• Korean Journal of Radiology
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• v.25 no.1
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• pp.33-42
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• 2024

Focal enhancement typically suggests local tumor progression (LTP) after renal cell carcinoma is percutaneously ablated. However, evaluating findings that are false positive or negative of LTP is less familiar to radiologists who have little experience with renal ablation. Various imaging features are encountered during and after thermal ablation. Ablation procedures and previous follow-up imaging should be reviewed before determining if there is LTP. Previous studies have focused on detecting the presence or absence of focal enhancement within the ablation zone. Therefore, various diagnostic pitfalls can be experienced using computed tomography or magnetic resonance imaging examinations. This review aimed to assess how to read images during or after ablation procedures, recognize imaging features of LTP and determine factors that influence LTP.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.172-179
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• 2017

Purpose: To evaluate the outcomes of stereotactic body radiation therapy (SBRT) for patients with liver oligo-recurrence and oligo-progression from various primary tumors. Materials and Methods: Between 2002 and 2013, 72 patients with liver oligo-recurrence (oligo-metastasis with a controlled primary tumor) and oligo-progression (contradictory progression of a few sites of disease despite an overall tumor burden response to therapy) underwent SBRT. Of these, 9 and 8 patients with uncontrollable distant metastases and patients immediate loss to follow-up, respectively, were excluded. The total planning target volume was used to select the SBRT dose (median, 48 Gy; range, 30 to 60 Gy, 3-4 fractions). Toxicity was evaluated using the Common Toxicity Criteria for Adverse Events v4.0. Results: We evaluated 55 patients (77 lesions) treated with SBRT for liver metastases. All patients had controlled primary lesions, and 28 patients had stable lesions at another site (oligo-progression). The most common primary site was the colon (36 patients), followed by the stomach (6 patients) and other sites (13 patients). The 2-year local control and progression-free survival rates were 68% and 22%, respectively. The 2- and 5-year overall survival rates were 56% and 20%, respectively. The most common adverse events were grade 1-2 fatigue, nausea, and vomiting; no grade ${\geq}3$ toxicities were observed. Univariate analysis revealed that oligo-progression associated with poor survival. Conclusion: SBRT for liver oligo-recurrence and oligo-progression appears safe, with similar local control rates. For liver oligo-progression, criteria are needed to select patients in whom improved overall survival can be expected through SBRT.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2793-2796
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• 2014

Background: Glioblastoma multiform (GBM) is a highly aggressive tumor with median survival of approximately 14 months. Management consists of maximal surgical resection followed by post-operative chemoradiation with concurrent then adjuvant temozolamide. The standard radiotherapy dose is 60Gy in 2-Gy fractions recommended by the radiation therapy oncology group (RTOG). With the vast majority of tumor recurrences occurring within the previous irradiation field and the poor outcome associated with standard therapy, regimens designed to deliver higher radiation doses to improve local control and enhance survival are needed. In this study, we report a single institutional experience in treatment of 68 consecutive patients with GBM, treated with resection, and given post-operative radiotherapy followed by concurrent and/or adjuvant chemotherapy. Results: Of the 80 patients who entered this study, 68 completed the treatment course; 45 (66.2%) males and 23 (33.8%) females with a mean age at diagnosis of $49.0{\pm}12.9$ (21-75) years. At a median follow up of 19 months, 39 (57.3%) patients had evidence of tumor progression and 36 (52.9%) had died. The median over all survival for all patients was 16 months and progression free survival for all patients was 6.02 months. All potential prognostic factors were analyzed to evaluate their effects on overall survival. Age ${\leq}50$ year, concurrent and adjuvant chemotherapy and extent of surgery had significant p values. We found lower progression rate among patients who received higher doses of radiotherapy (>60Gy). Higher radiation doses improved progression free survival (p=0.03). Despite increasing overall survival, this elevation was not significant. Conclusions: This study emphasize that higher radiation doses of (>60Gy) can improve local control and potentially survival, so we strongly advise prospective multi centric studies to evaluate the role of higher doses of radiotherapy on GBM patient outcome.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1053-1065
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• 2018

Objective: To evaluate the clinical impact of using registration software for ablative margin assessment on pre-radiofrequency ablation (RFA) magnetic resonance imaging (MRI) and post-RFA computed tomography (CT) compared with the conventional side-by-side MR-CT visual comparison. Materials and Methods: In this Institutional Review Board-approved prospective study, 68 patients with 88 hepatocellulcar carcinomas (HCCs) who had undergone pre-RFA MRI were enrolled. Informed consent was obtained from all patients. Pre-RFA MRI and post-RFA CT images were analyzed to evaluate the presence of a sufficient safety margin (${\geq}3mm$) in two separate sessions using either side-by-side visual comparison or non-rigid registration software. Patients with an insufficient ablative margin on either one or both methods underwent additional treatment depending on the technical feasibility and patient's condition. Then, ablative margins were re-assessed using both methods. Local tumor progression (LTP) rates were compared between the sufficient and insufficient margin groups in each method. Results: The two methods showed 14.8% (13/88) discordance in estimating sufficient ablative margins. On registration software-assisted inspection, patients with insufficient ablative margins showed a significantly higher 5-year LTP rate than those with sufficient ablative margins (66.7% vs. 27.0%, p = 0.004). However, classification by visual inspection alone did not reveal a significant difference in 5-year LTP between the two groups (28.6% vs. 30.5%, p = 0.79). Conclusion: Registration software provided better ablative margin assessment than did visual inspection in patients with HCCs who had undergone pre-RFA MRI and post-RFA CT for prediction of LTP after RFA and may provide more precise risk stratification of those who are treated with RFA.

• Radiation Oncology Journal
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• v.31 no.3
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• pp.125-130
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• 2013

Purpose: We investigated the role of radiotherapy (RT) for pancreatobiliary neuroendocrine tumors (PB-NETs). Materials and Methods: We identified 9 patients with PB-NETs who received RT between January 2005 and March 2012. Of these 9 patients, 4 were diagnosed with NETs in the pancreas and 5 were diagnosed with NETs in the gallbladder. All patients received RT to the primary tumor or resection bed with a median total irradiation dose of 50.4 Gy, with or without chemotherapy. Results: The tumor response rate and tumor control rate in the RT field were 60% and 100 %, respectively. All 4 patients who underwent surgery had no evidence of disease in the RT field. Of the 5 patients who received RT to the primary gross tumor, 1 had complete response, 2 had partial response, and 2 had stable disease in the RT field. The median time to progression was 11 months. Of the 9 patients, four patients had no progression, and 5 patients had progression of disease (locoregional, 2; distant, 2; locoregional/distant, 1). Of the 4 patients without progression, 3 were treated with RT in adjuvant or neoadjuvant setting, and one received RT to primary tumor. One patient experienced radiation-induced duodenitis at 3 months after concurrent chemoradiation without treatment-related mortality. Conclusion: RT can yield local control for advanced PB-NETs. RT should be considered an essential part of multimodality treatment in management of advanced PB-NETs.

• Korean Journal of Radiology
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• v.24 no.8
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• pp.719-728
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• 2023

Radiofrequency ablation (RFA) has been widely used to manage hepatocellular carcinomas (HCCs) equal to or smaller than 3 cm. No-touch RFA has gained attention and has recently been implemented in local ablation therapy for HCCs, despite its technical complexity, as it provides improved local tumor control compared to conventional tumor-puncturing RFA. This article presents the practice guidelines for performing no-touch RFA for HCCs, which have been endorsed by the Korean Society of Image-Guided Tumor Ablation (KSITA). The guidelines are primarily designed to assist interventional oncologists and address the limitations of conventional tumor-puncturing RFA with describing the fundamental principles, various energy delivery methods, and clinical outcomes of no-touch RFA. The clinical outcomes include technical feasibility, local tumor progression rates, survival outcomes, and potential complications.

• Radiation Oncology Journal
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• v.37 no.3
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• pp.224-231
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• 2019

Purpose: To investigate the patterns of recurrence in patients with neuroblastoma treated with radiation therapy to the primary tumor site. Materials and Methods: We retrospectively analyzed patients with high-risk neuroblastoma managed with definitive treatment with radiation therapy to the primary tumor site between January 2003 and June 2017. These patients underwent three-dimensional conformal radiation therapy or intensity-modulated radiation therapy. A total of 14-36 Gy was delivered to the planning target volume, which included the primary tumor bed and the selected metastatic site. The disease stage was determined according to the International Neuroblastoma Staging System (INSS). We evaluated the recurrence pattern (i.e., local or systemic), progression-free survival, and overall survival. Results: A total of 40 patients with high-risk neuroblastoma were included in this study. The median patient age was 4 years (range, 1 to 11 years). Thirty patients (75%) had INSS stage 4 neuroblastoma. At the median follow-up of 58 months, there were 6 cases of local recurrence and 10 cases of systemic recurrence. Among the 6 local failure cases, 4 relapsed adjacent to the radiation field. The other 2 relapsed in the radiation field (i.e., para-aortic and retroperitoneal areas). The main sites of distant metastasis were the bone, lymph nodes, and bone marrow. The 5-year progression-free survival was 70.9% and the 5-year overall survival was 74.3%. Conclusion: Radiation therapy directed at the primary tumor site provides good local control. It seems to be adequate for disease control in patients with high-risk neuroblastoma after chemotherapy and surgical resection.

• Radiation Oncology Journal
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• v.38 no.1
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• pp.26-34
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• 2020

Purpose: Intensity-modulated radiotherapy (IMRT) allows for more precise treatment, reducing unwanted radiation to nearby structures. We investigated the safety and feasibility of IMRT for anaplastic ependymoma patients below 3 years of age. Materials and Methods: A total of 9 anaplastic ependymoma patients below 3 years of age, who received IMRT between October 2011 and December 2017 were retrospectively reviewed. The median equivalent dose in 2 Gy fractions was 52.0 Gy (range, 48.0 to 60.0 Gy). Treatment outcomes and neurologic morbidities were reviewed in detail. Results: The median patient age was 20.9 months (range, 12.1 to 31.2 months). All patients underwent surgery. The rates of 5-year overall survival, freedom from local recurrence, and progression-free survival were 40.6%, 53.3%, and 26.7%, respectively. Of the 9 patients, 5 experienced recurrences (3 had local recurrence, 1 had both local recurrence and cerebrospinal fluid [CSF] seeding, and 1 had CSF seeding alone). Five patients died because of disease progression. Assessment of neurologic morbidity revealed motor dysfunction in 3 patients, all of whom presented with hydrocephalus at initial diagnosis because of the location of the tumor and already had neurologic deficits before radiotherapy (RT). Conclusion: Neurologic morbidity is not caused by RT alone but may result from mass effects of the tumor and surgical sequelae. Administration of IMRT to anaplastic ependymoma patients below 3 years of age yielded encouraging local control and tolerable morbidities. High-precision modern RT such as IMRT can be considered for very young patients with anaplastic ependymoma.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.12
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• pp.5281-5285
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• 2016

Background: Brachytherapy is the most commonly used conservative treatment for the uveal melanoma. The aim of this study was to evaluate therapeutic results of Ruthenium-106 plaque brachytherapy in the management of localized uveal melanoma cases. Methods: We reviewed retrospectively the clinical records of all patients treated in our department for an uveal melanoma, undergoing Ruthenium-106 plaque brachytherapy, from January 1996 to December 2015. We focused on clinical features, therapeutic characteristics, local and distant tumor control and side effects. Results: Nineteen patients were enrolled in our study. Mean age was 56.2 years (28-79) and the sex ratio was 1.37:1 males to females. Diagnosis was made on the basis of ophthalmological clinical examination, angiography, ultrasound and/or magnetic resonance. Median tumor diameter was 9.7 mm (6-13) and median thickness 4.4 mm (2.5-8). The dose of Ruthenium-106 plaque brachytherapy prescribed to the apex of each tumor was 70 Gy in all cases. The median radiation dose to the sclera surface was 226.4 Gy (range: 179.6-342.3) and the median total application time 115.2 hours (range: 27 to 237). After a median follow-up of 61.5 months, local control was achieved in 17 patients (89%): 16 demonstrated a partial tumor response and 1 tumor stabilization. Two patients suffered local progression leading to enucleation, one dying of hepatic metastasis. Radiation-induced complications were cataracts in 3 cases and vitreal hemorrhage in 2. Conclusion: Ruthenium-106 plaque brachytherapy is an efficient treatment for localized uveal melanoma, offering good local control with low toxicity.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.329-335
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• 2013

Objective : Brain metastases in primary breast cancer patients are considerable sources of morbidity and mortality. Gamma knife radiosurgery (GKRS) has gained popularity as an up-front therapy in treating such metastases over traditional radiation therapy due to better neurocognitive function preservation. The aim of this study was to clarify the prognostic factors for local tumor control and survival in radiosurgery for brain metastases from primary breast cancer. Methods : From March 2001 to May 2011, 124 women with metastatic brain lesions originating from a primary breast cancer underwent GKRS at a tertiary medical center in Seoul, Korea. All patients had radiosurgery as a primary treatment or salvage therapy. We retrospectively reviewed their clinical outcomes and radiological responses. The end point of this study was the date of patient's death or the last follow-up examination. Results : In total, 106 patients (268 lesions) were available for follow-up imaging. The median follow-up time was 7.5 months. The mean treated tumor volume at the time of GKRS was 6273 $mm^3$ (range, 4.5-27745 mm3) and the median dose delivered to the tumor margin was 22 Gy (range, 20-25 Gy). Local recurrence was assessed in 86 patients (216 lesions) and found to have occurred in 36 patients (83 lesions, 38.6%) with a median time of 6 months (range, 4-16 months). A treated tumor volume >5000 $mm^3$ was significantly correlated with poor local tumor control through a multivariate analysis (hazard risk=7.091, p=0.01). Overall survival was 79.9%, 48.3%, and 15.3% at 6, 12, and 24 months, respectively. The median overall survival was 11 months after GKRS (range, 6 days-113 months). Multivariate analysis showed that the pre-GKRS Karnofsky performance status, leptomeningeal seeding prior to initial GKRS, and multiple metastatic lesions were significant prognostic factors for reduced overall survival (hazard risk=1.94, p=0.001, hazard risk=7.13, p<0.001, and hazard risk=1.46, p=0.046, respectively). Conclusion : GKRS has shown to be an effective and safe treatment modality for treating brain metastases of primary breast cancer. Most metastatic brain lesions initially respond to GKRS, though, many patients have further CNS progression in subsequent periods. Patients with poor Karnofsky performance status and multiple metastatic lesions are at risk of CNS progression and poor survival, and a more frequent and strict surveillance protocol is suggested in such high-risk groups.