.001 
 
0.16 (0.05 - 0.54) 
0.003 
2017-2018 
118 (62.8) 
 
0.05 (0.02 - 0.16) 
<0.001 
 
0.08 (0.02 - 0.29) 
<0.001 
Age – Mean SD 
39.5 12.6 
 
0.99 (0.98 - 1.01) 
0.172 
 
0.99 (0.98 - 1.02) 
0.950 
Sex 
 
 
 
 
 
 
 
Female 
423 (75.8) 
 
Reference 
 
 
Reference 
 
Male 
143 (82.7) 
 
1.52 (0.98 - 2.36) 
0.061 
 
1.15 (0.64 - 2.05) 
0.650 
Nationality 
 
 
 
 
 
 
 
UAE National 
243 (73.2) 
 
Reference 
 
 
Reference 
 
Other national 
323 (80.9) 
 
1.56 (1.10 - 2.21) 
0.013 
 
1.63 (1.04 - 2.56) 
0.033 
Diagnosis 
 
 
 
 
 
 
 

 
9 
 
Others 
39 (67.2) 
 
Reference 
 
 
Reference 
 
PTC 
527 (78.3) 
 
1.76 (0.99 - 3.13) 
0.056 
 
1.82 (0.62 - 5.38) 
0.276 
Tumour size 
 
 
 
 
 
 
 
 1.0 cm 
99 (54.1) 
 
Reference 
 
 
Reference 
 
1.1-1.9 cm 
81 (73.0) 
 
2.29 (1.38 - 3.81) 
0.001 
 
2.22 (1.26 - 3.89) 
0.005 
2.0-3.9 cm 
130 (85.0) 
 
4.80 (2.82 - 8.15) 
<0.001 
 
4.66 (2.59 - 8.41) 
<0.001 
 4.0 cm 
78 (92.9) 
 
11.03 (4.58 - 26.59) 
<0.001 
 
9.82 (3.68 - 26.18) 
<0.001 
Stage 
 
 
 
 
 
 
 
I 
367 (72.7) 
 
Reference 
 
 
Reference 
 
II 
30 (90.9) 
 
3.76 (1.13 - 12.52) 
0.031 
 
0.77 (0.19 - 3.19) 
0.715 
III-IV 
22 (71.0) 
 
0.92 (0.41 - 2.04) 
0.836 
 
0.58 (0.10 - 3.25) 
0.633 
Lymph node 
 
 
 
 
 
 
 
No 
280 (68.3) 
 
Reference 
 
 
Reference 
 
Yes 
135 (87.7) 
 
3.30 (1.95 - 5.57) 
<0.001 
 
3.55 (1.86 - 6.78) 
<0.001 
AOR: Adjusted Odds Ratio, CI: Confidence Interval, OR: Odds Ratio, PTC: Papillary Thyroid Cancer, RAI: 
Radioactive Iodine, SD: Standard Deviation, UAE: United Arab Emirates 
 
 
154 
 
155 
Discussion 
156 
PTC represented the most common type of TC (92.1%) in our study with the majority having a 
157 
classical subtype. Follicular TC was found in 4.6% of the patients while anaplastic and 
158 
medullary cancers were rare. These findings are consistent with studies from the MENA region 
159 
as well as other parts of the world [3-9]. The mean age at diagnosis of TC in our study was 39.7 
160 
years which is lower compared to the age of 44.7 years from a large retrospective study of 12, 
161 
508 TC patients diagnosed between 1972-2014 from 8 cancer registries in southeast china [18]. 
162 
It is also lower that the mean age of 48 years from another retrospective study of 77, 276 TC 
163 
patients diagnosed in the period of 1974-2013 using the surveillance, epidemiology and end 
164 
results (SEER) cancer registry database in USA [19] or even from our same institution when 
165 
135 TC patients were studied between 1991-2005 [10]. However, the age at diagnosis was 
166 
similar to data from a retrospective study of 600 TC patients diagnosed between 2004-2005 in 
167 
nearby Saudi Arabia [7].  
168 
The proportion of patients with PTC subtype has increased during the study period, which is 
169 
consistent with global data, although with a lower magnitude [19-20]. The proportion of 
170 
advanced stage TC, however, decreased over the study period, which might be partly explained 
171 
by the increased detection of localized TC cases. The later has been largely ascribed to the 
172 
widespread use of imaging modalities to diagnose thyroid disorders and or other complaints 
173 
from surrounding neck structures as well as the increased utilization of fine-needle aspiration 
174 
to ascertain the nature of thyroid nodules [21-22]. This could also explain the increase in the 
175 
annual number of TC evaluated in our centre. However, no conclusions can be drawn regarding 
176 

 
10 
 
the temporal trend of TC, as our analysis was based on the absolute number of cases instead of 
177 
rates. 
178 
The 2015 ATA guidelines suggest either lobectomy or total thyroidectomy for the management 
179 
of TC for tumors 1-4 cm in size [2]. However, there is no universal consensus on the optimal 
180 
surgical extent in TC management and significant variations are observed worldwide [23]. In 
181 
our study, the majority of patients underwent total thyroidectomy (93.8%) with a small increase 
182 
in hemi-thyroidectomy toward the last few years of the study. This finding is similar to another 
183 
study retrospectively analyzing 44537 TC patients from SEER database between 2000-2014 in 
184 
US and documenting a lower utilization of lobectomy in low-risk TC [24]. Of interest, cheng 
185 
et al showed in 717 TC patients undergoing thyroidectomy between 2008-2016 that 44% of 
186 
those initially eligible for lobectomy would need a completion surgery due to the presence of 
187 
adverse histopathological features [25]. Similarly, kluijfohout et al evaluated 1000 patients with 
188 
TC (size 1-4 cm) who underwent total thyroidectomy between 2000-2010 and reported that 122 
189 
out of 287 (43%) of patients who are eligible for lobectomy based on the 2015 ATA guidelines  
190 
would need completion surgery due to the presence of high-risk features such as lymph node 
191 
involvement (18%) and angioinvasion (12%) [26]. Therefore, determining the extent of surgery 
192 
continues to be controversial with patient’s preference and surgical expertise are paramount in 
193 
the decision-making process. This issue is more apparent in microPTC, which represented about 
194 
a quarter of our cohort where all patients underwent surgery. This is in variance with the 
195 
growing evidence supporting active surveillance as a viable option in the majority of those 
196 
patients [27-29].   
197 
Traditionally, RAI was administered to a large proportion of TC patients following total 
198 
thyroidectomy. Subsequently, several but not all studies showed a limited benefit of RAI in 
199 
low- to intermediate-risk groups in reducing disease-related recurrence and or mortality [30-
200 
31]. Therefore, the decline in the use of RAI has been advocated for by many TC management 
201 
guidelines. Consistent with this, we noted a substantial decline in the use of RAI from 100% in 
202 
2008 to 60% in 2018. Similarly, Park et al showed a decline in RAI administration in 2015 
203 
compared to 1999 mostly in patients with localized disease [4]. Moreover, Sia et al reported a 
204 
decline in RAI use from 76.6% in 2002-2006 to 26.8% in 2017-2018 mostly in low-risk patients 
205 
[5]. The majority of our patients had tumor of <2cm in size with a limited number presenting 
206 
with advanced disease (1.9% Stage IV), suggesting overuse of RAI. However, data on RAI 
207 
indication in our study was not captured, therefore, precluding firm conclusions. Additionally, 
208 

 
11 
 
variation in RAI use is well reported in many countries such as the US and Canada  [32-33]. Of 
209 
interest, the use of RAI for example in T1 disease with unknown or negative lymph node status 
210 
varied between 15 – 83% among different centers in Canada [33]. This wide variation in RAI 
211 
use underscores the limited data and uncertainty in the management of a significant proportion 
212 
of TC patients, necessitating the need for high-quality studies with long term follow up data to 
213 
confidently guide management in such patients. 
214 
The odds of undergoing total thyroidectomy and or receiving RAI ablation were higher in non- 
215 
UAE nationals. This finding of ethnic variation in management of TC is intriguing and not well 
216 
reported in the literature. It might stem from the perceived risk of aggressive disease in certain 
217 
ethnicities. Lo et al retrospectively evaluated 723 patients with TC from Philippines with 5 
218 
years mean follow up and reported higher frequency of aggressive disease at presentation as 
219 
well as higher recurrence risk [34]. Furthermore, another study from the USA reported a higher 
220 
rate of adverse histology (microscopic extrathyroidal extension) in Chinese immigrants 
221 
compared to the non-Asian population [13]. Moreover, Tang et al retrospectively analyzed 
222 
70346 patients with TC from SEER database between 2004-2014 and showed worse overall 
223 
prognosis for black Americans with TC compared to white Americans [14]. Another factor 
224 
explaining this racial difference in the therapy might relate to the uncertainty in establishing 
225 
long-term follow-up plans in our country as 90% of the populations are non-nationals and many 
226 
of whom are workers with temporary living plans, which tempts the treating physician to adopt 
227 
an initial aggressive management strategy [35]. It would be interesting to explore which 
228 
ethnicity had advanced disease and or received aggressive therapy, but this information was not 
229 
captured in this study. Additional larger studies with long-term follow-up outcome data would 
230 
be important to clarify disease behaviour among different ethnicities.   
231 
Lymph node involvement in patients with TC is associated with increased recurrence risk and 
232 
mortality [36]. Therefore, it is not surprising for lymph node involvement to be a predictor for 
233 
RAI ablation as seen in our study. Tumour size was not associated with the extent of surgery in 
234 
our study, perhaps due to the low number of patients undergoing lobectomy. However, it was 
235 
associated with the need for RAI ablation. In 2015 ATA guidelines, tumor size is not an 
236 
indication for RAI ablation in the absence of other adverse features [2]. Nonetheless, it is 
237 
reassuring that the use of RAI has declined steadily during the study.  
238 
Our study has strengths and limitations. It is the first study in the MENA region to describe 
239 
trends in TC characteristics and management patterns following publications of professional 
240 

 
12 
 
TC management guidelines using a large number of patients. The main limitations of the study 
241 
relate to its retrospective nature with incomplete documentation of data that could alter the 
242 
decision of surgery and RAI such as the family history of TC, radiation exposure, and the 
243 
number and size of involved lymph nodes. In addition, the reasons for determining the extent 
244 
of surgery and the need/dose of RAI were not consistently recorded. Also, this study reflects 
245 
the experience from a large referral center and may not be generalizable to other centers in the 
246 
country.    
247 
Conclusion 
248 
In summary, there is a substantial increase in the annual number of TC patients evaluated in our 
249 
centre with the majority having PTC and stage 1 disease at diagnosis. Nationality and LN 
250 
involvement were independent predictors of total thyroidectomy, while the year of diagnosis, 
251 
nationality, LN involvement, and tumor size were predictors of RAI use.  More studies are 
252 
needed to understand factors affecting variation in TC management UAE. 
253 
 
 
254 

 
13 
 
Acknowledgement  
255 
The authors would like to thank Mr. Anvar Kandanath for data preparation and management.   
256 
 
257 
Disclosure Statement 
258 
The authors have no conflicts of interest to declare. 
259 
 
260 
Funding Source 
261 
There was no financial support for this work.  
262 
 
263 
Author Contributions 
264 
M.A., A.S., A.M., E.A., A.K.M. conceived and wrote the manuscript. A.F. performed the 
265 
statistical analysis. A.F., S.R., A.O.H. revised the manuscript for important intellectual 
266 
content. All authors reviewed and approved the final manuscript. 
267 
  
268 
 
269 
Provenance and peer review 
270 
Not commissioned, externally peer-reviewed 
271 

 
14 
 
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