Quality of Life and Nutritional Outcomes of Stomach-Preserving Surgery for Early Gastric Cancer: A Secondary Analysis of the SENORITA Randomized Clinical Trial.

Importance: The Sentinel Node Oriented Tailored Approach (SENORITA) randomized clinical trial evaluated quality of life (QoL) and nutritional outcomes between the laparoscopic sentinel node navigation surgery (LSNNS) and laparoscopic standard gastrectomy (LSG). However, there has been no report on the QoL and nutritional outcomes of patients who underwent stomach-preserving surgery among the LSNNS group. Objective: To compare long-term QoL and nutritional outcomes between patients who underwent stomach-preserving surgery and those who underwent standard gastrectomy and to identify factors associated with poor QoL outcomes in patients who underwent stomach-preserving surgery. Design, Setting, and Participants: This study is a secondary analysis of the SENORITA trial, a randomized clinical trial comparing LSNNS with LSG. Patients from 7 tertiary or general hospitals across the Republic of Korea were enrolled from March 2013 to December 2016, with follow-up through 5 years. Data were analyzed between August and September 2022. Among trial participants, patients who underwent actual laparoscopic standard gastrectomy in the LSG group and those who underwent stomach-preserving surgery in the LSNNS group were included. Patients who did not complete the baseline or any follow-up questionnaire were excluded. Intervention: Stomach-preserving surgery vs standard gastrectomy. Main Outcomes and Measures: Overall European Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORTC QLQ-C30) and stomach module (STO22) scores, body mass index, hemoglobin, protein, and albumin levels. Results: A total of 194 and 257 patients who underwent stomach-preserving surgery and standard gastrectomy, respectively, were included in this study (mean [SD] age, 55.6 [10.6] years; 249 [55.2%] male). The stomach-preserving group had better QoL scores at 3 months postoperatively in terms of physical function (87.2 vs 83.9), dyspnea (5.9 vs 11.2), appetite loss (13.1 vs 19.4), dysphagia (8.0 vs 12.7), eating restriction (10.9 vs 18.2), anxiety (29.0 vs 35.2), taste change (7.4 vs 13.0), and body image (19.5 vs 27.2). At 1 year postoperatively, the stomach-preserving group had significantly higher body mass index (23.9 vs 22.1, calculated as weight in kilograms divided by height in meters squared) and hemoglobin (14.3 vs 13.3 g/dL), albumin (4.3 vs 4.25 g/dL), and protein (7.3 vs 7.1 g/dL) levels compared to the standard group. Multivariable analyses showed that tumor location (greater curvature, lower third) was favorably associated with global health status (ß, 10.5; 95% CI, 3.2 to 17.8), reflux (ß, -8.4; 95% CI, -14.7 to -2.1), and eating restriction (ß, -5.7; 95% CI, -10.3 to -1.0) at 3 months postoperatively in the stomach-preserving group. Segmental resection was associated with risk of diarrhea (ß, 40.6; 95% CI, 3.1 to 78.1) and eating restriction (ß, 15.1; 95% CI, 1.1 to 29.1) at 3 years postoperatively. Conclusions and Relevance: Stomach-preserving surgery after sentinel node evaluation was associated with better long-term QoL and nutritional outcomes than standard gastrectomy. These findings may help facilitate decision-making regarding treatment for patients with early-stage gastric cancer. Trial Registration: ClinicalTrials.gov Identifier: NCT01804998.

Evaluation of the water-equivalent characteristics of the SP34 plastic phantom for film dosimetry in a clinical linear accelerator.

In this study, some confusing points about electron film dosimetry using white polystyrene suggested by international protocols were verified using a clinical linear accelerator (LINAC). According to international protocol recommendations, ionometric measurements and film dosimetry were performed on an SP34 slab phantom at various electron energies. Scaling factor analysis using ionometric measurements yielded a depth scaling factor of 0.923 and a fluence scaling factor of 1.019 at an electron beam energy of <10 MeV (i.e., R50 < 4.0 g/cm2). It was confirmed that the water-equivalent characteristics were similar because they have values similar to white polystyrene (i.e., depth scaling factor of 0.922 and fluence scaling factor of 1.019) presented in international protocols. Furthermore, percentage depth dose (PDD) curve analysis using film dosimetry showed that when the density thickness of the SP34 slab phantom was assumed to be water-equivalent, it was found to be most similar to the PDD curve measured using an ionization chamber in water as a reference medium. Therefore, we proved that the international protocol recommendation that no correction for measured depth dose is required means that no scaling factor correction for the plastic phantom is necessary. This study confirmed two confusing points that could occur while determining beam characteristics using electron film dosimetry, and it is expected to be used as basic data for future research on clinical LINACs.

Standard follow-up after curative surgery for advanced gastric cancer: secondary analysis of a multicentre randomized clinical trial (KLASS-02).

BACKGROUND: The benefit of regular follow-up after curative resection for gastric cancer is controversial as there is no evidence that it will improve survival. This study assessed whether regular follow-up leads to improved survival in patients after surgery for gastric cancer. METHODS: A secondary analysis was undertaken of patients who participated in an RCT of laparoscopic versus open distal gastrectomy for advanced gastric cancer between November 2011 and April 2015. Depending on whether patients were compliant with the initial trial follow-up protocol or not, they were analysed as having had either regular or irregular follow-up. Clinicopathological characteristics, recurrence patterns, detection, treatments, and survival were compared between the groups. RESULTS: The regular and irregular follow-up groups comprised 712 and 263 patients respectively. Disease recurrence within 36 months was more common in the regular group than in the irregular group (17.0 versus 11.4 per cent; P = 0.041). Recurrence patterns did not differ between the groups. The 3-year recurrence-free survival rate was worse in the regular than in the irregular group (81.2 versus 86.5 per cent; P = 0.031). However, the 5-year overall survival rate was comparable (84.5 versus 87.5 per cent respectively; P = 0.160). Multivariable analysis revealed that type of follow-up was not an independent factor affecting 5-year overall survival. CONCLUSION: Regular follow-up after radical gastrectomy was not associated with improved overall survival.

Consistency of dose rates after applying machine-specific reference correction factors for the gamma knife 16 mm collimator field.

BACKGROUND: The machine-specific reference (msr) correction factors ( k Q msr , Q 0 f msr , f ref $k_{{Q_{{\rm{msr}}}},\;{Q_0}}^{{f_{{\rm{msr}}}},{f_{{\rm{ref}}}}}$ ) were introduced in International Atomic Energy Agency (IAEA) Technical Report Series 483 (TRS-483) for reference dosimetry of small fields. Several correction factor sets exist for a Leksell Gamma Knife (GK) Perfexion or Icon. Nevertheless, experiments have not rigorously validated the correction factors from different studies. PURPOSE: This study aimed to assess the role and accuracy of k Q msr , Q 0 f msr , f ref $k_{{Q_{{\rm{msr}}}},\;{Q_0}}^{{f_{{\rm{msr}}}},{f_{{\rm{ref}}}}}$ values in determining the absorbed dose rates to water in the reference dosimetry of Gamma Knife. METHODS: The dose rates in the 16 mm collimator field of a GK were determined following the international code of practices with three ionization chambers: PTW T31010, PTW T31016 (PTW Freiberg GmbH, New York, NY), and Exradin A16 (Standard Imaging, Inc., Middleton, WI). A chamber was placed at the center of a solid water phantom (Elekta AB, Stockholm, Sweden) using a detector-specific insert. The reference point of the ionization chamber was confirmed using cone-beam CT images. Consistency checks were repeated five times at a GK site and performed once at seven GK sites. Correction factors from six simulations reported in previous studies were employed. Variations in the dose rates and relative dose rates before and after applying the k Q m s r , Q 0 f m s r , f r e f $k_{{Q_{msr}},\;{Q_0}}^{{f_{msr}},{f_{ref}}}$ were statistically compared. RESULTS: The standard deviation of the dose rates measured by the three chambers decreased significantly after any correction method was applied (p = 0.000). When the correction factors of all studies were averaged, the standard deviation was reduced significantly more than when any single correction method was applied (p ≤ 0.030), except for the IAEA TRS-483 correction factors (p = 0.148). Before any correction was applied, there were statistically significant differences among the relative dose rates measured by the three chambers (p = 0.000). None of the single correction methods could remove the differences among the ionization chambers (p ≤ 0.038). After TRS-483 correction, the dose rate of Exradin A16 differed from those of the other two chambers (p ≤ 0.025). After the averaged factors were applied, there were no statistically significant differences between any pairs of chambers according to Scheffe's post hoc analyses (p ≥ 0.051); however, PTW T31010 differed from PTW 31016 according to Tukey's HSD analyses (p = 0.040). CONCLUSION: The k Q msr , Q 0 f msr , f ref $k_{{Q_{{\rm{msr}}}},\;{Q_0}}^{{f_{{\rm{msr}}}},{f_{{\rm{ref}}}}}$ significantly reduced variations in the dose rates measured by the three ionization chambers. The mean correction factors of the six simulations produced the most consistent results, but this finding was not explicitly proven in the statistical analyses.

Clinical Efficacy of an Electronic Portal Imaging Device versus a Physical Phantom Tool for Patient-Specific Quality Assurance.

Pre-treatment patient-specific quality assurance (QA) is critical to prevent radiation accidents. The electronic portal imaging device (EPID) is a dose measurement tool with good resolution and a low volume-averaging effect. EPIbeam­an EPID-based portal dosimetry software­has been newly installed in three institutions in Korea. This study evaluated the efficacy of the EPID-based patient-specific QA tool versus the PTW729 detector (a previously used QA tool) based on gamma criteria and planning target volume (PTV). A significant difference was confirmed through the R statistical analysis software. The average gamma passing rates of PTW729 and EPIbeam were 98.73% and 99.60% on 3 mm/3% (local), 96.66% and 97.91% on 2 mm/2% (local), and 88.41% and 74.87% on 1 mm/1% (local), respectively. The p-values between them were 0.015 (3 mm/3%, local), 0.084 (2 mm/2%, local), and less than 0.01 (1 mm/1%, local). Further, the average gamma passing rates of PTW 729 and EPIbeam according to PTV size were 99.55% and 99.91% (PTV < 150 cm3) and 97.91% and 99.28% (PTV > 150 cm3), respectively. The p-values between them were 0.087 (PTV < 150 cm3) and 0.036 (PTV > 150 cm3). These results confirm that EPIbeam can be an effective patient-specific QA tool.

Laparoscopic vs Open Distal Gastrectomy for Locally Advanced Gastric Cancer: 5-Year Outcomes of the KLASS-02 Randomized Clinical Trial.

Importance: The long-term safety of laparoscopic distal gastrectomy for locally advanced gastric cancer (AGC) remains uncertain given the lack of 5-year follow-up results. Objective: To compare the 5-year follow-up results in patients with clinically AGC enrolled in the Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS)-02 randomized clinical trial who underwent laparoscopic or open distal gastrectomy. Design, Setting, and Participants: The KLASS-02, a multicenter randomized clinical trial, showed that laparoscopic surgery was noninferior to open surgery for patients with locally AGC. The present study assessed the 5-year follow-up results, including 5-year overall survival (OS) and relapse-free survival (RFS) rates and long-term complications, in patients enrolled in KLASS-02. From November 21, 2011, to April 29, 2015, patients aged 20 to 80 years diagnosed preoperatively with locally AGC were enrolled. Final follow-up was on June 15, 2021. Data were analyzed June 24 to September 9, 2021. Interventions: Patients were treated with R0 resection either by laparoscopic gastrectomy or open gastrectomy as the full analysis set of the KLASS-02 trial. Main Outcomes and Measures: Five-year OS and RFS rates, recurrence patterns, and long-term surgical complications were evaluated. Results: This study enrolled a total of 1050 patients. A total of 974 patients were treated with R0 resection; 492 (50.5%) in the laparoscopic gastrectomy group (mean [SD] age, 59.8 [11.0] years; 351 men [71.3%]) and 482 (49.5%) in the open gastrectomy group (mean [SD] age, 59.4 [11.5] years; 335 men [69.5%]). In patients who underwent laparoscopic and open distal gastrectomy, the 5-year OS (88.9% vs 88.7%) and RFS (79.5% vs 81.1%) rates did not differ significantly. The most common types of recurrence were peritoneal carcinomatosis (73 of 173 [42.1%]), hematogenous metastases (36 of 173 [20.8%]), and locoregional recurrence (23 of 173 [13.2%]), with no between-group differences in types of recurrence at each cancer stage. The correlation between 3-year RFS and 5-year OS at the individual level was highest in patients with stage III gastric cancer (ρ = 0.720). The late complication rate was significantly lower in the laparoscopic than in the open surgery group (32 of 492 [6.5%] vs 53 of 482 [11.0%]). The most common type of complication in both groups was intestinal obstruction (13 of 492 [2.6%] vs 24 of 482 [5.0%]). Conclusions and Relevance: The 5-year outcomes of the KLASS-02 trial support the 3-year results, which is the noninferiority of laparoscopic surgery compared with open gastrectomy for locally AGC. The laparoscopic approach can be recommended in patients with locally AGC to achieve the benefit of low incidence of late complications. Trial Registration: ClinicalTrials.gov Identifier: NCT01456598.

Laparoscopic Sentinel Node Navigation Surgery for Stomach Preservation in Patients With Early Gastric Cancer: A Randomized Clinical Trial.

PURPOSE: To compare postoperative complications, long-term survival, and quality of life (QOL) after laparoscopic sentinel node navigation surgery (LSNNS) and laparoscopic standard gastrectomy (LSG). METHODS: Five hundred eighty patients with preoperatively diagnosed stage IA gastric adenocarcinoma (≤ 3 cm) were assigned to undergo either LSG or LSNNS. Observers were not blinded to patient grouping. The primary outcome was 3-year disease-free survival (3y-DFS). Secondary outcomes included postoperative complications, QOL, 3-year disease-specific survival (3y-DSS), and 3-year overall survival (3y-OS). RESULTS: In total, 527 patients were included in the modified intention-to-treat analysis population for the primary outcome (LSG, 269; LSNNS, 258). Stomach-preserving surgery was performed in 210 patients (81%) in the LSNNS group. During the median follow-up duration, the 3y-DFS rates in the LSG and LSNNS groups were 95.5% and 91.8%, respectively (difference: 3.7%; 95% CI, -0.6 to 8.1). Three patients with recurrence and five with metachronous gastric cancer in the LSNNS group underwent standard surgery. Two patients with distant metastasis in both groups were treated with palliative chemotherapy. The 3y-DSS and 3y-OS rates in the LSG and LSNNS groups were 99.5% and 99.1% (P = .59) and 99.2% and 97.6% (P = .17), respectively. Postoperative complications occurred in 19.0% of the LSG group and 15.5% of the LSNNS group (P = .294). The LSNNS group showed better physical function (P = .015), less symptoms (P < .001), and improved nutrition than the LSG group. CONCLUSION: LSNNS did not show noninferiority to LSG for 3y-DFS, with a 5% margin. However, the 3y-DSS and 3y-OS were not different after rescue surgery in cases of recurrence/metachronous gastric cancer, and LSNNS had better long-term QOL and nutrition than LSG.

Early experience of laparoscopic resection and comparison with open surgery for gastric gastrointestinal stromal tumor: a multicenter retrospective study.

The advantages of laparoscopic resection over open surgery in the treatment of gastric gastrointestinal stromal tumor (GIST) are not conclusive. This study aimed to evaluate the postoperative and oncologic outcome of laparoscopic resection for gastric GIST, compared to open surgery. We retrospectively reviewed the prospectively collected database of 1019 patients with gastric GIST after surgical resection at 13 Korean and 2 Japanese institutions. The surgical and oncologic outcomes were compared between laparoscopic and open group, through 1:1 propensity score matching (PSM). The laparoscopic group (N = 318) had a lower rate of overall complications (3.5% vs. 7.9%, P = 0.024) and wound complications (0.6% vs. 3.1%, P = 0.037), shorter hospitalization days (6.68 ± 4.99 vs. 8.79 ± 6.50, P < 0.001) than the open group (N = 318). The superiority of the laparoscopic approach was also demonstrated in patients with tumors larger than 5 cm, and at unfavorable locations. The recurrence-free survival was not different between the two groups, regardless of tumor size, locational favorableness, and risk classifications. Cox regression analysis revealed that tumor size larger than 5 cm, higher mitotic count, R1 resection, and tumor rupture during surgery were independent risk factors for recurrence. Laparoscopic surgery provides lower rates of complications and shorter hospitalizations for patients with gastric GIST than open surgery.

Effect of non-curative endoscopic submucosal dissection on short-term outcomes of subsequent surgery for early gastric cancer.

BACKGROUND: With growing incidence of early gastric cancer (EGC), endoscopic submucosal dissection (ESD) is widely performed as a standard treatment for mucosal cancer. Due to the increasing application of ESD, the number of non-curative resection after ESD is also growing, leading to escalating number of patients who require additional gastrectomy with lymph node dissection after non-curative ESD. However, effects of ESD prior to surgery on technical difficulties during operation for EGC remain unclear. Therefore, this study aimed to determine the effect of non-curative ESD on short-term surgical outcomes in patients who underwent additional surgical treatment using propensity score matching method. METHODS: To evaluate the effect of ESD on short-term surgical outcomes in patients who underwent additional surgical treatment after a non-curative ESD procedure, patients were divided into two groups: (1) those who underwent additional gastrectomy after non-curative resection of ESD [ESD + Surgery (ES) Group], and (2) those who underwent gastrectomy as the initial treatment [Surgery Only (SO) Group]. To minimize differences in baseline demographic features that could potentially be associated with short-term outcomes, propensity-scored matching analysis was performed. RESULTS: After propensity-scored matching (1:1 matching), 140 patients altogether were selected and analyzed in this study. Complications were experienced by 18 (25.7%) patients in the ES group and 13 (18.6%) patients in the SO group, showing no significant (p < 0.416) difference between the two groups. CONCLUSIONS: Additional surgery after non-curative ESD can be safely applied, even within one month after ESD in terms of short-term complications.

Local complications are related to poor long-term outcome in patients undergoing curative gastrectomy for advanced gastric cancer.

Purpose: The present study was performed to investigate the effects of local complications (LC) on long-term survival and cancer recurrence in patients undergoing curative gastrectomy for gastric cancer. Methods: We analyzed 2,627 patients after curative gastrectomy for gastric cancer between January 2001 and December 2006. Patients were classified into groups no complications (NC), LC, or systemic complications (SC). Results: Among the 2,627 patients, 475 patients developed complications (LC group [n=374, 14.2%] and SC group [n=101, 3.9%]). The 5-year cancer-specific survival rate was significantly poorer in the LC group compared to the NC and SC groups (LC, 78.0%; NC, 85.4%; SC, 80.2%; P=0.007). The occurrence of LC was identified as a significant independent prognostic factor for overall and cancer-specific survival (hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.46-2.97; P=0.001 and HR, 1.77; 95% CI, 1.12-2.81; P=0.015). The tumor recurrence rates were higher in the LC group than the in other two groups (LC, 23.5%; NC, 15.4%; SC, 15.8%; P<0.001). The occurrence of LC was an independent predictor of tumor recurrence in patients undergoing curative gastrectomy for gastric cancer (HR, 1.55; 95% CI, 1.11-2.17; P=0.011). Conclusion: LC are associated with adverse long-term outcomes in patients after curative gastrectomy for advanced gastric cancer.

Comparison of surgical outcomes among different methods of esophagojejunostomy in laparoscopic total gastrectomy for clinical stage I proximal gastric cancer: results of a single-arm multicenter phase II clinical trial in Korea, KLASS 03.

BACKGROUND: Laparoscopic distal gastrectomy for early gastric cancer has been widely accepted, but laparoscopic total gastrectomy has still not gained popularity because of technical difficulty and unsolved safety issue. We conducted a single-arm multicenter phase II clinical trial to evaluate the safety and the feasibility of laparoscopic total gastrectomy for clinical stage I proximal gastric cancer in terms of postoperative morbidity and mortality in Korea. The secondary endpoint of this trial was comparison of surgical outcomes among the groups that received different methods of esophagojejunostomy (EJ). METHODS: The 160 patients of the full analysis set group were divided into three groups according to the method of EJ, the extracorporeal circular stapling group (EC; n = 45), the intracorporeal circular stapling group (IC; n = 64), and the intracorporeal linear stapling group (IL; n = 51). The clinicopathologic characteristics and the surgical outcomes were compared among these three groups. RESULTS: There were no significant differences in the early complication rates among the three groups (26.7% vs. 18.8% vs. 17.6%, EC vs. IC vs. IL; p = 0.516). The length of mini-laparotomy incision was significantly longer in the EC group than in the IC or IL group. The anastomosis time was significantly shorter in the EC group than in the IL group. The time to first flatus was significantly shorter in the IL group than in the EC group. The long-term complication rate was not significantly different among the three groups (4.4% vs. 12.7% vs. 7.8%; EC vs. IC vs. IL; p = 0.359), however, the long-term incidence of EJ stenosis in IC group (10.9%) was significantly higher than in EC (0%) and IL (2.0%) groups (p = 0.020). CONCLUSIONS: The extracorporeal circular stapling and the intracorporeal linear stapling were safe and feasible in laparoscopic total gastrectomy, however, intracorporeal circular stapling increased EJ stenosis.

Surgeon Quality Control and Standardization of D2 Lymphadenectomy for Gastric Cancer: A Prospective Multicenter Observational Study (KLASS-02-QC).

OBJECTIVE: To qualify surgeons to participate in a randomized trial comparing laparoscopic and open distal D2 gastrectomy for advanced gastric cancer. SUMMARY OF BACKGROUND DATA: No studies have sought to qualify surgeons for a randomized trial comparing laparoscopic and open D2 gastrectomy for advanced gastric cancer. METHODS: We conducted a multicenter prospective observational study evaluating unedited videos of laparoscopic and open D2 gastrectomy performed by 27 surgeons. Surgeons performed 3 of each laparoscopic and open distal gastrectomies with D2 lymphadenectomy for gastric cancer. Five peers reviewed each unedited video using a video assessment form. Based on experts' review of videos, a separate review committee decided surgeons as "Qualified" or "Not-qualified." RESULTS: Twelve surgeons (44.4%) were qualified on initial evaluation whereas the other 15 surgeons were not. Another 9 surgeons were finally qualified after re-evaluation. The median score for Qualified was significantly higher than Not-qualified (P < 0.001).Significant differences between Qualified and Not-qualified were noted both in operation type and in all evaluation area of surgical skill, perigastric, and extra-perigastric lymphadenectomy, although the inter-rater variability of the assessment score was low (kappa = 0.285). However, Not-qualified surgeons' scores improved upon re-evaluation of resubmitted videos.When compared laparoscopy with open surgery, median scores were similar between the 2 groups (P = 0.680). However, open gastrectomy scores for surgical skills were significantly higher than for laparoscopic surgery (P = 0.016). CONCLUSIONS: Our surgeon quality control study for gastrectomy represents a milestone in surgical standardization for surgical clinical trials. Our methods could also serve as a system for educating surgeons and assessing surgical proficiency.

Long-Term Outcomes of Laparoscopic Distal Gastrectomy for Locally Advanced Gastric Cancer: The KLASS-02-RCT Randomized Clinical Trial.

PURPOSE: It is unclear whether laparoscopic distal gastrectomy for locally advanced gastric cancer is oncologically equivalent to open distal gastrectomy. The noninferiority of laparoscopic subtotal gastrectomy with D2 lymphadenectomy for locally advanced gastric cancer compared with open surgery in terms of 3-year relapse-free survival rate was evaluated. PATIENTS AND METHODS: A phase III, open-label, randomized controlled trial was conducted for patients with histologically proven locally advanced gastric adenocarcinoma suitable for distal subtotal gastrectomy. The primary end point was the 3-year relapse-free survival rate; the upper limit of the hazard ratio (HR) for noninferiority was 1.43 between the laparoscopic and open distal gastrectomy groups. RESULTS: From November 2011 to April 2015, 1,050 patients were randomly assigned to laparoscopy (n = 524) or open surgery (n = 526). After exclusions, 492 patients underwent laparoscopic surgery and 482 underwent open surgery and were included in the analysis. The laparoscopy group, compared with the open surgery group, suffered fewer early complications (15.7% v 23.4%, respectively; P = .0027) and late complications (4.7% v 9.5%, respectively; P = .0038), particularly intestinal obstruction (2.0% v 4.4%, respectively; P = .0447). The 3-year relapse-free survival rate was 80.3% (95% CI, 76.0% to 85.0%) for the laparoscopy group and 81.3% (95% CI, 77.0% to 85.0%; log-rank P = .726) for the open group. Cox regression analysis after stratification by the surgeon revealed an HR of 1.035 (95% CI, 0.762 to 1.406; log-rank P = .827; P for noninferiority = .039). When stratified by pathologic stage, the HR was 1.020 (95% CI, 0.751 to 1.385; log-rank P = .900; P for noninferiority = .030). CONCLUSION: Laparoscopic distal gastrectomy with D2 lymphadenectomy was comparable to open surgery in terms of relapse-free survival for patients with locally advanced gastric cancer. Laparoscopic distal gastrectomy with D2 lymphadenectomy could be a potential standard treatment option for locally advanced gastric cancer.

Development of a Phosphor Screen with Mirror Coating to Improve Optical Properties in Radiography.

Phosphor screens have attracted increasing global interest because they can aid the acquisition of high-quality images while simultaneously reducing exposure. However, although increasing the thickness of the phosphor screen increases exposure efficiency due to scattered light, it also leads to a broader light spread, which results in poorer resolution. Hence, in this study, we implemented a reflector using a mirror-coating technique on the surface of a phosphor screen and analyzed its characteristics in terms of luminescence intensity and resolution. We present the fabrication and measurement of the phosphor screen based on a reflector containing Gd2O2S:Tb. The phosphor screen containing the reflector can be fabricated via the screen-printing method and roll-to-roll sputtering method. In particular, when compared to the condition without a reflector, Al and Cu reflectors showed improvements in luminescence intensity of 15.7% and 12.2%, respectively, as well as lower full widths at half maximum of 11.45 and 9.08, respectively. This quantitatively demonstrates that Cu and Al are suitable reflector materials to improve exposure efficiency while maintaining resolution in radiography systems. Moreover, because we did not utilize an optical assembly, which improves the transmission efficiency by matching the different refractive indices of the phosphor screen and photo-detector, we believe that the quantity of photons could be further improved if the reflectors were applied to a commercial product. Thus, future studies using single-layer anti-reflector coating techniques with optical assemblies are warranted.

Nutritional and Clinical Factors Affecting Weight and Fat-Free Mass Loss after Gastrectomy in Patients with Gastric Cancer.

After a gastrectomy, the nutritional status of patients with gastric cancer has great effect on the treatment outcome and patients' quality of life. We investigated the changes in body composition and nutrient intake after gastrectomy in 288 gastric cancer patients. A multiple linear regression analysis was used for each time period to verify the effects of nutritional and clinical factors on weight and fat-free mass loss rates. Gastric cancer patients who underwent a gastrectomy continued to experience weight and fat-free mass loss until three months after surgery and became stagnant at six months. The marginal mean of calorie intake per weight was 24.5, 26.8, and 29.4 kcal at one, three, and six months. The protein intake per kg lean mass was 1.14, 1.14, and 1.16 g at one, three, and six months, respectively. One month after surgery, the rate of weight loss increased significantly in females who received chemotherapy (p < 0.001). At one to three months postoperative, females who had undergone chemotherapy tended to significantly lose weight (p = 0.016). Females with a history of chemotherapy also showed a reduction in fat-free mass for one to three months (p = 0.036). Calorie intake was a significant factor in preventing fat-free mass weight loss at one month after surgery. Chemotherapy was an independent factor affecting the weight and fat-free mass loss rate up to six months after gastrectomy. Careful monitoring of weight and muscle mass changes following active nutritional intervention for sufficient nutrition support could be helpful for patients after gastrectomy.

Short-term Outcomes of a Multicenter Randomized Controlled Trial Comparing Laparoscopic Distal Gastrectomy With D2 Lymphadenectomy to Open Distal Gastrectomy for Locally Advanced Gastric Cancer (KLASS-02-RCT).

OBJECTIVE: The aim of the study was to evaluate the short-term outcomes of KLASS-02-RCT, a multicenter randomized controlled trial comparing laparoscopic distal gastrectomy (LDG) with D2 lymphadenectomy with open distal gastrectomy (ODG). SUMMARY BACKGROUND DATA: Although several benefits of laparoscopic gastric cancer surgery have been reported, strong evidence is still limited, especially in locally advanced gastric cancer which requires extensive lymph node dissection. METHODS: Enrollment criteria included histologically confirmed cT2-4a and N0-1 gastric adenocarcinoma. Thirty-day morbidity, 90-day mortality, postoperative pain, and recovery were compared between LDG and ODG groups. RESULTS: A total of 1050 patients were randomly assigned to LDG (n = 526) or ODG group (n = 524) between November 2011 and April 2015. After excluding patients who received bypass or no surgery, 1011 patients were analyzed as actual treatment group. Mean number of totally retrieved lymph nodes was similar in both groups (LDG = 46.6 vs ODG = 47.4, P = 0.451). Early morbidity rate was significantly lower after LDG (16.6%) than after ODG (24.1%; P = 0.003). Postoperative analgesics use and patients' reported pain score were significantly lower after LDG. First day of flatus was earlier after LDG (3.5 vs 3.7 d, P = 0.025) and postoperative hospital stay was shorter in LDG group (8.1 vs 9.3 d, P = 0.005). Ninety days' mortality rate was similar in both groups (LDG = 0.4% vs ODG = 0.6%, P = 0.682). CONCLUSIONS: Laparoscopic distal gastrectomy with D2 lymphadenectomy for locally advanced gastric cancer shows benefits in terms of lower complication rate, faster recovery, and less pain compared with open surgery.

Operation time as a simple indicator to predict the overcoming of the learning curve in gastric cancer surgery: a multicenter cohort study.

BACKGROUND: The aim of this study is to identify an indicator to predict the overcoming of the learning curve of distal gastrectomy in gastric cancer surgery. METHOD: A retrospective multicenter cohort study was conducted in 2100 patients who underwent radical distal gastrectomy performed by nine surgeons in eight hospitals between 2001 and 2006. For each surgeon, an individual CUSUM chart was formulated in terms of operation time or clinical outcomes, including severe complications, number of retrieved lymph nodes, positive resection margin, and hospital stay. The actual changing points (CPs) of the CUSUM charts were analyzed. Based on the CP, patients were divided into pre-CP and post-CP groups, and the clinicopathologic outcomes and survival data were compared between the groups. RESULTS: CP determined by operation time was more reliable than CP determined by a combination of clinical outcomes, as the former was correlated not only with short-term outcomes but also with survival. The outcomes were superior in the post-CP group in terms of numbers of harvested lymph nodes, sufficient lymph node harvesting (> 15), and negative proximal margins. In a survival analysis, the post-CP group showed better survival than the pre-CP group in stage II (76% vs 86.1% p = 0.010) and stage III (51.5% vs 60.6% p = 0.042). CONCLUSION: Overcoming the learning curve of distal gastrectomy for gastric cancer can be better predicted by operation time rather than by a combination of postoperative clinical parameters. It is recommended that surgeons initially operate on early stage cancer patients before overcoming the learning curve.

Effect of Laparoscopic Distal Gastrectomy vs Open Distal Gastrectomy on Long-term Survival Among Patients With Stage I Gastric Cancer: The KLASS-01 Randomized Clinical Trial.

IMPORTANCE: Laparoscopic distal gastrectomy is gaining popularity over open distal gastrectomy for gastric cancer because of better early postoperative outcomes. However, to our knowledge, no studies have proved whether laparoscopic distal gastrectomy is oncologically equivalent to open distal gastrectomy. OBJECTIVE: To examine whether the long-term survival among patients with stage I gastric cancer undergoing laparoscopic distal gastrectomy is noninferior to that among patients undergoing open distal gastrectomy. DESIGN: The Korean Laparoendoscopic Gastrointestinal Surgery Study (KLASS) group, which includes 15 surgeons from 13 institutes, conducted a phase 3, multicenter, open-label, noninferiority, prospective randomized clinical trial (KLASS-01) of patients with histologically proven, preoperative clinical stage I gastric adenocarcinoma from January 5, 2006, to August 23, 2010. Survival and recurrence status of the patients was determined in December 2016. INTERVENTIONS: Patients were randomly assigned (1:1) to laparoscopic distal gastrectomy (n = 705) or open distal gastrectomy (n = 711). Of these patients, 85 received a surgical approach opposite the one to which they were randomized (63 randomized to the open surgery group and 22 to the laparoscopic group). MAIN OUTCOMES AND MEASURES: Difference in 5-year overall survival between the laparoscopic and open distal gastrectomy groups. The noninferiority margin was prespecified as -5% (corresponding hazard ratio of 1.54), with an assumed survival of 90% after 5 years in the open surgery group. RESULTS: Among the 1416 patients (mean [SD] age, 57.3 [11.1] years; 940 [66.4%] male) included in the study, the 5-year overall survival rates were 94.2% in the laparoscopic group and 93.3% in the open surgery group (log-rank P = .64). Intention-to-treat analysis confirmed the noninferiority of the laparoscopic approach compared with the open approach (difference, 0.9 percentage points; 1-sided 97.5% CI, -1.6 to infinity). The 5-year cancer-specific survival rates were similar between the 2 groups (97.1% in the laparoscopic group and 97.2% in the open surgery group, log-rank P = .91; difference, -0.03 percentage points; 1-sided 97.5% CI, -1.8 to infinity). Per-protocol analysis results were consistent with the intention-to-treat results for overall and cancer-specific survival rates. CONCLUSIONS AND RELEVANCE: The KLASS-01 trial revealed similar overall and cancer-specific survival rates between patients receiving laparoscopic and open distal gastrectomy. Laparoscopic distal gastrectomy is an oncologically safe alternative to open surgery for stage I gastric cancer. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00452751.

A feasibility study of laparoscopic total gastrectomy for clinical stage I gastric cancer: a prospective multi-center phase II clinical trial, KLASS 03.

BACKGROUND: With improved short-term surgical outcomes, laparoscopic distal gastrectomy has rapidly gained popularity. However, the safety and feasibility of laparoscopic total gastrectomy (LTG) has not yet been proven due to the difficulty of the technique. This single-arm prospective multi-center study was conducted to evaluate the use of LTG for clinical stage I gastric cancer. METHODS: Between October 2012 and January 2014, 170 patients with pathologically proven, clinical stage I gastric adenocarcinoma located at the proximal stomach were enrolled. Twenty-two experienced surgeons from 19 institutions participated in this clinical trial. The primary end point was the incidence of postoperative morbidity and mortality at postoperative 30 days. The severity of postoperative complications was categorized according to Clavien-Dindo classification, and the incidence of postoperative morbidity and mortality was compared with that in a historical control. RESULTS: Of the enrolled patients, 160 met criteria for inclusion in the full analysis set. Postoperative morbidity and mortality rates reached 20.6% (33/160) and 0.6% (1/160), respectively. Fifteen patients (9.4%) had grade III or higher complications, and three reoperations (1.9%) were performed. The incidence of morbidity after LTG in this trial did not significantly differ from that reported in a previous study for open total gastrectomy (18%). CONCLUSIONS: LTG performed by experienced surgeons showed acceptable postoperative morbidity and mortality for patients with clinical stage I gastric cancer.

Safety of Laparoscopic Sentinel Basin Dissection in Patients with Gastric Cancer: an Analysis from the SENORITA Prospective Multicenter Quality Control Trial.

PURPOSE: We investigated complications after laparoscopic sentinel basin dissection (SBD) for patients with gastric cancer who were enrolled in a quality control study, prior to the phase III trial of sentinel lymph node navigation surgery (SNNS). MATERIALS AND METHODS: We analyzed prospective data from a Korean multicenter prerequisite quality control trial of laparoscopic SBD for gastric cancer and assessed procedure-related and surgical complications. All complications were classified according to the Clavien-Dindo Classification (CDC) system and were compared with the results of the previously published SNNS trial. RESULTS: Among the 108 eligible patients who were enrolled in the quality control trial, 8 (7.4%) experienced complications during the early postoperative period. One patient with gastric resection-related duodenal stump leakage recovered after percutaneous drainage (grade IIIa in CDC). The other postoperative complications were mild and patients recovered with supportive care. No complications were directly related to the laparoscopic SBD procedure or tracer usage, and there were no mortalities. The laparoscopic SBD complication rates and patterns that were observed in this study were comparable to those of a previously reported trial. CONCLUSIONS: The results of our prospective, multicenter quality control trial demonstrate that laparoscopic SBD is a safe procedure during SNNS for gastric cancer.