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.

Purpose: This study aimed to develop a graded prognostic assessment (GPA) model integrating genomic characteristics for elderly patients with glioblastoma (eGBM), and to compare the efficacy of different radiotherapy schedules. Materials and Methods: This multi-institutional retrospective study included patients aged ≥ 65 years who underwent surgical resection followed by radiotherapy with or without temozolomide (TMZ) for newly diagnosed eGBM. Based on the significant factors identified in the multivariate analysis for overall survival (OS), the molecular GPA for eGBM (eGBM-molGPA) was established. Results: A total of 334 and 239 patients who underwent conventionally fractionated radiotherapy (CFRT) and hypofractionated radiotherapy (HFRT) were included, respectively, with 86% of patients receiving TMZ-based chemoradiation. With a median follow-up of 17.4 months (range, 3.3 to 149.9 months), the median OS was 18.7 months for CFRT+TMZ group, 15.1 months for HFRT+TMZ group, and 10.4 months for radiotherapy alone group (CFRT+TMZ vs. HFRT+TMZ: hazard ratio [HR], 1.52; p < 0.001 and CFRT+TMZ vs. radiotherapy alone: HR, 2.52; p < 0.001). In a combined analysis with the NOA-08 and Nordic trials, CFRT+TMZ group exhibited the highest survival rates among all treatment groups. The eGBM-molGPA, which integrated four clinical and three molecular parameters, stratified patients into low-, intermediate-, and high-risk groups. CFRT+TMZ significantly improved OS compared to HFRT+TMZ or radiotherapy alone in the low-risk (p=0.023) and intermediate-risk groups (p < 0.001). However, in the high-risk group, there was no significant difference in OS between treatment options (p=0.770). Conclusion CFRT+TMZ may be more effective than HFRT+TMZ or radiotherapy alone for selected eGBM patients. The novel eGBM-molGPA model can guide treatment selection for this patient population.

Purpose: This study aimed to develop a graded prognostic assessment (GPA) model integrating genomic characteristics for elderly patients with glioblastoma (eGBM), and to compare the efficacy of different radiotherapy schedules. Materials and Methods: This multi-institutional retrospective study included patients aged ≥ 65 years who underwent surgical resection followed by radiotherapy with or without temozolomide (TMZ) for newly diagnosed eGBM. Based on the significant factors identified in the multivariate analysis for overall survival (OS), the molecular GPA for eGBM (eGBM-molGPA) was established. Results: A total of 334 and 239 patients who underwent conventionally fractionated radiotherapy (CFRT) and hypofractionated radiotherapy (HFRT) were included, respectively, with 86% of patients receiving TMZ-based chemoradiation. With a median follow-up of 17.4 months (range, 3.3 to 149.9 months), the median OS was 18.7 months for CFRT+TMZ group, 15.1 months for HFRT+TMZ group, and 10.4 months for radiotherapy alone group (CFRT+TMZ vs. HFRT+TMZ: hazard ratio [HR], 1.52; p < 0.001 and CFRT+TMZ vs. radiotherapy alone: HR, 2.52; p < 0.001). In a combined analysis with the NOA-08 and Nordic trials, CFRT+TMZ group exhibited the highest survival rates among all treatment groups. The eGBM-molGPA, which integrated four clinical and three molecular parameters, stratified patients into low-, intermediate-, and high-risk groups. CFRT+TMZ significantly improved OS compared to HFRT+TMZ or radiotherapy alone in the low-risk (p=0.023) and intermediate-risk groups (p < 0.001). However, in the high-risk group, there was no significant difference in OS between treatment options (p=0.770). Conclusion CFRT+TMZ may be more effective than HFRT+TMZ or radiotherapy alone for selected eGBM patients. The novel eGBM-molGPA model can guide treatment selection for this patient population.

Purpose: This study aimed to develop a graded prognostic assessment (GPA) model integrating genomic characteristics for elderly patients with glioblastoma (eGBM), and to compare the efficacy of different radiotherapy schedules. Materials and Methods: This multi-institutional retrospective study included patients aged ≥ 65 years who underwent surgical resection followed by radiotherapy with or without temozolomide (TMZ) for newly diagnosed eGBM. Based on the significant factors identified in the multivariate analysis for overall survival (OS), the molecular GPA for eGBM (eGBM-molGPA) was established. Results: A total of 334 and 239 patients who underwent conventionally fractionated radiotherapy (CFRT) and hypofractionated radiotherapy (HFRT) were included, respectively, with 86% of patients receiving TMZ-based chemoradiation. With a median follow-up of 17.4 months (range, 3.3 to 149.9 months), the median OS was 18.7 months for CFRT+TMZ group, 15.1 months for HFRT+TMZ group, and 10.4 months for radiotherapy alone group (CFRT+TMZ vs. HFRT+TMZ: hazard ratio [HR], 1.52; p < 0.001 and CFRT+TMZ vs. radiotherapy alone: HR, 2.52; p < 0.001). In a combined analysis with the NOA-08 and Nordic trials, CFRT+TMZ group exhibited the highest survival rates among all treatment groups. The eGBM-molGPA, which integrated four clinical and three molecular parameters, stratified patients into low-, intermediate-, and high-risk groups. CFRT+TMZ significantly improved OS compared to HFRT+TMZ or radiotherapy alone in the low-risk (p=0.023) and intermediate-risk groups (p < 0.001). However, in the high-risk group, there was no significant difference in OS between treatment options (p=0.770). Conclusion CFRT+TMZ may be more effective than HFRT+TMZ or radiotherapy alone for selected eGBM patients. The novel eGBM-molGPA model can guide treatment selection for this patient population.

Purpose: To evaluate patient‐reported experiences of 3 primary treatments for localized or locally advanced prostate cancer—radical prostatectomy (RP), radiation therapy (RT), and active surveillance (AS)—based on cross‐sectional data from a prospective registry, and to explore how these findings can inform a structured shared decision making (SDM) framework. Materials and Methods: Men with clinical stage cT3aN0M0 or lower were enrolled. Those who underwent RP or RT were surveyed 6–24 months posttreatment; men on AS had 6–60 months of follow‐up. All participants completed the EORTC QLQ‐PR25 (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Prostate Cancer Module), capturing urinary, bowel, hormonal, and sexual function. The Kruskal‐Wallis test evaluated group differences, with significance set at p<0.05. Results: Among 542 patients, 435 underwent RP, 73 received RT (43% with androgen deprivation therapy), and 34 were on AS. RP patients reported higher rates of urinary incontinence and sexual dysfunction, whereas RT patients had more severe urinary irritative and bowel symptoms. AS generally preserved baseline sexual function but still involved some urinary complaints and anxiety regarding disease progression. These findings underscore the distinct trade‐offs among the 3 management strategies, emphasizing the importance of individualized SDM that accounts for functional priorities and patient values. Conclusion Each treatment modality poses unique impacts on quality of life. Incorporating these patient‐reported data into SDM discussions can improve alignment between clinical recommendations and patient preferences, potentially reducing decisional regret and enhancing long‐term outcomes.

Purpose: To evaluate the placement accuracy and learning curve of SpaceOAR hydrogel and gold fiducial marker insertion in Korean prostate cancer patients undergoing carbon ion radiotherapy (CIRT), performed by a single urologist without prior experience. Materials and Methods: In this retrospective observational study, 104 prostate cancer patients scheduled for CIRT at Severance Hospital between November 2022 and October 2023 underwent simultaneous SpaceOAR hydrogel insertion and 2 gold fiducial markers placement under transrectal ultrasound guidance. Postprocedural magnetic resonance imaging scans assessed spacer placement accuracy using the SpaceOAR Symmetry Score. Complications were documented and graded according to the Common Terminology Criteria for Adverse Events v5.0. Statistical analyses evaluated the impact of age, prostate volume, and operative time on complication rates and procedural efficiency. Results: Spacer placement was successful in all cases, achieving SpaceOAR Symmetry Score of 2.0 or less in 85.58% of the cases. The average operative time for the first 50 cases was 12.70±3.40 minutes, while for the latter 54 cases was 12.50±5.35 minutes, which suggests no significant learnig curve exist. Complications occurred in 25 of patients (24.0%), with constipation (9.6%), weak urinary stream (4.8%) and perianal pain (3.8%) being the most common. Acute urinary retention (grade 2) occurred in 3 patients and was not related to patient age or the presence of benign prostatic hyperplasia. Other complications were rare and mostly mild (grade 1). Conclusions SpaceOAR hydrogel insertion with gold fiducial marker placement is a reliable and efficient procedure that can be effectively performed by urologists without prior experience in patients undergoing CIRT. The procedure demonstrates a significant learning curve, with operative efficiency improving over time, supporting its feasibility and potential for widespread adoption.

Purpose: This report offers a detailed examination of the inception and current state of the Heavy-ion Therapy Center (HITC) at the Yonsei Cancer Center (YCC), setting it apart as the world’s first center equipped with a fixed beam and two superconducting gantries for carbon-ion radiation therapy (CIRT). Materials and Methods: Preparations for CIRT at YCC began in 2013; accordingly, this center has completed a decade of meticulous planning and culminating since the operational commencement of the HITC in April 2023. Results: This report elaborates on the clinical preparation for adopting CIRT in Korea. It includes an extensive description of HITC’s facility layout at YCC, which comprises the accelerator and treatment rooms. Furthermore, this report delineates the clinical workflow, criteria for CIRT application, and the rigorous quality assurance processes implemented at YCC. It highlights YCC’s sophisticated radiation therapy infrastructure, collaborative initiatives, and the efficacious treatment of >200 prostate cancer cases utilizing CIRT. Conclusion This manuscript concludes by discussing the prospective influence of CIRT on the medical domain within Korea, spotlighting YCC’s pioneering contribution and forecasting the widespread integration of this groundbreaking technology.

Carbon-ion radiotherapy (CIRT) offers superior dose distributions and greater biological effectiveness than conventional photon-based radiotherapy (RT). Due to its higher linear energy transfer and relative biological effectiveness, CIRT is particularly effective against radioresistant tumors and those located near critical organs. Since the first dedicated CIRT facility was established in Japan in 1994, CIRT has demonstrated remarkable efficacy against various malignancies, including head and neck tumors, skull base and upper cervical spine tumors, non-small-cell lung cancer, hepatocellular carcinoma, pancreatic cancer, prostate cancer, and bone and soft tissue sarcomas. This narrative review provides a comprehensive overview of the current status of CIRT, highlighting its clinical indications and future directions. According to clinical studies, CIRT achieves high local control rates with manageable toxicity across multiple cancer types. For instance, in head and neck tumors (e.g., adenoid cystic carcinoma and mucosal melanoma), CIRT has achieved local control rates exceeding 80%. In early-stage non-small-cell lung cancer, CIRT has resulted in local control rates over 90% with minimal toxicity. Moreover, CIRT has shown promise in treating challenging cases of hepatocellular carcinoma and pancreatic cancer, where conventional therapies are limited. Nonetheless, the global adoption of CIRT remains limited due to high costs and complexity. Future directions include conducting randomized controlled trials to establish high-level evidence, integrating new technologies such as ultrahigh-dose-rate (FLASH) therapy, and expanding CIRT facilities globally with strategic planning and cost-effectiveness analyses. If these challenges are addressed, CIRT is poised to play a transformative role in cancer treatment, improving survival rates and the quality of life.

Purpose: This report offers a detailed examination of the inception and current state of the Heavy-ion Therapy Center (HITC) at the Yonsei Cancer Center (YCC), setting it apart as the world’s first center equipped with a fixed beam and two superconducting gantries for carbon-ion radiation therapy (CIRT). Materials and Methods: Preparations for CIRT at YCC began in 2013; accordingly, this center has completed a decade of meticulous planning and culminating since the operational commencement of the HITC in April 2023. Results: This report elaborates on the clinical preparation for adopting CIRT in Korea. It includes an extensive description of HITC’s facility layout at YCC, which comprises the accelerator and treatment rooms. Furthermore, this report delineates the clinical workflow, criteria for CIRT application, and the rigorous quality assurance processes implemented at YCC. It highlights YCC’s sophisticated radiation therapy infrastructure, collaborative initiatives, and the efficacious treatment of >200 prostate cancer cases utilizing CIRT. Conclusion This manuscript concludes by discussing the prospective influence of CIRT on the medical domain within Korea, spotlighting YCC’s pioneering contribution and forecasting the widespread integration of this groundbreaking technology.

Carbon-ion radiotherapy (CIRT) offers superior dose distributions and greater biological effectiveness than conventional photon-based radiotherapy (RT). Due to its higher linear energy transfer and relative biological effectiveness, CIRT is particularly effective against radioresistant tumors and those located near critical organs. Since the first dedicated CIRT facility was established in Japan in 1994, CIRT has demonstrated remarkable efficacy against various malignancies, including head and neck tumors, skull base and upper cervical spine tumors, non-small-cell lung cancer, hepatocellular carcinoma, pancreatic cancer, prostate cancer, and bone and soft tissue sarcomas. This narrative review provides a comprehensive overview of the current status of CIRT, highlighting its clinical indications and future directions. According to clinical studies, CIRT achieves high local control rates with manageable toxicity across multiple cancer types. For instance, in head and neck tumors (e.g., adenoid cystic carcinoma and mucosal melanoma), CIRT has achieved local control rates exceeding 80%. In early-stage non-small-cell lung cancer, CIRT has resulted in local control rates over 90% with minimal toxicity. Moreover, CIRT has shown promise in treating challenging cases of hepatocellular carcinoma and pancreatic cancer, where conventional therapies are limited. Nonetheless, the global adoption of CIRT remains limited due to high costs and complexity. Future directions include conducting randomized controlled trials to establish high-level evidence, integrating new technologies such as ultrahigh-dose-rate (FLASH) therapy, and expanding CIRT facilities globally with strategic planning and cost-effectiveness analyses. If these challenges are addressed, CIRT is poised to play a transformative role in cancer treatment, improving survival rates and the quality of life.