Rectal cancer, which accounts for approximately 40% of colorectal cancers, remains a major clinical concern. Recent advances in diagnostic imaging, surgical techniques, radiotherapy, and systemic treatment have steadily improved rectal cancer outcomes. Considering this, the Korean Rectal Cancer Multidisciplinary (KRCM) Committee has aimed to provide clinicians and policymakers with up-to-date, evidence-based clinical practice guidelines to support optimal decision-making, reflecting current evidence, the Korean healthcare context, and patient values and preferences. The Clinical Practice Guidelines for Rectal Cancer version 2.0 were developed through multidisciplinary collaboration with related academic societies, building upon and updating the KRCM Clinical Practice Guidelines version 1.0 (titled “Multidisciplinary guidelines for the management of rectal cancer”). These consensus guidelines of the KRCM were established based on a comprehensive literature review, evidence synthesis, with recommendation development guided by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology, and consideration of applicability in real-world clinical practice under the national health insurance system. Each recommendation has been presented with its strength and level of evidence.

Purpose: Radiotherapy (RT) remains a cornerstone of curative treatment for localized and locally advanced prostate cancer. However, dose escalation to improve tumor control is often constrained by the proximity of the rectum, which increases the risk of gastrointestinal (GI) and genitourinary toxicities. Biodegradable rectal spacers inserted between the prostate and rectum have emerged as an effective approach to reduce rectal radiation exposure. This guideline provides evidence-based recommendations on indications, contraindications, procedural standards, and clinical management for biodegradable rectal spacer insertion during prostate cancer RT. Materials and Methods: This guideline was developed by a multidisciplinary expert panel through a systematic review of the literature, analysis of international guidelines (National Comprehensive Cancer Network, European Association of Urology, American Society for Radiation Oncology), and expert consensus among radiation oncologists, radiologists, and urologists with clinical experience in spacer insertion. The strength of each recommendation and the level of evidence were classified according to the modified GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system. Results: Spacer insertion is conditionally recommended (Grade C, Level I) for patients receiving definitive external-beam RT without rectal invasion. It reduces the high-dose rectal irradiation volume (V70–75) by >50%, decreases acute GI toxicity, and helps maintain bowel-related quality of life. However, the benefit for late severe toxicity (grade 2 or higher) remains debated in recent meta-analyses. Contraindications include rectal invasion, anatomical inaccessibility, infection, and material hypersensitivity. Procedures should be performed under local anesthesia in a sterile environment by trained physicians. Short-course antibiotics and simulator-based training, including completion of multiple supervised cases, are advised. Conclusion Biodegradable rectal spacer insertion is clinically validated and effective in reducing acute rectal toxicity. Although pivotal trials demonstrated a favorable procedural safety profile, real-world postmarket data include reports of rare but severe procedural complications. This guideline provides standardized recommendations tailored to Korean clinical practice while remaining consistent with international standards, emphasizing the importance of operator training and careful patient selection.

Background: With the aging population and advancements in medical care worldwide, the number of older patients with end-stage kidney disease continues to rise. This study aimed to identify factors associated with osteoporosis and osteopenia in older patients undergoing incident hemodialysis and assess their impact on mortality. Methods: We analyzed a large multicenter retrospective cohort of patients aged ≥70 years undergoing incident hemodialysis to identify factors associated with osteoporosis using logistic regression analysis and to assess the association of death with osteoporosis and osteopenia using Cox multivariable analysis. Results: Among 710 patients, 39.0% and 19.6% had osteoporosis and osteopenia, respectively. Osteoporosis was significantly associated with female sex, a history of fractures, and the absence of phosphate binder use. During a median follow-up of 36.8 months, 348 participants (58.8%) died. Mortality rates were the highest in the osteoporosis group (79.8%), followed by the osteopenia (77.2%) and normal bone mineral density (BMD) groups (35.2%). Cox regression analysis revealed that even after adjusting for covariates, the osteoporosis group was significantly associated with a higher mortality risk than the normal BMD group. Osteoporosis at the start of hemodialysis was significantly associated with higher mortality. Conclusion We should consider the importance of bone health in patients undergoing incident hemodialysis and pay attention to the use of phosphate binders and fracture prevention.

Background: Obesity is a well-known risk factor for chronic kidney disease and its progression. However, the impact of obesity on the renal function of the elderly population is uncertain. We investigated the association between obesity and renal outcomes in the elderly. Methods: We analyzed 130,504 participants from the Korean National Health Insurance Service-Senior cohort. Obesity was classified according to body mass index (BMI), sex-specific waist circumference (WC), and the presence of metabolic syndrome. The primary outcome was renal function decline, defined as a decline in the estimated glomerular filtration rate (eGFR) of at least 50% from baseline or new-onset end-stage renal disease. Results: During a follow-up period of 559,531.1 person-years (median, 4.3 years), 2,486 participants (19.0%; incidence rate of 4.44 per 1,000 person-years) showed renal function decline. A multivariate Cox proportional hazards model revealed that BMI/WC was not associated with renal function decline. However, the group with metabolic syndrome had a significantly increased risk of renal function decline compared to the group without metabolic syndrome (adjusted hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.13–1.36). Compared with the non-metabolic syndrome group, the adjusted HRs (95% CI) for participants with one through five components were 0.96 (0.84–1.11), 1.10 (0.96–1.27), 1.24 (1.06–1.45), 1.37 (1.12–1.66), and 1.99 (1.42–2.79), respectively (p for trend < 0.001). Conclusion In elderly Korean adults, metabolic syndrome and the number of its components were associated with a higher risk of renal function decline, but BMI or WC was not significant.

Objective: This study aimed to evaluate reproductive outcomes according to the timing of testicular sperm retrieval. Methods: The study included 282 infertile couples divided into three groups: group A (freeze-thawed testicular sperm extraction [TESE] sperm, n=233), group B (fresh TESE sperm collected 1 day before ovum pickup, n=22), and group C (fresh TESE sperm collected on the same day as ovum pickup, n=27). The indications for TESE were surgically uncorrectable azoospermia or ejaculation failure, often accompanied by medical comorbidities such as diabetes mellitus and spinal cord injury. The outcome parameters assessed were fertilization rates, embryo quality, and clinical pregnancy rates. Results: The mean paternal age was 36.8±5.7 years, and the mean maternal age was 32.6±3.5 years. The mean duration of infertility was 2.9±1.8 years. The fertilization rates were 70.7%, 78.9%, and 73.0% for groups A, B, and C, respectively (p=0.047). The percentages of good-quality embryos were 68.2%, 65.3%, and 48.4%, respectively (p=0.007); specifically, the percentage of good-quality embryos was significantly lower in group C compared with the other two groups. Clinical pregnancy rates per transfer were similar at 51.1%, 50.0%, and 48.1% (p=0.958), with no differences observed in miscarriage rates. Conclusion Testicular sperm retrieval can be safely performed 1 day before ovum pickup, resulting in favorable fertility outcomes.

Background: Excess intake of added sugars contributes to obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), and premature mortality. Sugar-sweetened beverages (SSBs), the main source of added sugars, are consistently linked to adverse outcomes. Artificially sweetened beverages (ASBs) have been suggested as short-term substitutes, but evidence regarding benefits and harms remains inconclusive, and guidance is lacking. Methods: This consensus statement draws on a structured evidence review combining two approaches: an updated meta-analysis of randomized controlled trials (RCTs) assessing short- to intermediate-term effects of replacing SSBs with ASBs on weight and metabolic outcomes; and an umbrella review of systematic reviews of cohort studies evaluating long-term associations of SSBs and ASBs with major outcomes, including mortality, CVD, and T2DM. Results: In 14 RCTs (3–76 weeks), replacing SSBs with ASBs produced modest reductions in body weight (–0.73 kg) and body fat (–0.72%), with inconsistent effects on glycemic and cardiometabolic markers. Evidence from 20 systematic reviews of cohorts (up to 34 years follow-up) showed that higher intake of both SSBs and ASBs was associated with increased risks of T2DM, CVD, and mortality, with relative risks for ASBs similar to those for SSBs. Conclusion ASBs may serve as a short-term substitution for individuals with high SSB intake, particularly those at elevated metabolic risk. However, regular or long-term use is not recommended due to uncertain safety and potential reinforcement of sweet preference. Public health strategies should emphasize reducing both SSBs and ASBs, prioritizing water and unsweetened beverages as the ultimate goal.

Purpose: This study aimed to compare the acute effects of isometric handgrip (IHG) and wall squat (IWS) exercise on 24-hour ambulatory blood pressure (BP) and related indices in young men with prehypertension. Methods: Ten young men with prehypertension (aged 25.0±2.3 years) completed three randomized crossover conditions: IHG, IWS, and control. Twenty-four-hour ambulatory BP monitoring was used to assess 24-hour, daytime, and nighttime mean BP, BP variability (BPV; average real variability and standard deviation), morning BP, and nocturnal dipping pattern. Office BP was measured at baseline, 30 minutes, and 90 minutes after each condition. Results: Twenty-four hour, daytime, and nighttime systolic and diastolic BP did not differ significantly among conditions. BPV indices also showed no significant between-condition differences across 24-hour, daytime, or nighttime periods. Nocturnal systolic BP dipping averaged 5%–8% and did not differ among conditions, indicating a nondipper pattern in all trials. Morning systolic BP, sleep-trough surge, and prewaking surge were similar across conditions. Office BP showed no significant condition or interaction effects; however, both IHG and IWS tended to lower BP at 90 minutes compared with control session. Conclusion A single bout of IHG or IWS did not elicit significant changes in 24-hour ambulatory BP, BPV, morning BP, or dipping pattern in young men with prehypertension. Nonetheless, the small acute reductions in office and morning BP suggest that isometric exercise may have potential as a time-efficient adjunctive strategy for early BP management. Larger and longer-term studies are needed to confirm these findings.

Purpose: Inspiratory muscle strength training is a time-efficient strategy for lowering blood pressure, but the acute vascular effects and its hemodynamic characteristics remain unclear. This study aimed to determine the acute effects of inspiratory muscle strength exercise (IMSE) on vascular function and shear patterns. Methods: In a single-arm acute trial, 12 young adults (aged 26±2 years) performed a single bout of IMSE (about 8 minutes) consisting of 30 breaths (6 breaths×5 sets) at 60% of maximal inspiratory pressure. Vascular function indices were assessed as endothelial function and arterial stiffness. Measurements of endothelial function via flow-mediated dilation (FMD) in the brachial artery and arterial stiffness by carotid-femoral pulse wave velocity (cfPWV) were taken at baseline, 10 minutes, and 40 minutes post-IMSE. Shear rate (SR) responses were continuously obtained throughout the IMSE session at the brachial artery and were analyzed as mean SR, anterograde SR, and retrograde SR. Results: Compared to baseline, cfPWV significantly decreased (7.95±0.9 m/sec to 7.49±0.9 m/sec, p=0.033) and FMD increased (4.76%±1.0% to 6.26%±1.1%, p＜ 0.001) at post-10 min. Both cfPWV and FMD returned to baseline levels at post-40 min. During IMSE, mean SR and anterograde SR significantly increased (both, p＜ 0.05), whereas retrograde SR decreased (p=0.032) during inter-set rest periods. In addition, rhythmic fluctuations in SR were observed corresponding to inspiration and expiration phases. Conclusion These findings suggest that an acute bout of IMSE is associated with improved endothelial function and arterial stiffness. IMSE may elicit distinct hemodynamic responses during exercise, which may be linked to improvements in vascular function.

Background: s/Aims: Hepatocellular carcinoma (HCC) is the sixth most common cancer and second leading cause of cancer-related deaths in South Korea. This study evaluated the characteristics of Korean patients newly diagnosed with HCC in 2016-2018. Methods: Data from the Korean Primary Liver Cancer Registry (KPLCR), a representative database of patients newly diagnosed with HCC in South Korea, were analyzed. This study investigated 4,462 patients with HCC registered in the KPLCR in 2016-2018. Results: The median patient age was 63 years (interquartile range, 55-72). 79.7% of patients were male. Hepatitis B infection was the most common underlying liver disease (54.5%). The Barcelona Clinic Liver Cancer (BCLC) staging system classified patients as follows: stage 0 (14.9%), A (28.8%), B (7.5%), C (39.0%), and D (9.8%). The median overall survival was 3.72 years (95% confidence interval, 3.47-4.14), with 1-, 3-, and 5-year overall survival rates of 71.3%, 54.1%, and 44.3%, respectively. In 2016-2018, there was a significant shift toward BCLC stage 0-A and Child-Turcotte-Pugh liver function class A (P<0.05), although survival rates did not differ by diagnosis year. In the treatment group (n=4,389), the most common initial treatments were transarterial therapy (31.7%), surgical resection (24.9%), best supportive care (18.9%), and local ablation therapy (10.5%). Conclusions Between 2016 and 2018, HCC tended to be diagnosed at earlier stages, with better liver function in later years. However, since approximately half of the patients remained diagnosed at an advanced stage, more rigorous and optimized HCC screening strategies should be implemented.