Colon cancer: the 2023 Korean clinical practice guidelines for diagnosis and treatment.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Association of gut microbiome with immune microenvironment in surgically treated colorectal cancer patients.

This study explored the relationship between faecal microbiota distribution and local or systemic immune response in patients with colorectal cancer (CRC). The study population included 114 surgically treated CRC patients. Faeces were analysed using 16S rRNA gene sequencing. The immune score in tumour microenvironment was evaluated using CD3 and CD8 immunohistochemistry. Genetic alterations, microsatellite instability status and five systemic inflammatory markers were also analysed. Thirty of 114 (26.3%) CRC patients were categorised as the 'immune type' with a high density of T-cells. The immune type CRC cases showed lower angiolymphatic invasion and longer overall survival. Of the 123 selected bacterial species, Bacteroides fragilis and Collinsella aerofaciens were prevalent in immune CRC cases, whereas Odoribacter splanchnicus and Phascolarctobacterium succinatutens were prevalent in non-immune CRC patients. Bacteroides fragilis was associated with shorter disease free survival in univariable and multivariable survival analyses. Regarding systemic immunity, a high prevalence of C. aerofaciens was associated with a high modified Glasgow prognostic score. This study revealed a potential relationship among the gut microbiome, immune microenvironment, and disease progression in patients with CRC. Our findings suggest that abundant B. fragilis in patients with CRC is associated with a 'cold immune' tumour microenvironment.

Cost-Utility Analysis for Colorectal Cancer Screening According to the Initiating Age of National Cancer Screening Program in Korea.

BACKGROUND: This study aimed to identify the most cost-effective strategy for colorectal cancer screening using the fecal immunochemical test (FIT), focusing on screening initiation age in Korea. METHODS: We designed Markov simulation models targeting individuals aged 40 years or older. Twelve strategies combining screening initiation ages (40, 45, or 50 years old), termination ages (80 or no limit), and intervals (1 or 2 years) were modeled, and the most cost-effective strategy was selected. The robustness of the results was confirmed using one-way and probabilistic sensitivity analyses. Furthermore, the cost-effectiveness of the qualitative and quantitative FIT methods was verified using scenario analysis. RESULTS: The 2-year interval strategy with a screening age range of 45-80 years was the most cost-effective (incremental cost-utility ratio = KRW 7,281,646/quality adjusted life years). The most sensitive variables in the results were transition rate from advanced adenoma to local cancer and discount rate. The uncertainty in the model was substantially low. Moreover, strategies starting at the age of 40 years were also cost-effective but considered suboptimal. The scenario analysis showed that there was no significant difference in cost-effectiveness between strategies with various relative screening ratio of quantitative and qualitative method. CONCLUSION: The screening method for advancing the initiation age, as presented in the 2015 revised national screening recommendations, was superior regarding cost-effectiveness. This study provides a new paradigm for the development of a national cancer screening system in Korea, which can be utilized as a scientific basis for economic evaluations.

Long-term clinical outcomes after high and low ligations with lymph node dissection around the root of the inferior mesenteric artery in patients with rectal cancer.

PURPOSE: This study aimed to evaluate the long-term clinical outcomes based on the ligation level of the inferior mesenteric artery (IMA) in patients with rectal cancer. METHODS: This was a retrospective analysis of a prospectively collected database that included all patients who underwent elective low anterior resection for rectal cancer between January 2013 and December 2019. The clinical outcomes included oncological outcomes, postoperative complications, and functional outcomes. The oncological outcomes included overall survival (OS) and relapse-free survival (RFS). The functional outcomes, including defecatory and urogenital functions, were analyzed using the Fecal Incontinence Severity Index, International Prostate Symptom Score, and International Index of Erectile Function questionnaires. RESULTS: In total, 545 patients were included in the analysis. Of these, 244 patients underwent high ligation (HL), whereas 301 underwent low ligation (LL). The tumor size was larger in the HL group than in the LL group. The number of harvested lymph nodes (LNs) was higher in the HL group than in the LL group. There were no significant differences in complication rates and recurrence patterns between the groups. There were no significant differences in 5-year RFS and OS between the groups. Cox regression analysis revealed that the ligation level (HL vs. LL) was not a significant risk factor for oncological outcomes. Regarding functional outcomes, the LL group showed a significant recovery in defecatory function 1 year postoperatively compared with the HL group. CONCLUSION: LL with LNs dissection around the root of the IMA might not affect the oncologic outcomes comparing to HL; however, it has minimal benefit for defecatory function.

Silent pheochromocytoma in adrenal incidentaloma: unveiling clinical and radiological characteristics.

Purpose: Silent pheochromocytoma refers to tumors without signs and symptoms of catecholamine excess. This study aimed to clarify the clinical, radiological characteristics, and perioperative features of silent pheochromocytomas diagnosed after adrenalectomy for adrenal incidentaloma. Methods: Medical records of patients who underwent adrenalectomy for adrenal incidentaloma and were subsequently diagnosed with silent pheochromocytoma between January 2000 and December 2020 were retrospectively reviewed for demographic, diagnostic, surgical, and pathological findings. Results: Of the 130 patients who underwent adrenalectomy for incidentaloma, 8 (6.1%) were diagnosed with silent pheochromocytoma. Almost all patients had no hypertensive symptoms and their baseline hormonal levels remained within normal ranges. All patients exhibited tumor size >4 cm, precontrast Hounsfield unit >10, and absolute washout <60%. Intraoperative hypertensive events were noted in 2 patients (25.0%) in whom antiadrenergic medications were not administered. All patients in the intraoperative hypertensive event group exhibited atypical features on CT, whereas 83.3% of patients in the non-intraoperative hypertensive event group showed atypical features on CT imaging. Conclusion: Silent pheochromocytomas share radiological traits with malignant adrenal tumors. Suspicious features on CT scans warrant surgical consideration for appropriate treatment. Administering alpha-blockers can enhance hemodynamic stability during adrenalectomy in suspected silent pheochromocytoma cases.

Predictive factors for persistent hypercalcemia following parathyroidectomy in patients with persistent hyperparathyroidism after kidney transplantation: a retrospective cohort study.

BACKGROUND: Surgery for irreversible hyperparathyroidism is the preferred management for kidney transplant patients. The authors analyzed the factors associated with persistent hypercalcemia after parathyroidectomy in kidney transplant patients and evaluated the appropriate extent of surgery. MATERIALS AND METHODS: The authors retrospectively analyzed 100 patients who underwent parathyroidectomy because of persistent hyperparathyroidism after kidney transplantation at a tertiary medical center between June 2011 and February 2022. Patients were divided into two groups: 22 with persistent hypercalcemia after parathyroidectomy and 78 who achieved normocalcemia after parathyroidectomy. Persistent hypercalcemia was defined as having sustained hypercalcemia (≥10.3 mg/dl) 6 months after kidney transplantation. The authors compared the biochemical and clinicopathological features between the two groups. Multivariate logistic regression analysis was used to identify potential risk factors associated with persistent hypercalcemia following parathyroidectomy. RESULTS: The proportion of patients with serum intact parathyroid hormone (PTH) level is greater than 65 pg/ml was significantly high in the hypercalcemia group (40.9 vs. 7.7%). The proportion of patients who underwent less than subtotal parathyroidectomy was significantly high in the persistent hypercalcemia group (17.9 vs. 54.5%). Patients with a large remaining size of the preserved parathyroid gland (≥0.8 cm) had a high incidence of persistent hypercalcemia (29.7 vs. 52.6%). In the multivariate logistic regression analysis, the drop rate of intact PTH is less than 88% on postoperative day 1 (odds ratio 10.3, 95% CI: 2.7-39.1, P =0.001) and the removal of less than or equal to 2 parathyroid glands (odds ratio 6.8, 95% CI: 1.8-26.7, P =0.001) were identified as risk factors for persistent hypercalcemia. CONCLUSION: The drop rate of intact PTH is less than 88% on postoperative day 1 and appropriate extent of surgery for controlling the autonomic function were independently associated with persistent hypercalcemia. Confirmation of parathyroid lesions through frozen section biopsy or intraoperative PTH monitoring can be helpful in preventing the inadvertent removal of a parathyroid gland and achieving normocalcemia after parathyroidectomy.

Diagnostic consistency between computed tomography and adrenal vein sampling of primary aldosteronism: leading to successful curative outcome after adrenalectomy; a retrospective study.

BACKGROUND: Adrenal computed tomography (CT) is a useful tool for locating adrenal lesion in primary aldosteronism (PA) patients. However, adrenal vein sampling (AVS) is considered as a gold standard for subtype diagnosis of PA. The aim of this study was to investigate the consistency of CT and AVS for the diagnosis of PA subtypes and evaluate the concordance of surgical outcomes. MATERIALS AND METHODS: This retrospective study included 264 PA patients having both CT and AVS. Diagnostic consistency between CT and AVS was accessed, and clinical and biochemical outcomes were evaluated at 6 months after adrenalectomy. RESULTS: Of all, 207 (78%) had a CT unilateral lesion, 31 (12%) CT bilateral lesion, and 26 (10%) CT bilateral normal findings. Among the CT unilateral lesion group, 138 (67%) had ipsilateral AVS lateralization. For CT bilateral lesion and bilateral normal, AVS unilateral lateralization was found in 17 (55%) and 2 (8%), respectively. The consistency between CT lesion and AVS lateralization including CT unilateral with AVS ipsilateral, and CT bilateral lesion with AVS bilateral patients was 63.8% (152/238). Of 77 patients with available data out of 138 patients who underwent adrenalectomy with consistency between CT and AVS, the clinical success rate was 96%, for 17 inconsistency patients out of 22 patients who underwent adrenalectomy, the clinical success rate was 94% after adrenalectomy following the lateralization result of AVS. CONCLUSION: CT is a useful tool to diagnose the adrenal lesion in PA patients. However, AVS is more sufficient to detect the unilateral PA subtype, which could provide curable treatment to surgical candidates of PA such that AVS can identify patients with contralateral PA in CT unilateral lesion and unilateral PA in CT bilateral lesion. The surgical outcome was successful when an adrenalectomy was performed according to the AVS lateralization result.

Exfoliate cancer cell analysis in rectal cancer surgery: comparison of laparoscopic and transanal total mesorectal excision, a pilot study.

PURPOSE: Minimally invasive surgery (MIS) is currently the standard treatment for rectal cancer. However, its limitations include complications and incomplete total mesorectal resection (TME) due to anatomical features and technical difficulties. Transanal TME (TaTME) has been practiced since 2010 to improve this, but there is a risk of local recurrence and intra-abdominal contamination. We aimed to analyze samples obtained through lavage to compare laparoscopic TME (LapTME) and TaTME. METHODS: From June 2020 to January 2021, 20 patients with rectal cancer undergoing MIS were consecutively and prospectively recruited. Samples were collected at the start of surgery, immediately after TME, and after irrigation. The samples were analyzed for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) through a quantitative real-time polymerase chain reaction. The primary outcome was to compare the detected amounts of CEA and CK20 immediately after TME between the surgical methods. RESULTS: Among the 20 patients, 13 underwent LapTME and 7 underwent TaTME. Tumor location was lower in TaTME (7.3 cm vs. 4.6 cm, P=0.012), and negative mesorectal fascia (MRF) was more in LapTME (76.9% vs. 28.6%, P=0.044). CEA and CK20 levels were high in 3 patients (42.9%) only in TaTME. There was 1 case of T4 with incomplete purse-string suture and 1 case of positive MRF with dissection failure. All patients were followed up for an average of 32.5 months without local recurrence. CONCLUSION: CEA and CK20 levels were high only in TaTME and were related to tumor factors or intraoperative events. However, whether the detection amount is clinically related to local recurrence remains unclear.

Safety and feasibility of single-port surgery for posterior retroperitoneal adrenalectomy using the da Vinci SP robotic system: a retrospective cohort study.

BACKGROUND: This study demonstrates our experience of single-port robotic posterior retroperitoneal adrenalectomy (RPRA) using the da Vinci SP robot system and evaluates its technical feasibility and surgical outcomes. METHODS: We conducted a retrospective analysis of 250 RPRAs, including 117 conventional 3-port RPRAs, 103 reduced 2-port RPRAs, and 30 single-port RPRAs. Each RPRA type was compared by analyzing 30 patients in the early phase of surgery. RESULTS: All patients who underwent single-port RPRA showed excellent surgical outcomes. Age, sex, BMI, and tumor location site did not significantly differ between the three groups. In the early phase, the size of the adrenal tumor was similar between three groups, and it tended to increase as the number of ports increased (p < 0.001). The mean operation time was shorter for patients who underwent single-port RPRA than those who underwent RPRA types (p < 0.001). The numeric rating scale score did not significantly differ between the groups on most days. No major complications were observed, and no patients were converted to open surgery or required additional port insertion. CONCLUSION: Single-port RPA using the da Vinci SP robotic system showed the effectiveness of the surgical procedure and improved cosmetic outcomes for patients, while also enabling surgeons to perform operations with greater ease and convenience. Therefore, single-port RPRA could be a good alternative option for the treatment of adrenal tumors in selected situations.

Contralateral Low-to-Intermediate Suspicion Nodule Is Not a Contraindication for Lobectomy in Patients with Papillary Thyroid Carcinoma.

Background: The optimal extent of surgery for unilateral papillary thyroid carcinoma (PTC) with contralateral nodules remains unclear. This study evaluated the long-term outcomes in a large cohort of patients with unilateral PTC and contralateral low-to-intermediate suspicious nodules who underwent lobectomy. Methods: This retrospective cohort study included patients with unilateral PTC who underwent lobectomy between January 2016 and December 2017 at Asan Medical Center in Korea. Patients were divided into two groups, those with and without contralateral nodules at the time of lobectomy: the Present group and the Absent group. All contralateral nodules observed at the time of surgery and during follow-up were evaluated. Results: The study cohort consisted of 1761 patients (1879 nodules), including 700 (39.8%) with and 1061 (60.2%) without contralateral nodules. The median size of the contralateral nodules was 0.5 cm. After a median follow-up of 59 months, the median growth of the contralateral nodules in the Present group was 0.1 cm (range, -3.4 to 4.7 cm). Of the contralateral nodules present at the time of lobectomy, 54.7% remained unchanged, decreased in size, or disappeared; whereas 14.8% increased ≥0.3 cm. Of the 700 patients with contralateral nodules, 20 (2.9%) were diagnosed with contralateral PTC. The 5-year contralateral PTC disease-free survival rates in patients with and without contralateral nodules were 98.2% and 99.3% (p = 0.003), respectively, whereas the 5-year recurrence-free survival rates did not differ significantly in these two groups. Of the 39 patients who underwent completion thyroidectomy, 2 (5.1%) experienced permanent hypocalcemia. Conclusions: Lobectomy may be a safe and feasible initial treatment option for patients with unilateral low-risk PTC and contralateral low-to-intermediate suspicious nodules.

Diagnosis and management of acute colonic diverticulitis: results of a survey among Korean gastroenterologists.

BACKGROUND/AIMS: Some management strategies for acute colonic diverticulitis remain controversial in Korean real-world practice because their clinical features differ from those in the West. This study aimed to investigate the opinions of Korean physicians regarding the diagnosis and treatment of acute diverticulitis. METHODS: A web-based survey was conducted among gastroenterologists specializing on treating lower gastrointestinal disorders. The questionnaires concerned overall management strategies for colonic diverticulitis, including diagnosis, treatment, and follow-up. RESULTS: In total, 209 gastroenterologists responded to the survey. Less than one-fourth of the respondents (23.6%) answered that left-sided colonic diverticulitis is more likely to be complicated than right-sided colonic diverticulitis. Most respondents agreed that immunocompromised patients with diverticulitis have worse clinical outcomes than immunocompetent patients (71.3%). Computed tomography was the most preferred tool for diagnosing diverticulitis (93.9%). Approximately 89% of the respondents answered that they believed antibiotic treatment is necessary to treat acute uncomplicated diverticulitis. Most respondents (92.6%) agreed that emergency surgery is not required for diverticulitis with an abscess or microperforation without panperitonitis. Further, 94.7% of the respondents agreed that colon cancer screening is necessary in patients aged ≥ 50 years with diverticulitis after they have recovered from acute illness. Many respondents (71.4%) agreed that surgery for recurrent diverticulitis should be individualized. CONCLUSION: Opinions regarding management strategies for colonic diverticulitis among Korean gastroenterologists were well agreed upon in some areas but did not agree well in other areas. Evidence-based guidelines that meet the practical needs of the Korean population should be developed.

Effects of prior endoscopic resection on recurrence in patients with T1 colorectal cancer who underwent radical surgery.

PURPOSE: Endoscopic resection (ER) is a reliable treatment for early colorectal cancer without lymph node metastasis. We aimed to examine the effects of ER performed prior to T1 colorectal cancer (T1 CRC) surgery by comparing long-term survival after radical surgery with prior ER to that after radical surgery alone. METHODS: This retrospective study included patients who underwent surgical resection of T1 CRC at the National Cancer Center, Korea, between 2003 and 2017. All eligible patients (n = 543) were divided into primary and secondary surgery groups. To ensure similar characteristics between the groups, 1:1 propensity score matching was used. Baseline characteristics, gross and histological features, along with postoperative recurrence-free survival (RFS) between the two groups were compared. Cox proportional hazard model was used to identify the risk factors affecting recurrence after surgery. Cost analysis was performed to examine the cost-effectiveness of ER and radical surgeries. RESULTS: No significant differences were observed in 5-year RFS between the two groups in matched data (96.9% vs. 95.5%, p = 0.596) and in the unadjusted model (97.2% vs. 96.8%, p = 0.930). This difference was also similar in subgroup analyses based on node status and high-risk histologic features. ER before surgery did not increase the medical costs of radical surgery. CONCLUSION: ER prior to radical surgery did not affect the long-term oncologic outcomes of T1 CRC or significantly increased the medical costs. Attempting ER first for suspected T1 CRC would be a good strategy to avoid unnecessary surgery without concerns of worsening cancer-related prognosis.

Comparative outcomes of acute colonic diverticulitis in immunocompromised versus immunocompetent patients: a systematic review and meta-analysis.

BACKGROUND/AIMS: Immunocompromised patients with acute colonic diverticulitis are at high risk for complications and failure of non-surgical treatment. However, evidence on the comparative outcomes of immunocompromised and immunocompetent patients with diverticulitis is lacking. This systematic review and meta-analysis investigated the outcomes of medical treatment in immunocompromised and immunocompetent patients with diverticulitis. METHODS: A comprehensive literature search was conducted in PubMed, Embase, and the Cochrane Library. Studies comparing the clinical outcomes of immunocompromised and immunocompetent patients with diverticulitis were included. RESULTS: A total of 10 studies with 1,946,461 subjects were included in the quantitative synthesis. The risk of emergency surgery and postoperative mortality after emergency surgery was significantly higher in immunocompromised patients than in immunocompetent patients with diverticulitis (risk ratio [RR], 1.76; 95% confidence interval [CI], 1.31-2.38 and RR, 3.05; 95% CI, 1.70-5.45, respectively). Overall risk of complications associated with diverticulitis was non-significantly higher in immunocompromised than in immunocompetent patients (RR, 1.24; 95% CI, 0.95-1.63). Overall mortality irrespective of surgery was significantly higher in immunocompromised than in immunocompetent patients with diverticulitis (RR, 3.65; 95% CI, 1.73-7.69). By contrast, postoperative mortality after elective surgery was not significantly different between immunocompromised and immunocompetent patients with diverticulitis. In subgroup analysis, the risk of emergency surgery and recurrence was significantly higher in immunocompromised patients with complicated diverticulitis, whereas no significant difference was shown in mild disease. CONCLUSIONS: Immunocompromised patients with diverticulitis should be given the best medical treatment with multidisciplinary approach because they had increased risks of surgery, postoperative morbidity, and mortality than immunocompetent patients.

Stratification of rate of lymph node metastasis according to risk factors and oncologic outcomes in patients who underwent radical resection for rectal neuroendocrine tumors.

PURPOSE: Most predictive factors for lymph node metastasis in rectal neuroendocrine tumors (NETs) have been based on local and endoscopic resection. We aimed to evaluate the risk factors for lymph node metastasis in patients who underwent radical resection for rectal NETs and stratify the risk of lymph node metastasis. METHODS: Sixty-four patients who underwent radical resection for rectal NETs between January 2001 and January 2018 were included. We investigated the risk factors of lymph node metastasis using clinicopathologic data. We also performed a risk stratification for lymph node metastases using the number of previously known risk factors. For oncologic outcomes, the 5-year overall survival and recurrence-free survival were evaluated in both groups. RESULTS: Among the patients who underwent radical surgery, 32 (50.0%) had lymph node metastasis and 32 (50.0%) had non-lymph node metastasis. In the multivariable analysis, only the male sex was identified as a risk factor for lymph node metastasis (odds ratio, 3.695; 95% confidence interval, 1.128-12.105; P=0.031). When there were 2 or more known risk factors, the lymph node metastasis rate was significantly higher than when there were one or no risk factors (odds ratio, 3.667; 95% confidence interval, 1.023-13.143; P=0.046). There was also no statistical difference between the 2 groups in 5-year overall survival (P=0.431) and 5-year recurrence-free survival (P=0.144). CONCLUSION: We found that the rate of lymph node metastasis increased significantly when the number of known risk factors is 2 or more.

Short-term outcome of adrenal radiofrequency ablation of adrenal cysts: a single-center experience.

Percutaneous thermal ablation is a minimally invasive treatment for liver, kidney, lung, bone, and thyroid tumors. This treatment also has been used to treat adrenal tumors in patients, but there is no evidence for the efficacy of thermal ablation of adrenal cysts. The present study was performed to analyze the experience of a single center with percutaneous radiofrequency ablation (RFA) of adrenal cysts and to evaluate its efficacy. The present study enrolled all patients who underwent percutaneous RFA for unilateral adrenal cysts from 2019 to 2021. All patients underwent USG-guided percutaneous aspiration of cystic fluid, followed by RFA. A total nine patients with adrenal cysts were included in this study. All of them underwent technically successful percutaneous RFA, with no immediate complication. Follow-up CT 3 months after RFA showed that six of the nine adrenal cysts showed good responses, with reductions in cyst volume ranging from 86.4 to 97.9%. One patient had poor response in the cyst size (volume reduction rate 11.2%). She underwent secondary RFA with resulting that the cyst volume reduced by 91.1%. After a median follow-up period of 17.2 months, eight patients showed no evidence of regrowth. The patient, who showed evidence of regrowth, declined any other treatment and has been under regular surveillance. None of the nine patients developed adrenal insufficiency during the follow-up period. In conclusion, percutaneous RFA is a safe and effective minimally invasive treatment for adrenal cysts, suggesting that percutaneous RFA may be a good alternative option in selected patients.

The risk of surgical site infection of oral sulfate tablet versus sodium picosulfate for bowel preparation in colorectal cancer surgery: a randomized clinical trial.

Purpose: Oral sulfate tablets are abundantly used for bowel preparation before colonoscopy. However, their efficiency and safety for bowel preparation before colorectal surgery remain ill-defined. Herein, we aimed to compare the surgical site infection rates and efficiency between oral sulfate tablets and sodium picosulfate. Methods: We designed a prospective, randomized, phase 2 clinical trial. Patients with colorectal cancer aged 19-75 years who underwent elective bowel resection and anastomosis by minimally invasive surgery were administered oral sulfate tablets or sodium picosulfate. Eighty-three cases were analyzed from October 2020 to December 2021. Surgical site infection within 30 days after surgery was considered the primary endpoint. Postoperative morbidities, the degree of bowel cleansing, and tolerability were the secondary endpoints. Results: Surgical site infection was detected in 1 patient (2.5%) in the oral sulfate tablet group and 2 patients (4.7%) in the sodium picosulfate group, indicating no significant difference between the 2 groups. Postoperative morbidity and the degree of bowel cleansing bore no statistically significant differences. Furthermore, none of the investigated tolerability criteria, namely bloating, pain, nausea, vomiting, and discomfort, differed significantly between the 2 groups. The patients' willingness to reuse the drug was also not significantly different between the 2 groups. Conclusion: Although we could not establish the noninferiority of oral sulfate tablets to sodium picosulfate, we found no evidence suggesting that oral sulfate tablets are less safe or tolerable than sodium picosulfate in preoperative bowel preparation.

Efficacy and Safety of Endoscopic Clipping for Acute Anastomotic Bleeding After Colorectal Surgery.

PURPOSE: Anastomotic bleeding after colorectal surgery is a rare, mostly self-limiting, postoperative complication that could lead to a life-threatening condition. Therefore, prompt management is required. This study aimed to evaluate the efficacy and safety of endoscopic clipping for acute anastomotic bleeding after colorectal surgery. METHODS: We retrospectively reviewed the data of patients pathologically diagnosed with colorectal cancer at National Cancer Center, Korea from January 2018 to November 2020, which presented with anastomotic bleeding within the first postoperative week and were endoscopically managed with clips. RESULTS: Nine patients had anastomotic bleeding, underwent endoscopic management, and, therefore, were included in this study. All patients underwent laparoscopic (low/ultralow) anterior resection with mechanical double-stapled anastomosis. Anastomotic bleeding was successfully managed through a colonoscopy with clips on the first trial in all patients. Hypovolemic shock occurred in one patient, following anastomotic breakdown. CONCLUSION: Endoscopic clipping seems to be an effective and safe treatment for anastomotic bleeding with minimal physiologic stress, easy accessibility, and scarce postoperative complications. However, a surgical backup should always be considered for massive bleeding.

Risk Factors for Lymph Node Metastasis and Oncologic Outcomes in Small Rectal Neuroendocrine Tumors with Lymphovascular Invasion.

BACKGROUND/AIMS: Small rectal neuroendocrine tumors (NETs) are often managed with local resection (endoscopic or transanal excision) owing to their low risk of metastasis and recurrence. However, the clinical significance of lymphovascular invasion in resected specimens remains controversial. In this study, we aimed to analyze the frequency of and risk factors for lymph node metastasis proven by histopathologic examination after radical resection. METHODS: We retrospectively reviewed the records of 750 patients diagnosed with a rectal NET at four academic medical centers in South Korea between 2001 and 2019. The frequency of histopathologically proven lymph node metastasis and the associated risk factors were analyzed for small tumors (≤1.5 cm) with lymphovascular invasion. RESULTS: Among 750 patients, 75 had a small tumor (≤1.5 cm) with lymphovascular invasion, of whom 31 patients underwent endoscopic resection only and 44 patients underwent additional radical surgery. Among the 41 patients who underwent surgery and had available data, the rate of regional lymph node metastasis was 48.8% (20/41). In multivariate analysis, the Ki-67 index (odds ratio, 6.279; 95% confidence interval, 1.212 to 32.528; p=0.029) was an independent risk factor for lymph node metastasis. During the mean follow-up period of 37.7 months, only one case of recurrence was detected in the surgery group. The overall survival was not significantly different between radical resection and local resection (p=0.332). CONCLUSIONS: Rectal NETs with lymphovascular invasion showed a significantly high rate of regional lymph node metastasis despite their small size (≤1.5 cm).

The risk of colorectal neoplasm in ex- and never-smokers according to urinary cotinine level.

ABSTRACT: To investigate the relationship between urinary cotinine and colorectal neoplasm (CRN).The participants in the health screening cohort of the National Cancer Center who underwent screening colonoscopy between June 2007 and December 2009 were included. A total of 8121 subjects who underwent urinary cotinine measurement within 14 days from the index colonoscopy were included. Cotinine positivity was defined as having a urinary cotinine level ≥50 ng/mL. Follow-up colonoscopy data were collected by reviewing the patients' medical records.Patients were classified according to their urinary cotinine level and self-reported smoking status, and the number of patients with cotinine positivity was 1960 (24.1%). There was no significant difference in the cumulative CRN and advanced CRN (ACRN) risks according to the self-reported smoking status. However, cotinine positivity at the time of index colonoscopy was an independent risk factor for CRN (hazard ratio [HR]= 1.23, P = .006) in follow-up colonoscopy. Moreover, in never- and ex-smokers, cotinine positivity was an independent risk factor for CRN (HR = 1.95, P = .019; HR = 2.12, P = .003, respectively) and ACRN (HR = 8.89, P < .001; HR = 5.03, P = .003) during follow-up colonoscopy. The cumulative incidence of CRN and ACRN was higher in the cotinine-positive never- and ex-smokers than in the cotinine-negative never- and ex-smokers (P < .001 and P = .008, respectively).CRN or ACRN is more likely to occur at follow-up colonoscopy in the urinary cotinine-positive never- and ex-smokers than in the urinary cotinine-negative group. Therefore, urinary cotinine measurements may provide useful information on never- or ex-smokers undergoing screening colonoscopy.

Adherence to follow-up examination after positive fecal occult blood test results affects colorectal cancer mortality: A Korea population-based cohort study.

BACKGROUND: The impact of adherence to follow-up examination after a fecal occult blood test (FOBT) remains ill-defined. AIM: To evaluate the impact of adherence to the follow-up examination on clinical outcomes in individuals with positive FOBT results. METHODS: This was a retrospective cohort study involving Korean individuals aged 50 years or older who participated in the National Cancer Screening Program for CRC from 2009 to 2010. Individuals who underwent a confirmative examination within a year after positive FOBT results were included in compliant group, and those who did not were included in non-compliant group. The incidence and stage of CRC, and 5-year survival were compared between two groups. RESULTS: 5,914 were diagnosed with CRC in the compliant group and 2,973 in the non-compliant group. The proportion of advanced-stage CRC was significantly higher in the non-compliant group (localized CRC 44.6% vs. 36.7% and distant CRC 8.7% vs. 12.5%, p< 0.0001). The survival probability within 5 years was 71.0% in the non-compliant group and 85.9% in the compliant group (hazard ratio 1.70, 95% CI, 1.52-1.90, p< 0.001). CONCLUSION: Individuals who underwent follow-up examination 1 year or more after positive FOBT had a lower survival rate compared with that in those who underwent examination within 1 year.