Development and External Validation of the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer: Comparison with Two Western Risk Calculators in an Asian Cohort.

PURPOSE: We developed the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer (KPCRC-HG) that predicts the probability of prostate cancer (PC) of Gleason score 7 or higher at the initial prostate biopsy in a Korean cohort (http://acl.snu.ac.kr/PCRC/RISC/). In addition, KPCRC-HG was validated and compared with internet-based Western risk calculators in a validation cohort. MATERIALS AND METHODS: Using a logistic regression model, KPCRC-HG was developed based on the data from 602 previously unscreened Korean men who underwent initial prostate biopsies. Using 2,313 cases in a validation cohort, KPCRC-HG was compared with the European Randomized Study of Screening for PC Risk Calculator for high-grade cancer (ERSPCRC-HG) and the Prostate Cancer Prevention Trial Risk Calculator 2.0 for high-grade cancer (PCPTRC-HG). The predictive accuracy was assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots. RESULTS: PC was detected in 172 (28.6%) men, 120 (19.9%) of whom had PC of Gleason score 7 or higher. Independent predictors included prostate-specific antigen levels, digital rectal examination findings, transrectal ultrasound findings, and prostate volume. The AUC of the KPCRC-HG (0.84) was higher than that of the PCPTRC-HG (0.79, p<0.001) but not different from that of the ERSPCRC-HG (0.83) on external validation. Calibration plots also revealed better performance of KPCRC-HG and ERSPCRC-HG than that of PCPTRC-HG on external validation. At a cut-off of 5% for KPCRC-HG, 253 of the 2,313 men (11%) would not have been biopsied, and 14 of the 614 PC cases with Gleason score 7 or higher (2%) would not have been diagnosed. CONCLUSIONS: KPCRC-HG is the first web-based high-grade prostate cancer prediction model in Korea. It had higher predictive accuracy than PCPTRC-HG in a Korean population and showed similar performance with ERSPCRC-HG in a Korean population. This prediction model could help avoid unnecessary biopsy and reduce overdiagnosis and overtreatment in clinical settings.

High Incidence of Breast Cancer in Light-Polluted Areas with Spatial Effects in Korea.

We have reported a high prevalence of breast cancer in light-polluted areas in Korea. However, it is necessary to analyze the spatial effects of light polluted areas on breast cancer because light pollution levels are correlated with region proximity to central urbanized areas in studied cities. In this study, we applied a spatial regression method (an intrinsic conditional autoregressive [iCAR] model) to analyze the relationship between the incidence of breast cancer and artificial light at night (ALAN) levels in 25 regions including central city, urbanized, and rural areas. By Poisson regression analysis, there was a significant correlation between ALAN, alcohol consumption rates, and the incidence of breast cancer. We also found significant spatial effects between ALAN and the incidence of breast cancer, with an increase in the deviance information criterion (DIC) from 374.3 to 348.6 and an increase in R2 from 0.574 to 0.667. Therefore, spatial analysis (an iCAR model) is more appropriate for assessing ALAN effects on breast cancer. To our knowledge, this study is the first to show spatial effects of light pollution on breast cancer, despite the limitations of an ecological study. We suggest that a decrease in ALAN could reduce breast cancer more than expected because of spatial effects.

High prevalence of breast cancer in light polluted areas in urban and rural regions of South Korea: An ecologic study on the treatment prevalence of female cancers based on National Health Insurance data.

It has been reported that excessive artificial light at night (ALAN) could harm human health since it disturbs the natural bio-rhythm and sleep. Such conditions can lead to various diseases, including cancer. In this study, we have evaluated the association between ALAN and prevalence rates of cancer in females on a regional basis, after adjusting for other risk factors, including obesity, smoking, alcohol consumption rates and PM10 levels. The prevalence rates for breast cancer were found to be significantly associated with ALAN in urban and rural areas. Furthermore, no association was found with ALAN in female lung, liver, cervical, gastric and colon cancer. Despite the limitations of performing ecological studies, this report suggests that ALAN might be a risk factor for breast cancer, even in rural areas.

Lessons learned from a comparative analysis of surgical outcomes of and learning curves for laparoscopy-assisted distal gastrectomy.

PURPOSE: Before expanding our indications for laparoscopic gastrectomy to advanced gastric cancer and adopting reduced port laparoscopic gastrectomy, we analyzed and audited the outcomes of laparoscopy-assisted distal gastrectomy (LADG) for adenocarcinoma; this was done during the adoptive period at our institution through the comparative analysis of short-term surgical outcomes and learning curves (LCs) of two surgeons with different careers. MATERIALS AND METHODS: A detailed comparative analysis of the LCs and surgical outcomes was done for the respective first 95 and 111 LADGs performed by two surgeons between July, 2006 and June, 2011. The LCs were fitted by using the non-linear ordinary least squares estimation method. RESULTS: The postoperative morbidity and mortality rates were 14.6% and 0.0%, respectively, and there was no significant difference in the morbidity rates (12.6% vs. 16.2%, P=0.467). More than 25 lymph nodes were retrieved by each surgeon during LADG procedures. The LCs of both surgeons were distinct. In this study, a stable plateau of the LC was not achieved by both surgeons even after performing 90 LADGs. CONCLUSIONS: Regardless of the experience with gastrectomy or laparoscopic surgery for other organs, or the age of surgeon, the outcome was quite acceptable; the learning process differ according to the surgeon's experience and individual characteristics.

Medial arch orthosis for paediatric flatfoot.

PURPOSE: To evaluate any correlation between various foot angles and their respective American Orthopaedic Foot and Ankle Society (AOFAS) scores for pain, and the effectiveness of a medial arch orthosis. METHODS: 81 children with bilateral symptomatic flatfoot were randomised into orthosis (n=55) and control (n=26) groups. The orthosis group consisted of 33 male and 22 female patients aged 36 to 204 (mean, 99) months and they were given a medial arch support. The control group consisted of 15 male and 11 female patients aged 36 to 192 (mean, 100) months and they were managed with analgesics. Foot angles including anteroposterior (AP) and lateral talocalcaneal (TC) angles, AP and lateral talo- first metatarsal (TFM) angles, calcaneal pitch angle (in lateral plane), and talonavicular (TN) angle were measured, as were AOFAS scores for pain for the forefoot, midfoot, and hindfoot. RESULTS: After orthosis treatment, all AOFAS scores and all foot angles (except for the AP-TN angle) improved significantly. In the controls, all AOFAS scores (except for the midfoot score) and only the AP-TFM angle improved significantly. In the orthosis group, the AOFAS hindfoot score correlated positively with the lateral TC angle of the left foot (r=0.345, p=0.010) and negatively with the calcaneal pitch angle of the right foot (r=-0.33, p=0.015). In the control group, the lateral TFM angle of the left foot correlated negatively with the AOFAS forefoot (r=-0.566, p=0.003) and midfoot scores (r=-0.497, p=0.001), whereas the calcaneal pitch angle of the left foot correlated positively with the AOFAS forefoot score (r=0.497, p=0.010). CONCLUSION: Medial arch support orthosis significantly improved AOFAS scores and foot angles. Calcaneal pitch angle and lateral TC angle correlated well with AOFAS hindfoot scores.

A comparative pilot study of symptom improvement before and after phototherapy in Korean patients with perennial allergic rhinitis.

Although allergic rhinitis is not life threatening, it significantly influences the quality of a patient's life. This study is intended to evaluate the safety and efficacy of phototherapy with low-level energy of a 650 nm laser irradiation system in perennial allergic rhinitis patients. This clinical trial was an open-label, single-center study with 42 perennial allergic rhinitis subjects. Following laser irradiation in the nasal cavity with a laser irradiation system, the efficacy at weeks 1 through 4 was determined. The symptoms were scored with four parameters (nasal obstruction, rhinorrhea, sneezing and itching) before and after illumination of the laser, and the total score was recorded. A survey of Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) was conducted by patients before and after treatment. Following treatment, significant improvement in the clinical symptoms of nasal obstruction (P < 0.001), rhinorrhea (P = 0.005), sneezing (P = 0.001) and itching (P = 0.003) was reported by 68% of perennial allergic rhinitis patients. The overall RQLQ scores significantly improved by 45% from the baseline with the treatment after 4 weeks. These results indicate that phototherapy is an effective modality for treating perennial allergic rhinitis and is another option in the steroid-free management of immune-mediated mucosal diseases.

Rapid adaptation of robotic gastrectomy for gastric cancer by experienced laparoscopic surgeons.

BACKGROUND: Robotic surgery for gastric cancer patients has been increasing because of its many advantages over conventional laparoscopic surgery. Despite the suggestion that robotic surgery may lessen the learning curve for complex laparoscopic procedures, little is known about the learning curve for robotic gastrectomy. This study aimed to assess the learning curve of robotic gastrectomy for patients with cancer by analyzing the operation time. METHODS: The first 20 consecutive cases of robot-assisted distal gastrectomy with lymphadenectomy for gastric cancer performed by three experienced laparoscopic surgeons' using the da Vinci system were collected and reviewed. A nonlinear least-squares method was developed and used to analyze the learning curves. RESULTS: Overall, the mean operation time was 247.3 ± 45.7 min, depending on each surgeon's laparoscopic experience and the patient's characteristics. After control was used for confounding factors, the stabilized operation time decreased to 211.8 min. The operation time stabilized at 8.2 cases and was reduced 111.4 min from the first case. A stable operation time was reached in 9.6 cases by surgeon A, in 18.1 cases by surgeon B, and in 6 cases by surgeon C. The stable operation time was 149.2 min for surgeon A, 127.1 min for surgeon B, and 236.8 min for surgeon C, and the reduction in operation time from the first case to stabilization was 233 min for surgeon A, 76.7 min for surgeon B, and 154.6 min for surgeon C. CONCLUSIONS: Surgeons with sufficient experience in laparoscopic gastrectomy can rapidly overcome the learning curve for robotic gastrectomy. In addition, the surgeon's experience with laparoscopic gastrectomy affects the operation time after stabilization and the reduction in operation time.

The differential relationship between fat mass and bone mineral density by gender and menopausal status.

Osteoporosis and obesity are important public health problems in an aging society. We investigated the differential impacts of fat on bone mineral density (BMD) according to gender and menopausal status. We analyzed the baseline data of an ongoing observational cohort study, including a total of 502 healthy subjects 20-88 years of age (144 men, 159 premenopausal women, 199 postmenopausal women). Body composition and fat mass were measured using computed tomography and dual energy X-ray absorptiometry (DXA). BMD was measured at lumbar spines using DXA. In men and postmenopausal women, there was no significant correlation between fat and bone parameters after adjusting for age and body weight. However, in premenopausal women, BMD had significant negative correlations with waist circumference, total fat area, subcutaneous fat area, appendicular fat mass and percentage fat mass after adjusting for age and body weight. Furthermore, only in premenopausal women, the subjects with the highest quartile of percentage fat mass had the lowest BMD even after adjusting for confounding factors including age, body weight, physical activity, alcohol use and smoking history. Multiple linear regression analysis showed that percentage fat mass was a significant negative decisive factor for BMD in premenopausal women. Our study showed the differential relationship between fat mass and BMD according to gender and menopausal status. Only in premenopausal women did fat mass have a significant negative effect on bone mass. This result suggests the importance of reducing fat mass in order to achieve peak bone mass in young adult women.

Can the prostate risk calculator based on Western population be applied to Asian population?

BACKGROUND: We developed a korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Korean male population (http://pcrc.korea.ac.kr). We compared its performance to prostate-specific antigen (PSA) testing and the Prostate Risk Calculator 3 (PRC 3) based on data from the Dutch part of European Randomized Study of Screening for Prostate Cancer (ERSPC), which predicts biopsy results for previously unscreened men. METHODS: Data were collected from 602 Korean men who were previously unscreened and underwent initial ten-core prostate biopsies. Multiple logistic regression analysis was performed to determine the significant predictors. Area under the receiver operating characteristic curve (AUC) and calibration plots of both calculators were evaluated. RESULTS: Prostate cancer (PCa) was detected in 172 (28.6%) men. Independent predictors of a positive biopsy included advanced age, elevated PSA levels, reduced volume of the transition zone, and abnormal digital rectal examination findings. The AUC of the KPCRC was higher than the PRC 3 and PSA alone on internal and external validation. Calibration plots of the KPCRC showed better performance than the other models on internal and external validation. Applying a cut-off of 10% of KPCRC implied that 251 of the 602 men (42%) would not have been biopsied and that 12 of the 172 PCa cases (7%) would not have been diagnosed. CONCLUSIONS: The KPCRC improves the performance of the PRC 3 and PSA testing in predicting Korean population's risk of PCa. It implies that Asian populations need their own risk calculators for PCa.

Learning curve of single port laparoscopic cholecystectomy determined using the non-linear ordinary least squares method based on a non-linear regression model: An analysis of 150 consecutive patients.

INTRODUCTION: Single port laparoscopic surgery has come to the forefront of minimally invasive surgery. For those familiar with conventional techniques, however, this type of operation demands a different type of eye/hand coordination and involves unfamiliar working instruments. Herein, the authors describe the learning curve and the clinical outcomes of single port laparoscopic cholecystectomy for 150 consecutive patients with benign gallbladder disease. METHOD: All patients underwent single port laparoscopic cholecystectomy using a homemade glove port by one of five operators with different levels of experiences of laparoscopic surgery. The learning curve for each operator was fitted using the non-linear ordinary least squares method based on a non-linear regression model. RESULTS: Mean operating time was 77.6 ± 28.5 min. Fourteen patients (6.0%) were converted to conventional laparoscopic cholecystectomy. Complications occurred in 15 patients (10.0%), as follows: bile duct injury (n = 2), surgical site infection (n = 8), seroma (n = 2), and wound pain (n = 3). One operator achieved a learning curve plateau at 61.4 min per procedure after 8.5 cases and his time improved by 95.3 min as compared with initial operation time. Younger surgeons showed significant decreases in mean operation time and achieved stable mean operation times. In particular, younger surgeons showed significant decreases in operation times after 20 cases. CONCLUSION: Experienced laparoscopic surgeons can safely perform single port laparoscopic cholecystectomy using conventional or angled laparoscopic instruments. The present study shows that an operator can overcome the single port laparoscopic cholecystectomy learning curve in about eight cases.

Palm surface area database and estimation formula in Korean children using the alginate method.

Studies of palm surface area (PSA) have been investigated as an important reference area unit in physiology and medicine today. Most previous PSA studies have been limited to adults. The purpose of this study was to archive Korean children's PSA data and to calculate an optimized formula for estimating PSA. A total of 305 people, 186 boys and 119 girls all aged between 7 and 18 years, were recruited for this study and their PSA was directly measured by a useful, accurate, and quick method--the alginate method. Mean PSA for males and females was found and the optimized formula for estimating PSA was computed. It would be meaningful to note that this trial was the first to generate data from Korean children, which could be widely available for utilization in anthropometry, toxicology research, thermal physiology and in skin burn studies for Asian children.

Initial biopsy outcome prediction in Korean patients-comparison of a noble web-based Korean prostate cancer risk calculator versus prostate-specific antigen testing.

We developed and validated a novel Korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy in a Korean population. Data were collected from 602 Koreans who underwent initial prostate biopsies due to an increased level of prostate-specific antigen (PSA), a palpable nodule upon digital rectal examination (DRE), or a hypoechoic lesion upon transrectal ultrasound (TRUS). The clinical and laboratory variables were analyzed by simple and multiple logistic regression analysis. The area under the receiver operating characteristic curve (AUC) was computed to compare its performance to PSA testing alone. Prostate cancer was detected in 172 (28.6%) men. Independent predictors included age, DRE findings, PSA level, and prostate transitional zone volume. We developed the KPCRC using these variables. The AUC for the selected model was 0.91, and that of PSA testing alone was 0.83 (P < 0.001). The AUC for the selected model with an additional dataset was 0.79, and that of PSA testing alone was 0.73 (P = 0.004). The calculator is available on the website: http://pcrc.korea.ac.kr. The KPCRC improved the performance of PSA testing alone in predicting the risk of prostate cancer in a Korean population. This calculator would be a practical tool for physicians and patients.

Surgeon subspecialty as a factor in improving long-term outcomes for gastric cancer: Twenty years of experience in Korea.

BACKGROUND: The results of gastric cancer treatment have improved during the past 2 decades. In addition to early diagnosis, surgeon experience and subspecialty may influence long-term outcomes. This study analyzed data accumulated during the past 20 years regarding the impact of surgical subspecialty on gastric cancer prognosis. DESIGN: A 20-year, retrospective study. SETTING: Korea University Guro Hospital, Seoul. PATIENTS: A total of 2797 patients admitted between 1984 and 2003 with surgically treated, pathologically confirmed, primary gastric adenocarcinoma. MAIN OUTCOME MEASURE: Long-term survival. RESULTS: The incidence of total gastrectomy and the number of retrieved lymph nodes increased during the study period. In curative cases, 5-year survival improved from 66.1% to 76.6%, and this survival gain was restricted to stages I, III, and IV. A Cox proportional hazards regression model showed that age, sex, tumor location, type of resection, stage, and the interaction between period of study and surgical subspecialty were independent prognostic factors. CONCLUSIONS: This large, long-term cohort study demonstrates that the management of gastric cancer has been largely successful, with favorable trends in prognostic factors. Successful outcomes are realized more often by gastric surgical specialists. Efforts must be made to improve the treatment of patients with stage II gastric cancer because the improvements in long-term results have plateaued.

Analysis of callus pattern of tibia lengthening in achondroplasia and a novel method of regeneration assessment using pixel values.

OBJECTIVE: To relate morphology of new bone formation to outcome after tibial lengthening performed in patients with achondroplasia. MATERIAL AND METHODS: A retrospective analysis of 60 tibial segments in 30 achondroplasia patients was performed. There were 22 female patients and eight male patients, with a mean age of 9.8 years. New bone formation was classified by shape, homogeneity and density. Pixel values in relation to original bone were measured using a picture-archiving communication system (PACS). Clinical outcome was described by the external fixator and maturation indices. RESULTS: Mean lengthening was 9.2 cm (range 3-12.7 cm). The mean external fixator index was 23.4 (range 15.1-50). The mean maturation index was 12.3 days/cm (range 6-40 days/cm). Homogeneous pathways were associated with the best clinical results (fixator index 20.4, maturation index 10.8), followed by heterogeneous pathway (external fixator index 26.5, maturation index 16.8) and radiolucent pathway (fixator index 31.2, maturation index 21.4). Both cylindrical (external fixator index 25.2, maturation index 14.5) and concave (external fixator index 26.6, maturation index 16.3) callus shapes were favourable. Mineralization of new bone became equal to that of normal bone within 16 weeks (mean) for homogeneous pathway, 12 weeks for heterogeneous pathway and 32 weeks for lucent pathway. CONCLUSION: The type of new bone formation seen on radiographs is related to clinical outcome, with homogeneous pathways being the most favourable ones.

Advanced gastric cancer in the middle one-third of the stomach: Should surgeons perform total gastrectomy?

BACKGROUND AND OBJECTIVES: To determine which optimal surgical procedure for middle-third advanced gastric cancer (AGC) based on comparative study of the long-term prognosis between total gastrectomy (TG) and distal gastrectomy (DG). METHODS: Between March 1993 and December 2005, 402 patients with middle-third AGC who underwent gastric resection were enrolled in this study. We analyzed the long-term prognosis according to the length of the proximal resection margin (PRM) and the extent of gastric resection, and determined independent prognostic factors. RESULTS: TG was performed in 244 patients (60.7%) and DG was performed in 158 patients (39.3%). There were no significant differences in the 5-year survival rates according to the length of PRM. The 5-year survival rates of patients who underwent DG were significantly higher than the rates of the patients who underwent TG in curative cases (67.8% vs. 58.4%, P = 0.037). Nevertheless, there was no significant difference in the stage-stratified survival rates according to the extent of gastric resection. Multivariate analysis revealed that surgical curability, extent of lymphadenectomy, and stage were independent prognostic factors. CONCLUSION: If curative resection can be performed, the long-term prognosis of patients with middle-third AGC was not affected by the length of PRM or the extent of gastric resection.