The role of liquid-based cytology in the investigation of colorectal lesions: a cytohistopathological correlation and evaluation of diagnostic accuracy.

BACKGROUND AND AIMS: The role of cytologic techniques is not widely accepted even if it is well documented that the cytologic investigation of colorectal tract could complement the biopsy and increase the correct diagnosis of carcinomas. This study aims to evaluate the role of Thin-Prep(R) liquid-based cytology in the investigation of colorectal lesions. MATERIALS AND METHODS: We compared the diagnostic accuracy of Thin-Prep(R) with that of biopsy in 158 patients with signs and symptoms of the lower gastrointestinal tract. Each patient underwent colonoscopy, followed by tissue biopsy and brush cytology. Brushing material was obtained and prepared according to the operating manual of Thin-Prep(R). RESULTS: The rate of unsatisfactory smears was 5% (8/158) with liquid-based technique and appeared to be slightly higher than the respective of biopsy [3.2% (5/158) (5 vs 3.2%, P = 0.18)]. Based on the final diagnosis, 89 out of 93 total malignant cases and 53 out of 53 total benign cases were correctly diagnosed with Thin-Prep(R) technique (four false negatives). Accurate diagnosis with biopsy was performed in 87 out of 93 total malignant cases and 53 out of 53 total benign cases with biopsy (six false negatives). Neither in Thin-Prep(R) technique nor in biopsy were false-positive cases observed. The sensitivities of detecting malignancy by Thin-Prep(R) and biopsy were 95.7, and 93.5%, respectively (no significant difference, P = 0.239). The sensitivity was augmented (98.9%) when the two techniques were combined, and this difference was found to be statistically significant (98.9 vs 92.9, P = 0.01, and 98.9 vs 95.7, P = 0.039). CONCLUSIONS: Liquid-based cytology appears to be an easy, highly accurate, and reliable cytologic method for the diagnostic approach of colorectal diseases and could be applied as complementary to biopsy for the improvement of the diagnosis. Moreover, could be used for DNA ploidy analysis and immmunohistochemical studies.

Potential of radial basis function neural networks in discriminating benign from malignant lesions of the lower urinary tract.

OBJECTIVE: To investigate the potential value of morphometry and neural network tools for discriminating benign from malignant nuclei and lesions of the lower urinary tract. STUDY DESIGN: The study group consisted of 33 cases of lithiasis, 41 cases of inflammation, 66 cases of benign hyperplasia of the prostate, 4 cases of carcinoma in situ, 48 cases of grade 1 transitional cell carcinoma of the bladder (TCCB) and 123 cases of grade 2 and 3 TCCB. Images of routinely processed voided urine smears stained by the Giemsa technique were analyzed by a custom image analysis system. Analysis of the images gave a data set of features from 31,158 nuclei. A radial basis function (RBF)-type neural network was employed to discriminate benign from malignant nuclei, based on the extracted morphometric and textural features. Subsequently a second RBF classifier was employed to discriminate benign from malignant cases. The nuclei from 156 randomly selected cases (50% of total cases) was used as a training set, and the nuclei from the remaining 159 cases made up the test set. Similarly, in an attempt to discriminate at the patient level, the same 156 cases were used to train an RBF classifier; the remaining 159 cases were used for the test set. The cases used for training and testing the 2 classifiers (nuclear and patient level) were the same for the 2 kinds of classifiers. RESULTS: Application of the RBF classifier permitted the correct classification of 93.64% of benign nuclei and 85.61% of malignant, giving an overall accuracy of 84.45%. At the patient level the RBF classifier permitted an overall accuracy of 94.97%. These results were on the test sets. CONCLUSION: The role of nuclear morphologic features in the cytologic diagnosis of lower urinary tract alterations was confirmed by the results of this study. The observed overlap in feature space indicates that the nuclear characteristics do not form strictly separate clusters; that fact explains the difficulty morphologists have with reproducible identification of nuclei from the lower urinary tract. Application of RBF offers good classification at the nuclear and patient level and promises to become a powerful tool for everyday practice in the cytologic laboratory.

Study on the morphology and reproducibility of the diagnosis of endometrial lesions utilizing liquid-based cytology.

BACKGROUND: The objective of the current study was to determine the diagnostic cytomorphologic criteria for liquid-based cytology and to evaluate the reproducibility and usefulness of the cytologic diagnosis in endometrial lesions. METHODS: A total of 162 direct endometrial samplings taken from postmenopausal women were evaluated by 2 skilled cytopathologists in endometrial cytology. The cytologic diagnosis was made according to the 1994 classification scheme of the World Health Organization. After establishment of the criteria, three additional cytopathologists without any experience in liquid-based endometrial cytology examined the same cases to determine interobserver variability. The intraobserver variability also was evaluated by all the observers. RESULTS: The cytomorphologic criteria were established in the following four diagnostic categories: atrophic endometrium, hyperplasia without atypia, hyperplasia with atypia, and adenocarcinoma. The overall interobserver agreement was nearly perfect with a kappa value of 0.89 during the checking round and ranged from moderate to substantial with kappa values of 0.48-0.80, respectively, in the other diagnostic rounds (P < 0.0001); hyperplasia with atypia was found to be the most difficult category to identify correctly. Furthermore, the intraobserver agreement ranged from substantial to perfect with kappa values of 0.61-1.00 in all diagnostic rounds (P < 0.0001). CONCLUSIONS: Liquid-based cytology allows for standardized and reproducible endometrial preparations, which in turn allows the application of common diagnostic criteria among cytopathologists. Furthermore, liquid-based cytology in combination with endometrial sampling could be a useful tool for the outpatient diagnosis of endometrial lesions, which could reduce unnecessary curettage.

The role of liquid-based cytology in the investigation of breast lesions using fine-needle aspiration: a cytohistopathological evaluation.

INTRODUCTION: Liquid-based cytology processing of breast fine-needle aspiration (FNA) specimens has been used in our institution since 1999. The aim of this study was to investigate the role of liquid-based cytology (Thin-Prep(R)) in the evaluation of breast FNA specimens. PATIENTS AND METHODS: This study was carried out on 352 cases corresponding to equal number of women (134 malignant and 218 benign) examined from September 1999 to June 2003. A direct to vial study was planned. Aspirated material was directly immersed to cytolytR vial (Cytyc Corporation, Boxborough, MA). The specimens were transported to the laboratory non-refrigerated within 24 hr. Thin-Prep slides were made using the Thin-Prep 2000 processor. The remaining material was embedded in paraffin. RESULTS: Altogether, 352 cases were examined and unsatisfactory smears were observed in 14 (3.9 %) out of all cases. The histologic examination verified that 128 out of 131 total malignant cases and 203 out of 207 total benign cases were correctly diagnosed with the cytological technique. False positives were found in four cases and false negative in three cases. Liquid-based technique presented a sensitivity of 97.7%, a specificity of 98%, a positive predictive value (PPV) of 96.9%, a PNV of 98.5%, and an over all accuracy (OA) of 97.9%. CONCLUSIONS: The processing of FNA breast specimens using liquid-based cytology offers an accurate diagnostic tool. Liquid-based cytology could reduce the uncertainty based in the cytological evaluation of FNA, because it offers the possibility to embed material in paraffin and take tissue sections with histological appearance identical to those observed in routine histological sections. Moreover it offers the potential advantage of retraining extra material for the purpose of ploidy analysis and immunohistochemical study in order to offer information concerning the expression of prognostic markers such as p53, MIB-1, steroid hormone receptors, and EGFR.

Application of discriminant analysis and quantitative cytologic examination to gastric lesions.

OBJECTIVE: To investigate of the potential value of morphometry and discriminant analysis for the classification of benign and malignant gastric cells and lesions. STUDY DESIGN: The data set consisted of 13,300 cells from 120 cases composed of 30 cases of cancer, 26 cases of gastritis and 64 cases of ulcer according to the final histologic diagnosis. The cytologic diagnosis was divided into 5 categories (gastritis, ulcer, inflammatory dysplasia, cancer and true dysplasia). Classification was attempted at 2 levels: the cell level to classify individual cells and the case level to classify individual cases. For the cellular classification the measured cells from 50% of available cases were selected as a training set to construct a model. The cells from the remaining cases were used as a test set to validate the model. Similarly for case classification, the same 50% of cases that were used for cell classification were used as a training set and the remaining cases as a test set. Images of routinely processed gastric smears stained by the Papanicolaou technique were analyzed by a customized image analysis system. RESULTS: Application of discriminant analysis on the test set gave correct classification of 98.4% of benign cells and 67.1% of malignant cells. On case classification, 100% accuracy was achieved for benign and malignant cases, both for the training and test sets. CONCLUSION: The application of discriminant analysis described in this paper could produce significant classification results at the cellular and individual case level.