Thongchai Bhongmakapat

Association between multidrug resistance-associated protein 1 and poor prognosis in patients with nasopharyngeal carcinoma treated with radiotherapy and concurrent chemotherapy

ATP-binding cassette (ABC) multidrug transporters have been associated with chemoresistance, which is a major obstacle in attempts to improve clinical outcome of patients with nasopharyngeal carcinoma (NPC). In this study, we investigated 3 ABC multidrug transporters including MDR1, MRP1, and BCRP for their potential as prognostic indicators in patients with NPC. We examined the protein expression profiles of MDR1, MRP1, and BCRP in NPC tissues from 60 patients with advanced stages who were treated with radiotherapy and concurrent chemotherapy. The clinicopathologic features, patterns of treatment failure, and survival data were compared with the transporter expression. Univariate analyses were performed to determine the prognostic factors that influenced treatment failure and patient survival. We found that MRP1 expression was strongly predictive of both 5-year survival (P = .025) and disease-free survival (P < .001). However, neither MDR1 nor BCRP expression was correlated with the clinicopathologic parameters. Interestingly, the incidence of recurrence and metastasis for patients in the MRP1-positive group was significantly higher than that in the MRP1-negative group (P = .003). With multivariate analysis, MRP1 expression at the time of diagnosis before the treatment was identified as an independent prognostic factor for both 5-year survival (P = .041) and disease-free survival (P = .001). MRP1 expression can therefore be used as a potent molecular risk factor and a guide for chemotherapeutic regimens in patients with advanced stages of NPC.

Evaluation of Real-time Polymerase Chain Reaction for Detection of the 16S Ribosomal RNA Gene of Mycobacterium tuberculosis and the Diagnosis of Cervical Tuberculous Lymphadenitis in a Country With a High Tuberculosis Incidence

BACKGROUND Tuberculous lymphadenitis (TBL) is the most common form of extrapulmonary tuberculosis. Currently, the standard diagnostic test for TBL is culture, which takes more than several weeks to yield results. We studied a real-time polymerase chain reaction (PCR) for rapid detection of Mycobacterium tuberculosis in cervical lymph node specimens obtained from patients in a country where the tuberculosis incidence is high. METHODS Patients with cervical lymphadenopathy were prospectively enrolled between April 2009 and March 2010. Clinical specimens obtained through fine-needle aspiration (FNA) and excisional biopsy were tested for M. tuberculosis by the COBAS TaqMan MTB Test, a real-time PCR assay for detecting the 16S ribosomal RNA gene of M. tuberculosis. Mycobacterial culture and histopathological findings from tissue biopsy specimens were used as a reference standard for sensitivity and specificity calculations. RESULTS Of 73 patients, 41 received a diagnosis of TBL. For biopsy specimens, the sensitivity of real-time PCR was 63.4%, and the specificity was 96.9%. For FNA specimens, the sensitivity was 17.1%, and the specificity was 100%. The sensitivity of real-time PCR of biopsy specimens was comparable to that of tissue culture but significant lower than that of histopathological examination (P < .01). CONCLUSIONS Real-time PCR did not increase the yield for rapid diagnosis of TBL.

Nasopharyngeal carcinoma segmentation using a region growing technique

PurposeThis paper proposes a new image segmentation technique for identifying nasopharyngeal tumor regions in CT images. The technique is modified from the seeded region growing (SRG) approach that is simple but sensitive to image intensity of the initial seed.MethodsCT images of patients with nasopharyngeal carcinoma (NPC) were collected from Ramathibodi hospital, Thailand. Tumor regions in the images were separately drawn by three experienced radiologists. The images are used as standard ground truth for performance evaluation. From the ground truth images, common sites of nasopharyngeal tumor regions are different from head to neck. Before the segmentation, each CT image is localized: above supraorbital foramen (Group I), below oropharynx (Group III), or between these parts (Group II). Representatives of the CT images in each part are separately generated based on the Self-Organizing Map (SOM) technique. The representative images contain invariant features of similar NPC images. For a given CT slice, a possible tumor region can be approximately determined from the best matching representative image. Mode intensity within this region is identified and used in the SRG technique.ResultsFrom 6,606 CT images of 31 NPC patients, 578 images contained the tumors. Because NPC images above the supraorbital foremen were insufficient for study (6 images from 1 subject), they were excluded from the analysis. The CT images with inconsistent standard ground truth images, metastasis cases, and bone invasion were also disregarded. Finally, 245 CT images were taken into account. The segmented results showed that the proposed technique was efficient for nasopharyngeal tumor region identification. For two seed generation, average corresponding ratios (CRs) were 0.67 and 0.69 for Group II and Group III, correspondingly. Average PMs were 78.17 and 82.47%, respectively. The results were compared with that of the traditional SRG approach. The segmentation performances of the proposed technique were obviously superior to the other one. This is because possible tumor regions are accurately determined. Mode intensity, which is used in place of the seed pixel intensity, is less sensitive to the initial seed location. Searching nearby tumor pixels is more efficient than the traditional technique.ConclusionA modified SRG technique based on the SOM approach is presented in this paper. Initially, a possible tumor region in a CT image of interest is approximately localized. Mode intensity within this region is determined and used in place of the seed pixel intensity. The tumor region is then searched and subsequently grown. The experimental results showed that the proposed technique is efficient and superior to the traditional SRG approach.

Automatic segmentation of nasopharyngeal carcinoma from CT images: Region growing based technique

This paper describes a framework for automatic nasopharyngeal carcinoma segmentation from CT images. The proposed technique is based on the Region Growing Method. It is automatic segmentation in which an initial seed is generated without human intervention. The seed is generated from a probabilistic map representing the chances of it being tumor. This map is created from three probabilistic functions based on location of the tumor, intensities, and non-tumor region respectively. The pixel in which the probability is the highest will be selected as potential seeds. Only one representative of these seeds will be selected as an initial seed. Then the seed will be used for region growing subsequently. The experimental results showed that the potential seeds and initial seed were correctly determined with a percentage accuracy of 81.60% and 95.10%. The seed was grown in preprocessed CT images for identifying the nasopharyngeal carcinoma region. The results showed that, perfect match and corresponding ratio were 71.31% and 53.00% respectively

Automatic Segmentation of Nasopharyngeal Carcinoma from CT Images

This paper presents an automatic segmentation technique for identifying nasopharyngeal carcinoma regions in CT images. The proposed technique is based on the region growing method by which an initial seed is automatically generated. A probabilistic map representing a chance of being the tumor pixel in each CT image will be created and used for initial seed determination. This map is generated from three probabilistic functions established upon location of the tumor considered, intensities of the tumor pixels, and asymmetry of organs respectively. A representative of potential tumor pixels will be selected as an initial seed. The experimental results showed that seeds were correctly determined with the percent accuracy of 84.32%. These seeds were grown in preprocessed CT images for identifying the nasopharyngeal carcinoma regions subsequently. The results showed that, for no metastasis cases, perfect match and corresponding ratio were 85.03% and 52.44% respectively and 29.26% and 28.03% correspondingly for metastasis cases. This resulted from a single seed generated in each CT image. It was unable to identify more than one tumor region.

A Small Absorbable Stent for Treatment of Anterior Glottic Web

A new one-stage approach for treatment of selected anterior glottic web has been successful. This case report illustrates its simplicity in microlaryngoscopy with complete lysis of the anterior glottic web by CO(2) laser. Then a small neck horizontal incision is made at the level of anterior commissure to gain exposure to thyroid cartilage. Absorbable suture is passed through the midline of thyroid cartilage below and above the anterior commissure. A knot is tied over thyroid ala. The suture acts as a tiny stent to prevent recurrence of the web.

Dealing with missing values for effective prediction of NPC recurrence

This paper aims to investigate missing data techniques for effective prediction of nasopharyngeal carcinoma (NPC) recurrence. The techniques include listwise deletion, imputations by mean, k-nearest neighbor, and expectation maximization. The completed data are used to predict the presence or absence of NPC recurrence in each year by means of logistic regression, multilayer perceptron with backpropagation training, and naive bayes. Five year predictions are carried out. Validity of each predictive model is assured by 10-fold cross validation. Their results are compared in order to determine proper missing data treatment and the most efficient prediction technique. The results showed that EM imputation was superior to the other missing data techniques because it can be efficiently applied to all predictive models. The multilayer perceptron with backpropagation training gave the highest prediction performance and it was the most robust to the data completed by different missing data techniques.

Prediction of nasopharyngeal carcinoma recurrence by neuro-fuzzy techniques

Neuro-fuzzy techniques for prediction of nasopharyngeal carcinoma recurrence are mainly focused in this paper. A technique, named Generalized Neural Network-type Single Input Rule Modules connected fuzzy inference method is proposed. In the study, clinical data of patients with nasopharyngeal carcinoma were collected from Ramathibodi hospital, Thailand. In total, 495 records were taken into account. Relevant factors were extracted and employed in developing predictive models. The results showed that the proposed technique was superior to the other neuro-fuzzy techniques, stand-alone neural network, logistic regression and Cox proportional hazard model. Accuracy and AUC above 80% and 0.8 could be achieved. To show validity of the proposed technique, two nonlinear problems, i.e., function approximation and the XOR classification problems, are studied. Simulation results showed that the proposed technique could simplify the problem by converting the original nonlinear input into the lower complexity one. In addition, it can solve the XOR problem whereas the traditional approach cannot tackle this problem.

Comparison of neuro-fuzzy based techniques in nasopharyngeal carcinoma recurrence prediction

This paper aims to compare neuro-fuzzy based techniques for effective prediction of nasopharyngeal carcinoma (NPC) recurrence. The techniques include an artificial neural network (ANN), adaptive neuro-fuzzy inference systems (ANFIS), the functional-type single input rule modules connected fuzzy inference method (F-SIRMs method) and the functional and neural network type SIRMs method (F-NN-SIRMs method). All models are produced to predict the presence or absence and timing of the NPC recurrence. Five years predictions are carried out. Validity of each predictive model is assured by 10-fold cross validation. The results show that the F-NN-SIRMs method is superior to the other techniques in a sense that it provides the higher prediction performance.

Clinicopathologic Findings and Treatment Outcome of Laryngectomized Patients with Laryngeal Cancer and Hypopharyngeal Cancer: An Experience in Thailand

Objective: To evaluate the clinicopathologic findings and treatment outcome in laryngectomized patients with laryngeal cancer and hypopharyngeal cancer. Materials and Methods: The authors retrospectively reviewed the medical records of 212 patients who had been newly diagnosed and treated with laryngectomy between January 2000 and December 2010. The age, gender, clinical manifestations, associated predisposing condition, tumor WHO grade, AJCC tumor stage, maximum tumor size, anatomical involvement, type of surgery, postoperative sequelae, treatment and therapeutic outcome were analyzed. Results: The present study included laryngeal cancer (n = 155) and hypopharyngeal cancer (n = 57). The patients’ age ranged from 38 to 84 years, with the mean age of 62.08±9.67 years. The common clinical presentations were hoarseness (73.6%), cervical lymphadenopathy (35.8%), sorethroat (22.2%), and odynophagia (14.6%). The laryngeal cancer commonly involves true vocal cord (86.5%), anterior commissure (65.8%), false vocal cord (56.8%), laryngeal ventricle (53.5%), subglottis (47.1%), and paraglotic space (35.5%), respectively. Fifty-three percent of cases had stage IV cancer. The most common postoperative surgical sequela was hypothyroidism (77.8%). The overall 5-year survivals for laryngeal cancer and hypopharyngeal cancer were 55% and 9%, respectively. The 5-year survival for node-negative cases was 61.8% versus 17% for node-positive cases (p< 0.001). AJCC stage of laryngeal cancer and hypopharyngeal cancer was a significant predictor of 5-year survival (p< 0.001 and p = 0.004, respectively). Conclusions: The advanced AJCC stage, advanced T stage, advanced N stage, extracapsular tumor spread, and tumor invasion of false vocal cord, epiglottis, preepiglottic space, paraglottic space, thyroid cartilage, cricothyroid membrane were found to significantly augment the decrease of 5-year survival in laryngeal cancer. Only advanced AJCC stage was significantly associated with 5-year survival rate in hypopharyngeal cancer.