Publications by authors named "Chinock Cheong"

Background: Total neoadjuvant therapy has been introduced to enhance oncological outcomes and minimize toxicity in locally advanced rectal cancer, but the superiority between the induction and consolidation of therapy remain unclear.

Objective: To evaluate oncological and postoperative outcomes by comparing induction chemotherapy and consolidation chemotherapy with conventional chemoradiotherapy in patients with locally advanced rectal cancer.

Data Sources: Systematic searches of PubMed, Embase, and Cochrane databases wereperformed for studies published from the database's inception until June 2023.

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Background: We review and analyze research on the application of machine learning (ML) and deep learning (DL) models to lymph node metastasis (LNM) prediction in patients with T1 colorectal cancer (CRC). Predicting LNM before radical surgery is important in patients with T1 CRC. However, current surgical treatment guidelines are limited.

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Purpose: Current guidelines recommend endoscopic resection for rectal neuroendocrine tumors (RNETs) under 10 mm. Incomplete resections necessitate salvage procedures, highlighting the need for complete R0 resection. This study evaluates the efficacy and safety of wide hot snare polypectomy (WHSP) compared to endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) for the salvage treatment of small RNETs.

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Purpose: Compared with extracorporeal anastomosis (ECA), intracorporeal anastomosis (ICA) is expected to provide some benefits, including a shorter operation time and less intraoperative bleeding. Nevertheless, the benefits of ICA have mainly been evaluated in nonrandomized studies. Owing to the recent update of randomized controlled trials (RCTs) for minimally invasive surgery (MIS) of right hemicolectomy (RHC), the need to measure the actual effect by synthesizing the outcomes of these studies has emerged.

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The standard treatments for locally advanced rectal cancer typically involved neoadjuvant therapy with either short-course radiation or long-course chemoradiation, followed by radical surgery and adjuvant chemotherapy. While the advancement of surgical techniques and the adoption of multimodal therapy have greatly contributed to reducing local failure, there has been limited improvement in overall survival, primarily due to the stagnation in systemic failure. In response to this challenge, a new strategy known as total neoadjuvant therapy (TNT) has emerged, involving the administration of both full-dose chemotherapy and radiation before surgery.

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Background: An underweight individual is defined as one whose Body Mass Index (BMI) is < 18.5 kg/m. Currently, the prognosis in patients with colorectal cancer (CRC) who are also underweight is unclear.

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Although gastrointestinal stromal tumors (GISTs) are rare disease and rectal GISTs is only 5% of total GISTs, they have the worst prognosis. Due to narrow pelvis, tumor rupture or positive resection margin are common in the management of rectal GISTs. The impact of neoadjuvant treatment on the clinical outcomes of rectal gastrointestinal stromal tumors (GISTs) remains unclear.

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In colorectal cancer, whereas mucinous adenocarcinoma (MAC) has several poor clinical prognostic factors compared to adenocarcinoma (AC), the prognosis of MAC remains controversial. We evaluated the prognosis of MAC without distant metastasis and the effects of adjuvant chemotherapy using health insurance registry data managed by South Korea. Patients with colorectal cancer between January 2014 and December 2016 were included (AC, 22,050 [96.

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Purpose: Conservative treatment is the first-line therapy for acute colonic diverticulitis without severe complications, but treatment failure may increase hospitalization duration, medical costs, and morbidities. Usage of the modified Hinchey classification is insufficient to predict the outcome of conservative management. We aimed to investigate the clinical efficacy of the modified Hinchey classification and to evaluate predictive factors such as inflammatory markers for the failure of conservative management.

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Background: Preoperative chemoradiotherapy (CRT) is a standard treatment modality for locally advanced rectal cancer. However, CRT alone cannot improve overall survival. Approximately 20% of patients with CRT-resistant tumors show disease progression.

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Background: We investigated the differences in biological behaviors of sporadic colorectal cancer (CRC) between young and elderly patients. CRC is a common cancer, with a mean age at onset of > 65 years. However, recent reports indicate increasing rates in younger populations.

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Backgrounds/aims: On the basis of acceptable oncologic results, ultralow anterior resection (ULAR) and colo-anal anastomosis plus hand-sewn coloanal anastomosis have been performed for treating very low-lying rectal cancer. However, many patients experience bowel dysfunction after ULAR. Studies have provided inadequate data on bowel dysfunctions and only a few functional studies have focused on low rectal cancer.

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Extramammary Paget disease (EMPD) is a rare cutaneous neoplasm. Perianal Paget disease (PPD) is a subset of EMPD manifesting perianal lesions. Two cases of PPD in Severance Hospital are described in this article.

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Although laparoscopic resection for colon cancer has been proven safe and feasible when compared with open resection, currently no clear evidence is available regarding minimally invasive surgery for rectal cancer. This type of surgery may benefit patients by allowing fast recovery of normal dietary intake and bowel function, reduced postoperative pain, and shorter hospitalization. Therefore, minimally invasive surgeries such as laparoscopic or robot surgery have become the predominant treatment option for colon cancer.

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Purpose: In patients with colorectal cancer, preoperative staging using various imaging technologies is important for establishing the treatment plan and predicting the prognosis. Although computed tomography (CT) has been used most widely, the versatility of CT accuracy was primarily because of the lack of specialization. In this study, we aimed to identify whether any advancement in abdominal CT accuracy in the prediction of local staging has occurred.

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Purpose: Tumors at the level of the anorectal junction had required total levator-ani muscle excision to achieve an adequate resection margin. However, in the cases of tumor invading ipsilateral levator-ani muscle and intact external sphincter, en bloc resection of rectum with levator-ani muscle including tumor would be possible. This hemilevator excision (HLE) technique enables preserving the anal sphincter function while obtaining oncologic clearance and avoiding permanent colostomy in those patients.

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Backgrounds: Although transanal endoscopic surgery is practiced worldwide, there is no consensus on comparative outcomes between transanal endoscopic operation (TEO) and transanal excision (TAE). In this study, we reviewed our experiences with these techniques and compared patients who underwent TEO and TAE using propensity score matching (PSM).

Methods: A total of 207 patients underwent local rectal tumor excision between January 2008 and November 2015.

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There has been little enthusiasm for performing robotic colectomy for colon cancer in recent years due to multiple factors, one being that the previous robotic systems such as the da Vinci Si (dVSi) were poorly designed for multi-quadrant surgery. The new da Vinci Xi (dVXi) system enables colectomy with central mesocolic excision to be performed easily in a single docking procedure. We developed a universal port placement strategy to allow right and left hemicolectomies to be performed via a suprapubic approach and a Pfannensteil extraction site.

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The aim of this study is to investigate if retrieval of 12 lymph nodes (LNs) is sufficient to avoid stage migration as well as to evaluate the prognostic impact of insufficient LN retrieval in different treatment settings of rectal cancer, particularly in the case of preoperative chemoradiotherapy (pCRT).The data of all patients with biopsy proven rectal adenocarcinoma who underwent curative surgery between January 2005 and December 2012 were analyzed. Univariate and multivariate analyses for oncologic outcomes were performed in LN metastasis or no LN metastasis (LN-) group.

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Anastomotic leakage (AL) is a well-known cause of morbidity after low anterior resection (LAR) for rectal cancer, but its impact on oncologic outcome is not well understood. The aim of this study is to investigate the impact of AL on long-term oncologic outcome and to identify factors associated with AL that may affect prognosis after LAR for rectal cancer.A retrospective analysis of patients who underwent curative resection for rectal cancer without diverting stoma was performed.

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