Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Yong Chan Ahn is active.

Publication


Featured researches published by Yong Chan Ahn.


Journal of Clinical Oncology | 2012

Phase III Trial Comparing Capecitabine Plus Cisplatin Versus Capecitabine Plus Cisplatin With Concurrent Capecitabine Radiotherapy in Completely Resected Gastric Cancer With D2 Lymph Node Dissection: The ARTIST Trial

Jeeyun Lee; Do Hoon Lim; Sung Kim; Se Hoon Park; Joon Oh Park; Young Suk Park; Ho Yeong Lim; Min Gew Choi; Tae Sung Sohn; Jae Hyung Noh; Jae Moon Bae; Yong Chan Ahn; Insuk Sohn; Sin-Ho Jung; Cheol Keun Park; Kyoung-Mee Kim; Won Ki Kang

PURPOSE The ARTIST (Adjuvant Chemoradiation Therapy in Stomach Cancer) trial was the first study to our knowledge to investigate the role of postoperative chemoradiotherapy therapy in patients with curatively resected gastric cancer with D2 lymph node dissection. This trial was designed to compare postoperative treatment with capecitabine plus cisplatin (XP) versus XP plus radiotherapy with capecitabine (XP/XRT/XP). PATIENTS AND METHODS The XP arm received six cycles of XP (capecitabine 2,000 mg/m2 per day on days 1 to 14 and cisplatin 60 mg/m2 on day 1, repeated every 3 weeks) chemotherapy. The XP/XRT/XP arm received two cycles of XP followed by 45-Gy XRT (capecitabine 1,650 mg/m2 per day for 5 weeks) and two cycles of XP. RESULTS Of 458 patients, 228 were randomly assigned to the XP arm and 230 to the XP/XRT/XP arm. Treatment was completed as planned by 75.4% of patients (172 of 228) in the XP arm and 81.7% (188 of 230) in the XP/XRT/XP arm. Overall, the addition of XRT to XP chemotherapy did not significantly prolong disease-free survival (DFS; P = .0862). However, in the subgroup of patients with pathologic lymph node metastasis at the time of surgery (n = 396), patients randomly assigned to the XP/XRT/XP arm experienced superior DFS when compared with those who received XP alone (P = .0365), and the statistical significance was retained at multivariate analysis (estimated hazard ratio, 0.6865; 95% CI, 0.4735 to 0.9952; P = .0471). CONCLUSION The addition of XRT to XP chemotherapy did not significantly reduce recurrence after curative resection and D2 lymph node dissection in gastric cancer. A subsequent trial (ARTIST-II) in patients with lymph node-positive gastric cancer is planned.


Journal of Clinical Oncology | 2009

Phase II Trial of Concurrent Radiation and Weekly Cisplatin Followed by VIPD Chemotherapy in Newly Diagnosed, Stage IE to IIE, Nasal, Extranodal NK/T-Cell Lymphoma: Consortium for Improving Survival of Lymphoma Study

Seok Jin Kim; Ki-Hyun Kim; Byung-Soo Kim; Chul Yong Kim; Cheolwon Suh; Jooryung Huh; Sangwook Lee; Jinseok Kim; Jaeho Cho; Gyeong Won Lee; Ki Mun Kang; Hyeon Seok Eom; Hong Ryull Pyo; Yong Chan Ahn; Young Hyeh Ko; Won Seog Kim

PURPOSE On the basis of the benefits of frontline radiation in early-stage, extranodal, natural killer (NK)/T-cell lymphoma (ENKTL), we conducted a phase II trial of concurrent chemoradiotherapy (CCRT) followed by three cycles of etoposide, ifosfamide, cisplatin, and dexamethasone (VIPD). PATIENTS AND METHODS Thirty patients with newly diagnosed, stages IE to IIE, nasal ENKTL received CCRT (ie radiation 40 to 52.8 Gy and cisplatin 30 mg/m(2) weekly). Three cycles of VIPD (etoposide 100 mg/m(2) days 1 through 3, ifosfamide 1,200 mg/m(2) days 1 through 3, cisplatin 33 mg/m(2) days 1 through 3, and dexamethasone 40 mg days 1 through 4) were scheduled after CCRT. RESULTS All patients completed CCRT, which resulted in 100% response that included 22 complete responses (CRs) and eight partial responses (PRs). The CR rate after CCRT was 73.3% (ie, 22 of 30 responses; 95% CI, 57.46 to 89.13). Twenty-six of 30 patients completed the planned three cycles of VIPD, whereas four patients did not because they withdrew (n = 2) or because they had an infection (n = 2). The overall response rate and the CR rate were 83.3% (ie; 25 of 30 responses; 95% CI, 65.28 to 94.36) and 80.0% (ie, 24 of 30 responses; 95% CI, 65.69 to 94.31), respectively. Only one patient experienced grade 3 toxicity during CCRT (nausea), whereas 12 of 29 patients experienced grade 4 neutropenia. The estimated 3-year, progression-free and overall survival rates were 85.19% (95% CI, 72.48 to 97.90) and 86.28% (95% CI, 73.97 to 98.59), respectively. CONCLUSION Patients with newly diagnosed, stages IE to IIE, nasal ENKTL are best treated with frontline CCRT.


Annals of Oncology | 2001

CHOP followed by involved field radiation: Is it optimal for localized nasal natural killer/T-cell lymphoma?

Woo-Sik Kim; S.-Y. Song; Yong Chan Ahn; Young-Hyeh Ko; C.-H. Baek; Dae Yong Kim; S.-S. Yoon; Hyang-Woo Lee; Won Ki Kang; Hyo-Rak Lee; C. H. Park; Keunchil Park

The present study aimed to analyse the treatment outcome of four cycles of CHOP (cyclophosphamide-vincristine-doxorubicin-prednisolone) followed by involved field radiation therapy (IF RT) for the treatment of stage I-II nasal natural killer (NK)/T-cell lymphoma. From March 1995 to December 1999, 17 patients (median age 41 years; range 30-66) with localized nasal NK/T-cell lymphoma were enrolled. B symptoms were noted in five patients (31%). Sixteen of seventeen patients (94%) were of low risk when classified according to the International Prognostic Index (IPI). The treatment plan consisted of four cycles of CHOP chemotherapy followed by IF RT of 45 Gy. Two patients received radiation during the first or second cycle of CHOP because of bleeding from the primary tumour site. Both patients achieved complete responses (CRs). In the remaining 15 patients, after 4 cycles of CHOP, 6 CRs and 3 partial responses (PRs) were achieved (53% of response rate). IF RT was given to six patients (four in CR, one in PR and one in PD), and all six patients achieved CR. Overall, CR was achieved in 10 of 17 patients (58%). The planned sequential chemoradiotherapy was completed in only 6 of 17 patients (35%) because of the progression during chemotherapy. None of the patients who achieved CR experienced relapse of lymphoma during follow-up. The estimated overall three-year survival rate was 59%. In univariate analysis, B symptoms and stage were significant prognostic factors for response and overall survival (P < 0.05). The present study suggests that four cycles of CHOP followed by IF RT is not satisfactory for treating patients with localized nasal NK/T-cell lymphoma, and that further exploration for improved therapy is needed.


Clinical Cancer Research | 2009

Metabolic Tumor Volume of [18F]-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Predicts Short-Term Outcome to Radiotherapy With or Without Chemotherapy in Pharyngeal Cancer

Man Ki Chung; Han-Sin Jeong; Sang Gyu Park; Jeon Yeob Jang; Young-Ik Son; Joon Young Choi; Seung Hyup Hyun; Keunchil Park; Myung-Ju Ahn; Yong Chan Ahn; Hyung Jin Kim; Young-Hyeh Ko; Chung-Hwan Baek

Purpose: This study aimed to investigate whether metabolic tumor volume (MTV) measured from [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) predicts short-term outcome to radiotherapy with or without chemotherapy and disease-free survival (DFS) in patients with pharyngeal cancers. Experimental Design: The MTVs of primary sites with or without neck nodes were measured in 82 patients. Short-term outcome was assessed using the treatment response evaluation by the Response Evaluation Criteria in Solid Tumors and recurrence events during follow-up (complete response/no recurrence or residual disease/recurrence). Results: A total of 64 patients had complete response/no recurrence as of the last follow-up. A cutoff of 40 mL for the MTV was the best discriminative value for predicting treatment response. By univariate analyses, patients with MTV >40 mL showed a significantly lower number of complete response/no recurrence than did patients with MTV ≤40 mL [68.2% versus 87.8%; hazard ratio (HR), 3.34; 95% confidence interval (95% CI), 1.09-10.08; P = 0.03], as is the same in tumor-node-metastasis stage (87.5% for I-II versus 90% for III versus 63.8% for IV; P = 0.02). However, MTV was only a significant predictor of short-term outcome by multivariate analyses (HR, 4.09; 95% CI, 1.02-16.43; P = 0.04). MTV >40 mL indicated a significantly worse DFS than MTV ≤40 mL (HR, 3.42; 95% CI, 1.04-11.26;P = 0.04). The standardized uptake value for the primary tumor did not show any correlation with treatment outcome or DFS. Conclusion: MTV has a potential value in predicting short-term outcome and DFS in patients with pharyngeal cancers. (Clin Cancer Res 2009;15(18):5861–8)


Human Gene Therapy | 2001

Interleukin 12 Gene Therapy of Cancer by Peritumoral Injection of Transduced Autologous Fibroblasts: Outcome of a Phase I Study

Won Ki Kang; Chaehwa Park; Hyunah Lee Yoon; Won Seog Kim; Sung-Soo Yoon; Mark H. Lee; Keunchil Park; Ki-Hyun Kim; Hyun Sik Jeong; Jeong-A Kim; Seok-Jin Nam; Jung-Hyun Yang; Young-Ik Son; Chung-Hwan Baek; J. Han; Howe J. Ree; Eil Soo Lee; Sun Hee Kim; Dae Won Kim; Yong Chan Ahn; Seung Jae Huh; Yeon Hyeon Choe; Je-Ho Lee; Mary H. Park; Gyoung-Sun Kong; Eun-Young Park; Yoon-Koo Kang; Yung-Jue Bang; Nam-Sun Paik; Soon Nam Lee

A phase I dose-escalation clinical trial of peritumoral injections of interleukin 12 (IL-12)-transduced autologous fibroblasts was performed in patients with disseminated cancer for whom effective treatment does not exist. The goals of this study were to assess the safety and toxicities as well as the efficacy, and ancillarily the immunomodulatory effects, of peritumoral IL-12 gene transfer. Primary dermal fibroblasts cultured from the patients were transduced with retroviral vector carrying human IL-12 genes (p35 and p40) as well as the neomycin phosphotransferase gene (TFG-hIL-12-Neo). Patients received four injections at intervals of 7 days. Nine patients were enrolled in this dose-escalation study, with secreted IL-12 doses ranging from 300 ng/24 hr for the first three patients to 1000, 3000, and 5000 ng/24 hr for two patients in each subsequent dosage level. Although a definite statement cannot be made, there appears to be perturbation of systemic immunity. Also, the locoregional effects mediated by tumor necrosis factor alpha (TNF-alpha) and CD8+ T cells were observed with tumor regression. Treatment-related adverse events were limited to mild to moderate pain at the injection site; clinically significant toxicities were not encountered. Transient but clear reductions of tumor sizes were observed at the injected sites in four of nine cases, and at noninjected distant sites in one melanoma patient. Hemorrhagic necrosis of tumors was observed in two melanoma patients. These data indicate that gene therapy by peritumoral injection of IL-12-producing autologous fibroblasts is feasible, and promising in patients with advanced cancer.


British Journal of Cancer | 2008

ERCC1 expression as a predictive marker of squamous cell carcinoma of the head and neck treated with cisplatin-based concurrent chemoradiation.

Hyun Jung Jun; Myung Ju Ahn; Hyo Song Kim; Seong Yoon Yi; Jeung-Whan Han; S. K. Lee; Yong Chan Ahn; H. S. Jeong; Y. I. Son; J. H. Baek; Kyunghee Park

The excision repair cross-complementation group 1 (ERCC1) enzyme plays a rate-limiting role in the nucleotide excision repair pathway and is associated with resistance to platinum-based chemotherapy. The purpose of this study was to evaluate the role of ERCC1 expression as a predictive marker of survival in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) treated with cisplatin-based concurrent chemoradiotherapy (CCRT). ERCC1 expression was assessed by immunohistochemical staining. The median age of the 45 patients analysed was 56 years (range 27–75 years), and 82% were men; 73% of all specimens showed high expression of ERCC1. The overall tumour response rate after CCRT was 89%. The median follow-up was 53.6 months (95% CI, 34.5–72.7 months). The 3-year progression-free survival (PFS) and overall survival (OS) rates were 58.7 and 61.3%, respectively. Univariate analyses showed that patients with low expression of ERCC1 had a significantly higher 3-year PFS (83.3 vs 49.4%, P=0.036) and OS (91.7 vs 45.5%, P=0.013) rates. Multivariate analysis showed that low expression of ERCC1 was an independent predictor for prolonged survival (HR, 0.120; 95% CI, 0.016–0.934, P=0.043). These results suggest that ERCC1 expression might be a useful predictive marker of locally advanced SCCHN in patients treated with cisplatin-based CCRT.


Medical Physics | 2002

Film dosimetry for intensity modulated radiation therapy: Dosimetric evaluation

Sang Gyu Ju; Yong Chan Ahn; Seung Jae Huh; Inhwan Jason Yeo

X-ray film has been used for the dosimetry of intensity modulated radiation therapy (IMRT). However, the over-response of the film to low-energy photons is a significant problem in photon beam dosimetry, especially in regions outside penumbra. In IMRT, the radiation field consists of multiple small fields and their outside-penumbra regions; thus, the film dosimetry, for it involves the source of over-response in its radiation field. In this study we aim to verify and possibly improve film dosimetry for IMRT. Two types of modulated beams were constructed by combining five to seven different static radiation fields using 6 MV x rays. For verifying film dosimetry, x-ray films and an ion chamber were used to measure dose profiles at various depths in a phantom. The film setups include both parallel and perpendicular arrangements against the beam incident direction. In addition, to reduce an over-response, we placed 0.01 in. (0.25 mm) thick lead filters on both sides of the film. Compared with ion-chamber measurement, measured dose profiles showed the film over-response at outside-penumbra and low-dose regions. The error increased with depths and approached 15% as a maximum for the field size of 15 cm x 15 cm at 10 cm depth. The use of filters reduced the error down to 3%. In this study we demonstrated that film dosimetry for IMRT involves sources of error due to its over-response to low-energy photons, with the error most transparent in the low-dose region. The use of filters could enhance the accuracy in film dosimetry for IMRT. In this regard, the use of an optimal filter condition is recommended.


Head and Neck-journal for The Sciences and Specialties of The Head and Neck | 2013

Prognostic value of 18F-FDG PET/CT in patients with squamous cell carcinoma of the tonsil: comparisons of volume-based metabolic parameters.

Seung Hwan Moon; Joon Young Choi; Hwan Joo Lee; Young-Ik Son; Chung-Hwan Baek; Yong Chan Ahn; Keunchil Park; Kyung-Han Lee; Byung-Tae Kim

The prognostic significance of volume‐based metabolic parameters measured by 18F‐fluorodeoxyglucose positron emission tomography/CT (18F‐FDG PET/CT) is not established. We evaluated the prognostic value of metabolic parameters in patients with squamous cell carcinoma (SCC) of the tonsil.


International Journal of Radiation Oncology Biology Physics | 2000

Fractionated stereotactic radiation therapy for extracranial head and neck tumors

Yong Chan Ahn; Kyu Chan Lee; Dae Yong Kim; Seung Jae Huh; Inh Wan Yeo; Do Hoon Lim; Moon Kyung Kim; Kyung Hwan Shin; Suk Won Park; Seung Hee Chang

BACKGROUND This study is to report the clinical experiences of fractionated stereotactic radiation therapy (FSRT) for extracranial head and neck tumors. METHODS AND MATERIALS Between the period of July 1995 and November 1998, 48 patients with extracranial head and neck tumors were given FSRT as a boost and sole modality. Individualized treatment planning was performed using XKnife-3 system with relocatable Gill-Thomas-Cosman frame. In 24 patients, FSRT was applied as a boost technique following the 2-dimensional conventional external radiation therapy (ERT); in 24 patients FSRT was the sole radiotherapy modality. The primary diseases in the boost group consisted of nasopharynx cancer (19), lacrimal gland adenoid cystic carcinoma (3), orbital lymphoma (1), and skull-base recurrence of maxillary sinus adenoid cystic carcinoma (1). The primary diseases in the sole modality group consisted of recurrent nasopharynx cancer (12), orbital pseudotumor (4), skull-base recurrence of maxillary sinus, submandibular gland, and hypopharynx cancers (3), orbital rhabdomyosarcoma (2), orbital lymphoma (1), orbital metastasis of neuroblastoma (1), and nasal cavity melanoma (1). The fractionation schedule was to give 5 treatments per one week and the fractional doses were 2.0-3 Gy depending on the treatment aim and the FSRT volume. The FSRT doses varied depending on the nature of the primary diseases. RESULTS The local tumor response in nasopharynx cancer patients was excellent compared to retrospective data without occurrence of unexpectedly severe complication. FSRT to other regions was well tolerated by the patients and resulted in good to excellent local tumor responses with no unacceptable side effects as expected by the authors. CONCLUSION Based on the current observations, FSRT is a very effective and safe modality in the treatment of extracranial head and neck tumors.


Radiotherapy and Oncology | 1996

Radiotherapy of intracranial germinomas

Seung Jae Huh; Kyung Hwan Shin; Il Man Kim; Yong Chan Ahn; Sung Whan Ha; Charn Il Park

Between 1980 and 1992, 32 patients with intracranial germinomas were treated with radiation. All patients were confirmed histopathologically prior to treatment. Of the 32 intracranial germinomas reviewed, 14 were located in the suprasellar region, 12 in the basal ganglia and thalamus, four in the pineal, and two in both the pineal and suprasellar regions. Three patients had subarachnoid seeding. Craniospinal irradiation was undertaken for 29 patients. The median dose of 54 Gy was delivered to the tumor bed, 36 Gy to the whole brain and 24 Gy to the spinal axis. Five and 10-year survival rates were 96.9 and 96.9%, respectively. Local control was achieved in all patients except one who died of persistent tumor after 2 months following radiotherapy. No intracranial recurrence or spinal metastasis were found. Tumor site did not relate to the prognosis. One patient developed severe intellectual deterioration, three patients had vertebral growth impairment. The present study confirms the excellent result with radiotherapy alone for patients with germinomas.

Collaboration


Dive into the Yong Chan Ahn's collaboration.

Top Co-Authors

Avatar

Do Hoon Lim

Samsung Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Dongryul Oh

Samsung Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge