Summary: | 碩士 === 長庚大學 === 管理學院碩士學位學程在職專班醫務管理組 === 100 === BACKGROUND
Thyroid cancer is the most common malignant tumor in the endocrinology clinic, however, which is about 5% part of malignant rate among thyroid neoplasm/nodule. The challenge in clinical aspect is how to early detect thyroid cancer from those suspicious subjects. The way of biopsy using Fine-needle aspiration (FNA) of the thyroid gland has proven to be an important and widely accepted, cost-effective, safe, and accurate method for patients with thyroid nodules. Unfortunately, the lack of a standardized reporting format has caused confusion and ambiguity in interpreting of thyroid disease classification. In 2007, the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was reached consensus during National Cancer Institute State of Science Conference on thyroid fine-needle aspiration that defines a diagnostic terminology, which is implemented now.
STUDY AIMS
The aims of this study were, first, to evaluate the consistent rate between cytotechnologist and cytopathologist using kappa statistic based on the new classification system- TBSRTC. Second, we would like to report the distribution of diagnosis into TBSRTC categories and compare the distributions of other studies from literature. Third, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated by distinguishing validity of malignant. To compare the risk of malignancy, we compared conventional and new diagnostic classification for predicting thyroid cancer risk.
MATERIALS and METHODS
A total of 229 thyroid FNAs, from Jan 2009 to Mar 2010, were examined at our institution using conventional Papanicolaou system for comparison between traditional and new system classification. On the other hand, the total 3244 of thyroid FNAs, from Dec 2010 to Dec 2011, were used for distribution comparison of new TBSRTC system. The blind design was performed to evaluate the diagnosis consistence between cytotechnologist and cytopathologist using Bethesda system. The accuracy index, including sensitivity, specificity, positive predictive value, and negative predictive value, were conducted for comparison of conventional and Bethesda system.
RESULTS
Based on the Bethesda system classification, besides the slight higher proportion in Nondiagnostic or Unsatisfactory group, our results showed that diagnostic distribution were close to other studies which based on same classification. The diagnosis validity between cytotechnologist and cytopathologist showed a high degree of consistence (Kappa=0.92).The validity of Bethesda system is better than traditional Papanicolaou system in sensitivity, positive predictive value and negative predictive value for thyroid cancer risk (53.7%、65.5% and 82.1% vs. 40.3%、62.8% and 78.6%).
CONCLUSIOIN
The results of our study demonstrated that the recently proposed Bethesda classification system is excellent for reporting thyroid FNAs, which set up the standard classification in thyroid clinical report. Our result demonstrated the high agreement rate between cytotechnologist and cytopathologist. The new Bethesda classification system can enhance the validity of FNAs thyroid cancer diagnosis.
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