RESULTS
During the study period, participation was offered to a total of 506
patients, of whom 429 were valid for evaluation.
Figure 1 depicts the
flow diagram of the
study and the classification of the evaluated patients according to
their risk factors. The final population consisted of 301 (70.2%) women
and 128 (29.8%) men with a mean age of 49.1±11.0 years and a BMI of
42.6±5.8 kg/m2. Morbid obesity (BMI≥40
kg/m2) was present in 283 (66.2%) patients. As shown,
129 (30.1%; CI 25.9-34.6) patients were classified as having one or
more risk factors for thyroid cancer. Abnormal palpation was present in
38 (8.9%; CI 6.5-11.9) individuals. Elevated TSH/hypothyroidism was the
most prevalent risk factor (19.6%; CI 16.1-23.6). Prevalence of risk
factors was significantly higher among women (34.4% vs 17.4%;
P<0.001). Radiation exposure was not present in any patient.
Sixty-nine (16.1%; CI 12.8-19.9) patients harboured thyroid nodules
with indication for FNAB according to the ATA guideline [16]. This
value was significantly higher than expected (10%; P<0.0001)
[15]. Prevalence of thyroid nodules was significantly higher
in women (18.9% vs 9.4%; P=0.014). Patients with thyroid nodules were
significantly older (54.210.0 vs. 48.212.1; P<0.005). Body
mass index was not different between patients with or without thyroid
nodules (P=0.49).
Sixty-three patients underwent FNAB. Table 1 shows the FNAB results, the
corresponding US risk categories and the final surgical diagnosis when
available. Initially, six nodules received a Bethesda 3 diagnosis, which
was confirmed in a second FNAB in 2 cases; the second FNAB of the four
remaining nodules rendered a Bethesda 2 diagnosis.
Six patients were lost for follow-up before performing the FNAB; two of
these nodules were classified as high suspicion pattern according to the
ATA guideline (moderately suspicious according to ACR) with a maximum
diameter of 12 mm.
Four patients were operated on the basis of cytological results with 3
final cases of papillary thyroid cancer and one case of nodular
hyperplasia (cytological diagnosis: Bethesda 4). The clinical and
pathological characteristics of papillary thyroid cases are shown in
Table 2. An additional case was operated despite a benign FNAB result on
the basis of mild local symptoms with a final result of nodular
hyperplasia.
In 111 (25.9%) patients, thyroid nodules with no indication of FNAB
were found. In 48 (43.2%) patients follow-up sonographies were
performed after a median time of 14 months. During follow-up, 26 months
after the initial screening, we detected enlarged suspicious
lymphadenopathies in a 47yr old male patient with a hypoechoic isthmic
nodule of 8mm. The final diagnosis was papillary thyroid carcinoma
(multicentric, infiltrative follicular variant) pT1bN1bM0 with a largest
nodule of 11mm. At first evaluation, TSH was normal and TPOAbs were
undetectable. Therefore, risks of malignancy were 0.93% (CI 0.02-1.84)
for the entire screened cohort; 2.2% (CI 0.9-5.5) for patients with
thyroid nodules and 5.8% (CI 2.3-14.0) for those nodules with
indication of FNAB.
Table 3 depicts the percentage of thyroid nodules according to thyroid
palpation and risk factors. As shown, the presence of an abnormal
palpation was associated with a significantly higher prevalence of
thyroid nodules, whereas the prevalence of thyroid nodules was not
dependent on the presence of risk factors. Additional comparisons
considering as risk factor a TPOAb level above 100 IU/ml and excluding
patients with treated hypothyroidism did not find significant
differences between groups in the prevalence of thyroid nodules.
Table 4 shows the prevalence of thyroid nodules according to the
individual risk factors. The presence of thyroid nodules was, again, not
dependent on the presence of any of the assessed risk factors.