Nam Kyu Kim

Comparative study of transrectal ultrasonography, pelvic computerized tomography, and magnetic resonance imaging in preoperative staging of rectal cancer.

PURPOSE: The preoperative assessment of rectal cancer wall invasion and regional lymph node metastasis is essential for the planning of optimal therapy. This study was done to determine the accuracy and clinical usefulness of transrectal ultrasonography, pelvic computed tomography, and magnetic resonance imaging in preoperative staging. METHODS: A total of 89 patients with rectal cancer were examined with transrectal ultrasonography (n=89), pelvic computed tomography (n=69), and magnetic resonance imaging with endorectal coil (n=73). The results obtained by these diagnostic modalities were compared with the histopathologic staging of specimens. RESULTS: In staging depth of invasion, the overall accuracy was 81.1 percent (72/89) by transrectal ultrasonography, 65.2 percent (45/69) by computed tomography, and 81 percent (59/73) by magnetic resonance imaging. Overstaging was 10 percent (9/89) by transrectal ultrasonography, 17.4 percent (12/69) by computed tomography, and 11 percent (8/73) by magnetic resonance imaging; and understaging was 8 of 89 (8.9 percent) by transrectal ultrasonography, 12 of 69 (17.4 percent) by computed tomography, and 6 of 73 (8 percent) by magnetic resonance imaging. In staging lymph node metastasis, the overall accuracy rate was 54 of 85 (63.5 percent) in transrectal ultrasonography, 39 of 69 (56.5 percent) in computed tomography, and 46 of 73 (63 percent) in magnetic resonance imaging. The sensitivity was 24 of 45 (53.3 percent) in transrectal ultrasonography, 14 of 25 (56 percent) in computed tomography, and 33 of 42 (78.5 percent) in magnetic resonance imaging; and specificity was 30 of 40 (75.0 percent) in transrectal ultrasonography, 25 of 44 (56.8 percent) in computed tomography, and 13 of 31 (41.9 percent) in magnetic resonance imaging. The accuracy in detection of positive lateral pelvic lymph nodes under magnetic resonance imaging (n=8) was 12.5 percent. The accuracy in detection of posterior vaginal wall invasion was 100 percent in transrectal ultrasonography (n=7) and 100 percent in magnetic resonance imaging (n=3), but 28.5 percent in computed tomography (n=7). CONCLUSIONS: Both transrectal ultrasonography and magnetic resonance imaging with endorectal coil exhibited similar accuracy and were superior to conventional computed tomography in preoperative assessment of depth of invasion and adjacent organ invasion. Because transrectal ultrasonography is a safer and more cost-effective modality than magnetic resonance imaging, transrectal ultrasonography is an appropriate method for preoperative staging of rectal cancer. Further efforts will be needed to provide a better staging of lymph node involvement.

Assessment of Sexual and Voiding Function After Total Mesorectal Excision With Pelvic Autonomic Nerve Preservation in Males With Rectal Cancer

AbstractPURPOSE: Total mesorectal excision with pelvic autonomic nerve preservation has been reported to be an optimal surgery for rectal cancer. It minimizes local recurrence and sexual and urinary dysfunction. The aim of this study was to assess the safety of total mesorectal excision with pelvic autonomic nerve preservation in terms of voiding and sexual function in males with rectal cancer. METHODS: We performed urine flowmetry using Urodyn® and a standard questionnaire using the International Index of Erectile Function and the International Prostate Symptom Score before and after surgery in 68 males with rectal cancer. RESULTS: Significant differences in mean maximal urinary flow rate and voided volume were seen before and after surgery (18.9 ± 5.7 vs. 13.7 ± 7.0, 240 ± 91.9 vs. 143 ± 78; P < 0.05, P < 0.05, respectively), but no differences in residual volume before and after surgery were apparent (4.4 ± 2.6 vs. 8.1 ± 4.4; P > 0.05). The total International Prostate Symptom Score was increased after surgery from 6.2 ± 5.8 to 9.8 ± 5.9 (P < 0.05). There were no changes of score for one of each of seven International Prostate Symptom Score items in 49 patients (73.5 percent) to 61 patients (89.7 percent). Five International Index of Erectile Function domain scores (erectile function, intercourse satisfaction, orgasmic function, sexual desire, and overall satisfaction) were significantly decreased after surgery (18.2 ± 9.3 vs. 13.5 ± 9, 8.4 ± 4.2 vs. 4.4 ± 2.9, 5.8 ± 2.9 vs. 4.4 ± 2.9, 6.1 ± 2.4 vs. 4.8 ± 2, 6.1 ± 2.2 vs. 4.5 ± 2.3, respectively; P < 0.05). Erection was possible in 55 patients (80.9 percent); penetration ability was possible in 51 patients (75 percent). Complete inability for erection and intercourse was observed in three patients (5.5 percent). Retrograde ejaculation was noted in 9 patients (13.2 percent). International Index of Erectile Function domains such as sexual desire and overall satisfaction were greatly decreased in 39 patients (57.4 percent) and 43 patients (63.2 percent), respectively. Multiple regression analysis of factors affecting postoperative sexual dysfunction showed that age older than 60 years (sexual desire, P = 0.019), within six months (erectile function, P = 0.04; intercourse satisfaction, P = 0.011; orgasmic function, P = 0.03), lower rectal cancer (erectile function, P = 0.02; intercourse satisfaction, P = 0.036; orgasmic function, P = 0.027) were significant factors adversely affecting sexual function. CONCLUSION: Total mesorectal excision with pelvic autonomic nerve preservation showed relative safety in preserving sexual and voiding function. The International Prostate Symptom Score and International Index of Erectile Function questionnaires were useful in assessing urinary and sexual function.

Comparative study of resection and radiofrequency ablation in the treatment of solitary colorectal liver metastases

BACKGROUND We compared outcomes in patients with solitary colorectal liver metastases treated by either hepatic resection (HR) or radiofrequency ablation (RFA). METHODS A retrospective analysis from a prospective database was performed on 67 consecutive patients with solitary colorectal liver metastases treated by either HR or RFA. RESULTS Forty-two patients underwent HR and 25 patients underwent RFA. The 5-year overall and local recurrence-free survival rates after HR (50.1% and 89.7%, respectively) were higher than after RFA (25.5% and 69.7%, respectively) (P = .0263 and .028, respectively). In small tumors less than 3 cm (n = 38), the 5-year survival rates between HR and RFA were similar, including overall (56.1% vs 55.4%, P = .451) and local recurrence-free (95.7% vs 85.6%, P = .304) survival rates. On multivariate analysis, tumor size, metastases treatment, and primary node status were significant prognostic factors. CONCLUSIONS HR had better outcomes than RFA for recurrence and survival after treatment of solitary colorectal liver metastases. However, in tumors smaller than 3 cm, RFA can be recommended as an alternative treatment to patients who are not candidates for surgery because the liver metastases is poorly located anatomically, the functional hepatic reserve after a resection would be insufficient, the patients comorbidity inhibits a major surgery, or extrahepatic metastases are present.

Whole genome analysis for liver metastasis gene signatures in colorectal cancer.

Liver metastasis is one of the major causes of death in colorectal cancer (CRC) patients. To understand this process, we investigated whether the gene expression profiling of matched colorectal carcinomas and liver metastases could reveal key molecular events involved in tumor progression and metastasis. We performed experiments using a cDNA microarray containing 17,104 genes with the following tissue samples: paired tissues of 25 normal colorectal mucosa, 27 primary colorectal tumors, 13 normal liver and 27 liver metastasis, and 20 primary colorectal tumors without liver metastasis. To remove the effect of normal cell contamination, we selected 4,583 organ‐specific genes with a false discovery rate (FDR) of 0.0067% by comparing normal colon and liver tissues using significant analysis of microarray, and these genes were excluded from further analysis. We then identified and validated 46 liver metastasis‐specific genes with an accuracy of 83.3% by comparing the expression of paired primary colorectal tumors and liver metastases using prediction analysis of microarray. The 46 selected genes contained several known oncogenes and 2 ESTs. To confirm that the results correlated with the microarray expression patterns, we performed RT‐PCR with WNT5A and carbonic anhydrase II. Additionally, we observed that 21 of the 46 genes were differentially expressed (FDR = 2.27%) in primary tumors with synchronous liver metastasis compared with primary tumors without liver metastasis. We scanned the human genome using a cDNA microarray and identified 46 genes that may play an important role in the progression of liver metastasis in CRC.

DNA methylation predicts recurrence from resected stage III proximal colon cancer

In colorectal cancer (CRC), DNA methylation anomalies define distinct subgroups termed CpG island methylator phenotype 1 (CIMP1), CIMP2, and CIMP‐negative. The role of this classification in predicting recurrence and disease‐free survival (DFS) in resected stage III CRC was evaluated.

Multicenter Analysis of Risk Factors for Anastomotic Leakage After Laparoscopic Rectal Cancer Excision The Korean Laparoscopic Colorectal Surgery Study Group

Objective:To assess the risk factors for clinical anastomotic leakage (AL) in patients undergoing laparoscopic surgery for rectal cancer. Background:Little data are available about risk factors for AL after laparoscopic rectal cancer resection. Methods:This was a retrospective analysis of 1609 patients with rectal cancer who had undergone laparoscopic surgery for rectal cancer with sphincter preservation. Clinical data related to AL were collected from 11 institutions. Univariate and multivariate analyses were performed to determine the risk factors for AL. Results:AL was noted in 101 (6.3%) of the patients. The leakage rate ranged from 2.0% to 10.3% for each hospital (P = 0.04). In patients without protective stomas (n = 1187), male sex [hazard ratio (HR), 3.468], advanced tumor stage (HR, 2.520), lower tumor level (HR, 2.418), preoperative chemoradiation (HR, 6.284), perioperative transfusion (HR, 10.705), and multiple firings of the linear stapler (HR, 6.181) were significantly associated with AL. Our theoretical model suggested that the HR for patients with 2 risk factors was significantly higher than that the HR for patients with no or only 1 risk factor. Conclusions:Male sex, low anastomosis, preoperative chemoradiation, advanced tumor stage, perioperative bleeding, and multiple firings of the linear stapler increased the risk of AL after laparoscopic surgery for rectal cancer. A diverting stoma might be mandatory in patients with 2 or more of the risk factors identified in this analysis.

Oncologic outcomes after neoadjuvant chemoradiation followed by curative resection with tumor-specific mesorectal excision for fixed locally advanced rectal cancer: Impact of postirradiated pathologic downstaging on local recurrence and survival

Objective:The purpose of this study was to determine the oncologic outcomes and clinical factors affecting survival in patients who underwent neoadjuvant chemoradiotherapy following tumor specific mesorectal excision for locally advanced, fixed rectal cancer. Summary Background Data:Neoadjuvant chemoradiation therapy has resulted in significant tumor downstaging, which enhances curative resection and subsequently improves local disease control for rectal cancer. However, oncologic outcomes, according to clinical factors, have not yet been fully understood in locally advanced and fixed rectal cancer. Methods:A total of 114 patients who had undergone neoadjuvant chemoradiation for advanced rectal cancer (T3 or T4 and node positive) were investigated retrospectively. Chemotherapy was administered intravenously with 5-FU and leucovorin during weeks 1 and 5 of radiotherapy. The total radiation dose was 5040 cGY in 25 fractions delivered over 5 weeks. Tumor-specific mesorectal excision was done 4 to 6 weeks after the completion of neoadjuvant chemoradiation. Survival and recurrence rates, according to the pathologic stage, were evaluated. Moreover, factors affecting survival were investigated. Results:The 5-year survival rates according to pathologic stage were: 100% in pathologic complete remission (n = 10), 80% in stage I (n = 23), 56.8% in stage II (n = 34), and 42.3% in stage III (n = 47) (P = 0.0000). Local, systemic, and combined recurrence rates were 11.4%, 22.8%, and 3.5%, respectively. Multivariate analysis showed that the pathologic N stage and operation method were the independent factors affecting survival rate. Conclusion:Pathologic complete remission showed excellent oncologic outcomes, and the pathologic N stage was the most important factor for oncologic outcomes.

Preoperative staging of rectal cancer with MRI: accuracy and clinical usefulness.

AbstractBackground: Preoperative staging is essential for planning of optimal therapy for patients with rectal cancer. Recently, magnetic resonance imaging (MRI) is used frequently because of its benefits of clear pelvic image are better than other diagnostic methods. The purpose of this study was to determine accuracy rates and clinical usefulness of MRI in preoperative staging of rectal cancer. Methods: Between February, 1997, and December, 1999, 217 patients with histologically proven rectal cancer were staged preoperatively and had surgical resections performed. MRI criteria for depth of invasion was determined by the degree of disruption of the rectal wall. Metastatic perirectal lymph nodes were considered to be present if they showed heterogenous texture, irregular margin, and enlargement (.10 mm). Results: The accuracy of the MRI for determining depth of invasion was 176/217 (81%) and regional lymph node invasion was 110/217 (63%). In the T stage, accuracy rate of T1 was 3/4 (75%), T2 was 20/37 (54%), T3 was 141/162 (87%), and T4 was 12/14 (86%), respectively. The specificity of lymph node invasion was 45/110 (41%) and the sensitivity was 91/107 (85%). The accuracy rate of regional lymph node involvement was 136/217 (63%). T1 and T2 were overstaged in 1/4 (25%) and 17/37 (46%), respectively, and T3 was understaged in 15/162 (9.2%). The accuracy rate to detect metastatic lateral pelvic lymph node was 4/14 (29%) after lateral pelvic lymph node dissection was done in 14 patients under MRI. The accuracy rate in assessing levator ani muscle tumor involvement was 8/11 (72%). Conclusions: MRI showed a good, comparable accuracy rate for determining depth of tumor invasion, compared with transrectal ultrasonography, which still has a low accuracy rate for detecting metastatic lymph node. MRI with endorectal coil may increase the accuracy rate of T1 and T2 lesions. In addition, clear sagittal and coronal sectional pelvic images can give a lot of information about adjacent organ invasion or any invasion of levator ani muscle. MRI can be useful for choosing an appropriate extent of lymph node dissection and type of surgery.

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.

Risk Factors for Anastomotic Leakage after Laparoscopic Intracorporeal Colorectal Anastomosis with a Double Stapling Technique

BACKGROUND Laparoscopic rectal transection carries the risk of anastomotic leakage because of its technical difficulty and long staple line with an inadequate cutting angle. Our objective was to investigate the risk factors affecting anastomotic leakage after laparoscopic intracorporeal colorectal anastomosis with a double stapling technique. STUDY DESIGN Between November 2006 and September 2008, 270 consecutive patients underwent laparoscopic sigmoidectomy and anterior resection with double stapling technique for distal sigmoid and rectal cancer. Data were collected prospectively. Univariate and multivariate analyses were performed to determine risk factors for anastomotic leakage. Additionally, we evaluated the relationship between the number of stapler firings and clinical parameters. RESULTS Anastomotic leakage was noted in 17 (6.3%) of 270 patients. In univariate analyses, tumor location (p = 0.021), operation time (p = 0.025), number of stapler firings (p = 0.040), and diameter of the circular stapler (p = 0.022) were significant risk factors for anastomotic leakage. Multivariate analyses showed that middle or lower rectal cancer was an independent factor affecting anastomotic leakage (p = 0.013). The number of stapler firings increased significantly in men (p = 0.023), in patients with a tumor at a lower level (p = 0.034), and in those with longer operation times (p < 0.001). CONCLUSIONS A reduction in the number of linear stapler firings is necessary to avoid anastomotic leakage after laparoscopic colorectal anastomosis with a double stapling technique. We recommend that a diverting ileostomy is mandatory in patients with middle and lower rectal cancer where multiple linear staplers were used.