In Ja Park

Asan Medical Center, Sŏul, Seoul, South Korea

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Publications (66)153.72 Total impact

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    ABSTRACT: Mismatch repair (MMR) status has been proposed, with some controversy, as a prognostic and predictive marker in stage II colon cancer. The aim of this study was to evaluate the association between MMR and survival in stage II colon cancer. A total of 860 patients with curatively resected stage II colon cancer were selected for inclusion between January 2003 and December 2008. Tumors lacking expression of MLH1 and/or MSH2, as determined by immunohistochemistry, were classified as having deficient MMR (dMMR), whereas other tumors were classified as having proficient MMR (pMMR). Clinical risk (CR) factors were used to divide patients into high or standard CR groups. Of 860 patients, 14.7 % were dMMR, 42.4 % had ≥1 CR factors, and 85.8 % patients received adjuvant chemotherapy. MMR status did not affect disease-free survival (DFS; hazard ratio [HR] 1.191, p = 0.415) or overall survival (OS; HR 1.300, p = 0.344). Among CR factors, only pathologic T4 disease tended to associate with poor OS (HR 1.979, p = 0.071). Adjuvant chemotherapy was associated with better DFS (HR 0.393, p < 0.0001) in patients with pMMR tumors. However, in patients with dMMR tumors, adjuvant chemotherapy was not associated with DFS. MMR status did not affect DFS or OS in patients with stage II colon cancer. In patients treated with adjuvant chemotherapy, dMMR was not associated with DFS and OS. However, adjuvant chemotherapy was associated with improved DFS in pMMR patients.
    Annals of Surgical Oncology 08/2015; DOI:10.1245/s10434-015-4807-6 · 3.94 Impact Factor
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    ABSTRACT: The types of anastomotic leakage that develop following rectal cancer surgery and their impact on long-term outcomes are not well documented. This study aimed to compare the clinical characteristics of various types of anastomotic leakage after anterior resection in rectal cancer patients and evaluate their impact on the long-term oncologic outcomes. This study analyzed data obtained from 2510 consecutive patients who underwent anterior resection for rectal cancers. Of these patients, 141 (5.6 %) developed anastomotic leakage. Three types of leakage were categorized according to presentation: generalized peritonitis (type I), localized peritonitis (type II), and fistula or chronic sinus (type III). The clinical characteristics and oncologic outcomes were compared. Type I leakage was the most common (I 44.7 %, n = 63; II 30.5 %, n = 43; III 24.8 %, n = 35). Type III occurred more frequently in women (p = 0.001) and patients with low rectal cancer (p < 0.001). Patients with type II or III leakage more frequently underwent radiation therapy (p < 0.001) and diverting ostomy (p < 0.001). Leakage management differed according to the type of leakage (p < 0.001). The local recurrence-free survival rate was significantly lower in patients with type II and III leakage (p = 0.014). The clinical characteristics and oncologic results are distinct for each type of anastomotic leakage. Only a type II or III leakage increases the risk of local recurrence. Each type of leakage should thus be considered a different disease entity.
    International Journal of Colorectal Disease 08/2015; DOI:10.1007/s00384-015-2359-7 · 2.42 Impact Factor
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    ABSTRACT: To explore the role of adjuvant chemotherapy for patients with ypT0-2N0 rectal cancer treated by preoperative chemoradiation therapy (PCRT) and radical resection. A national consortium of 10 institutions was formed, and patients with ypT0-2N0 mid- and low-rectal cancer after PCRT and radical resection from 2004 to 2009 were included. Patients were categorized into 2 groups according to receipt of additional adjuvant chemotherapy: Adj CTx (+) versus Adj CTx (-). Propensity scores were calculated and used to perform matched and adjusted analyses comparing relapse-free survival (RFS) between treatment groups while controlling for potential confounding. A total of 1016 patients, who met the selection criteria, were evaluated. Of these, 106 (10.4%) did not receive adjuvant chemotherapy. There was no overall improvement in 5-year RFS as a result of adjuvant chemotherapy [91.6% for Adj CTx (+) vs 87.5% for Adj CTx (-), P=.18]. There were no differences in 5-year local recurrence and distant metastasis rate between the 2 groups. In patients who show moderate, minimal, or no regression in tumor regression grade, however, possible association of adjuvant chemotherapy with RFS would be considered (hazard ratio 0.35; 95% confidence interval 0.14-0.88; P=.03). Cox regression analysis after propensity score matching failed to show that addition of adjuvant chemotherapy was associated with improved RFS (hazard ratio 0.81; 95% confidence interval 0.39-1.70; P=.58). Adjuvant chemotherapy seemed to not influence the RFS of patients with ypT0-2N0 rectal cancer after PCRT followed by radical resection. Thus, the addition of adjuvant chemotherapy needs to be weighed against its oncologic benefits. Copyright © 2015 Elsevier Inc. All rights reserved.
    International journal of radiation oncology, biology, physics 07/2015; 92(3):540-547. DOI:10.1016/j.ijrobp.2015.02.020 · 4.18 Impact Factor
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    ABSTRACT: Colorectal cancer (CRC) with microsatellite instability (MSI) is characterized by frequent poor differentiation or mucinous histology. The purpose of this study was to evaluate the association of MSI with clinicopathological features and the oncologic outcome in patients with a mucinous component. CRC tissue samples were analyzed for histology and MSI. Patients were grouped according to the mucinous content as follows: >50%, mucinous adenocarcinoma (MA), ≤50%, adenocarcinoma with mucinous component (AMC) and none, non-mucinous adenocarcinoma (NMA). Clinicopathological parameters and survival were compared between patient groups. Of 2025 patients, 84 (4%) had MA and 124 (6%) had AMC. In addition, 202 (10%) had MSI. Patients with MA and AMC tended to have a younger age of onset, right-colon predilection, large-sized tumour and high frequency of MSI compared with those with NMA (P < 0.001). MA and AMC patients with MSI showed a trend towards right-colon predilection and infrequent lymph-node metastasis compared with those with microsatellite stability (MSS, P = 0.005-0.03). There were no survival differences between the three groups, but patients with MSI-MA demonstrated lower four-year recurrence and better overall survival rates than those with MSS-MA (P = 0.018 and P = 0.046). Clinicopathological features of AMC and MA were similar and closely associated with MSI status. Although the prognosis of AMC and MA were not different from that of NMA, survival of patients with an MSI-MA tumour was significantly better than that of MSS-MA tumours. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Colorectal Disease 06/2015; 17(8). DOI:10.1111/codi.13027 · 2.02 Impact Factor
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    In Ja Park
    Annals of Coloproctology 04/2015; 31(2):41-2. DOI:10.3393/ac.2015.31.2.41
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    ABSTRACT: To evaluate the predictive value of the lymph node (LN) ratio (LNR, number of metastatic LNs/ examined LNs) for recurrence in patients with rectal cancer and to compare its applicability according to preoperative chemoradiotherapy (PCRT). From 2000 to 2009, 967 patients with metastatic LNs after curative resection for locally advanced rectal cancer were identified. Patients were categorized according to PCRT (PCRT vs No PCRT). The cut-off LNR was determined based on the pN1 vs pN2 when the recommended number of LNs was harvested. The 5-year recurrence-free survival (RFS) rates using the Kaplan-Meier method were compared according to p/yp N stage and the LNR in each group. Among patients with the same p/ypN stage, the 5-year RFS rate differed according to the LNR. In addition, the 5-year RFS rate was significantly different between pN and LNR groups in patients with No PCRT. In PCRT group, however, only LNR was associated with prognosis. On multivariate analysis, both pN and LNR were significant independent prognostic factors for 5-year RFS in the No PCRT group. In the PCRT group, only LNR category was found to be associated with RFS (HR = 2.36, 95%CI: 1.31-3.84, and P = 0.001). The LNR is an important prognostic predictor of RFS in rectal cancer patients especially treated with PCRT. Current pN categories could not discriminate between prognostic groups of RFS after PCRT.
    03/2015; 21(11):3274-81. DOI:10.3748/wjg.v21.i11.3274
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    ABSTRACT: This retrospective study compared the recurrence-free survival (RFS) and local recurrence rates of patients who received preoperative chemoradiotherapy (PCRT) for cT3N0 vs. those who did not. We analyzed the records of 593 patients with transrectal ultrasound (TUS) or magnetic resonance image (MRI)-staged cT3N0 mid and low locally advanced rectal cancer, including 255 who received PCRT and 338 who did not. The RFS and cumulative local recurrence rates were compared in the two groups. We also investigated the rates of pathologic complete response (pCR) and mesorectal lymph node (LN) involvement in the PCRT group. The overall pCR rate was 13.3 %. Of the 338 non-PCRT patients, 125 (37.0 %) had pathologically positive mesorectal LNs. Sphincter-preserving surgery was performed in 431 (72.7 %) of the 593 patients, with similar rates in the two groups. However, the sphincter preservation rate in patients with low rectal cancer was higher among those who received PCRT than among those who did not (64.8 vs. 47 %, P = 0.002). The 5-year RFS (76.4 vs. 75.5 %, P = 0.92) and local recurrence (3.9 vs. 3.0 %, P = 0.97) rates were similar in the PCRT and non-PCRT groups. Although PCRT did not improve the RFS or local recurrence rates, it increased the chance of sphincter preservation in patients with low rectal cancer. The advantages of PCRT for patients with cT3N0 should be re-evaluated considering the limitation of pretreatment staging, oncologic benefits, and improved sphincter preservation.
    Surgery Today 02/2015; DOI:10.1007/s00595-015-1136-0 · 1.21 Impact Factor
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    ABSTRACT: According to the 2010 World Health Organization classification, all gastrointestinal neuroendocrine tumors (NETs) are classified as malignant except for L-cell-type (glucagon-like peptide [GLP] and peptide YY [PYY]-producing) NETs. However, L-cell immunophenotype in rectal NETs has not been widely studied previously. Immunohistochemical labeling of L-cell markers with GLP1 and PYY was performed in 208 surgically or endoscopically resected rectal NET cases with tissue microarrays and was compared with clinicopathologic features and patient survival. Rectal NETs with non-L-cell immunophenotype and large tumor size (>1 cm) were associated with increased tumor grading, advanced T category, lymphovascular and perineural invasions, and lymph node and distant metastases (P<0.001, each). Rectal NET patients with non-L-cell phenotype and measuring >1 cm had significantly worse survival outcome than other groups by univariate (P<0.001) and multivariate (P<0.001) analyses. In summary, non-L-cell immunophenotype and large tumor size are associated with increased tumor grading and staging, concurrently indicating that they are independently poor prognostic indicators in rectal NET patients. Therefore, combining L-cell phenotype and tumor size can demonstrate the clinical behavior of rectal NETs more precisely than use of L-cell immunophenotype alone.
    American Journal of Surgical Pathology 02/2015; 39(5). DOI:10.1097/PAS.0000000000000400 · 4.59 Impact Factor
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    In Ja Park
    Annals of Coloproctology 02/2015; 31(1):7-8. DOI:10.3393/ac.2015.31.1.7
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    ABSTRACT: To ascertain pathologic stage as a prognostic indicator for rectal cancer patients receiving preoperative chemoradiotherapy (PCRT). Patients with mid- and low rectal carcinoma (magnetic resonance imaging - based clinical stage II or III) between 2000 and 2009 and treated with curative radical resection were identified. Patients were divided into two groups: PCRT and No-PCRT. Recurrence-free survival (RFS) was examined according to pathologic stage and addition of adjuvant treatment. Overall, 894 patients were identified. Of these, 500 patients received PCRT. Adjuvant chemotherapy was delivered to 81.5% of the No-PCRT and 94.8% of the PCRT patients. Adjuvant radiotherapy was given to 29.4% of the patients in the No PCRT group. The 5-year RFS for the No-PCRT group was 92.6% for Stage I, 83.3% for Stage II, and 72.9% for Stage III. The 5-year RFS for the PCRT group was 95.2% for yp Stage 0, 91.7% for yp Stage I, 73.9% for yp Stage II, and 50.7% for yp Stage III. Pathologic stage can predict prognosis in PCRT patients. 5-year RFS is significantly lower among PCRT patients than No-PCRT patients in pathologic stage II and III. These results should be taken into account when considering adjuvant treatment for patients treated with PCRT.
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    ABSTRACT: To ascertain pathologic stage as a prognostic indicator for rectal cancer patients receiving preoperative chemoradiotherapy (PCRT). Patients with mid- and low rectal carcinoma (magnetic resonance imaging - based clinical stage II or III) between 2000 and 2009 and treated with curative radical resection were identified. Patients were divided into two groups: PCRT and No-PCRT. Recurrence-free survival (RFS) was examined according to pathologic stage and addition of adjuvant treatment. Overall, 894 patients were identified. Of these, 500 patients received PCRT. Adjuvant chemotherapy was delivered to 81.5% of the No-PCRT and 94.8% of the PCRT patients. Adjuvant radiotherapy was given to 29.4% of the patients in the No PCRT group. The 5-year RFS for the No-PCRT group was 92.6% for Stage I, 83.3% for Stage II, and 72.9% for Stage III. The 5-year RFS for the PCRT group was 95.2% for yp Stage 0, 91.7% for yp Stage I, 73.9% for yp Stage II, and 50.7% for yp Stage III. Pathologic stage can predict prognosis in PCRT patients. 5-year RFS is significantly lower among PCRT patients than No-PCRT patients in pathologic stage II and III. These results should be taken into account when considering adjuvant treatment for patients treated with PCRT.
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    ABSTRACT: Objectives: This study investigates the clinical significance of the gene encoding AP-2ε (TFAP2E) in colorectal cancer (CRC) patients undergoing curative resection. Methods: A single-institution cohort of 248 patients who underwent curative resection of stage I/II/III CRCs between March and December 2004 was enrolled, and 193 patients whose tumors were available for the determination of the TFAP2E methylation status were included in the analysis. Results: TFAP2E hypermethylation was detected in 112 patients (58%) and was significantly associated with distally located CRCs, low pathologic T stage (T1/T2), and stage I tumors. After a median follow-up of 86.3 months, the patients with TFAP2E hypermethylation tended to show better relapse-free survival (RFS) and overall survival (OS) than the patients with TFAP2E hypomethylation (5-year RFS rate: 90 vs. 80%, p = 0.063; 6-year OS rate: 88 vs. 80%, p = 0.083). Multivariate analysis showed that the pathologic nodal stage and TFAP2E methylation status were independent prognostic factors for RFS and OS, and they remained significant factors in the subgroup analysis that included 154 patients with stage II/III CRCs who had received adjuvant chemotherapy. Conclusions: TFAP2E hypermethylation is associated with good clinical outcomes and may be considered as an independent prognostic factor in patients with curatively resected CRCs. © 2014 S. Karger AG, Basel.
    Oncology 10/2014; 88(2):122-132. DOI:10.1159/000362820 · 2.61 Impact Factor
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    In Ja Park
    Annals of Coloproctology 10/2014; 30(5):208-9. DOI:10.3393/ac.2014.30.5.208
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    ABSTRACT: The impact of the number of retrieved lymph nodes (LNs) on oncological outcomes in patients with rectal cancer remains unclear. This study was designed to evaluate the prognostic implications of the number of retrieved LNs in patients with rectal cancer receiving preoperative chemoradiotherapy (CRT). The study cohort consisted of 859 patients with locally advanced (cT3-4 or cN+) mid to low rectal cancer that had been treated with preoperative CRT and radical resection between 2000 and 2009. Multivariate analysis and the Kaplan-Meier method were used to evaluate the influence of the number of retrieved LNs on disease-free survival (DFS). The median number of LNs retrieved from included patients was 13 (interquartile range [IQR] 9-17). Multivariate analysis confirmed the independent prognostic importance of the number of retrieved LNs on DFS (hazard ratio = 0.97, 95 % confidence interval = 0.95-0.99, p = 0.029). The 3-year DFS rate in patients with yp stage II rectal cancer was associated with the total number of retrieved LNs. DFS was associated with the number of LNs retrieved from patients with rectal cancer who received preoperative CRT, especially among patients with ypT3-4 N0 stage tumors. The oncological importance of the number of retrieved LNs should be considered when treating these patients.
    Journal of Gastrointestinal Surgery 08/2014; 18(10). DOI:10.1007/s11605-014-2509-1 · 2.39 Impact Factor
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    06/2014; 10(1):29-34. DOI:10.14216/kjco.140029
  • In Ja Park · Jin Cheon Kim
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    ABSTRACT: In the era of preoperative chemoradiotherapy (CRT) for rectal cancer, the role of lateral pelvic lymph node dissection (LPLND) has become much more complicated because preoperative CRT affects both the lateral pelvic lymph nodes (LPLN) and the main tumor. Most previous studies do not demonstrate the benefits of LPLND following preoperative CRT in comparison with total mesorectal excision, although some authors have argued that selective LPLND is beneficial. LPLN treatment strategies differ depending on whether the disease was considered systemic metastatic disease or local disease which can be treated using surgical resection. The role of LPLND in rectal cancer is better evaluated on the basis of its oncologic impact rather than technical feasibility. Here, we review LPLN metastasis status in rectal cancer, whether LPLN metastasis is systemic or local disease, and studies on the use of LPLND to treat rectal cancer.
    Current Colorectal Cancer Reports 06/2014; 10(2):157-163. DOI:10.1007/s11888-014-0212-y
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    ABSTRACT: Purpose Selecting the best surgical approach for treating complete rectal prolapse involves comparing the operative and functional outcomes of the procedures. The aims of this study were to evaluate and compare the operative and functional outcomes of abdominal and perineal surgical procedures for patients with complete rectal prolapse. Methods A retrospective study of patients with complete rectal prolapse who had operations at a tertiary referral hospital and a university hospital between March 1990 and May 2011 was conducted. Patients were classified according to the type of operation: abdominal procedure (AP) (n = 64) or perineal procedure (PP) (n = 40). The operative outcomes and functional results were assessed. Results The AP group had the younger and more men than the PP group. The AP group had longer operation times than the PP group (165 minutes vs. 70 minutes; P = 0.001) and longer hospital stays (10 days vs. 7 days; P = 0.001), but a lower overall recurrence rate (6.3% vs. 15.0%; P = 0.14). The overall rate of the major complication was similar in the both groups (10.9% vs. 6.8%; P = 0.47). The patients in the AP group complained more frequently of constipation than of incontinence, conversely, in the PP group of incontinence than of constipation. Conclusion The two approaches for treating complete rectal prolapse did not differ with regard to postoperative morbidity, but the overall recurrence tended to occur frequently among patients in the PP group. Functional results after each surgical approach need to be considered for the selection of procedure.
    Annals of Surgical Treatment and Research 05/2014; 86(5):249-55. DOI:10.4174/astr.2014.86.5.249
  • In Ja Park · Chang Sik Yu
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    ABSTRACT: In patients with locally advanced rectal cancer, preoperative chemoradiotherapy has proven to significantly improve local control and cause lower treatment-related toxicity compared with postoperative adjuvant treatment. Preoperative chemoradiotherapy followed by total mesorectal excision or tumor specific mesorectal excision has evolved as the standard treatment for locally advanced rectal cancer. The paradigm shift from postoperative to preoperative therapy has raised a series of concerns however that have practical clinical implications. These include the method used to predict patients who will show good response, sphincter preservation, the application of conservative management such as local excision or "wait-and-watch" in patients obtaining a good response following preoperative chemoradiotherapy, and the role of adjuvant chemotherapy. This review addresses these current issues in patients with locally advanced rectal cancer treated by preoperative chemoradiotherapy.
    World Journal of Gastroenterology 02/2014; 20(8):2023-2029. DOI:10.3748/wjg.v20.i8.2023 · 2.43 Impact Factor
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    In Ja Park
    Annals of Coloproctology 02/2014; 30(1):7-8. DOI:10.3393/ac.2014.30.1.7
  • 12/2013; 9(2):134-138. DOI:10.14216/kjco.13025

Publication Stats

729 Citations
153.72 Total Impact Points

Institutions

  • 2004–2015
    • Asan Medical Center
      Sŏul, Seoul, South Korea
  • 2008–2014
    • University of Ulsan
      • Department of Surgery
      Urusan, Ulsan, South Korea
  • 2004–2014
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
  • 2013
    • University of Texas MD Anderson Cancer Center
      Houston, Texas, United States
  • 2012
    • Kyung Hee University
      • Graduate School of East-West Medical Science
      Sŏul, Seoul, South Korea
  • 2008–2009
    • Kyungpook National University
      • School of Medicine
      Daikyū, Daegu, South Korea