Diagnostic accuracy of preoperative palpation- versus ultrasound-guided thyroid fine needle aspiration cytology: an observational study

Figures & data

Figure 1. Study design.

Table 1. Demographics, presentation, predisposing factors and procedures performed in thyroid gland surgery (n = 1174).

Variable	Value	Variable	Value
Age (mean±SD)	46.3 ± 11.7	Irregular margin (n = 1097)	26 (2.4%)
Males	288 (24.5%)	Microcalcifications (n = 1096)	89 (8.1%)
Females	886 (75.5%)	Number of nodules	2 (1–2)
Nationality		Nodules size (in mm) (n = 920)	29.5 ± 18.1
Qatari	401 (34.2%)	Nodules size (in cm)
Non-Qatari	773 (65.8%)	≤2 cm	286 (31.1%)
Body mass index	29.9 ± 6.9	>2 cm	634 (68.9%)
Presenting symptoms		Comorbidities
Firm neck mass	393 (35.1%)	Hyperthyroidism	175 (15.1%)
Dysphagia	228 (19.5%)	Hypertension	165 (14.2%)
Dyspnea	204 (17.5%)	Diabetes mellitus	142 (12.2%)
Pain	121 (10.4%)	Dyslipidemia	80 (6.9%)
Hard neck mass	149 (13.3%)	Hypothyroidism	53 (4.6%)
Hoarseness	70 (6.0%)	Coronary artery disease	20 (1.7%)
Palpable lymph nodes	34 (2.9%)	Stroke	4 (0.3%)
Ultrasound characteristics of thyroid nodules		Smoking	43 (3.7%)
Purely cystic nodule (n = 1094)	180 (16.6%)	Risk factors
Nodules with a cystic component containing colloid (n = 1100)	116 (10.5%)	History of nodule or goiter	809 (69.7%)
Calcification around the periphery of a nodule (n = 1095)	80 (7.3%)	History of unrelated cancer	26 (2.2%)
Mixed solid/cystic (n = 1100)	453 (41.2%)	Family history of thyroid cancer	19 (1.6%)
Solid hypoechoic nodule (n = 1095)	341 (31.1%)	Multiple Endocrine Neoplasia (parathyroid)	6 (0.5%)
Solid hyperechoic nodule (n = 1092)	134 (12.3%)	History of head and neck radiation	1 (0.1%)

Table 2. FNA and histopathological characterization (n = 1174).

Variable	Value	Variable	Value
Histopathology	855 (84.5%)	Location of carcinoma (n = 246)
Completion total thyroidectomy	683 (58.8%)	Unilateral	174 (70.7%)
Left hemithyroidectomy	201 (17.3%)	Bilateral	58 (23.6%)
		Isthmus	14 (5.7%)
Right hemithyroidectomy	277 (23.9%)	Adenoma	134 (11.4%)
Isthmusectomy	72 (6.2%)	Confined to thyroid	166 (76.5%)
Biopsy of thyroid	21 (1.8%)	Minimal extrathyroid extension	24 (11.1%)
Lymph node dissection	78 (6.7%)	Perithyroid soft tissues only	19 (8.8%)
Resection of metastasis	11 (0.9%)	Tumor invades beyond thyroid capsule into subcutaneous tissues	8 (3.7%)
Cancer/malignancy	264 (22.8%)	Excision margins (n = 210)
Cancer type		Free of tumor	171 (81.4%)
Papillary carcinoma	236 (89.4%)	Microscopic tumor at margin	32 (15.2%)
Medullary carcinoma	11 (4.2%)	Macroscopic tumor at margin	7 (3.3%)
Follicular carcinoma	8 (3.0%)	US-guided FNA	392 (33.4%)
Hurthle cell carcinoma	6 (2.3%)	Palpation-guided FNA	570 (48.6%)
Anaplastic carcinoma	2 (0.8%)	No FNA done	212 (18.0%)
Poorly differentiated carcinoma	1 (0.4%)	Frozen section intraoperative	18 (1.6%)
		Operative time (min)	121.8 ± 46.7

Table 3. Comparison of US-guided FNA vs. palpation-guided FNA cases.

	US-guided FNA (n = 392)	Palpation-guided FNA (n = 570)	p value
Age	46.6 ± 11.9	46.2 ± 11.6	0.66
Females	308 (78.6%)	421 (73.9%)	0.09 for all
Males	84 (21.4%)	149 (26.1%)
BMI	30.6 ± 7.1	29.7 ± 6.9	0.07
Preoperative cytology
Benign cytology	215 (55.4%)	398 (70.1%)	0.001
Indeterminate	58 (14.8%)	52 (9.2%)	0.007
Suspicion of malignancy	101 (25.9%)	93 (16.3%)	0.001
Malignancy	45 (11.5%)	47 (8.2%)	0.09
Unsatisfactory	51 (13.1%)	98 (17.3%)	0.07
Postoperative histopathology
Adenoma	63 (16.3%)	66 (11.6%)	0.03
Malignancy	109 (28.1%)	130 (22.8%)	0.07

Table 4. Diagnostic accuracy of FNA cytology (US-guided vs. palpation-guided) for suspicion of malignancy with confirmed diagnosis of cancer by histopathology.

	Suspicion of malignancy		Malignancy on cytology
	US-guided FNA (n = 392)	Palpation-guided FNA (n = 570)	US-guided FNA (n = 392)	Palpation-guided FNA (n = 570)
Cancer diagnosis by histopathology
Sensitivity	69.7%	52.3%	36.7%	33.1%
Specificity	91.1%	94.3%	98.2%	99.1%
Positive predictive value	75.3%	73.1%	88.9%	91.5%
Negative predictive value	88.6%	87.0%	79.9%	83.2%
Positive likelihood ratio	7.8	9.21	20.5	47.4%
Negative likelihood ratio	0.33	0.51	0.64	0.68
Accuracy	85.1%	84.7%	81.1%	84.0%

Figure 2. Shows the overview of FNA findings in both groups with its final surgical pathology findings (P-FNA: palpation-guided FNA; US-FNA: ultrasound-guided FNA).

Table 5. Comparison of US-guided FNA findings with postoperative diagnosis.

	US-guided FNA
Post-operative diagnosis	Benign cytology (n = 215)	Suspicion of malignancy (n = 101)	Malignancy (n = 45)	Indeterminate (n = 58)	Unsatisfactory (n = 51)
Benign	162 (75.3%)	13 (12.9%)	4 (8.9%)	35 (60.3%)	35 (68.6%)
Malignancy	24 (11.2%)	76 (75.2%)	40 (88.9%)	11 (19.0%)	10 (19.6%)
Adenoma	29 (13.5%)	12 (11.9%)	1 (2.2%)	12 (20.7%)	6 (11.8%)
	Palpation-guided FNA
Post-operative diagnosis	Benign cytology (n = 398)	Suspicion of malignancy (n = 93)	Malignancy (n = 47)	Indeterminate (n = 52)	Unsatisfactory (n = 98)
Benign	304 (76.4%)	15 (16.1%)	3 (6.4%)	27 (51.9%)	67 (68.4%)
Malignancy	46 (11.6%)	68 (73.1%)	43 (91.5%)	17 (32.2%)	16 (16.3%)
Adenoma	48 (12.1%)	10 (10.8%)	1 (2.1%)	8 (15.4%)	15 (15.3%)

Table 6. Comparison of FNA findings by the Bethesda system for predicted risk of malignancy.

			FNA category
Authors	Year	n	Benign (%)	Suspicion of malignancy (%)	Malignancy (%)	Unsatisfactory (%)	Indeterminate (%)
Bethesda system [33]	2010	-	0–3	60–75	97–99	1–4	5–15
Jo et al. [34]	2010	892	1.1	70.0	98.1	8.9	17
Williams et al. [35]	2013	1117	16	94.1	100	18.2	24.7
Yang et al. [36]	2007	1052	7.3	64.7	98.6	10.9	13.5
Wu et al. [37]	2011	221	3	56	100	14	6
Tepeoglu et al. [38]	2014	1021	0	91.4	100	-	12.7
Present study
Palpation-FNA	2019	570	11.6	73.1	91.5	16.3	32.2
US-FNA	2019	392	11.2	75.2	88.9	19.6	19.0

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