Jeonghyun Kang

The impact of robotic surgery for mid and low rectal cancer: a case-matched analysis of a 3-arm comparison--open, laparoscopic, and robotic surgery.

Objective:The objective of this study was to clarify the impact of robotic surgery (RS) in the management of mid and low rectal cancer in comparison with open surgery (OS) and laparoscopic surgery (LS). Background:The benefits of RS in the treatment of rectal cancer have not yet been clearly described. Methods:Using propensity scores for adjustment of sex, age, body mass index, tumor stage, and tumor height, a well-balanced cohort with 165 patients in each group, was created by matching each patient who underwent RS as the study group with one who underwent OS or LS as the control group (RS:OS = 1:1, RS:LS = 1:1 match). Pathological results, morbidity, perioperative recovery, and short-term oncological results were compared between the 3 groups. Results:In RS and LS, the time to first flatus and resumed soft diet and length of hospital stay were significantly shortened compared with OS. Robotic surgery showed better recovery outcomes than LS with regard to time to resumed soft diet and length of hospital stay. The visual analog scale was significantly lower in the RS than in the OS and LS from postoperative days 1 to 5. The voiding problem and circumferential resection margin involvement rate were significantly lower in the RS group than in the OS group. No significant difference in 2-year disease-free survival was observed among the 3 groups. Conclusions:Robotic surgery may be an effective tool in the effort to maximize the advantages of minimally invasive surgery in the management of mid to low rectal cancer.

Optimal Total Mesorectal Excision for Rectal Cancer: the Role of Robotic Surgery from an Expert's View

Total mesorectal excision (TME) has gained worldwide acceptance as a standard surgical technique in the treatment of rectal cancer. Ever since laparoscopic surgery was first applied to TME for rectal cancer, with increasing penetration rates, especially in Asia, an unstable camera platform, the limited mobility of straight laparoscopic instruments, the two-dimensional imaging, and a poor ergonomic position for surgeons have been regarded as limitations. Robotic technology was developed in an attempt to reduce the limitations of laparoscopic surgery. The robotic system has many advantages, including a more ergonomic position, stable camera platform and stereoscopic view, as well as elimination of tremor and subsequent improved dexterity. Current comparison data between robotic and laparoscopic rectal cancer surgery show similar intraoperative results and morbidity, postoperative recovery, and short-term oncologic outcomes. Potential benefits of a robotic system include reduction of surgeons fatigue during surgery, improved performance and safety for intracorporeal suture, reduction of postoperative complications, sharper and more meticulous dissection, and completion of autonomic nerve preservation techniques. However, the higher cost for a robotic system still remains an obstacle to wide application, and many socioeconomic issues remain to be solved in the future. In addition, we need more concrete evidence regarding the merits for both patients and surgeons, as well as the merits compared to conventional laparoscopic techniques. Therefore, we need large-scale prospective randomized clinical trials to prove the potential benefits of robot TME for the treatment of rectal cancer.

Tumor Volume Changes Assessed by Three-Dimensional Magnetic Resonance Volumetry in Rectal Cancer Patients After Preoperative Chemoradiation: The Impact of the Volume Reduction Ratio on the Prediction of Pathologic Complete Response

PURPOSE The aim of this study was to determine the correlation between tumor volume changes assessed by three-dimensional (3D) magnetic resonance (MR) volumetry and the histopathologic tumor response in rectal cancer patients undergoing preoperative chemoradiation therapy (CRT). METHODS AND MATERIALS A total of 84 patients who underwent preoperative CRT followed by radical surgery were prospectively enrolled in the study. The post-treatment tumor volume and tumor volume reduction ratio (% decrease ratio), as shown by 3D MR volumetry, were compared with the histopathologic response, as shown by T and N downstaging and the tumor regression grade (TRG). RESULTS There were no significant differences in the post-treatment tumor volume and the volume reduction ratio shown by 3D MR volumetry with respect to T and N downstaging and the tumor regression grade. In a multivariate analysis, the tumor volume reduction ratio was not significantly associated with T and N downstaging. The volume reduction ratio (>75%, p = 0.01) and the pretreatment carcinoembryonic antigen level (< or =3 ng/ml, p = 0.01), but not the post-treatment volume shown by 3D MR (< or = 5 ml), were, however, significantly associated with an increased pathologic complete response rate. CONCLUSION More than 75% of the tumor volume reduction ratios were significantly associated with a high pathologic complete response rate. Therefore, limited treatment options such as local excision or simple observation might be considered after preoperative CRT in this patient population.

Prognostic impact of the lymph node ratio in rectal cancer patients who underwent preoperative chemoradiation

The purpose of this study was to investigate the prognostic impact of the lymph node ratio (LNR) in ypN‐positive rectal cancer patients who received preoperative chemoradiation (preop‐CRT).

Thymidylate Synthase Gene Polymorphism Affects the Response to Preoperative 5-Fluorouracil Chemoradiation Therapy in Patients With Rectal Cancer

PURPOSE This study aims to correlate thymidylate synthase (TS) gene polymorphisms with the tumor response to preoperative 5-fluorouracil (5-FU)-based chemoradiation therapy (CRT) in patients with rectal cancer. METHODS AND MATERIALS Forty-four patients with rectal cancer treated with 5-FU-based preoperative CRT were prospectively enrolled in this study. Thymidylate synthase expression and TS gene polymorphisms were evaluated in tumor obtained before preoperative CRT and were correlated with the pathologic response, as assessed by histopathologic staging (pTNM) and tumor regression grade. RESULTS Patients exhibited 2R/3R and 3R/3R tandem repeat polymorphisms in the TS gene. With regard to TS expression in these genotypes, 2R/3RC and 3RC/3RC were defined as the low-expression group and 2R/3RG, 3RC/3RG, and 3RG/3RG as the high-expression group. There was no significant correlation between TS expression and tumor response. There was no significant difference in the tumor response between patients homozygous for 3R/3R and patients heterozygous for 2R/3R. However, 13 of 14 patients in the low-expression group with a G>C single-nucleotide polymorphism (SNP) (2R/3RC [n = 5] or 3RC/3RC [n = 9]) exhibited a significantly greater tumor downstaging rate, as compared with only 12 of 30 patients in the high-expression group without the SNP (2R/3RG [n = 10], 3RC/3RG [n = 9], or 3RG/3RG [n = 11]) (p = 0.001). The nodal downstaging rate was also significantly greater in this low-expression group, as compared with the high-expression group (12 of 14 vs. 14 of 30, p = 0.014). However, there was no significant difference in the tumor regression grade between these groups. CONCLUSIONS This study suggests that SNPs within the TS enhancer region affect the tumor response to preoperative 5-FU-based CRT in rectal cancer.

A stercoral perforation of the descending colon

This is a case report on a stercoral perforation of the descending colon that was not adequately treated in the first operation. Re-operation was required in order to revise the primary repair site and to remove the impacted fecaloma.

Cost-effectiveness of robotic surgery for rectal cancer focusing on short-term outcomes: a propensity score-matching analysis.

AbstractAlthough the total cost of robotic surgery (RS) is known to be higher than that of laparoscopic surgery (LS), the cost-effectiveness of RS has not yet been verified. The aim of the study is to clarify the cost-effectiveness of RS compared with LS for rectal cancer.From January 2007 through December 2011, 311 and 560 patients underwent totally RS and conventional LS for rectal cancer, respectively. A propensity score-matching analysis was performed with a ratio of 1:1 to reduce the possibility of selection bias. Costs and perioperative short-term outcomes in both the groups were compared. Additional costs due to readmission were also analyzed.The characteristics of the patients were not different between the 2 groups. Most perioperative outcomes were not different between the groups except for the operation time. Complications within 30 days of surgery were not significantly different. Total hospital charges and patients’ bill were higher in RS than in LS. The total hospital charges for patients who recovered with or without complications were higher in RS than in LS, although their short-term outcomes were similar. In patients with complications, the postoperative course after RS appeared to be milder than that of LS. Total hospital charges for patients who were readmitted due to complications were similar between the groups.RS showed similar short-term outcomes with higher costs than LS. Therefore, cost-effectiveness focusing on short-term perioperative outcomes of RS was not demonstrated.

Learning Curve for Single-Incision Laparoscopic Anterior Resection for Sigmoid Colon Cancer

BACKGROUND Compared with conventional laparoscopic surgery, single-incision laparoscopic surgery produces better cosmetic benefits. The aim of this study was to investigate the learning curve for single-incision laparoscopic anterior resection (SILAR) for sigmoid colon cancer using multidimensional methods. STUDY DESIGN From September 2009 through May 2014, one hundred and thirteen patients underwent SILAR for sigmoid colon cancer by a single surgeon at Severance Hospital. The learning curve was analyzed using moving average, cumulative sum control chart (CUSUM), and risk-adjusted CUSUM methods. For risk-adjusted CUSUM, surgical failure was defined as conversion to open surgery or conventional laparoscopic surgery, morbidity within 30 days after surgery, <12 harvested lymph nodes, or local recurrence. RESULTS Using the moving average method, the peak point for operation time occurred at the 65(th) case (173 minutes). The CUSUM method also showed the operation time peak point at the 65(th) case. However, the risk-adjusted CUSUM curve did not ascend after the 61st case. The operation time and hospital stay for the 60 phase 1 patients (cases 1 to 60) were longer than for 53 phase 2 patients (cases 61 to 113) (166.6 vs 140 minutes; p < 0.001 and 7.1 vs 5.5 days; p = 0.009). Phase 2 patients had a significantly larger tumor diameter and more harvested lymph nodes. CONCLUSIONS The learning curve for SILAR for sigmoid colon cancer was 61 to 65 cases according to multidimensional statistical analyses. Single-incision laparoscopic anterior resection is feasible for surgeons experienced in laparoscopic surgery. However, SILAR required more cases for proficiency than the number previously reported for conventional laparoscopic surgery, likely because of its technical challenges.

Multicenter Analysis of Long-Term Oncologic Impact of Anastomotic Leakage After Laparoscopic Total Mesorectal Excision: The Korean Laparoscopic Colorectal Surgery Study Group.

Abstract This study aims to validate the oncologic outcomes of anastomotic leakage (AL) after laparoscopic total mesorectal excision (TME) in a large multicenter cohort. The impact of AL after laparoscopic TME for rectal cancer surgery has not yet been clearly described. This was a multicenter retrospective study of 1083 patients who underwent laparoscopic TME for nonmetastatic rectal cancer (stage 0–III). AL was defined as an anastomotic complication within 30 days of surgery irrespective of requiring a reoperation or interventional radiology. Estimated local recurrence (LR), disease-free survival (DFS), and overall survival (OS) were compared between the leakage group and the no leakage group using the log-rank method. Multivariate Cox-regression analysis was used to adjust confounding for survival. The incidence of AL was 6.4%. Mortality within 30 days of surgery occurred in 1 patient (1.4%) in the leakage group and 2 patients (0.2%) in the no leakage group. The leakage group showed a higher LR rate (6.4% vs 1.8%, P = 0.011). Five-year DFS and OS were significantly lower in the leakage group than the no leakage group (DFS 71.7% vs 82.1%, P = 0.016, OS 81.8% vs 93.5%, P = 0.007). Multivariate analysis showed that AL was an independent poor prognostic factor for DFS and OS (hazard ratio [HR] = 1.6; 95% confidence intervals [CI]: 1.0–2.6; P = 0.042, HR = 2.1; 95% CI: 1.0–4.2; P = 0.028, respectively). AL after laparoscopic TME was significantly associated with an increased rate of LR, systemic recurrence and poor OS.

Transanal specimen extraction in robotic rectal cancer surgery

The aim of this study was to identify the benefits of robotic transanal specimen extraction (RTSE) compared with minilaparotomy specimen extraction (MSE).