1. A study of the accuracy of fine needle aspiration cytology in thyroid pathology
Honored evaluation committee and students, distinguished guests, my name is Alexandra Contra and I am going to present you today a study of the accuracy of fine needle aspiration cytology in thyroid pathology.
Author: Alexandra Contra 6th Grade MG
Coordinator: Lecturer dr. Georgescu Rares

2. FNA cytology- summary data from literature
Diagnosis procedure
economical
accurate
efficient
FNA cytology for the thyroid gland is considered to be the most efficient, economical and accurate diagnosis procedure for selecting the thyroid nodules which need to be referred for surgery. 2

3. FNA cytology – summary data from literature
Sensitivity
Specificity
Overall accuracy
PPV
NPV FP FN
65-98%
72-100%
75-90%
94-99%
66-97%
0-8%
1-12%
PPV: Positive predictive value NPV: Negative predictive value
FP: False positive FN: False negative
Statistical analysis conducted in various medical institutions around the world, showed a wide range of results but for a brief understanding, summary data from the literature is described as follows: a sensitivity and specificity ranging from 65-98% respectively from % and an overall accuracy which can reach 90% are very good indicators for the test. Of course, like any other test, it has it’s own diagnosis pitfalls and limitations. For example, the FP and FN rate which depend on many aspects: specimen adequacy, sampling techniques, the skill of the physician, the experience of the pathologist and many others. 3

4. Purpose of the study 2011 2013 Accuracy Of FNA Cytology Diagnosis
patients diagnosed with thyroid nodules
Surgery Department, Private Medical Clinic ‘’PULS’’
2011 to
2013
FNA cytology
The purpose of this study is to asses the accuracy of FNA cytology in the diagnosis of thyroid pathology of the patients who were referred to the Surgery Department of the Private Medical Clinic ‘’PULS’’, Târgu Mureş from 2011 to 2013.
Diagnosis
Accuracy Of FNA Cytology 4

5. Materials And Method Retrospective study 319 cases of thyroid nodules
Ethical approval from UMF Târgu Mureş
Written informed consent from the clinic
Retrospective study
319 cases of thyroid nodules
FNA cytology at the ‘’PULS’’ clinic
Cytological diagnosis at ‘’SANTOMAR’’ private laboratory
According to Bethesda
We have been conducting a retrospective study on 319 cases of thyroid nodules which were further investigated through FNA cytology at the private medical clinic ‘’PULS’’. Cytology diagnosis was determined at ‘’SANTOMAR’’ private laboratory in Cluj Napoca and was established in conformity with the Bethesda classification. All the FNA procedures and cytological readings were made by the same physician respectively by the same pathologist, in order to reduce the diagnosis pitfall as much as possible.
Ethical approval was obtained from the Ethics Commission of UMF Targu Mures and a written informed consent was waved by the review board of the clinic.
All the FNA procedures - same surgeon
All the cytological readings - same pathologist 5

6. Materials And Method FNA Cytology Telephonic questionnaire
All of the FNA cytology cases gathered from 2011 to 2013 in the clinics archive were automatically selected. In order to obtain medical information afterwards the cytology test, we contacted the patients for a telephonic questionnaire. The most relevant part of the questionnaire was that were the patient informed us if surgical intervention OR only medical treatment followed. Patients where surgical intervention followed were asked for the histopathology results. The ones in which only medical treatment followed were questioned about the most recent ecographic review so we can confirm the stability of the nodule at least 6 months after FNA test.
Medical treatment followed
Thyroidectomy/ Lobectomy followed
Ecographic follow-up at least 6 months after the FNA 6
Histopathology

7. The telephonic questionnaire
1. Accuses of painful sensations during the FNA procedure?
2. Accuses of local complications after the FNA procedure?
or treatment followed?
Medical
Surgical
The telephonic questionnaire consisted in a few key questions which were developed depending on the cases so we can obtain the most accurate information.
Ecographicaly followed-up nodule data
Histopathology diagnosis 7

8. Criteria for excluding from the study
NO contact details WERE NOT monitored by an endocrinologist after the FNA cytology DID NOT answer to the questionnaire
The criteria for excluding from the study were: patients who couldn’t been contacted by phone
patients who were not monitored after the FNA cytology test by an endocrinologist
patients who refused to answer to the questionnaire
The statistical calculations were made using MedCalc. 8
Statistical calculations were made using MedCalc

9. Median age and prevalence on gender
Results
Median age and prevalence on gender
Variable
Sex
Female
289 (90,6%)
Male
30 (9,4%)
Variable
Age
Sample size
319
Lowest Value 17
Highest value 82
Arithmetic mean 53
The occurrence in female was 90,6% and the median age was 53 years, as reported in other literature. 9

10. Pain during the procedure
Local complications and pain related questionnaire
Pain during the procedure
YES 19 NO
198
Total
217
Local complications
Intensive pain 1
Hematoma 4 No
212
Total
217
Only 19 patients out of the 217 who answered the questionnaire accused pain during the procedure.
Only 5 patients out of the 217 who answered the questionnaire accused local complications: intensive pain for a few days (1 case) and hematoma (4cases). 10

11. Cytology results
FNAC results were interpreted as benign in 210 cases (69.30%), indeterminate in 46 cases, suspect in 4 cases, malignant in 1 case and inadequate in 42 cases (13,9%) – the last one, after excluding 11 cases of cystic lesions (? Worth mentioning? )
There is a quite remarking difference between the number of indeterminate cases and the number of suspicious or malignant cases which could be explained by the reduced number of smears read by the pathologist (only 2 instead of 6~10 smears)

12. Histology results and correlations with the cytology
Benign 34
69,4%
Malign 15
30,6%
Total 49
Histology and cytology correlations
Benign
Indeterminate
Malign
Inadequate
Suspect 14 13 6 1 34 4 2 15
Total
18 (36.7%)
17 (34.7%)
1 (2.0%)
10 (20.4%)
3 (6.1%) 49
Out of the 303 cases, we had histopathology data on 49 patients. This was the gold standard we used to correlate the correspondent FNAC results when possible. 34 cases (69,4%)out of 49, turned up to be benign and 15 of them (30,6%) had malignant results.
The correlation made between the FNAC and the gold standard revealed some discordances.
4 out of 18 benign FNAC turned up to be malignant and 13 out of 17 indeterminate FNAC were benign. Also one suspicious FNAC case turned up to be benign. 12

13. Criterion values and coordinates of the ROC curve
Our results
Standard range worldwide
Thyroid FNA cytology
Sensitivity
Specificity
Overall accuracy
PPV
NPV FP FN
76,47%
83,1%
82,3%
35,1%
96,7%
16,9%
23,0%
This being told, we obtained a sensitivity of 76,47%, a specificity of 83,1% and a total accuracy of 82,3%. All these results are in conformity with the literature data published so far. A high specificity test always comes in hand with a high NPV as you can see in our results. But FNAC to golden standard correlation discordances like those mentioned before affected the FP respectively the FN rate as you can see in the table.
Thyroid FNA cytology
Sensitivity
Specificity
Overall accuracy
PPV
NPV FP FN
65-98%
72-100%
75-90%
94-99%
66-97%
0-8%
1-12% 13

14. ROC Curve AUC = 0,798 AUC intervals: 0,9-1,0 excellent
0,8-0,9 very good
0,7-0,8 good
0,6-0,7 medium
0,5-0,6 weak
<0, very weak
p=0,0001
Despite the relatively high FP and FN rates, the AUC has a value of 0,798 and a statistically significant p value, which assures us that the procedure has a very good accuracy. 14

15. FNA cytology first line diagnostic test
Conclusions
FNA cytology first line diagnostic test
Good accuracy
Minor complications
Reduces surgery
Painless maneuver
FNA cytology is a painless maneuver for the most of the patients. Therefore, local anesthesia is not compulsory.
Local complications occur rarely and they are minor.
FNA cytology has a good accuracy in the initial diagnosis of the patients with thyroid nodules or diffuse lesions avoiding unnecessary surgery in most of the cases. 15

16. Discussions
Incidentalomas- worth puncturing?
Optimal number of smear readings?
PPV and FP interpretation?
FN value interpretation?
Like any other test, FNAC has it’s own diagnosis pitfalls which I believe that are worth mentioning.
FNAC cytology on an incidentaloma (nodule <10mm) may increase the rate of inadequate results.
A reduced number of smear readings/patient may influence the results increasing the number of indeterminate results which in histopathology may prove to be benign. This, translated into statistical terms, may mean a low PPV and high FP rates.
As a last remark, increased FN value may be due to microfollicular type of papillary carcinoma which can be easily missed when puncturing. 16

17. Bibliography
1. Joe D. Jakowski, M.D, PathologyOutlines.com, Inc. 2013
2. American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi medical guidlines for clinical practice for the diagnosis and management of thyroid nodules, Endocrine Practice vol 12 No1 January/February 2006, 63.
3. Edmund S. Cibas, MD, Syed Z. Ali, MD, The Bethesda System for Reporting Thyroid Cytopathology, Am J Clin Pathol 2009;132:
Thank you very much for your attention! 17