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Purpose: The luminal subtype of breast cancer has heterogeneous biological characteristics with respect to the expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor-2 (HER2), and Ki-67. We analyzed luminal B breast cancer subcategorized by PR expression and identified clinically relevant prognostic factors.Methods: We collected the clinical and pathologic data of 247 breast cancer patients (stage 1-4) who were diagnosed with luminal B subtype, defined as ER- and/or PR-positive and/or HER2-positive and with a high Ki-67 proliferation index (>14%). We classified them into PR intact and PR low groups according to PR expression pattern. We also analyzed the clinical and pathological data of each group, including age at diagnosis, tumor size, node metastasis, breast and axillary operative method, margin involvement, tumor-node-metastasis (TNM) stage, histological grade, nuclear grade, number of tumors, and expression of ER, PR, Ki-67, and Bcl-2; evaluated recurrence or metastatic characteristics; and analyzed disease-free survival (DFS) and overall survival (OS) in both groups.Results: Among the 247 luminal B breast cancer patients (stage 1-4), 141 were classified into the PR intact group (57.1%) and 106 into the PR low group (42.9%). The PR low group was associated with age >50 years (p=0.001), low Bcl-2 expression (p

Purpose: The biggest concern related to ductal carcinoma in situ (DCIS) is local recurrence and recurrence patterns. The purpose of this study was to investigate the relationship between clinicopathological factors and relapse in patients treated with DCIS.Methods: We reviewed medical records of 104 patients who were diagnosed as DCIS between January 1999 and December 2015 at a single institute. We compared and analyzed clinicopathological factors such as age at diagnosis, preoperative lesions on ultrasonography, preoperative tumor markers, operation methods in the breast, histological grade, nuclear grade, resection margin, comedonecrosis, estrogen receptor/ progesterone receptor expression, human epidermal factor receptor 2/neu expression, Ki-67, postoperative implementation of adjuvant hormonal therapy, and radiotherapy by dividing them into recurrent and non-recurrent groups.Results: Seventeen patients (16.3%) of 104 patients relapsed in the ipsilateral or contralateral breast. The median follow-up period of non-relapsed group was 4.9 years (range, 0.5–19.15) and the median follow-up period of relapsed group was 3.5 years (range, 1.4–14.13). Clinicopathological factors that were significantly related to relapse were nuclear grade (p=0.022) and Ki-67 (p=0.025) based on the results of chi-square or Fisher’s exact analysis. In multivariate analysis using logistic regression, Ki-67 (p=0.021) was significantly associated with DCIS relapse.Conclusion: This study suggested that the higher Ki-67 over 14% was strongly associated with DCIS relapse.

Background Thisretrospective cohort study analyzed the risk of gastrointestinal (GI) cancer in patients who underwent hysterectomy due to a benign gynecologic disease in comparison with the no hysterectomy group using Korean health insurance data. Methods This population-based retrospective cohort study was conducted using insurance data provided by the Health Insurance Review and Assessment Service (HIRA) from January 1, 2007, to December 31, 2020. The hysterectomy group included 40- to 59-year-old women who underwent hysterectomy with uterine leiomyoma or uterine endometriosis from January 1, 2011, to December 31, 2014. The control group included women aged 40 to 59 years who visited medical institutions for medical examination from January 1, 2011 to December 31, 2014. Results The hysterectomy and no hysterectomy groups comprised 66,204 and 89,768 subjects, respectively. The median ages in the no hysterectomy group and hysterectomy group were 48 (range: 43–53) and 46 (range: 44–49) years, respectively. In the unadjusted results of the analysis, all colorectal cancer (CRC) increased in the hysterectomy alone group (HR 1.222, 95% confidence interval (CI) 1.016-1.47, p = 0.033), sigmoid colon cancer increased in the hysterectomy alone group (HR 1.71, 95% CI 1.073-2.724, p = 0.024), and rectal cancer increased in the hysterectomy with adnexal surgery group (HR 1.924, 95% CI 1.073-2.724, p = 0.002). The adjusted results showed that all CRC increased in the hysterectomy alone group (HR 1.406, 95% CI 1.057-1.871, p = 0.019), colon cancer increased in the hysterectomy alone group (HR 1.523, 95% CI 1.068-2.17, p = 0.02), and rectal cancer increased in the hysterectomy with adnexal surgery group (HR 1.933, 95% CI 1.131-3.302, p = 0.016). The all-cause mortality of GI cancer increased in the hysterectomy alone group (HR 3.495, 95% CI 1.347-9.07, p = 0.001). Conclusions This study showed that the risk of all CRC increased in women who underwent hysterectomy compared with women who did not. In particular, the risk of rectal cancer was significantly higher in the women who underwent hysterectomy with adnexal surgery than in the controls.

Purpose: Nanoxel®-M is a low-molecular-weight, non-toxic, biodegradable, docetaxel-loaded methoxy-poly (ethylene glycol)-block-poly (D,L-lactide) (mPEG-PDLLA) micellar formulation. We conducted a multicenter trial to evaluate the safety and toxicity of Nanoxel®-M and the quality of life (QoL) of Korean breast cancer patients treated with this formulation.Methods: Patients received adjuvant Nanoxel®-M with a schedule comprising four alternating cycles of doxorubicin with cyclophosphamide, followed by either Nanoxel®-M or Nanoxel®-M with cyclophosphamide after surgery for early breast cancer. We analyzed hematological and non-hematological toxicity profiles and alterations in patient QoL using the Korean version of the European organization for research and treatment of cancer core 30-item quality of life questionnaire. Fifty-five operable breast cancer patients with stage II or III disease were enrolled from four centers in Korea.Results: Regarding safety and toxicity profiles, grade 3/4 toxicity presented as anemia in 0.5%, neutropenia in 61.8%, febrile neutropenia in 4.5%, mucositis in 1.4%, and edema in 0.5% of patients during 220 total cycles. However, all-grade thrombocytopenia was not observed among hematological toxicities. No grade 3/4 nausea, vomiting, diarrhea, hand foot syndrome, dyspnea, allergic reaction, edema, or peripheral neuropathy were observed. Furthermore, no vehicle-related hypersensitivity reactions occurred when using Nanoxel®-M.Conclusion: Our findings indicate that Nanoxel®-M could be used to treat operable breast cancer patients, compare favorably with docetaxel in terms of hypersensitivity reactions and the incidence of taxane-induced peripheral neuropathy, and is associated with a similar incidence of febrile neutropenia.

Purpose: It is known that as the T stage of a carcinoma progresses, the prognosis becomes poorer. However, there are few studies about factors that affect the prognosis of T4 advanced colon cancer. This study aimed to identify the prognostic factors associated with disease-free survival (DFS) and overall survival (OS) in T4 colon cancer.Methods: Patients diagnosed with stage T4 on histopathology after undergoing curative surgery for colon cancer between March 2009 and March 2018 were retrospectively analyzed for factors related to postoperative survival. Primary outcomes were DFS and OS.Results: Eighty-two patients were included in the study. DFS and OS of the pathologic (p) T4b group were not inferior to that of the pT4a group. Multivariate analysis showed that differentiation (hazard ratio [HR], 4.994; P = 0.005), and laparoscopic surgery (HR, 0.323; P = 0.008) were significant prognostic factors for DFS, while differentiation (HR, 7.904; P ≤ 0.001) and chemotherapy (HR, 0.344; P = 0.038) were significant prognostic factors for OS.Conclusion: Tumor differentiation, laparoscopic surgery, and adjuvant chemotherapy were found to be significant prognostic factors in patients with T4 colon cancer. Adjuvant chemotherapy and curative resections by laparoscopy might improve the prognosis in these patients.

Purpose: To identify factors significantly associated with the mortality of patients with left colonic perforation, and to compare the outcome of Hartmann’s procedure (HP) and primary repair (PR) or primary anastomosis (PA) in patients with left colonic perforation without factors associated with mortality.Methods: This retrospective study included patients who underwent surgery for left colonic perforation from January 2009 to February 2018. Preoperative factors related to postoperative mortality, including vital signs, laboratory findings, and intraoperative findings, were analyzed by type of operation. The chi-square, Fisher exact, and Mann-Whitney U-tests were used to analyze the data.Results: Ninety-one patients were included (36 men, 55 women), and 15 (16.5%) died postoperatively. Prognostic factors were age, leukopenia, thrombocytopenia, bleeding tendency, acute kidney injury, hemodynamic instability, and the existence of feculent ascites. Leukopenia and longer operative time were independent risk factors for mortality. Seventy-nine patients did not have leukopenia and 30 of these patients who underwent PR without diversion were excluded from the subanalysis. HP was performed in 30 patients, and PR with diversion and PA with or without diversion were performed in 19. Compared to the other operative methods, HP had no advantage in reducing hospital mortality (P=0.458) and morbidity.Conclusion: Leukopenia could be an objective prognostic factor for left colonic perforation. Although HP is the gold standard for septic left colonic perforation, it did not improve the hospital mortality of the patients without leukopenia. For such patients, PR or PA may be suggested as an alternative option for left colonic perforation.

Objective The aim of this study was to identify predictive factors for pathologic central lymph node metastasis (CLNM) in patients with clinically negative CLNM (cN0) papillary thyroid microcarcinoma (PTMC) to suggest a specific group of cN0 PTMC patients who benefit from prophylactic central lymph node dissection (CLND). Background PTMC have excellent prognosis, however, 8% have recurrent disease. Recurrence is associated with regional lymph node metastasis. It has been reported that pathologic CLNM is found in 30 to 65% of cN0 PTMC patients. However, prophylactic CLND for cN0 PTMC remains controversial. Methods We reviewed the records of papillary thyroid carcinoma patients with a tumor size on preoperative ultrasonography (US) of ≤10 mm and negative CLNM on preoperative physical examination, US, and positron emission tomography/computed tomography (PET/CT), who underwent total thyroidectomy or thyroid lobectomy with prophylactic CLND between April 2010 and February 2013. In total, 163 patients were included. We evaluated the relationship between preoperatively assessable factors including age, gender, body mass index, preoperative metformin use, primary tumor size through preoperative US, the maximum standardized uptake value (SUVmax) of the primary tumor through preoperative PET/CT, and the bilaterality of the primary tumor and pathologic CLNM. Results A SUVmax of the primary tumor of >3 was an independent preoperatively assessable factor predictive of pathologic CLNM in cN0 PTMC patients. Conclusions Prophylactic CLND might be considered in cN0 PTMC patients with a SUVmax of the primary tumor of > 3 to reduce the risks of residual CLNM and recurrence.

Summary: Background/Objective: Axillary lymph node staging (ALNS) is an important step in the treatment of breast cancer and sentinel lymph node biopsy (SLNB) is a standard procedure for ALNS. Recently, the use of positron emission tomography/computed tomography (PET/CT) for whole body staging in patients with breast cancer has been increasing. The negative predictive value (NPV) of the specific diagnostic modality is the crucial value for excluding axillary lymph node metastasis (ALNM) and guiding the decision not to proceed with axillary lymph node dissection. The aim of this study was to identify patient groups in which PET/CT yields a high NPV for ALNS. Methods: We reviewed data from the records of 262 patients with breast cancer who underwent PET/CT before surgery between February 2009 and March 2018. We searched for factors associated with pathological axillary lymph node metastasis in patients with negative ALNM on PET/CT. Then, we calculated the NPV of PET/CT for ALNS in the patient group without the identified factors and in all patients. Results: Age ≥75 years and tumor size on ultrasonography (US) ≥ 15 mm were the associated factors; the NPV of PET/CT in patients without these factors compared to all patients was 97.2% versus 88.7%. Conclusion: The NPV of PET/CT for ALNS in patients younger than 75 years and with tumor size on US

Traditionally, thermal-based desalination was favored because it is easily adaptable and can produce high-quality water. Because humans have used thermal-based desalination for thousands of years to obtain freshwater by boiling salted feedwater, this traditional method has been expanded to forms such as multistage flash and multieffect distillation. However, with the development of membrane technology, membrane-based desalination has attracted increasing attention. Among these membrane-based desalination technologies, reverse osmosis (RO) is one of the most widely utilized technology for water treatment. The preference for RO for desalination has increased obviously. The capacities of installed RO plants for seawater desalination are higher than 65% of the overall installed capacities for seawater desalination in 2013. With the reduction in the overall cost of desalination systems, the capacity for desalination has continuously increased. Under these circumstances, the importance of RO systems has also tremendously increased.

Internally staged design (ISD) was introduced as a method to lower front reverse osmosis (RO) element fluxes, yielding operational benefits. Systematic selection of the best ISD combinations has not been conducted as it is dependent on operating conditions (i.e., RO recovery and average flux). This study aimed to optimize seawater reverse osmosis (SWRO) operations using ISD for better product water quality and energy efficiency. A total of 36 ISD combinations were configured with three commercial SWRO membranes and systematically examined under varying operating conditions which were simulations of typical SWRO operation. A Pareto-optimal front, a non-dominated feasible solution set, was created to understand the tradeoff relationship between permeate quality and specific energy consumption while considering all parameters. The Pareto-optimal front was classified into five phases, and an analysis of phase changes provided optimal parameter settings for SWRO operation. However, the occurrence of colloidal fouling altered optimal ISD combinations on the Pareto-optimal front. Particularly, when SWRO membranes were fouled at high-recovery and -flux conditions, ISD combinations employing three different membrane types exhibited superior performance in terms of energy efficiency. With these results, the best SWRO operation was suggested depending on its performance requirements, and the advantages of ISD were further delineated.

The overall goal is to study the effect of low-level laser therapy (LLLT) on membrane distribution of major water channel protein aquaporin 5 (AQP5) in salivary gland during hyperglycemia. Par C10 cells treated with high glucose (50 mM) showed a reduced membrane distribution of AQP5. The functional expression of AQP5 was downregulated due to intracellular Ca2+ overload and ER stress. This reduction in AQP5 expression impairs water permeability and therefore results in hypo-salivation. A reduced salivary flow was also observed in streptozotocin (STZ)-induced diabetic mice model and the expression of AQP5 and phospho-AQP5 was downregulated. Low-level laser treatment with 850 nm (30 mW, 10 min = 18 J/cm2) reduced ER stress and recovered AQP5 membrane distribution via serine phosphorylation in the cells. In the STZ-induced diabetic mouse, LLLT with 850 nm (60 J/cm2) increased salivary flow and upregulated of AQP5 and p-AQP5. ER stress was also reduced via downregulation of caspase 12 and CHOP. In silico analysis confirmed that the serine 156 is one of the most favorable phosphorylation sites of AQP5 and may contribute to the stability of the protein. Therefore, this study suggests high glucose inhibits phosphorylation-dependent AQP5 membrane distribution. High glucose induces intracellular Ca2+ overload and ER stress that disrupt AQP5 functional expression. Low-level laser therapy with 850 nm improves salivary function by increasing AQP5 membrane distribution in hyperglycemia-induced hyposalivation.

Managing shale gas produced water (SGPW) is one of the greatest challenges for shale gas industry due to its high salinity and water volume. Osmotically enhanced dewatering (OED) has great potential for treating SGPW because of its higher water recovery and lower energy consumption. This study systematically investigated the effects of operating conditions on OED performance through numerical simulation of membrane modules. The simulation results first showed that OED achieved higher water recovery over forward osmosis (FO) due to less internal concentration polarization (ICP). Water recovery could be higher with decreasing feed flow fraction, increasing normalized membrane area, and increasing hydraulic driving force fraction. It was also demonstrated that OED-RO hybrid process was able to yield more water with similar energy efficiency as one-stage RO, for SGPW of 28.5 g/L total dissolved solids (TDS) under realistic conditions considering inefficiency associated with pump and energy recovery device (ERD). Lastly, to validate our findings, OED experiments were performed with pre-treated real SGPW as a feed solution, and exhibited good agreement with the simulation results. Specifically, water recovery was achieved up to 67% with a high rejection rate of over 97% for most ions at a hydraulic pressure of 30 bar. Our modeled and experimental observations suggest that the OED-RO process can be an energy-efficient process in concentrating high salinity wastewater.

Seawater reverse osmosis (SWRO) desalination is required to produce high-quality water to meet stricter water standards, which could be satisfied with single-pass RO through the advancement of reverse osmosis (RO) membranes. In this study, a novel single-pass RO configuration was proposed to further improve permeate quality. Split partial single-pass (SSP) RO is a design in which the permeate from the rear RO element(s) in a pressure vessel is blended with the RO feed. This blending resulted in the dilution of the feed, leading to the production of high-quality permeate with lower energy demand. Modeling of the RO process demonstrates that SSP RO had the highest energy efficiency when the permeate from the 7th element (i.e., the last one in the single pass RO configuration) was circulated back and mixed with the feed. For typical SWRO operating conditions, SSP RO was effectively able to improve permeate quality. In fact, SSP RO produced an approximately 15% purer permeate compared to conventional single-pass RO. SSP RO was also always more energy-efficient than the two-pass RO configurations. The economic feasibility of the design was assessed further and the possibility of its practical application explored.

Purpose The aim of this study is to determine the predictable factors that affect the clinical course, especially the hospital stay, the operation performed, and to determine factors that will be helpful in deciding whether in-hospital or outpatient treatment is appropriate. Methods We retrospectively collected medical data for patients who had been diagnosed with acute diverticulitis at Inje University Sanggye Paik Hospital between January and December 2016. In total, 117 patients were enrolled in this study. We examined clinical factors, including age, sex, body mass index, pain, body temperature, white blood cell count, C-reactive protein, nil per os (NPO) time, hospital duration, computed tomography (CT) findings, location of diverticulitis, operation performed, and presence of comorbidity (e.g., hypertension and diabetes mellitus). Results In the multivariate analysis, the statistically significant factor related with hospital duration was the presence of perforation on the CT scan (P < 0.001). Longer NPO time was related with pain score (>7) (P = 0.011). Operations were mainly performed in patients with left-sided colonic diverticulitis (P = 0.012). Conclusion We suggest a perforation finding on the CT scan, a severe pain score at least above 7 on a numeric rating pain scale, and a left-sided lesion are absolute indications for in-hospital management.

Purpose The aim of this study was to evaluate whether the perioperative carcinoembryonic antigen (CEA) ratio could be used as a determinant for adjuvant therapy after curative surgery in stage II colorectal cancer. Methods Data for 119 patients with stage II colorectal cancer who underwent radical surgery between 2010 and 2013 were collected. The perioperative CEA ratio was defined as the postoperative/preoperative serum CEA level, and the patients were grouped according to their perioperative CEA ratios: high ratio (≥0.5) and low ratio (

Purposes To identify factors significantly associated with mortality of patients with left colonic perforation, and to compare the outcome of the Hartmann procedure (HP) and primary repair (PR) or primary anastomosis (PA) in left colonic perforation patients without factors associated with mortality. Methods This retrospective study included patients who underwent surgery for left colonic perforation from January 2009 to February 2018. Preoperative factors related to postoperative mortality, including vital signs, laboratory findings, and intraoperative findings, were analyzed by type of operation. The chi-square, Fisher exact, and Mann-Whitney U tests were used to analyze the data. Results Ninety-one patients were included (36 men, 55 women), and 15 (16.5%) died postoperatively. Risk factors were age, leukopenia, thrombocytopenia, bleeding tendency, acute renal failure, hemodynamic instability, and existence of generalized peritonitis and feculent ascites. Advanced age, leukopenia, and acute renal failure were independent risk factors for mortality. Seventy-nine patients did not have leukopenia, and among them, 30 patients who underwent PR without diversion were excluded from the sub-analysis. HP was performed in 30 patients, and PR with diversion and PA with or without diversion were performed in 19. Compared to the other operative methods, HP had no benefit for reducing overall mortality (p=0.458) and morbidity. Conclusions Leukopenia could be an objective prognostic factor for left colonic perforation. Although HP is the gold standard for septic left colonic perforation, it did not improve overall mortality of the patients without leukopenia. For such patients, PR or PA could be a good option for left colonic perforation.

Appendectomy, which comprises most benign intra-abdominal surgeries, is currently assisted by laparoscopy in most cases. However, many patients complain of postoperative shoulder or subcostal pain after laparoscopic surgery. In some cases, the pain lasts even several weeks after surgery. This study aimed to analyze unmodifiable clinicopathological factors of patients who underwent laparoscopic appendectomy and to minimize preoperative and postoperative discomfort.Patients admitted for laparoscopic appendectomy for acute appendicitis with an American Society of Anesthesiology (ASA) grades I and II, and ages 12~70 years were enrolled in the study. Postoperative shoulder or subcostal pain was assessed using the visual analogue scale (VAS) for pain and analyzed with the clinicopathological factors of the patients, including age, sex, weight, height, body mass index (BMI), and abdominal circumference (AC) difference.Of the 124 patients, 40 complained of postoperative shoulder or subcostal pain with a VAS score of ≥4. The risk of the postoperative shoulder or subcostal pain increased in women (The risk of postoperative shoulder or subcostal pain after laparoscopic appendectomy was significantly increased with lower weight.

Purpose: Small bowel obstruction (SBO) is a common disease that requires hospitalization. The most common cause of SBO is postoperative adhesion. Delayed timing of operations in patients who need surgical intervention results in mortality or morbidity. A number of studies on SBO have established criteria for emergency surgery. However, few objective clinical parameters are available for screening patients who need a delayed operation. Therefore, we analyzed factors that affect the clinical course of SBO to select appropriate therapeutic plans for reducing the risk of complications in these patients.Methods: We investigated the clinical characteristics of patients admitted to the surgery department of our hospital between January 1, 2015, and December 31, 2016, who were diagnosed with SBO. Patients were divided into an operative treatment group (n = 12) and a conservative treatment group (n = 96). We compared clinical characteristics between the 2 groups.Results: The operative treatment group underwent more operations before SBO than the conservative treatment group (P = 0.007). Initial leukocyte counts (P = 0.004) and C-reactive protein (CRP) levels (P = 0.028) were elevated in the operative group. Body mass index (BMI) was lower in the operative group (P = 0.013).Conclusion: The number of operations before SBO, leukocyte counts, CRP levels, and BMI were useful parameters for selecting patients who needed an urgent operation for SBO.

Owing to the significant increase in seawater desalination, seawater exhibiting extreme conditions of high salinity and high temperature cannot be avoided in the production of fresh water. Although seawater reverse osmosis (SWRO) is one of the most energy-saving desalination technologies, it might not be favorable for treating extreme seawater due to the operational limitations associated with the single-stage SWRO configuration. To overcome these limitations, the applicability of two-stage SWRO was examined. The recovery of single-stage SWRO was limited to 31% for stable operation, whereas two-stage SWRO, utilizing pressure exchangers as energy recovery devices, achieved 34% recovery for the same number of pressure vessels. Furthermore, the maximum water fluxes in the front SWRO elements were reduced under the design constraints of the two-stage configuration than that of the single-stage configuration. The two-stage SWRO system was energy-efficient with high recovery; however, under extreme conditions, the permeate quality was similar to that of single-stage SWRO. To improve the applicability of two-stage SWRO, internally staged design (ISD) and split partial second pass (SPSP) can be adopted. ISD can reduce water fluxes in the front elements, increasing system recovery, whereas SPSP design enables the reverse osmosis system to produce high-quality permeate with low additional energy.

Seawater reverse osmosis (SWRO) is usually combined with brackish reverse osmosis (BWRO) to improve the water quality in seawater desalination; however, this configuration often results in high energy consumption. Consequently, membrane capacitive deionization (MCDI) has been suggested as a lower energy alternative technology, but cyclic operation within the cell (i.e., discontinuous operation of ad/desorption) is a main disadvantage. On the other hand, flow electrode capacitive deionization (FCDI) can be continuously operated by using a flow electrode. In this study, the feasibility of a SWRO-FCDI system was examined by using a suitable electrolyte in the flow electrode: seawater or SWRO concentrate. In addition, by employing a selective ion exchange membrane (IEM), the FCDI was able to selectively remove monovalent ions rather than divalent ions, unlike BWRO, thus producing a final product water containing divalent ions, which is more suitable for corrosion control in the subsequent pipe distribution systems. As a result, the remineralization process can be minimized. To test the SWRO-FCDI concept, actual SWRO permeate was first treated in a single mode with an electrolyte comprising real seawater in a flow electrode, and the feasibility of long-term operation was proven by batch-mode, which allowed the optimization of the FCDI active area.

While single-stage is the general configuration for seawater reverse osmosis (SWRO), the two-stage design can increase the overall recovery of an SWRO system. Due to its high-recovery operation, the specific energy consumption (SEC) of two-stage SWRO is higher than that of single-stage. Thus, the two-stage configuration has not been extensively applied in the current desalination market. In contrast, recent studies have reported that the two-stage design can lower the SEC of SWRO compared to that of single-stage. However, the analyses were biased towards SEC, and the practical design aspects (e.g., permeate quality, water flux, and design ratios) were not systemically considered. Thus, this study examines the applicability of a two-stage SWRO system with a capacity of 100,000 m3/d that employs 1200 pressure vessels (PVs). Two-stage SWRO actually consumed a greater amount of energy than that of single-stage for typical SWRO recovery with the same number of PVs. In contrast, single- and two-stage SWRO produced permeate similar in quality, while the two-stage exhibited superior water-flux distribution along the PVs. Additionally, optimal ratios of permeate flow rate and number of PVs were determined by energy recovery devices type, where the ratio of 1:2 was selected for the reverse osmosis system with a pressure exchanger and 2:1 for that with a Pelton turbine. Considering SEC and other operational aspects, the use of two-stage SWRO was feasible at a 50–70% recovery rate.