Prognostic Significance of Bulky Nodal Disease in Anal Cancer Management: A Multi Institutional Study.

Purpose: This study aimed to assess the prognostic significance of bulky nodal involvement in patients with anal squamous cell carcinoma treated with definitive chemoradiotherapy. Materials and Methods: We retrospectively analyzed medical records of patients diagnosed with anal squamous cell carcinoma who underwent definitive chemoradiotherapy at three medical centers between 2004 and 2021. Exclusion criteria included distant metastasis at diagnosis, 2D radiotherapy, and salvage treatment for local relapse. Bulky N+ was defined as nodes with a long diameter of 2 cm or greater. Results: A total of 104 patients were included, comprising 51 with N0, 46 with non-bulky N+, and 7 with bulky N+. The median follow-up duration was 54.0 months (range, 6.4-162.2 months). Estimated 5-year progression-free survival (PFS), loco-regional recurrence-free survival (LRRFS), and overall survival (OS) rates for patients with bulky N+ were 42.9%, 42.9%, and 47.6%, respectively. Bulky N+ was significantly associated with inferior PFS, LRRFS and OS compared to patients without or with non-bulky N+, even after multivariate analysis. We proposed a new staging system incorporating bulky N+ as N2 stage, with estimated 5-year LRRFS, PFS, and OS rates of 81.1%, 80.6%, and 86.2% for stage I, 67.7%, 60.9%, and 93.3% for stage II, and 42.9%, 42.9%, and 47.6% for stage III disease, enhancing the predictability of prognosis. Conclusion: Patients with bulky nodal disease treated with standard chemoradiotherapy experienced poor survival outcomes, indicating the potential necessity for further treatment intensification.

Evidence-based clinical recommendations for hypofractionated radiotherapy: exploring efficacy and safety - Part 1. Brain and head and neck.

Advances in radiotherapy (RT) techniques, including intensity-modulated RT and image-guided RT, have allowed hypofractionation, increasing the fraction size over the conventional dose of 1.8-2.0 Gy. Hypofractionation offers advantages such as shorter treatment times, improved compliance, and under specific conditions, particularly in tumors with a low α/ß ratio, higher efficacy. It was initially explored for use in RT for prostate cancer and adjuvant RT for breast cancer, and its application has been extended to various other malignancies. Hypofractionated RT (HFRT) may also be effective in patients who are unable to undergo conventional treatment owing to poor performance status, comorbidities, or old age. The treatment of brain tumors with HFRT is relatively common because brain stereotactic radiosurgery has been performed for over two decades. However, re-irradiation of recurrent lesions and treatment of elderly or frail patients are areas under investigation. HFRT for head and neck cancer has not been widely used because of concerns regarding late toxicity. Thus, we aimed to provide a comprehensive summary of the current evidence for HFRT for brain tumors and head and neck cancer and to offer practical recommendations to clinicians faced with the challenge of choosing new treatment options.

Long-term toxicities after allogeneic hematopoietic stem cell transplantation with or without total body irradiation: a population-based study in Korea.

PURPOSE: To compare long-term toxicity incidences, including secondary cancer (SC) with or without total body irradiation (TBI), in Asian patients receiving allogeneic hematopoietic stem cell transplantation (HSCT) using a nationwide database. MATERIALS AND METHODS: We identified 4,554 patients receiving HSCT for leukemic disease from 2009 to 2016 using the healthcare bigdata system of Korea. Incidence rate ratios (IRRs) for SC, cataracts, hypothyroidism, chronic kidney disease (CKD), myocardial infarction, or strokes were compared, and standardized incidence ratios (SIR) of SC was also estimated. RESULTS: TBI was conducted on 1,409 patients (30.9%). No overall survival differences based on TBI were observed. With a median follow-up duration of 58.2 months, 143 patients were diagnosed with subsequent SC (3.4%). Incidence rates per 1,000 person-year were 6.56 (95% confidence interval [CI], 4.8-8.8) and 7.23 (95% CI, 5.9-8.8) in the TBI and no-TBI groups, respectively (p = 0.594). Also, the SIR (95% CI) was not significantly increased by TBI (1.32 [0.86-1.94] vs. 1.39 [1.08-1.77] in the no-TBI group). In the young age group (0-19 years), SIRs were increased in both groups regardless of TBI (8.60 vs. 11.96). The IRRs of cataracts (1.60; 95% CI, 1.3-2.0), CKD (1.85; 95% CI, 1.3-2.6), and hypothyroidism (1.50; 95% CI, 1.1-2.1) were significantly increased after TBI. However, there were no significant differences in the occurrence of myocardial infarction and stroke according to TBI. CONCLUSION: Our results suggest that modern TBI may not additionally increase the risk of SC after allogeneic HSCT, although increased risks of other diseases were noted. Physicians should carefully consider individualized risks and benefits of TBI, with a particular focus by age group.

Risk of clinically significant cardiovascular disease associated with postoperative radiotherapy in non-small cell lung cancer patients receiving surgical resection followed by adjuvant chemotherapy: A Korean nationwide cohort study.

BACKGROUND: There are no large-scale datasets that analyze the relationship between postoperative radiotherapy (PORT) and various cardiovascular diseases (CVDs) in patients with locally advanced non-small cell lung cancer (NSCLC). Therefore, we aimed to investigate the incidences of CVDs with PORT using a national population-based database. METHODS: Patients diagnosed with NSCLC who underwent curative surgery followed by adjuvant chemotherapy were included from 2007 to 2017. Patients with a prior diagnosis of heart failure (HF), atrial fibrillation (AFib), or heart surgery were excluded. A total of 11,141 patients were included in the final analysis. PORT was used in 1334 patients. Most patients received lobectomy with mediastinal lymph node dissection. RESULTS: Major adverse cardiac events mostly occurred within 3-4 years from the diagnosis. After the median follow-up duration of 70.6 months, HF was the most diagnosed disease (5.3 %), followed by AFib (4.5 %), stroke (4.1 %), and pulmonary embolism (3.5 %). All the incidences of clinically significant CVDs did not differ by PORT. This result remained unchanged after the propensity score matching comparison. Age ≥ 65, underlying hypertension, and history of ischemic heart disease were the most related factors to the occurrence of HF and AFib. No significant difference in CVD-free survivals according to PORT status was observed. When stratified by proposed scoring, there were no subgroups showed increased incidence by PORT. CONCLUSIONS: These results suggest that PORT had no significant impact on various CVD occurrences in NSCLC patients without underlying heart disease.

Intrathoracic Progression Is Still the Most Dominant Failure Pattern after First-Line Chemo-immunotherapy in Extensive-Stage Small-Cell Lung Cancer: Implications for Thoracic Radiotherapy.

PURPOSE: This study aimed to compare the failure patterns before and after the introduction of immunotherapy and to determine the role of thoracic radiotherapy (TRT) in extensive-stage small-cell lung cancer (ES-SCLC) treatment. MATERIALS AND METHODS: We retrospectively reviewed 294 patients with ES-SCLC, of which 62.2% underwent chemotherapy alone, 13.3% underwent chemotherapy followed by consolidative TRT (TRT group), and 24.5% underwent chemotherapy with immune checkpoint inhibitor (ICI group). We performed propensity-score matching (PSM) to compare each treatment group. RESULTS: The median follow-up duration was 10.4 months. At the first relapse, in the cohort showing objective response, the proportion of cases showing intrathoracic progression was significantly lower in the TRT group (37.8%) than in the chemotherapy-alone (77.2%, p < 0.001) and the ICI (60.3%, p=0.03) groups. Furthermore, in the subgroup analysis, TRT showed benefits related to intrathoracic progression-free survival (PFS) in comparison with ICI in patients with less than two involved extrathoracic sites (p=0.008) or without liver metastasis (p=0.02) or pleural metastasis (p=0.005) at diagnosis. After PSM, the TRT group showed significantly better intrathoracic PFS than both chemotherapy-alone and ICI groups (p < 0.001 and p=0.04, respectively), but showed no significant benefit in terms of PFS and overall survival in comparison with the ICI group (p=0.17 and p=0.31, respectively). CONCLUSION: In ES-SCLC, intrathoracic progression was the most dominant failure pattern after immunotherapy. In the era of chemoimmunotherapy, consolidative TRT can still be considered a useful treatment strategy for locoregional control.

Risk Factors for Distant Metastasis in Extrahepatic Bile Duct Cancer after Curative Resection (KROG 1814).

PURPOSE: Risk factors predicting distant metastasis (DM) in extrahepatic bile duct cancer (EHBDC) patients treated with curative resection were investigated. MATERIALS AND METHODS: Medical records of 1,418 EHBDC patients undergoing curative resection between Jan 2000 and Dec 2015 from 14 institutions were reviewed. After resection, 924 patients (67.6%) were surveilled without adjuvant therapy, 297 (21.7%) were treated with concurrent chemoradiotherapy (CCRT) and 148 (10.8%) with CCRT followed by chemotherapy. To exclude the treatment effect from innate confounders, patients not treated with adjuvant therapy were evaluated. RESULTS: After a median follow-up of 36.7 months (range, 2.7 to 213.2 months), the 5-year distant metastasis-free survival (DMFS) rate was 57.7%. On multivariate analysis, perihilar or diffuse tumor (hazard ratio [HR], 1.391; p=0.004), poorly differentiated histology (HR, 2.014; p < 0.001), presence of perineural invasion (HR, 1.768; p < 0.001), positive nodal metastasis (HR, 2.670; p < 0.001) and preoperative carbohydrate antigen (CA) 19-9 ≥ 37 U/mL (HR, 1.353; p < 0.001) were significantly associated with inferior DMFS. The DMFS rates significantly differed according to the number of these risk factors. For validation, patients who underwent adjuvant therapy were evaluated. In patients with ≥ 3 factors, additional chemotherapy after CCRT resulted in a superior DMFS compared with CCRT alone (5-year rate, 47.6% vs. 27.7%; p=0.001), but the benefit of additional chemotherapy was not observed in patients with 0-2 risk factors. CONCLUSION: Tumor location, histologic differentiation, perineural invasion, lymph node metastasis, and preoperative CA 19-9 level predicted DM risk in resected EHBDC. These risk factors might help identifying a subset of patients who could benefit from additional chemotherapy after resection.

Definitive radiotherapy in patients with clinical T1N0M0 esophageal squamous cell carcinoma: A multicenter retrospective study (KROG 21-10).

PURPOSE: To assess the failure pattern and analyze the treatment scheme of definitive radiation therapy (RT) for T1N0M0 esophageal squamous cell carcinoma (ESCC). METHODS: We performed a multi-institutional retrospective analysis in T1N0M0 ESCC patients who underwent definitive RT from 2010 to 2019. Patterns of failure were demonstrated as in-, and out-field locoregional, and distant metastasis. In the analysis, freedom-from locoregional recurrence (FFLRR) and their association with clinicopathologic factors were evaluated. Propensity score matching in cT1b patients was done. RESULTS: 168 patients were included with a median follow-up of 34.0 months, and 26 cT1a, 116 cT1b disease. The rates of 3-year all and locoregional recurrence for cT1a were 30.5% and 24.1% and those for cT1b were 27.1% and 25.9%, respectively. Among 116 cT1b patients, 69 patients received elective nodal irradiation (ENI) and 47 received involved field irradiation (IFI). After propensity score matching, the 3-year FFLRR rate was 84.5%. There was no difference between ENI and IFI in FFLRR (P = 0.831) and OS (P = 0.525). The 3-year FFLRR was 83.8% (95% Confidence interval (CI), 61.8-93.8%) in IFI group and 85.3% (95% CI, 65.1-94.3%) in ENI group. In multivariate analysis, concurrent chemotherapy use was marginally associated with FFLRR (Hazard ratio, 0.16; P = 0.064). CONCLUSION: cT1a patients who cannot receive endoscopic resection showed similar failure rates as cT1b patients, questioning the staging accuracy and raised the need for thorough treatment like chemoradiotherapy. In cT1b patients, IFI with 50 to 60 Gy and concurrent chemotherapy could be reasonable.

Exploring the past, present, and future of postoperative radiotherapy for N2 stage non-small cell lung cancer.

Despite conventionally applied postoperative radiotherapy (PORT) in pathological N2 (pN2) stage non-small cell lung cancer (NSCLC) considering high locoregional recurrence, its survival benefit has been a continuous topic of debate. Although several randomized clinical trials have been conducted, many of them have been withdrawn or analyzed without statistical significance due to slow accrual, making it difficult to determine the efficacy of PORT. Recently, the results of large-scale randomized clinical trials have been published, which showed some improvement in disease-free survival with PORT, but finally had no impact on overall survival. Based on these results, it was expected that the debate over PORT in pN2 patients with NSCLC would come to an end. However, since pN2 patients have different clinicopathologic features, it has become more important to carefully select the patient population who will benefit from PORT. In addition, given the development of systemic treatments such as molecular-targeted therapy and immunotherapy, it is crucial to evaluate whether there is any benefit to PORT in the midst of these recent changes. Therefore, determining the optimal treatment approach for NSCLC pN2 patients remains a complex issue that requires further research and evaluation.

Clinical outcomes of radical radiotherapy for pulmonary sarcomatoid carcinoma.

PURPOSE: Pulmonary sarcomatoid carcinoma (PSC) is recognized for its aggressiveness and poor prognosis. The role of radical radiotherapy in PSC remains uncertain due to its scarcity and limited data. In the absence of an effective systemic agent, this study aims to explore the possibility of cure and to investigate potential prognostic factors and treatment outcomes. MATERIALS AND METHODS: From January 2005 to December 2021, 149 PSC patients were identified. Among 62 patients who received radiotherapy for lung lesions, 25 who underwent palliative radiotherapy and 16 who underwent surgery were excluded. RESULTS: The median patient age was 71 years. The majority were male, and 17 patients (81.0%) were diagnosed at an advanced stage. After radical radiotherapy, distant metastasis (47.6%) was the most common site of failure, while the local recurrence rate was quite low (9.5%). Eventually, five patients (26.3%) demonstrated either a partial response or complete remission, including three complete remissions with durable responses. The median progression-free survival (PFS) and overall survival were 4.6 months and 7.9 months, respectively. Univariate and multivariate analyses revealed that a tumor size >5 cm was associated with a worse prognosis (p = 0.045), while a radiation dose >58 GyEQD2 was significantly associated with better PFS (p = 0.038). CONCLUSION: This study demonstrates clinical outcomes after radical radiotherapy in managing PSC, suggesting tumor size and radiation dose could be a predictor of a systemic response. Given the known bad prognosis but complete remission could be achieved in certain subgroups, future research should explore the potential strategies using radical radiotherapy for this challenging patient population.

Prognostic Implication of Focal Breast Edema on Preoperative Breast Magnetic Resonance Imaging in Breast Cancer Patients.

PURPOSE: In this study, we investigated the prognostic implications of focal breast edema on preoperative breast magnetic resonance imaging (MRI) in patients with breast cancer. METHODS: Data of 899 patients with breast cancer at a single institution were retrospectively analyzed. The patients were divided into an edema-positive group (EPG) and an edema-negative group (ENG) based on the presence of peritumoral, prepectoral, or subcutaneous edema. Two radiologists evaluated the presence or absence of focal edema and its subtypes on preoperative breast MRI. Clinicopathologic characteristics and survival outcomes were compared between the two groups and among the three subtypes using Pearson's χ² test, Kaplan-Meier estimator, and Cox proportional hazards model. RESULTS: There were 399 (44.4%) and 500 (55.6%) patients in the EPG and ENG, respectively. The EPG showed significantly higher rates of axillary lymph node metastasis (55.6% vs. 19.2%, p < 0.001) and lymphovascular invasion (LVI) (57.9% vs. 12.6%, p < 0.001) than the ENG. Patients in the EPG showed significantly worse overall survival (OS) rate (log-rank p < 0.001; hazard ratio [HR], 4.83; 95% confidence interval [CI], 2.56-9.11) and recurrence-free survival rate (log-rank p < 0.001; HR, 3.00; 95% CI, 1.94-4.63) than those in the ENG. After adjusting for other variables, focal breast edema remained a significant factor affecting the OS rate, regardless of the edema type. Specifically, the presence of subcutaneous edema emerged as the strongest predictor for OS with the highest HR (p < 0.001; HR, 9.10; 95% CI, 3.05-27.15). CONCLUSION: Focal breast edema on preoperative breast MRI implies a higher possibility of LVI and axillary lymph node metastasis, which can lead to a poor prognosis. A detailed description of focal breast edema, especially subcutaneous edema, on preoperative breast MRI may provide prognostic predictions. More intensive surveillance is required for patients with breast cancer and focal preoperative breast edema.

Evaluation of Efficacy and Safety Using Low Dose Radiation Therapy with Alzheimer's Disease: A Protocol for Multicenter Phase II Clinical Trial.

BACKGROUND: Alzheimer's disease (AD), the most common cause of dementia, is a neurodegenerative disease resulting from extracellular and intracellular deposits of amyloid-ß (Aß) and neurofibrillary tangles in the brain. Although many clinical studies evaluating pharmacological approaches have been conducted, most have shown disappointing results; thus, innovative strategies other than drugs have been actively attempted. OBJECTIVE: This study aims to explore low-dose radiation therapy (LDRT) for the treatment of patients with AD based on preclinical evidence, case reports, and a small pilot trial in humans. METHODS: This study is a phase II, multicenter, prospective, single-blinded, randomized controlled trial that will evaluate the efficacy and safety of LDRT to the whole brain using a linear accelerator in patients with mild AD. Sixty participants will be randomly assigned to three groups: experimental I (24 cGy/6 fractions), experimental II (300 cGy/6 fractions), or sham RT group (0 cGy/6 fractions). During LDRT and follow-up visits after LDRT, possible adverse events will be assessed by the physician's interview and neurological examinations. Furthermore, the effectiveness of LDRT will be measured using neurocognitive function tests and imaging tools at 6 and 12 months after LDRT. We will also monitor the alterations in cytokines, Aß42/Aß40 ratio, and tau levels in plasma. Our primary endpoint is the change in cognitive function test scores estimated by the Alzheimer's Disease Assessment Scale-Korea compared to baseline after 6 months of LDRT. CONCLUSIONS: This study is registered at ClinicalTrials.gov [NCT05635968] and is currently recruiting patients. This study will provide evidence that LDRT is a new treatment strategy for AD.

Total neoadjuvant therapy with short-course radiotherapy Versus long-course neoadjuvant chemoradiotherapy in Locally Advanced Rectal cancer, Korean trial (TV-LARK trial): study protocol of a multicentre randomized controlled trial.

BACKGROUND: For locally advanced rectal cancer (LARC), total neoadjuvant therapy (TNT) may enhance tumour response, reduce recurrence, and improve patient compliance compared to upfront surgery. Recent studies have shown that chemoradiotherapy (CRT) followed by consolidation chemotherapy leads to higher rate of pathologic complete response (pCR) than induction chemotherapy followed by CRT. However, an optimal TNT regimen that maximise the pCR rate and minimise toxicity has not been established. Therefore, the aim of this trial was to investigate whether preoperative short-course radiotherapy followed by chemotherapy with four cycles of CAPOX can double the pCR rate compared to a standard schedule of long-course preoperative CRT in patients with LARC. METHODS: This is a multi-centre, prospective, open label, randomised controlled trial. Patients with clinical primary tumour stage 3 and higher or regional node-involved rectal cancer located within 10 cm from the anal verge were randomly assigned equally to short-course radiotherapy (25 Gy in 5 fractions over 1 week) followed by four cycles of CAPOX (intravenous oxaliplatin [130 mg/m2, once a day] on day 1 and capecitabine [1,000 mg/m2, twice a day] from days 1 to 14) (TNT) or CRT (50.4 Gy in 28 fractions over 5 weeks, concurrently with concomitant oral capecitabine 825 mg/m2 twice a day). After preoperative treatment, total mesorectal excision was performed 2-4 weeks in the TNT group and 6-10 weeks in the CRT group, followed by optional additional adjuvant chemotherapy. The primary endpoint is the pCR rate, and secondary endpoints include disease-related treatment failure, quality of life, and cost-effectiveness. Assuming a pCR rate of 28% and 15% in the TNT and CRT groups, respectively, and one-side alpha error rate of 0.025 and power of 80%, 348 patients will be enrolled considering 10% dropout rate. DISCUSSION: The TV-LARK trial will evaluate the superiority of employed TNT regimen against the standard CRT regimen for patients with LARC. We aimed to identify a TNT regimen that will improve the pCR rate and decrease systemic recurrence in these patients. TRIAL REGISTRATION: Cris.nih.go.kr ID: KCT0007169 (April 08, 2022). The posted information will be updated as needed to reflect the protocol amendments and study progress.

Treatment patterns and results of salvage treatment for regional recurrences after stereotactic ablative radiotherapy for primary non-small cell lung cancer.

PURPOSE: Stereotactic ablative radiotherapy (SABR) for early-stage lung cancer has shown promising results; however, regional recurrence (RR) development is not uncommon, and salvage treatment strategies have not been established. We aimed to investigate treatment patterns, prognostic factors, and survival outcomes. MATERIALS AND METHODS: A retrospective analysis of 391 patients who underwent SABR for primary lung cancer from 2012 to 2019 was performed. Among these patients, 90 patients showed recurrence, including local recurrence (n = 9), RR (n = 33), distant metastasis (DM) (n = 57), and RR with simultaneous DM (n = 8). The median follow-up duration was 17.3 months. RESULTS: The median age was 75 years, and most patients underwent primary SABR due to poor lung function (69.7%). Various salvage treatments were performed in cases of RR, including chemotherapy (n = 15), radiotherapy (n = 7), concurrent chemoradiotherapy (n = 2), and best supportive care (n = 9). The median overall survival (OS) and post-recurrence OS (PR-OS) were 22.9 and 11.2 months, respectively. In multivariate analysis, age ≤75 years (HR = 0.36, p = 0.040), isolated recurrence (HR = 0.34, p = 0.037), and radiotherapy without chemotherapy (HR = 0.25, p = 0.024) were significant prognostic factors for PR-OS. CONCLUSIONS: Despite various salvage treatments, PR-OS was less than 1 year after RR in our frail patients group who underwent primary SABR. The toxicities of salvage chemotherapy could be quite severe; thus, careful patient selection is required. Further research is needed to validate our findings.

Patterns of locoregional recurrences and suggestion of the clinical target volume in resected perihilar extrahepatic cholangiocarcinoma.

Purpose: To evaluate the patterns of locoregional recurrence (LRR) in patients with perihilar extrahepatic cholangiocarcinoma (PEHC) treated with radical resection and to suggest the optimal target volume for elective nodal irradiation. Methods: Medical records of PEHC patients who underwent radical resection between January 2000 and September 2021 at five institutions were reviewed. Patients who were confirmed with LRR in the follow-up imaging study were included. The LRR sites were mapped onto the corresponding sites in template computed tomography images. The margin around the vascular structure was investigated to generate the clinical target volume (CTV) covering the common sites of regional recurrences. Results: A total of 87 LRRs in 46 patients were identified, 29 (33.3%) of which were local recurrences and 58 (66.7%) were regional recurrences. The most common site of local recurrence was the liver resection margin (n = 16), followed by the anastomosis site (n = 8). Regional recurrences were observed most commonly in the para-aortic area (n = 13), followed by in the aortocaval space (n = 11), portal vein area (n = 11), and portocaval area (n = 9). Nodal CTV was generated by adding an individualized margin around the portal vein, aorta, common hepatic artery, celiac artery, and left gastric artery. Conclusions: The LRR patterns in the resected PEHC were evaluated and specific guidelines for nodal CTV delineation were provided, which may help physicians delineating the target volume in postoperative radiotherapy for PEHC. These findings need further validation in a lager cohort.

No survival benefit with early incorporation of thoracic radiotherapy using daily fractionation in patients with limited-stage small cell lung cancer undergoing chemoradiotherapy in the modern era: A systematic review and meta-analysis.

BACKGROUND: When concurrent chemoradiotherapy (CCRT) is administered for limited-stage small cell lung cancer (LS-SCLC), the early incorporation of thoracic radiotherapy (TRT) is generally recommended. However, it is controversial if this approach is really beneficial with most commonly used daily fractionated TRT in the modern era. METHODS: A systematic literature search was performed using several databases following the PRISMA guidelines from Jan 2000 to Nov 2022. We excluded twice-daily TRT-based studies. The hazard ratio (HR) for survival following late TRT as a primary effect size was pooled from comparisons within individual studies according to the timing of daily fractionated TRT (early vs. late). RESULTS: A total of 10 studies including 10,164 analyzable patients met all inclusion criteria. 'Early' timing usually referred to TRT within 1-2 cycles of concurrent chemotherapy. The pooled results demonstrated that the risk of death was not significantly increased following late TRT compared with early TRT (HR 1.01, 95% CI 0.84-1.20, p = 0.94). All sensitivity analysis and planned subgroup analyses showed similar results. In comparison with early TRT, late TRT did not significantly increase the risk of progression (HR 0.94, 95% CI 0.80-1.11, p = 0.48). Furthermore, late TRT was beneficial in alleviating grade 3 or higher esophagitis (OR 0.42, p = 0.01), but no significant differences was found in pneumonitis (OR 0.62, p = 0.38), and neutropenia (OR 0.57, p = 0.11). No evidence of publication bias was found. CONCLUSIONS: This is the first meta-analysis to support the late incorporation of TRT in managing patients with LS-SCLC undergoing daily fractionated CCRT in the modern era. This approach may not compromise survival and can prevent severe acute toxicities. Further prospective studies of the daily fractionated TRT timing are warranted.

Efficacy of Prophylactic Cranial Irradiation According to the Risk of Extracranial Recurrence in Limited-Stage Small Cell Lung Cancer.

PURPOSE: We aimed to evaluate the effectiveness of prophylactic cranial irradiation (PCI) for "early brain metastasis", which occurs before extracranial recurrence (ECR), and "late brain metastasis", which occurs after ECR, in limited-stage small cell lung cancer (LS-SCLC). Materials and Methods: We retrospectively analyzed 271 LS-SCLC patients who underwent definitive chemoradiation. All patients were initially staged with brain magnetic resonance imaging and positron emission tomography. Intracranial recurrence (ICR), ECR, progression-free rate (PFR), and overall survival (OS) were analyzed as clinical endpoints. The competing risk of the first recurrence with ICR (ICRfirst) was evaluated. Significantly associated variables in multivariate analysis of ECR were considered as ECR risk factors. Patients were stratified according to the number of ECR risk factors. RESULTS: The application of PCI was associated with higher PFR (p=0.008) and OS (p=0.045). However, PCI was not associated with any of the clinical endpoints in multivariate analysis. The competing risk of ICRfirst was significantly decreased with the application of PCI (hazard ratio, 0.476; 95% confidence interval, 0.243 to 0.931; p=0.030). Stage III disease, sequential, and stable disease after thoracic radiation were selected as ECR risk factors. For patients without these risk factors, the application of PCI was significantly associated with increased OS (p=0.048) and a decreased risk of ICRfirst (p=0.026). CONCLUSION: PCI may play a role in preventing early brain metastasis rather than late brain metastasis after ECR, suggesting that only patients with a low risk of ECR may currently benefit from PCI.

Regional lymph node recurrence after stereotactic body radiation therapy for lung cancer: Patterns of recurrence, treatment approaches, and clinical outcomes (KROG 21-09).

PURPOSE: To present the multi-institutional data on patterns of recurrence, treatment approaches, and clinical outcomes for regional lymph node (LN) recurrence after stereotactic body radiation therapy (SBRT) for primary lung cancer. MATERIALS AND METHODS: The medical records of 114 patients who experienced regional LN recurrence as the first recurrence after lung SBRT were retrospectively reviewed. Patterns of recurrence were classified as local recurrence, regional recurrence, and distant metastasis. Clinical outcomes including progression-free survival (PFS) and overall survival (OS) were analyzed. RESULTS: Half of the patients had regional LN recurrence only. The most common simultaneous recurrence was distant metastasis (38.6 %). Common sites of regional recurrence were ipsilateral hilar (47.2 %), ipsilateral upper mediastinal (40.6 %), and subcarinal (42.5 %) LN stations. 24 (21.1 %) patients underwent salvage radiation therapy (RT), and 44 (38.6 %) patients underwent palliative treatment. Better OS was observed in the salvage RT group (p = 0.025). The 1-year PFS and OS rates were 27.7 % and 55.2 %, respectively, with salvage RT, 14.0 % and 39.9 %, respectively, with palliative treatment, and 22.8 % and 26.8 %, respectively, with no additional treatment. Multivariate analysis showed that salvage RT (PFS, HR 0.463, p = 0.050; OS, HR 0.312, p = 0.002), palliative treatment (PFS, HR 0.436, p = 0.013; OS, HR 0.553, p = 0.050), and simultaneous distant metastasis (PFS, HR 2.335, p = 0.005; OS, HR 1.726, p = 0.054) affected clinical outcomes. CONCLUSION: Many cases of regional LN recurrence are confined to the locoregional area of patients, and appropriate treatment can improve the prognosis of these patients.

Whole-Genome Sequencing Reveals Mutational Signatures Related to Radiation-Induced Sarcomas and DNA-Damage-Repair Pathways.

Radiation-induced sarcoma (RIS) is a rare but serious late complication arising from radiotherapy. Despite unfavorable clinical outcomes, the genomic footprints of ionizing radiation in RIS development remain largely unknown. Hence, this study aimed to characterize RIS genomes and the genomic alterations in them. We analyzed whole-genome sequencing in 11 RIS genomes matched with normal genomes to identify somatic alterations potentially associated with RIS development. Furthermore, the abundance of mutations, mutation signatures, and structural variants in RIS were compared with those in radiation-naïve spontaneous sarcomas. The mutation abundance in RIS genomes, including one hypermutated genome, was variable. Cancer-related genes might show different types of genomic alterations. For instance, NF1, NF2, NOTCH1, NOTCH2, PIK3CA, RB1, and TP53 showed singleton somatic mutations; MYC, CDKN2A, RB1, and NF1 showed recurrent copy number alterations; and NF2, ARID1B, and RAD51B showed recurrent structural variations. The genomic footprints of nonhomologous end joining are prevalent at indels of RIS genomes compared with those in spontaneous sarcoma genomes, representing the genomic hallmark of RIS genomes. In addition, frequent chromothripsis was identified along with predisposing germline variants in the DNA-damage-repair pathways in RIS genomes. The characterization of RIS genomes on a whole-genome sequencing scale highlighted that the nonhomologous end joining pathway was associated with tumorigenesis, and it might pave the way for the development of advanced diagnostic and therapeutic strategies for RIS.

Low-dose RaDiation therapy for patients with KNee osteoArthritis (LoRD-KNeA): a protocol for a sham-controlled randomised trial.

INTRODUCTION: Low-dose radiation therapy (LDRT) for osteoarthritis (OA) has been performed for several decades. However, supporting evidence from randomised studies using modern methodologies is lacking, and a recently published randomised study failed to show the significant benefit of LDRT. The presented trial aims to evaluate the efficacy and safety of LDRT for patients with knee OA. METHODS AND ANALYSIS: This prospective, multicentre, randomised trial will be conducted in the Republic of Korea. A total of 114 participants will be randomly assigned (1:1:1) to receive sham irradiation, 0.3 Gy/6 fractions of LDRT or 3 Gy/6 fractions of LDRT. Key inclusion criteria are primary knee OA with Kellgren-Lawrence grade 2-3 and visual analogue scale 50-90 when walking at the baseline. The primary endpoint is the rate of responders at 4 months after LDRT according to the OARSI-OMERACT criteria. Concomitant use of analgesics is prohibited until the primary efficacy evaluation is scheduled. ETHICS AND DISSEMINATION: Currently, approval from the Ministry of Food and Drug Safety of the Republic of Korea and the institutional review board of each participating hospital has been obtained. Patient enrolment began in October 2022 and is ongoing at three participating sites. The results will be disseminated to academic audiences and the public via publication in an international peer-reviewed journal and presentation at conferences. This trial will provide valuable information on the safety and efficacy of LDRT for patients with knee OA. TRIAL REGISTRATION NUMBER: NCT05562271.

Analysis of Once-Daily Thoracic Radiotherapy Dose According to the Underlying Lung Disease in Patients with Limited-Stage Small Cell Lung Cancer Undergoing Concurrent Chemoradiotherapy.

PURPOSE: In the treatment of concurrent chemoradiotherapy (CCRT) in limited-stage small cell lung cancer, the optimal once-daily radiotherapy (RT) dose/fractionation remain unclear although it is the most frequently used. Therefore, this study aimed to compare the treatment outcomes and toxicities of modest dose RT (≤ 54 Gy) with those of standard dose RT (> 54 Gy) and investigate the benefit of the high dose based on patient factors. MATERIALS AND METHODS: Since 2004, our institution has gradually increased the thoracic RT dose. Among the 225 patients who underwent CCRT, 84 patients (37.3%) received > 54 Gy. Because the patients treated with RT > 54 Gy were not randomly assigned, propensity score matching (PSM) was performed. RESULTS: The proportion of patients treated with > 54 Gy increased over time (p=0.014). Multivariate analysis revealed that the overall tumor stage and dose > 54 Gy (hazard ratio, 0.65; p=0.029) were independent prognostic factors for overall survival (OS). PSM confirmed that thoracic RT doses of > 54 Gy showed significantly improved progression-free survival (3-year, 42.7% vs. 24.0%; p < 0.001) and OS (3-year, 56.2% vs. 38.5%; p=0.003). Sensitivity analysis also showed that 60 Gy resulted in better survival than 54 Gy. However, in patients with underlying lung disease, OS benefit from > 54 Gy was not observed but considerable rates of severe pulmonary toxicities were observed (p=0.001). CONCLUSION: Our analysis supports that the 60 Gy RT dose should be considered in the once-daily regimen of CCRT for limited-stage small cell lung cancer without underlying lung disease, but RT dose > 54 Gy did not seem to benefit for patients with chronic obstructive pulmonary disease or interstitial lung disease. Further study is needed to validate these results.