Ji-hoon Jung

Effect of Helicobacter pylori eradication on metachronous recurrence after endoscopic resection of gastric neoplasm.

OBJECTIVES:Although many epidemiologic studies have shown that Helicobacter pylori (H. pylori) eradication has prophylactic effects on gastric cancer, their results are less clear in high-risk populations. We conducted this study to examine whether H. pylori eradication would affect the occurrence of metachronous gastric cancer after endoscopic resection in patients with early gastric cancer.METHODS:We retrospectively analyzed 2,089 adults who underwent endoscopic resection of gastric low-grade neoplasia, high-grade neoplasia, or differentiated invasive neoplasia from 2004 to 2008 at Asan Medical Center. Of these, a total of 1,007 patients with early gastric cancer were enrolled in this study. We evaluated the demographic data, the pathology, and the incidence of metachronous recurrence by dividing them into three groups: those without active H. pylori infection (Hp negative group, n=340), those who successfully underwent H. pylori eradication (eradicated group, n=485), and those who failed or did not undergo H. pylori eradication (noneradicated group, n=182).RESULTS:Metachronous recurrence was diagnosed in 75 patients, including 17 in the Hp, 34 in the eradicated, and 24 in the noneradicated groups. Median time to metachronous recurrence was 18 months (range, 7–75 months). The incidence of metachronous gastric cancer was 10.9 cases per 1,000 person-years in the Hp negative group, 14.7 cases per 1,000 person-years in the eradicated group, and 29.7 cases per 1,000 person-years in the noneradicated group. The hazard ratios in the noneradicated group compared with the Hp negative and eradicated groups were 2.5 (P<0.01) and 1.9 (P=0.02), respectively. H. pylori eradication reduced metachronous recurrence of gastric neoplasm, which was also shown in the secondary analysis of 1,487 patients with low-grade neoplasia and early gastric cancer.CONCLUSIONS:Successful H. pylori eradication may reduce the occurrence of metachronous gastric cancer after endoscopic resection in patients with early gastric cancer.

Quantitative metabolic parameters measured on F-18 FDG PET/CT predict survival after relapse in patients with relapsed epithelial ovarian cancer

OBJECTIVE This study aimed to evaluate the prognostic value of quantitative metabolic parameters measured on F-18 FDG PET/CT (FDG PET/CT) at the time of the first relapse in patients with relapsed epithelial ovarian cancer (EOC). METHODS Fifty-six relapsed EOC patients were retrospectively included. Quantitative metabolic parameters including maximum standardized uptake value (SUVmax), whole-body metabolic tumor volume (WBMTV), and whole-body total lesion glycolysis (WBTLG) were measured on FDG PET/CT at the time of the first relapse. Post-relapse survival (PRS) was calculated from the date of diagnosis of relapsed disease to the date of death or last follow-up. Univariate and multivariate analyses for PRS were performed using clinical and quantitative metabolic parameters. RESULTS Thirty-two patients died from the disease during the follow-up period (median: 46.2 months). On univariate and multivariate analyses, the platinum-free interval, type of second-line treatment, WBMTV, and WBTLG were all significant prognostic factors for PRS. The subgroup of patients who were platinum-sensitive with low WBMTV and low WBTLG showed better prognosis, when compared with other subgroups (log-rank test, p<0.001). Patients treated with secondary cytoreductive surgery (SCS) followed by second-line chemotherapy showed significantly longer duration of PRS than patients treated with second-line chemotherapy only (mean PRS=61 vs. 36 months, χ(2)=8.68, p=0.032). CONCLUSION Our results suggest that quantitative metabolic parameters measured on FDG PET/CT at the time of the first relapse have significant predictive values for PRS. Incorporating quantitative metabolic parameters and conventional clinical parameters has a superior prognostic discrimination compared with conventional clinical parameters alone.

Preoperative Prediction of Cervical Lymph Node Metastasis Using Primary Tumor SUVmax on 18F-FDG PET/CT in Patients with Papillary Thyroid Carcinoma.

Objectives The aim of the current study was to evaluate the value of preoperative 18F-FDG (FDG) PET/CT in predicting cervical lymph node (LN) metastasis in patients with papillary thyroid carcinoma (PTC). Methods One hundred and ninety-three newly diagnosed PTC patients (M: F = 25:168, age = 46.8 ± 12.2) who had undergone pretreatment FDG PET/CT and had neck node dissection were included in this study. The FDG avidity of the primary tumor and the SUVmax of the primary tumor (pSUVmax) were analyzed for prediction of LN metastasis. Detectability by ultrasonography (US) and FDG PET/CT for cervical LN metastasis were also assessed and compared with the pSUVmax. Results The FDG avidity of the primary tumor was identified in 118 patients (FDG avid group: 61.0%, M: F = 16:102, age 47.0 ± 12.7 years) and pSUVmax ranged from 1.3 to 35.6 (median 4.6) in the FDG avid group. The tumor size in the FDG avid group was bigger and there was a higher incidence of LN metastasis compared to the FDG non-avid group (0.93 vs. 0.59 cm, p <0.001 and 49.2 vs. 33.3%, p <0.05). In the FDG avid group, patients with LN metastasis had higher pSUVmax than patients without LN metastasis (8.7 ± 8.3 vs. 5.7 ± 5.1, p <0.001). The incidence of central LN metastasis in patients with a pSUVmax >4.6 was 54%; however, the detectability of central LN metastasis by US and FDG PET/CT were 10.3% and 3.6%, respectively. Conclusion A high FDG avidity of the primary tumor was related to LN metastasis in PTC patients. Therefore, patients with a high pSUVmax should be cautiously assessed for LN metastasis and might need a more comprehensive surgical approach.

Quantification of Intratumoral Metabolic Macroheterogeneity on 18F-FDG PET/CT and Its Prognostic Significance in Pathologic N0 Squamous Cell Lung Carcinoma.

Purpose This study aimed to develop a novel quantification method for intratumoral metabolic macroheterogeneity (IMMH) on 18F-FDG PET/CT and evaluate its prognostic significance in pathologic N0 (pN0) squamous cell lung carcinoma (SQCLC) patients. Patients and Methods A total of 83 patients who underwent pretreatment 18F-FDG PET/CT and were diagnosed with pN0 SQCLC after curative surgery were examined. Patients with tumor measuring greater than 2 cm were included. Metabolic parameters (SUVmax, metabolic tumor volume, and total lesion glycolysis) for the primary lesions were calculated on the 18F-FDG PET/CT, and IMMH was quantified as the macroheterogeneity factor (MHF), defined as surface/spherical surface area having volume of the primary tumor multiplied by the sphericity. Heterogeneity of the primary tumor was also visually assessed (visual heterogeneity score) and compared with MHF. Univariate and multivariate analyses for recurrence were performed using the Cox proportional hazards regression. Results Recurrence was observed in 27 (32.5%) of 83 patients during follow-up period (37.6 ± 25.5 months). Significant correlations were observed between the visual heterogeneity score and the MHF (R = 0.534, P < 0.001). Macroheterogeneity factor was significantly higher in patients who experienced recurrence (median, 1.073 vs 1.016; P = 0.004). Univariate analysis showed that MHF was only significant prognostic factor for recurrence (P = 0.019), and multivariate analysis after adjusting for age, sex, tumor size, histologic grade, and pathologic T stage, high MHF exhibited an association with increased risk of recurrence. Conclusions New quantification method for IMMH on 18F-FDG PET/CT was developed, and the heterogeneity parameter MHF was well correlated with visual heterogeneity. Macroheterogeneity factor on pretreatment 18F-FDG PET/CT was the sole prognostic factor predicting recurrence in pN0 SQCLC patients.

Clinical impact of (18) F-FDG positron emission tomography/CT on adenoid cystic carcinoma of the head and neck.

The purpose of this retrospective study was to assess the diagnostic value of 18F‐fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT and the prognostic value of metabolic PET parameters in patients with adenoid cystic carcinoma of the head and neck (ACCHN).

Observation of irreversible current path in polymer dielectric using conductive atomic force microscope

During the measurement of the electrical properties of a metal-polymer-metal capacitor, it was found that the capacitor exhibited write-once-read-many-times (WORM) memory behavior, even though it was made of the dielectric polymer, polystyrene. The initial low conductance state changed to a high conductance state when a threshold voltage was applied, but this final state never reverted to the initial state. This phenomenon only appeared in sub-100-nm-thick films. To understand this phenomenon, conductive atomic force microscopy (CAFM) was used. The current distribution measured with CAFM showed an irreversible current path had formed near particles in the polymer film. For reproducibility, particles were intentionally inserted into the polymer film during the fabrication of metal-polymer-metal capacitors, and the same current mechanism was found. From these results, it is concluded that the purification and cleaning process of organic devices severely affects the device characteristics. In addition, particle-insertion appears to be a promising method for fabrication low-cost and air-stable WORM type memory for various applications.

CONSORT-Independent prognostic value of asphericity of pretherapeutic F-18 FDG uptake by primary tumors in patients with breast cancer

Background: The aim of this study was to evaluate the prognostic implication of asphericity (ASP); spatial irregularity; of pretherapeutic 18F 2-deoxy-2-fluoro-D-glucose (18F FDG) tumor uptake in patients with invasive ductal carcinoma (IDC) of the breast. Methods: One hundred thirty-one female IDC patients (mean age = 48.1 ± 10.4 years), with pathological tumor size greater than 2 cm were retrospectively evaluated using 18F FDG positron emission tomography/computed tomography (PET/CT). ASP of 18F FDG distribution was calculated on the basis of the deviation of the tumor shape from spherical symmetry. Progression-free survival (PFS) was predicted on the basis of the univariate and multivariate analyses of the measured clinicopathologic factors and metabolic PET parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)]. Results: The PFS rate among the 131 patients was 90.1%. The mean follow-up time was 50 months for the entire study cohort and 26 months for the patients with recurrent disease. It is evident from the univariate analysis that N stage, hormonal receptor (Estrogen, ER/Progesterone, PR) status, MTV (⩽4.2 mL), and ASP (⩽15.1%) affected the PFS. Hazard ratios (HRs) estimated from the multivariate Cox regression analysis show that N stage (HR = 17.6), ASP (HR = 11.9), and hormonal receptor status (HR = 6.9) were independent prognostic factors in predicting PFS. In the subgroup of patients with lymph node metastasis, ASP (HR = 10.9) and hormonal receptor status (HR = 9.1) were independent prognostic factors for PFS. Conclusion: ASP of 18F FDG uptake is an independent predictor of outcome in IDC patients, and can be used for prognostic stratification.

Risk factors for radioactive iodine-avid metastatic lymph nodes on post I-131 ablation SPECT/CT in low- or intermediate-risk groups of papillary thyroid cancer

Objective Post I-131 ablation single-photon emission computed tomography (SPECT)/CT can show radioactive iodine (RAI)-avid cervical metastatic lymph nodes (mLN) in differentiated thyroid cancer. This study aimed to evaluate the incidence of RAI-avid mLN on post I-131 ablation SPECT/CT and the risk factors related to metastasis among patients with papillary thyroid cancer (PTC) in the low- or intermediate-risk groups. Study design and setting Among 339 patients with PTC who underwent total thyroidectomy followed by I-131 ablation, 292 (228 women, 64 men) belonging to the low- or intermediate-risk groups before I-131 ablation, and with sufficient clinical follow-up data were enrolled. The risk groups were classified based on the American Thyroid Association 2015 guideline. Each patient was followed-up for at least 24 months after the ablation (median: 30 months). The clinical, pathologic, and biochemical factors of PTC were reviewed, and their relationships to RAI-avid mLN on SPECT/CT were analyzed. Results Of the 292 patients, 61 and 231 belonged to the low-and intermediate-risk groups, respectively. Four (6.5%) patients in the low-risk group and 31 (13.0%) patients in the intermediate-risk group had RAI-avid mLN. A high preablation TSH-stimulated serum thyroglobulin (Tg) level in the low- or intermediate-risk group predicted the presence of RAI-avid mLN (cut-off = 0.5; hazard ratio (HR): 2.96; p = 0.04). In the subgroup analysis by risk group, TSH-stimulated serum Tg only predicted RAI-avid mLN in the low-risk group (cut-off = 1.0; HR: 5.3; p = 0.03). Conclusion The incidence of RAI-avid mLN on postablation SPECT/CT was relatively high in both low- and intermediate-risk patients with PTC, and high preablation TSH-stimulated serum Tg level was a predictor of metastasis, especially in the low-risk group. A selective treatment approach should be considered in patients with high preablation TSH-stimulated serum Tg level.

High Prevalence of Thyroid Disease and Role of Salivary Gland Scintigraphy in Patients with Xerostomia

PurposeAlthough Sjögren’s syndrome (SS) is the most common disease causing xerostomia, autoimmune thyroid diseases can also affect the salivary glands. The aim of our study was to estimate the prevalence of thyroid diseases (TD) in subjects with symptoms of xerostomia and evaluate the efficacy of salivary gland scintigraphy (SGS) in the detection of TD in patients with SS and without SS.MethodsWe retrospectively reviewed the SGS findings of 173 subjects (men:women, 29:144) with symptoms of xerostomia. Ejection fractions (EF) in the parotid and submandibular glands were calculated. Thyroid disease was diagnosed on the basis of the results of the visual assessment of tracer uptake in the thyroid gland on SGS images as well as serological thyroid function tests.ResultsBased on the American-European Criteria, 94 patients were diagnosed with SS. Hashimoto’s thyroiditis was diagnosed in 63 patients, subacute thyroiditis in 23, subclinical hypothyroidism in five, and Graves’ disease in one. There were significant differences in the EF values of the parotid and submandibular glands between patients with TD and those with undetermined diagnoses.ConclusionsMore than half of patients with xerostomia exhibited TD. Thyroid assessment by SGS is feasible, and SGS appears to be useful for the patients with xerostomia caused by TD. SGS may be the first imaging modality capable of evaluating both salivary gland function and thyroid gland status in patients with xerostomia. This strategy would make the requirement for additional workup for thyroid disease.

Relationship between initial and time-dependent cracks in charge transport of solution-processed organic thin-film transistor

ABSTRACT We report on the comprehensive effect of initial and time-dependent crack on the charge transport of 6, 13-bis (triisopropylsilyethynyl) pentacene (TIPS-PEN) thin-film transistors (TFTs) upon exposure to air. Among the two types of TIPS-PEN films, with and without initial thermal cracks, temporally generated cracks were found to be severely affected by the initial status of the thermal cracks upon air-exposure. After 12 months of air-exposure, the charge transport characteristics of TIPS-PEN TFTs with initial thermal cracks degraded up to 98%, while those without initial thermal cracks degraded only 88%. Based on our long-term experimental results, we conclude that the initial physical status of the cracks play a significant role in the growth of time-dependent cracks and the capability of charge transport in solution-processed TFTs.