Is Laparoscopic Complete Mesocolic Excision and Central Vascular Ligation Really Necessary for All Patients With Right-Sided Colon Cancer?

Colon cancer treatment is on the way to evolution over several decades. The minimally invasive surgery has improved postoperative short-term outcomes. Adjuvant chemotherapy has prolonged the survival of advanced colon cancer patients. Hohenberger proposed the noble concept of complete mesocolic excision (CME) which consists of 3 components: plane surgery, sufficient longitudinal bowel resection, and central vascular ligation (CVL). Mesocolic plane surgery shares the same surgical principle of total mesorectal excision, which is maintaining the intact mesothelial envelope. However, there remain debates about the extent of bowel resection and the level of CVL for maximizing lymph node dissection. There is no solid clinical evidence for the oncological necessity and benefit of extended radical dissection in right hemicolectomy. CME with CVL based on open surgery has been adopted in laparoscopic surgery. So, it is also necessary to look at how the CME could be transformed and successfully implanted in the laparoscopic era. Recent rapid advances in surgical technology and cancer biology are preparing for fundamental changes in cancer surgery. In this study, we reviewed the history, oncological necessity, and compatibility of CME for the right hemicolectomy in the laparoscopic era and outline the new perspectives on the evolution of cancer surgery.

Reconsideration of the Safety of Laparoscopic Rectal Surgery for Cancer

The oncological outcomes of laparoscopic rectal cancer surgery were evaluated in recent multicenter randomized clinical trials (RCTs). The MRC-CLASSIC, COLOR II, and COREAN trials found no differences in local recurrence or disease-free survival rate between laparoscopic and open surgery. However, the noninferiority of laparoscopic surgery with respect to open surgery for rectal cancer was not established on statistical analysis in the ACOSOG Z6051 and the ALaCaRT trials. Quality of total mesorectal excision (TME) is one of the most important prognostic factors. Incomplete TME had unfavorable oncologic outcomes compared to complete TME. Although TME quality can be clearly identified on pathologic evaluation, there is controversy regarding the acceptable range of oncologically safe TME for laparoscopic surgery. It is not certain whether near-complete TME has an unfavorable oncologic impact and whether laparoscopic surgery with near-complete TME is an oncological threat. Therefore, the surgical community will be interested in the long-term outcomes and meta-analyses of ongoing large-scale RCTs. Laparoscopic rectal cancer surgery has been steadily improving its safety for oncology surgery, which has been reported consistently in various multicenter RCTs. To improve surgical quality, colorectal surgeons should choose the most appropriate surgical technique, including laparoscopic surgery.

Clinical Significance of Discordance between Carcinoembryonic Antigen Levels and RECIST in Metastatic Colorectal Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to investigate the prognostic implications of carcinoembryonic antigen (CEA) levels that are inconsistent with Response Evaluation Criteria in Solid Tumor (RECIST) responses in metastatic colorectal cancer patients. MATERIALS AND METHODS: We retrospectively evaluated 360 patients with at least one measurable lesion who received first-line palliative chemotherapy. CEA-response was defined as CEA-complete response (CR; CEA normalization), CEA-partial response (PR; ≥ 50% decrease in CEA levels), CEA-progressive disease (PD; ≥ 50% increase in CEA levels), and CEA-stable disease (SD; non-CR/PR/PD). Overall survival (OS) and progression-free survival (PFS) were evaluated according to CEA-response. RESULTS: In RECIST-PR patients, poorer CEA-response was associated with disease progression at the subsequent evaluation. In RECIST-SD patients, CEA-CR and -PR were associated with lower disease progression rates than CEA-PD at the subsequent evaluation. Correlations between survival outcome and CEA-response in same-category RECIST patients were assessed. In RECIST-PR patients, discordant CEA-response (CEA-PD/SD) was associated with poorer survival than CEA-CR/PR (median OS and PFS, 44.0 and 15.4 [CEA-CR], 28.9 and 12.5 [CEA-PR], 21.0 and 9.8 [CEA-SD], and 13.0 and 7.0 [CEA-PD] months, respectively; all p < 0.001). In RECIST-SD patients, favorable CEA-response produced better survival (median OS and PFS, 26.8 and 21.0 [CEA-CR], 21.0 and 11.0 [CEA-PR], 16.1 and 8.2 [CEA-SD], and 12.2 and 6.0 [CEA-PD] months, respectively; all p < 0.001). RECIST-PD patients with CEA-CR showed longer OS than those with CEA-PD. Multivariate analysis demonstrated that discordant CEA-response is a powerful prognostic factor for RECIST-PR and RECIST-SD patients. CONCLUSION: Among patients of the same RECIST-response categories, CEA-response patterns are significantly prognostic and strongly predictive of subsequent evaluation outcomes.

Experiencing Transanal TME with a Cadaveric Model

Transanal total mesorectal excision (taTME) is known to be a novel surgical approach for patients who are difficult to resolve with the traditional trans-abdominal approach. However, most of the colorectal surgeons are unfamiliar with the technique, which can lead to serious complications such as urethral injury. Hence, training through the fresh frozen cadaver has been gradually included in the formal taTME training course. The authors trained the taTME procedure with two cadavers in 2016. Two surgeons who were experts in trans-anal minimally invasive surgery and had minimal experiences in taTME performed the procedure. The total procedure time from the purse string suture to the anterior communication took about 65 minutes. The procedure proceeded well without any inadvertent injury to anatomic structures. The usefulness of the cadaveric model in training taTME was confirmed and the experience of single port surgery and trans-anal operation before the cadaveric training is considered to be important.

28 Years of the Journey for Laparoscopic Surgery and Memories of People Who Gave so much of Themselves to Support Me During the Time

No abstract available.

Long-term oncologic outcomes of laparoscopic surgery for splenic flexure colon cancer are comparable to conventional open surgery

PURPOSE: Few studies about laparoscopic surgery for splenic flexure colon cancer have been published. This study aims to compare the short- and long-term outcomes of laparoscopic surgery for splenic flexure colon cancer with those of conventional open surgery. METHODS: From January 2004 to December 2010, 51 consecutive patients who underwent curative resection for stages I–III splenic flexure colon cancer were enrolled. Thirty-three patients underwent laparoscopy-assisted colectomy, while 18 patients underwent conventional open colectomy. Short- and long-term outcomes of the 2 groups were compared. RESULTS: There were no differences in baseline characteristics, intra- and postoperative complications. The laparoscopy group showed longer operation time (median [interquartile range, IQR]: 295.0 [255.0–362.5] minutes vs. 180.0 [168.8–206.3] minutes, P < 0.001). In the laparoscopy group, return of bowel function was faster (median [IQR]: 3 [2–4] vs. 4 [3–5], P = 0.007) and postoperative hospital stay was shorter (median [IQR]: 9 [8–11] vs. 10.5 [9–19], P = 0.026). There were no statistically significant differences in overall survival rate (84.3% vs. 76.0%, P = 0.560) or disease-free survival rate (93.8% vs. 74.5%, P = 0.078) between the 2 groups. CONCLUSION: Laparoscopic surgery for splenic flexure colon cancer has better short-term outcomes than open surgery, as well as acceptable long-term outcomes. Laparoscopic surgery can be a safe and feasible alternative to conventional open surgery for splenic flexure colon cancer.

Multimodal Assessments Are Needed for Restaging after Neoadjunvant Chemoradiation Therapy in Rectal Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Restaging after neoadjuvant treatment is done for planning the surgical approach and, increasingly, to determine whether additional therapy or resection can be avoided for selected patients. MATERIALS AND METHODS: Local restaging after neoadjuvant chemoradiation therapy (nCRT) was performed in 270 patients with locally advanced (cT3or4 or N+) rectal cancer. Abdomen and pelvic computed tomography (APCT) was used in all 270 patients, transrectal ultrasound (TRUS) in 121 patients, and rectal magnetic resonance imaging (MRI) in 65 patients. Findings according to imaging modalities were correlated with pathologic stage using Cohen's kappa (κ) to test agreement and intra-class correlation coefficient α to test reliability. RESULTS: Accuracy for prediction of ypT stage according to three imaging modalities was 45.2% (κ=0.136, α=0.380) in APCT, 49.2% (κ=0.259, α=0.514) in rectal MRI, and 57.9% (κ=0.266, α=0.520) in TRUS. Accuracy for prediction of ypN stage was 66.0% (κ=0.274, α=0.441) in APCT, 71.8% (κ=0.401, α=0.549) in rectal MRI, and 66.1% (κ=0.147, α=0.272) in TRUS. Of 270 patients, 37 (13.7%) were diagnosed as pathologic complete responder after nCRT. Rectal MRI for restaging did not predict complete response. On the other hand, TRUS did predict three complete responders (κ=0.238, α=0.401). CONCLUSION: APCT, rectal MRI, and TRUS are unreliable in restaging rectal cancer after nCRT. We think that multimodal assessment with rectal MRI and TRUS may be the best option for local restaging of locally advanced rectal cancer after nCRT.

Novel Methods of Lymph Node Evaluation for Predicting the Prognosis of Colorectal Cancer Patients with Inadequate Lymph Node Harvest / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Lymph node metastasis is an important factor for predicting the prognosis of colorectal cancer patients. However, approximately 60% of patients do not receive adequate lymph node evaluation (less than 12 lymph nodes). In this study, we identified a more effective tool for predicting the prognosis of patients who received inadequate lymph node evaluation. MATERIALS AND METHODS: The number of metastatic lymph nodes, total number of lymph nodes examined, number of negative metastatic lymph nodes (NL), lymph node ratio (LR), and the number of apical lymph nodes (APL) were examined, and the prognostic impact of these parameters was examined in patients with colorectal cancer who underwent surgery from January 2004 to December 2011. In total, 806 people were analyzed retrospectively. RESULTS: In comparison of different lymph node analysis methods for rectal cancer patients who did not receive adequate lymph node dissection, the LR showed a significant difference in overall survival (OS) and the APL predicted a significant difference in disease-free survival (DFS). In the case of colon cancer patients who did not receive adequate lymph node dissection, LR predicted a significant difference in DFS and OS, and the APL predicted a significant difference in DFS. CONCLUSION: If patients did not receive adequate lymph node evaluation, the LR and NL were useful parameters to complement N stage for predicting OS in colon cancer, whereas LR was complementary for rectal cancer. The APL could be used for prediction of DFS in all patients.

Three Dimensional Laparoscopy Improves Surgical Performance: Comparative Study in a Cadaver

PURPOSE: Conventional laparoscopy using a two-dimensional (2D) has limited performance because of insufficient representation of the stereoscopic effect. Development of three-dimensional (3D) imaging technology has improved depth perception, shortened the execution time and reduced error number. This study was designed to identify the effects of 3D imaging on surgical performance for skilled professionals and surgical residents. METHODS: Two laparoscopic skills tasks, each with three repetitions, were performed by seven experienced laparoscopic surgeons, two minimally experienced laparoscopic surgeons, and three inexperienced surgical residents under both 2D and 3D conditions with two cadavers. Outcome measures were time for task completion and subjective assessment of performance. RESULTS: Suturing was completed by all participants and anchoring with V-Loc was performed by 10 participants. Suturing and anchoring time were significantly shorter with 3D laparoscopic in all participants (suturing time, p=0.011; anchoring time, p=0.005). Significant differences were observed between experienced and minimally experienced surgeons (suture time, p=0.021; anchoring time, p=0.018). There was no significant difference among inexperienced surgical residents, but they preferred 3D imaging over 2D. CONCLUSION: 3D laparoscopy is associated with a significantly shorter time for performance by experienced surgeons. Our results suggest that 3D laparoscopy will be helpful for surgeons conducting laparoscopic procedures.

Reduced port laparoscopic surgery for colon cancer is safe and feasible in terms of short-term outcomes: comparative study with conventional multiport laparoscopic surgery

PURPOSE: Laparoscopic surgery was previously accepted as an alternative surgical option in treatment for colorectal cancer. Nowadays, single-port laparoscopic surgery (SPLS) is introduced as a method to maximize advantages of minimally invasive surgery. However, SPLS has several limitations compared to conventional multiport laparoscopic surgery (CMLS). To overcome those limitations of SPLS, reduced port laparoscopic surgery (RPLS) was introduced. This study aimed at evaluating the short-term outcomes of RPLS. METHODS: Patients who underwent CMLS and RPLS of colon cancer between August 2011 and December 2013 were included in this study. Short-term clinical and pathological outcome were compared between the 2 groups. RESULTS: Thirty-two patients underwent RPLS and 217 patients underwent CMLS. Shorter operation time, less blood loss, and faster bowel movement were shown in RPLS group in this study. In terms of postoperative pain, numeric rating scale (NRS) of RPLS was lower than that of CMLS. Significant differences were shown in terms of tumor size, harvested lymph node, perineural invasion, and pathological stage. No significant differences were confirmed in terms of other surgical outcomes. CONCLUSION: In this study, RPLS was technically feasible and safe. Especially in terms of postoperative pain, RPLS was comparable to CMLS. RPLS may be a feasible alternative option in selected patients with colon cancer.

Polyethylene Glycol (PEG-3350, Colyte) Poisoning due to Intra-Peritoneal Leakage in an Elderly Patient / 대한구급학회지

Polyethylene glycol (PEG)-3350 is the most frequently used lavage solution for bowel cleansing prior to colonoscopy or elective surgery because its large molecular weight means that it is poorly absorbed. However, if it leaks into the peritoneal cavity, complications may arise. Few published studies have assessed the absorption, distribution, metabolism and excretion of PEG. Moreover, no published clinical data regarding complications due to the intra-peritoneal leakage of PEG-3350 could be found. We report on an elderly patient who developed the poisoning caused by leaking of PEG-3350 during bowel preparation. It resulted in severe metabolic acidosis, hypernatremia, hyperosmolality and a high anion gap, but it was effectively treated with early continuous renal replacement therapy after surgery.

Comparative study between transanal tube and loop ileostomy in low anterior resection for mid rectal cancer: a retrospective single center trial

PURPOSE: To investigate the efficacy and safety of the transanal tube (TAT) in preventing anastomotic leak (AL) in rectal cancer surgery. METHODS: Clinical data of the patients who underwent curative surgery for mid rectal cancer from February 2010 to February 2014 were reviewed retrospectively. Rectal cancers arising 5 to 10 cm above the anal verge were selected. Patients were divided into the ileostomy, TAT, or no-protection groups. Postoperative complications including AL and postoperative course were compared. RESULTS: We included 137 patients: 67, 35, and 35 patients were included in the ileostomy, TAT, and no-protection groups, respectively. Operation time was longer in the ileostomy group (P = 0.029), and more estimated blood loss was observed (P = 0.018). AL occurred in 5 patients (7.5%) in the ileostomy group, 1 patients (2.9%) in the TAT group, and 6 patients (17.1%) in the no-protection group (P = 0.125). Patients in the ileostomy group resumed diet more than 1 day earlier than those in the other groups (P = 0.000). Patients in the no-protection group had about 1 or 2 days longer postoperative hospital stay (P = 0.048). The ileostomy group showed higher late complication rates than the other groups as complications associated with the stoma itself or repair operation developed (P = 0.019). CONCLUSION: For mid rectal cancer surgery, the TAT supports anastomotic site protection and diverts ileostomy-related complications. Further large scale randomized controlled studies are needed to gain more evidence and expand the range of TAT usage.

Polyethylene Glycol (PEG-3350, Colyte) Poisoning due to Intra-Peritoneal Leakage in an Elderly Patient / 대한중환자의학회지

Polyethylene glycol (PEG)-3350 is the most frequently used lavage solution for bowel cleansing prior to colonoscopy or elective surgery because its large molecular weight means that it is poorly absorbed. However, if it leaks into the peritoneal cavity, complications may arise. Few published studies have assessed the absorption, distribution, metabolism and excretion of PEG. Moreover, no published clinical data regarding complications due to the intra-peritoneal leakage of PEG-3350 could be found. We report on an elderly patient who developed the poisoning caused by leaking of PEG-3350 during bowel preparation. It resulted in severe metabolic acidosis, hypernatremia, hyperosmolality and a high anion gap, but it was effectively treated with early continuous renal replacement therapy after surgery.

Niti CAR 27 Versus a Conventional End-to-End Anastomosis Stapler in a Laparoscopic Anterior Resection for Sigmoid Colon Cancer

PURPOSE: The Niti CAR 27 (ColonRing) uses compression to create an anastomosis. This study aimed to investigate the safety and the effectiveness of the anastomosis created with the Niti CAR 27 in a laparoscopic anterior resection for sigmoid colon cancer. METHODS: In a single-center study, 157 consecutive patients who received an operation between March 2010 and December 2011 were retrospectively assessed. The Niti CAR 27 (CAR group, 63 patients) colorectal anastomoses were compared with the conventional double-stapled (CDS group, 94 patients) colorectal anastomoses. Intraoperative, immediate postoperative and 6-month follow-up data were recorded. RESULTS: There were no statistically significant differences between the two groups in terms of age, gender, tumor location and other clinical characteristics. One patient (1.6%) in the CAR group and 2 patients (2.1%) in the CDS group experienced complications of anastomotic leakage (P = 0.647). These three patients underwent a diverting loop ileostomy. There were 2 cases (2.1%) of bleeding at the anastomosis site in the CDS group. All patients underwent a follow-up colonoscopy (median, 6 months). One patient in the CAR group experienced anastomotic stricture (1.6% vs. 0%; P = 0.401). This complication was solved by using balloon dilatation. CONCLUSION: Anastomosis using the Niti CAR 27 device in a laparoscopic anterior resection for sigmoid colon cancer is safe and feasible. Its use is equivalent to that of the conventional double-stapler.

The nutritional risk is a independent factor for postoperative morbidity in surgery for colorectal cancer

PURPOSE: The authors evaluate the prevalence of malnutrition and its effect on the postoperative morbidity of patients after surgery for colorectal cancer. METHODS: Three hundred fifty-two patients were enrolled prospectively. Nutritional risk screening 2002 (NRS 2002) score was calculated through interview with patient on admission. Clinical characteristics, tumor status and surgical procedure were recorded. RESULTS: The prevalence of patients at nutritional risk was 28.1 per cent according to the NRS 2002. The rate of postoperative complication was 27%. There was a significant difference in postoperative complication rates between patients at nutritional risk and those not at risk (37.4% vs. 22.9%, P = 0.006). Nutritional risk was identified as an independent predictor of postoperative complications (odds ratio, 3.05; P = 0.045). Nutritional risk increased the rate of anastomotic leakage (P = 0.027) and wound infection (P = 0.01). CONCLUSION: NRS may be a prognostic factor for postoperative complication after surgery for colorectal cancer. A large scaled prospective study is needed to confirm whether supplementing nutritional deficits reduces postoperative complication rates.

Advantages of Interval Laparoscopic Appendectomy for Periappendiceal Abscess

PURPOSE: Laparoscopic appendectomy is a common procedure for treatment of appendicitis. However, in some complicated cases, like periappendiceal abscess, deciding on treatment options is very challenging. Early appendectomy or interval appendectomy may be possible, but remains controversial. METHODS: We prospectively studied the advantages of interval appendectomy in 21 patients with periappendiceal abscess using a laparoscopic method versus 14 patients with immediate initial laparotomy. RESULTS: In the interval appendectomy group (INT group), in periappendiceal abscess, use of a laparoscopic method was advantageous in terms of operation time (p<0.001), less fasting time (p<0.001), and fewer postoperative complications (p=0.032). However, the total cost in the INT group was 1,686,000+/-940,000 South Korean won (KRW) compared with 1,506,000+/-322,000 KRW in the early appendectomy group (EAR group) (p=0.007) because patients in the INT group required two hospital visits. The total length of hospital stay postoperatively, was 7.31+/-2.726 days in the INT group, compared with 9.21+/-3.378 days in the EAR group (p=0.537). CONCLUSION: We recommend interval appendectomy as the preferable approach for the periappendiceal abscess, as it can result in more favorable postoperative surgical outcomes, fewer complications, and less antibiotic usage.

Advantages of Interval Laparoscopic Appendectomy for Periappendiceal Abscess

PURPOSE: Laparoscopic appendectomy is a common procedure for treatment of appendicitis. However, in some complicated cases, like periappendiceal abscess, deciding on treatment options is very challenging. Early appendectomy or interval appendectomy may be possible, but remains controversial. METHODS: We prospectively studied the advantages of interval appendectomy in 21 patients with periappendiceal abscess using a laparoscopic method versus 14 patients with immediate initial laparotomy. RESULTS: In the interval appendectomy group (INT group), in periappendiceal abscess, use of a laparoscopic method was advantageous in terms of operation time (p<0.001), less fasting time (p<0.001), and fewer postoperative complications (p=0.032). However, the total cost in the INT group was 1,686,000+/-940,000 South Korean won (KRW) compared with 1,506,000+/-322,000 KRW in the early appendectomy group (EAR group) (p=0.007) because patients in the INT group required two hospital visits. The total length of hospital stay postoperatively, was 7.31+/-2.726 days in the INT group, compared with 9.21+/-3.378 days in the EAR group (p=0.537). CONCLUSION: We recommend interval appendectomy as the preferable approach for the periappendiceal abscess, as it can result in more favorable postoperative surgical outcomes, fewer complications, and less antibiotic usage.

Occurrence and Prognosis of Symptomatic Venous Thromboembolism in Colorectal Cancer Surgery Patients

PURPOSE: Colorectal cancer (CRC) has a high risk for postoperative thromboembolic complications such as venous thromboembolism (VTE) compared to other surgical diseases, but the relationship between VTE and CRC in Asian patients remains poorly understood. The present study examined the incidence of symptomatic VTE in Korean patients who underwent surgery for CRC. We also identified risk factors, incidence and survival rate for VTE in these patients. MATERIALS AND METHODS: The patients were identified from the CRC database treated from January 2011 to December 2012 in a single institution. These patients were classified into VTE and non-VTE groups, their demographic features were compared, and the factors which had significant effects on VTE and mortality between the two groups were analyzed. RESULTS: We analyzed retrospectively a total of 840 patients and the incidence of VTE was 3.7% (31 patients) during the follow-up period (mean, 17.2 months). Histologic subtype (mucinous adenocarcinoma) and previous history of VTE affected the incidence of VTE on multivariate analysis. There was a statistically significant difference in survival rate between the VTE and non-VTE group, but VTE wasn't the factor affecting survival rate on multivariate analysis. Comparing differences in survival rate for each pathologic stage, there was only a significant difference in stage II patients. CONCLUSION: Among CRC patients after surgery, the incidence of VTE was approximately 3% within 1 year and development of VTE wasn't a significant risk factor for death in our study but these findings are not conclusive due to our small sample size.

Adenocarcinoma arising from Meckel's diverticulum in the ileum with malrotation of the midgut / 대한외과학회지

Meckel's diverticulum (MD) is a true congenital diverticulum that is remnant by incomplete obliteration of the omphalomesenteric duct. It is the most common congenital anomaly of the gastrointestinal tract, with an estimated prevalence of 2% (0.3% to 3% in autopsy studies). About 90% of MD occurs within 100 cm of the ileocecal valve. A primary malignant tumor arising within an MD is extremely uncommon. Malignancies are reported to account for only 0.5% to 3.2% of the complications. Carcinoids are the most common malignant tumors occurring in MD. Adenocarcinomas are extremely uncommon and very poor prognosis has been reported. We report a case of radiographically diagnosed chronic inflammatory mass caused by adenocarcinoma arising from MD in the ileum with malrotation of the midgut incidentally discovered at exploration.

Comparison between preoperative and postoperative concurrent chemoradiotherapy for rectal cancer: an institutional analysis

PURPOSE: To evaluate the treatment outcomes of preoperative versus postoperative concurrent chemoradiotherapy (CRT) on locally advanced rectal cancer. MATERIALS AND METHODS: Medical data of 114 patients with locally advanced rectal cancer treated with CRT preoperatively (54 patients) or postoperatively (60 patients) from June 2003 to April 2011 was analyzed retrospectively. 5-Fluorouracil (5-FU) or a precursor of 5-FU-based concurrent CRT (median, 50.4 Gy) and total mesorectal excision were conducted for all patients. The median follow-up duration was 43 months (range, 16 to 118 months). The primary end point was disease-free survival (DFS). The secondary end points were overall survival (OS), locoregional control, toxicity, and sphincter preservation rate. RESULTS: The 5-year DFS rate was 72.1% and 48.6% for the preoperative and postoperative CRT group, respectively (p = 0.05, the univariate analysis; p = 0.10, the multivariate analysis). The 5-year OS rate was not significantly different between the groups (76.2% vs. 69.0%, p = 0.23). The 5-year locoregional control rate was 85.2% and 84.7% for the preoperative and postoperative CRT groups (p = 0.98). The sphincter preservation rate of low-lying tumor showed significant difference between both groups (58.1% vs. 25.0%, p = 0.02). Pathologic tumor and nodal down-classification occurred after the preoperative CRT (53.7% and 77.8%, both p < 0.001). Acute and chronic toxicities were not significantly different between both groups (p = 0.10 and p = 0.62, respectively). CONCLUSION: The results confirm that preoperative CRT can be advantageous for improving down-classification rate and the sphincter preservation rate of low-lying tumor in rectal cancer.