Han-Sin Jeong

TAILORING THE CHARACTERISTICS OF GRAPHITE OXIDES BY DIFFERENT OXIDATION TIMES

Graphite oxide was synthesized using various oxidation times and characterized by its physical and chemical properties. The degree of oxidation of the graphite oxide was systematically controlled via oxidation time up to 24h. Three phases of interlayer distances were identified by x-ray diffraction: pristine graphite (3.4A), intermediate (4A) and fully expanded graphite oxide (6A) phases. These phases were distinguished by an atomic ratio of O/C, which occurred from the different compositions of epoxide, carboxyl and hydroxyl groups. The band gap of the graphite oxides was also tuned via the oxidation time, resulting in direct band gap engineering from 1.7 to 2.4eV and strong correlation with the atomic ratio of O/C. (Some figures in this article are in colour only in the electronic version)

Metabolic Tumor Volume of [18F]-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Predicts Short-Term Outcome to Radiotherapy With or Without Chemotherapy in Pharyngeal Cancer

Purpose: This study aimed to investigate whether metabolic tumor volume (MTV) measured from [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) predicts short-term outcome to radiotherapy with or without chemotherapy and disease-free survival (DFS) in patients with pharyngeal cancers. Experimental Design: The MTVs of primary sites with or without neck nodes were measured in 82 patients. Short-term outcome was assessed using the treatment response evaluation by the Response Evaluation Criteria in Solid Tumors and recurrence events during follow-up (complete response/no recurrence or residual disease/recurrence). Results: A total of 64 patients had complete response/no recurrence as of the last follow-up. A cutoff of 40 mL for the MTV was the best discriminative value for predicting treatment response. By univariate analyses, patients with MTV >40 mL showed a significantly lower number of complete response/no recurrence than did patients with MTV ≤40 mL [68.2% versus 87.8%; hazard ratio (HR), 3.34; 95% confidence interval (95% CI), 1.09-10.08; P = 0.03], as is the same in tumor-node-metastasis stage (87.5% for I-II versus 90% for III versus 63.8% for IV; P = 0.02). However, MTV was only a significant predictor of short-term outcome by multivariate analyses (HR, 4.09; 95% CI, 1.02-16.43; P = 0.04). MTV >40 mL indicated a significantly worse DFS than MTV ≤40 mL (HR, 3.42; 95% CI, 1.04-11.26;P = 0.04). The standardized uptake value for the primary tumor did not show any correlation with treatment outcome or DFS. Conclusion: MTV has a potential value in predicting short-term outcome and DFS in patients with pharyngeal cancers. (Clin Cancer Res 2009;15(18):5861–8)

Subclinical lymph node metastasis in papillary thyroid microcarcinoma: A study of 551 resections

BACKGROUND In clinically node-negative papillary thyroid microcarcinoma (PTMC), the frequency of subclinical lymph node metastasis (LNM) in the central cervical compartment (subclinical central LNM) has been reported to be as great as 65%. Routine prophylactic central compartment lymph node dissection (CLND) has been debated, because the risk of operative complications might outweigh its prognostic benefit. We aimed to study clinicopathologic factors associated with subclinical central LNM to be considered for determination of prophylactic CLND. METHODS A total of 551 patients diagnosed with clinically node-negative PTMC from 2005 to 2009 were included. All patients underwent total thyroidectomy (TT) and prophylactic CLND. Clinicopathologic risk factors of subclinical central LNM were analyzed. In addition, we investigated recurrences and postoperative complications after TT and CLND. RESULTS Among the 551 patients, 202 (37%) had subclinical central LNM. On univariate and multivariate analyses, male gender, tumor multifocality, and extrathyroidal extension were independently predictive of subclinical central LNM. During 3-year follow-up, there were no recurrences in the central cervical compartment. The frequency of permanent hypocalcemia and permanent vocal fold palsy were 1.1% and 1.3%, respectively. CONCLUSION Frequency of subclinical central LNM was high in PTMC. It was managed effectively with prophylactic CLND. In addition, prophylactic CLND did not cause significant permanent morbidities. We recommend that clinicopathologic features, such as male gender, tumor multifocality, and extrathyroidal extension, be considered for determination of prophylactic CLND in patients with PTMC.

Use of integrated 18F-FDG PET/CT to improve the accuracy of initial cervical nodal evaluation in patients with head and neck squamous cell carcinoma.

We investigated the accuracy of performing cervical nodal evaluation with using integrated 18F‐fluoro deoxyglucose positron emission tomography (PET)/CT for squamous cell carcinoma (SCC) of the head and neck as compared with using PET and contrast‐enhanced CT (CECT) alone.

Integrated 18F-FDG PET/CT for the initial evaluation of cervical node level of patients with papillary thyroid carcinoma: comparison with ultrasound and contrast-enhanced CT

Objective  To compare the diagnostic accuracy of integrated 18F‐fluorodeoxyglucose PET/CT with ultrasonography (US) and contrast enhanced CT (CECT) alone in the initial evaluation of cervical lymph node levels of patients with papillary thyroid carcinoma.

Role of 18F-FDG PET/CT in Management of High-Grade Salivary Gland Malignancies

The role of 18F-FDG PET/CT for planning the treatment of high-grade salivary gland malignancies was investigated and was compared with that with using contrast-enhanced CT. Methods: The subjects chosen for the study had high-grade cancer of the salivary gland, as confirmed by surgical pathology. The diagnostic values from 37 CT and PET/CT scans of 33 subjects were compared. The ability to predict the extent of the disease was compared by performing a subsite-based analysis for the primary lesions and a level-by-level analysis for the neck node levels as well as for the final TNM staging. The surgical pathology (67.6%) and clinical follow-up examinations (32.4%) were used as the reference standards. Furthermore, the changes made in each subjects care, based on a PET/CT examination, were compared with the treatment received without using the PET/CT data. Results: Using a primary subsite-based analysis, the diagnostic accuracy for predicting the pathologic tumor extent was significantly higher for PET/CT (91.0%) compared with that using CT alone (70.1%, P < 0.001). For the neck nodes on a level-by-level analysis, the metastasis could be predicted more accurately on the basis of a PET/CT examination (97.6%) than with using only CT (86.0%, P = 0.01). PET/CT was also far superior to CT in terms of the TNM staging (83.7% vs. 62.1%, P = 0.03). For 43.2% of the subjects, changes in the clinical decision making were made as a result of the PET/CT scan data over what was previously determined by using the CT scans alone. Conclusion: PET/CT provides more accurate diagnostic information for the evaluation of high-grade salivary cancer than does CT and it has a major impact on making treatment decisions for patients with a high-grade salivary malignancy.

Tumor Volume Assessment by 18F-FDG PET/CT in Patients with Oral Cavity Cancer with Dental Artifacts on CT or MR Images

The purpose of this study was to investigate the clinical usefulness of PET/CT or CT-attenuated PET in the evaluation of patients with oral cavity cancer (OCC) in whom dental artifacts distorted the conventional CT or MR images of the oral cavity. Methods: A PET/CT scan, in addition to a CT or MRI scan, was performed in 69 patients with OCC who had dentures or dental implants. A total of 64 PET/CT, 64 CT, and 27 MR images were analyzed including images from scans performed on 40 patients with OCC without dental artifacts on the conventional images; these were used for comparison. The CT-attenuated PET scan for the detection of primary tumors was compared with the CT or MRI scan. We also evaluated the correlation between the PET/CT volume and the pathologic volume using a regression analysis. In addition, subgroup analysis was performed to determine what proportion of subjects benefited most from the PET/CT. Results: CT-attenuated PET detected more primary tumors than did CT in patients with OCC with dental artifacts (95.3% vs. 75.0%, respectively; P = 0.0016). PET/CT volume with a standardized uptake value (SUV) cutoff point of 3.5 predicted the pathologic volume more accurately than did the other cutoff points in patients with OCC with or without artifacts. After comparing pathologic volume and PET/CTSUV 3.5 volume, the following regression equation was developed: log (pathologic volume) = 0.6 × log (PET/CTSUV 3.5 volume) + 1.3 (R2 = 0.42, P < 0.0001). Subgroup analysis showed that the prediction of the pathologic volume from the PET/CT images was more reliable for tumors that were more than 2 cm in depth (R2 = 0.72). Conclusion: For patients with OCC with dental artifacts on the conventional imaging, PET/CT could provide useful clinical information about the primary tumors, particularly in cases with advanced tumors.

Treatment for extracranial arteriovenous malformations of the head and neck

Conclusions. For extracranial arteriovenous malformations of the head and neck (HNAVMs), in which the nidus was accessible via the percutaneous route, ethanol sclerotherapy was a feasible and safe first-line treatment, although successful outcomes were obtained for only about half of the subjects. For other HNAVMs, surgical excision with embolization may be the best choice of treatment. Objective. To suggest a treatment protocol for patients with HNAVMs by comparing the treatment outcomes and complications of ethanol sclerotherapy with those of surgical excision combined with embolization. Material and methods. Twenty patients who had been diagnosed with HNAVM and treated between 1995 and 2002 were retrospectively reviewed. Ethanol sclerotherapy, surgical excision and embolization were used as treatments, either alone or in various combinations. The treatment outcomes and complications with the different modalities were analyzed. Results. Ethanol sclerotherapy was used for 12 cases, with a success rate of 50.0% and a permanent complication rate of 8.3%. Surgical excision combined with embolization was used for 13 patients. Although all patients achieved successful resolution of their HNAVM after surgical excision, 15.4% suffered from permanent complications. In total, 16/20 patients (80.0%) eventually achieved a ≥75% reduction in the size of their lesions.

Investigation of the Lack of Angiogenesis in the Formation of Lymph Node Metastases

BACKGROUND To date, antiangiogenic therapy has failed to improve overall survival in cancer patients when used in the adjuvant setting (local-regional disease with no detectable systemic metastasis). The presence of lymph node metastases worsens prognosis, however their reliance on angiogenesis for growth has not been reported. METHODS Here, we introduce a novel chronic lymph node window (CLNW) model to facilitate new discoveries in the growth and spread of lymph node metastases. We use the CLNW in multiple models of spontaneous lymphatic metastases in mice to study the vasculature of metastatic lymph nodes (n = 9-12). We further test our results in patient samples (n = 20 colon cancer patients; n = 20 head and neck cancer patients). Finally, we test the ability of antiangiogenic therapy to inhibit metastatic growth in the CLNW. All statistical tests were two-sided. RESULTS Using the CLNW, we reveal the surprising lack of sprouting angiogenesis during metastatic growth, despite the presence of hypoxia in some lesions. Treatment with two different antiangiogenic therapies showed no effect on the growth or vascular density of lymph node metastases (day 10: untreated mean = 1.2%, 95% confidence interval [CI] = 0.7% to 1.7%; control mean = 0.7%, 95% CI = 0.1% to 1.3%; DC101 mean = 0.4%, 95% CI = 0.0% to 3.3%; sunitinib mean = 0.5%, 95% CI = 0.0% to 1.0%, analysis of variance P = .34). We confirmed these findings in clinical specimens, including the lack of reduction in blood vessel density in lymph node metastases in patients treated with bevacizumab (no bevacizumab group mean = 257 vessels/mm(2), 95% CI = 149 to 365 vessels/mm(2); bevacizumab group mean = 327 vessels/mm(2), 95% CI = 140 to 514 vessels/mm(2), P = .78). CONCLUSION We provide preclinical and clinical evidence that sprouting angiogenesis does not occur during the growth of lymph node metastases, and thus reveals a new mechanism of treatment resistance to antiangiogenic therapy in adjuvant settings. The targets of clinically approved angiogenesis inhibitors are not active during early cancer progression in the lymph node, suggesting that inhibitors of sprouting angiogenesis as a class will not be effective in treating lymph node metastases.

Questionnaire evaluation of sequelae over 5 years after parotidectomy for benign diseases

The aim of this study was to evaluate long-term (more than 5 years) quality of life issues after parotidectomy for the treatment of benign disease. A questionnaire survey was performed after institutional review board approval, on patients who had undergone any type of parotidectomy for benign salivary diseases. Fifty-three patients were surveyed at more than 5 years (the long term group) and 39 patients at 1-2 years after surgery (the control group). The questionnaire included the items on self perception of known sequelae. Descriptive and comparative analyses were performed to determine major sources of discomfort and changes in sequelae over time. Possible factors that contribute to sequelae were also analysed for significance. Freys syndrome was identified as the most serious self-perceived sequela, and resulting discomfort worsened with time (P=0.01). Scores for other sequelae were similar in the two study groups. Subjective perception of Freys syndrome was significantly different (P<0.001) according to the extent of surgery, and it was most serious in total parotidectomy cases, even from 1 year postoperatively. Of the sequelae of parotidectomy for benign diseases, Freys syndrome was of greatest concern to patients, even at more than 5 years postoperatively. Therefore, additional measures which prevent or ameliorate Freys syndrome are likely to improve long-term quality of life after parotidectomy.