Multicenter study of prognostic factors in paraaortic lymph node dissection for metastatic colorectal cancer.

Purpose: The role of paraaortic lymph node dissection (PALND) in colorectal cancer (CRC) has been less evaluated than surgical treatments for other distant metastases. We evaluated surgical outcomes after PALND and identified prognostic factors. Methods: The medical records of patients who underwent PALND for paraaortic lymph node metastasis (PALNM) were reviewed retrospectively. All patients were categorized into the M1a group (isolated PALNM, n = 27), and the M1bc group (distant metastases other than PALNM, n = 26). Three severity factors (PALNM-SF: number of harvested paraaortic lymph nodes [hLN], ≥14; number of metastatic paraaortic lymph nodes [mLN], ≥5; and lymph nodes ratio [mLN/hLN], ≥0.5) were defined to determine their effects on survival. Results: The 5-year overall survival (OS) of the M1a and M1bc groups were 61.1% and 6.4%, respectively (P = 0.0013). The 5-year disease-free survival (DFS) of the M1a group was 47.4%, and the 3-year DFS of the M1bc group was 9.1% (P < 0.001). Patients with 2 or more PALNM-SFs showed worse OS than those with 1 PALNM-SF (P = 0.017). In multivariate analysis, M1bc (non-isolated PALNM) was the only significant factor for survival. In the M1a group, patients with 2 or more PALNM-SFs showed significantly worse survival than those with a single PALNM-SF. In multivariate analysis, 2 or more PALNM-SF was a significant factor for survival. Conclusion: PALND for CRC provided favorable outcomes in the survival of an isolated PALNM, although this was uncertain for non-isolated PALNMs. The PALNM-SFs helped assess the prognosis after PALND.

Nomogram for predicting the overall survival of underweight patients with colorectal cancer: a clinical study.

BACKGROUND: An underweight individual is defined as one whose Body Mass Index (BMI) is < 18.5 kg/m2. Currently, the prognosis in patients with colorectal cancer (CRC) who are also underweight is unclear. METHODS: Information on South Korean patients who underwent curative resection for CRC without distant metastasis was collected from health insurance registry data between January 2014 and December 2016. We compared the overall survival (OS) of underweight and non-underweight (BMI ≥ 18.5 kg/m2) patients after adjusting for confounders using propensity score matching. A nomogram to predict OS in the underweight group was constructed using the significant risk factors identified in multivariate analysis. The predictive and discriminative capabilities of the nomogram for predicting 3- and 5-year OS in the underweight group were validated and compared with those of the tumor, node, and metastasis (TNM) staging system in the training and validation sets. RESULTS: A total of 23,803 (93.6%) and 1,644 (6.4%) patients were assigned to the non-underweight and underweight groups, respectively. OS was significantly worse in the underweight group than in the non-underweight group for each pathological stage (non-underweight vs. underweight: stage I, 90.1% vs. 77.1%; stage IIA, 85.3% vs. 67.3%; stage IIB/C, 74.9% vs. 52.1%; and stage III, 73.2% vs. 59.4%, P < 0.001). The calibration plots demonstrated that the nomogram exhibited satisfactory consistency with the actual results. The concordance index (C-index) and area under the receiver operating characteristic curve (AUC) of the nomogram exhibited better discriminatory capability than those of the TNM staging system (C-index, nomogram versus TNM staging system: training set, 0.713 versus 0.564, P < 0.001; validation set, 0.691 versus 0.548, P < 0.001; AUC for 3- and 5- year OS, nomogram versus TNM staging system: training set, 0.748 and 0.741 versus 0.610 and 0.601; validation set, 0.715 and 0.753 versus 0.586 and 0.579, respectively). CONCLUSIONS: Underweight patients had worse OS than non-underweight patients for all stages of CRC. Our nomogram can guide prognostic predictions and the treatment plan for underweight patients with CRC.

Prognosis and Sensitivity of Adjuvant Chemotherapy in Mucinous Colorectal Adenocarcinoma without Distant Metastasis.

In colorectal cancer, whereas mucinous adenocarcinoma (MAC) has several poor clinical prognostic factors compared to adenocarcinoma (AC), the prognosis of MAC remains controversial. We evaluated the prognosis of MAC without distant metastasis and the effects of adjuvant chemotherapy using health insurance registry data managed by South Korea. Patients with colorectal cancer between January 2014 and December 2016 were included (AC, 22,050 [96.8%]; MAC, 729 [3.2%]). We observed no difference in overall survival (OS) between AC and MAC in stages I and II. However, MAC showed a worse OS than AC in stage III disease, especially in patients administered chemotherapy (p < 0.001). These findings persisted after propensity score matching of clinical characteristics between AC and MAC. In addition, transcriptome analysis of The Cancer Genome Atlas (TCGA) data showed increased chemoresistance-associated pathways in MAC compared to AC. In consensus molecular subtypes (CMS) classification, unlike in AC, CMSs 1, 3, and 4 comprised most of MAC and the proportions of CMSs 3 and 4 increased with stage progression. These results suggest clues to overcome resistance to chemotherapy and develop targeted treatments in MAC.

Treatment outcomes of patients with involved resection margin after rectal cancer surgery: A nationwide population-based cohort study in South Korea.

BACKGROUND: The involvement of resection margins after rectal cancer surgery by malignant tumors is a negative prognostic factor. Therefore, it is important to analyze treatment outcomes and establish adjuvant therapy. METHODS: The Health Insurance Review and Assessment Service collects data from medical institutions in South Korea. We reviewed the database of this prospectively collected cohort for patients who underwent curative resection for rectal cancer. RESULTS: Of the 5,620 patients, 113 (2.0%) were diagnosed with resection margin involvement after surgery. The resection margins of patients with mid-rectal cancer, pathologic stage III, mucinous/signet ring cell carcinoma, and undergoing emergency surgery were more frequently involved. Neoadjuvant chemoradiotherapy was a significant preventive factor for resection margin involvement (odds ratio = 0.53; 95% confidence interval [CI], 0.32-0.87; p = 0.012). The OS of patients with adjuvant treatment was better than that of patients without adjuvant treatment (5-year overall survival [OS]: 62.8% vs. 46.3%, p = 0.02). The administration of chemoradiotherapy was also significantly associated with better OS (hazard ratio = 0.36; 95% CI, 0.17-0.77; p = 0.009). CONCLUSION: Efforts to acquire wider resection margins are necessary for patients with mid-rectal cancer, pathologic stage III, mucinous/signet ring cell carcinoma, and emergency surgery. Neoadjuvant chemoradiotherapy was a significant preventive factor for involved resection margin. Patients with resection margin involvement showed better OS after adjuvant treatment than those without adjuvant treatment. The adjuvant chemoradiotherapy was helpful to prevent the worse prognosis of these patients.

Clinical characteristics of rectal cancer patients with neoadjuvant chemoradiotherapy: a nationwide population-based cohort study in South Korea.

PURPOSE: Neoadjuvant chemoradiotherapy has been accepted as a standard treatment for stage II-III rectal cancer. This study aimed to evaluate the clinical characteristics of patients who underwent neoadjuvant chemoradiotherapy for rectal cancer and effects on overall survival (OS) of neoadjuvant chemoradiotherapy in South Korea. METHODS: Patients who underwent curative resection for rectal cancer from 2014 to 2016 were retrospectively reviewed from the database of the National Quality Assessment program in South Korea. Patients were categorized into the upfront surgery group and neoadjuvant chemoradiotherapy group. We evaluated factors associated with the administration of neoadjuvant chemoradiotherapy and its effects on OS. Inverse probability of treatment weighting was performed to account for baseline differences between subgroups. RESULTS: A total of 6,141 patients were categorized into the upfront surgery group (n = 4,237) and neoadjuvant chemoradiotherapy group (n = 1,904). The neoadjuvant chemoradiotherapy was more frequently administered to male, midrectal cancer, and younger patients. In the neoadjuvant chemoradiotherapy group, old age, underweight, and pathologic stage were significant risk factors of OS, and male sex, the level of tumor and clinical stages were not associated with OS. After adjustment, the OS of the neoadjuvant chemoradiotherapy group followed the OS of the upfront surgery group of the same pathologic stage. CONCLUSION: Male sex and the level of tumor were not related to the OS of rectal cancer patients with neoadjuvant chemoradiotherapy. The OS of patients who underwent neoadjuvant chemoradiotherapy was decided by their pathologic stages regardless of clinical stages.

Effects of the proximity of metastasis to the central vessels of the liver on surgical outcomes and survival in colorectal cancer with liver metastasis.

BACKGROUND: Resectability of liver metastasis is important to establish a treatment strategy for patients with colorectal cancer. We aimed to evaluate the effect of the distance from metastasis to the centre of the liver on surgical outcomes and survival after hepatectomy. METHODS: The clinical data of a total of 155 patients who underwent hepatectomy for colorectal cancer with liver metastasis were retrospectively reviewed. We measured the minimal length from metastasis to the bifurcation of the portal vein at the primary branch of the Glissonean tree and defined it as 'centrality'. The postoperative outcomes and survival among the patients were then analysed. RESULTS: Anatomic resections were more frequently performed, and the operative time was longer in the patients with high centrality (≤1.5 cm) than in the patients with low centrality (>1.5 cm). A size of ≥5 cm for the largest lesion, a number of lesions of ≥3 and centrality of ≤1.5 cm were found to be the independent risk factors of a positive resection margin after hepatectomy. The patients with high centrality showed worse recurrence-free survival than those with low centrality; however, there was no significant difference found in the overall survival. In the multivariate analysis, high centrality was not found to be associated with worse recurrence-free and overall survival. CONCLUSION: Centrality significantly affected the surgical outcomes and treatment strategy for liver metastasis but did not influence the survival of the patients with colorectal cancer. Active efforts through surgical resections are important to treat liver metastasis of high centrality.

Effect of anaemia on the response to preoperative chemoradiotherapy for rectal cancer.

BACKGROUNDS: Radiation therapy with concurrent chemotherapy is an important treatment for rectal cancer, especially for advanced stage disease. Low serum haemoglobin levels are accepted as a negative indicator in the response to radiation therapy. This study aimed to evaluate the relationship between anaemia and the response to preoperative chemoradiotherapy for rectal cancer and its effect on oncologic outcomes. METHODS: We retrospectively reviewed medical records of primary rectal cancer patients who were treated with preoperative chemoradiotherapy followed by total mesorectal excision between January 2011 and December 2015. Anaemia was defined as serum haemoglobin levels ≤9 g/dL before or during radiotherapy. Patients were divided into good and poor responders according to pathologic tumour regression grades. The effect of anaemia on the response to radiation therapy, recurrence-free survival and overall survival were analysed after subgroup analysis. RESULTS: Overall, 301 and 394 patients were categorized into good and poor responder groups, respectively. Proportions of anaemia patients were higher in the poor responder group than in the good responder group (7.6% versus 4.0%, P = 0.042). Anaemia was associated with less pathologic complete regression but was not a risk factor for worse recurrence-free or overall survival. There was no significant difference in survival between patients with and without anaemia. CONCLUSION: Haemoglobin levels ≤9 g/dL before or during radiotherapy were risk factors for achieving pathologic complete regression after preoperative chemoradiotherapy for rectal cancer. However, anaemia was not independently associated with worse survival outcomes.

Short-term Outcomes of Elective 2-Stage Restorative Proctocolectomy for Ulcerative Colitis in Korea: Does Laparoscopy Have Benefits?

PURPOSE: This study aimed to compare the short-term outcomes of the open and laparoscopic approaches to 2-stage restorative proctocolectomy (RPC) for Korean patients with ulcerative colitis (UC). METHODS: We retrospectively analyzed the medical records of 73 patients with UC who underwent elective RPC between 2009 and 2016. Patient characteristics, operative details, and postoperative complications within 30 days were compared between the open and laparoscopic groups. RESULTS: There were 26 cases (36%) in the laparoscopic group, which had a lower mean body mass index (P = 0.025), faster mean time to recovery of bowel function (P = 0.004), less intraoperative blood loss (P = 0.004), and less pain on the first and seventh postoperative days (P = 0.029 and P = 0.027, respectively) compared to open group. There were no deaths, and the overall complication rate was 43.8%. There was no between-group difference in the overall complication rate; however, postoperative ileus was more frequent in the open group (27.7% vs. 7.7%, P = 0.043). Current smoking (odds ratio [OR], 44.4; P = 0.003) and open surgery (OR, 5.4; P = 0.014) were the independent risk factors for postoperative complications after RPC. CONCLUSION: Laparoscopic RPC was associated with acceptable morbidity and faster recovery than the open approach. The laparoscopic approach is a feasible and safe option for surgical treatment for UC in selective cases.

Resident Learning Curve for Laparoscopic Appendectomy According to Seniority.

PURPOSE: To delineate the learning curve (LC) for laparoscopic appendectomy (LA) performed by residents according to seniority in training. METHODS: Between October 2015 and November 2016, 150 patients underwent LA by three residents (in their first, second, and third year of training) under supervision. The patients were non-randomly assigned to each resident. The data were reviewed and analyzed retrospectively from prospectively collected database. The perioperative outcomes were compared between the three residents including operation time, complication, conversion, and so on. The LCs were evaluated by the moving average method and cumulative sum control chart (CUSUM) for operation time and surgical completion. RESULTS: Baseline characteristics and perioperative outcomes were similar except for age and location of the appendix among the three groups. Operation time was not different among the three residents (43.9, 45.3, and 48.4 min for A, B, and C, respectively). The moving average method for operation time showed a decreasing tendency for all residents. CUSUM for operation time showed that the peak points occurred at the 24th, 18th, and 31st cases for resident A, B, and C, respectively. In terms of surgical failure, residents A, B, and C reached steady states after the 35th, 11th, and 16th cases, respectively. Perforation of the appendix base was the only risk factor for surgical failure. CONCLUSION: The LC for LA by residents was 11-35 cases according to multidimensional statistical analyses. The accumulation of surgical experience of residents might affect the LC, especially for surgical completion rather than for operation time.

Long-term Transanal Excision Outcomes in Patients With T1 Rectal Cancer: Comparative Analysis of Radical Resection.

PURPOSE: Transanal excision (TAE) is an alternative surgical procedure for early rectal cancer. This study compared long-term TAE outcomes, in terms of survival and local recurrence (LR), with total mesorectal excision (TME) in patients with pathologically confirmed T1 rectal cancer. METHODS: T1 rectal adenocarcinoma patients who underwent surgery from 1990 to 2011 were retrospectively reviewed. Patients that were suspected to have preoperative lymph node metastasis were excluded. Demographics, recurrence, and survival were analyzed based on TAE and TME surgery. RESULTS: Of 268 individuals, 61 patients (26%) underwent TAE, which was characterized by proximity to the anus, submucosal invasion depth, and lesion infiltration, compared with TME patients (P < 0.001-0.033). During a median follow-up of 10.4 years, 12 patients had systemic and/or LR. Ten-year cancer-specific survival in the TAE and TME groups was not significantly different (98% vs. 100%). However, the 10-year LR rate in the TAE group was greater than that of TME group (10% vs. 0%, P < 0.001). Although 5 of the 6 TAE patients with LR underwent salvage surgery, one of the patients eventually died. The TAE surgical procedure (hazard ratio, 19.066; P = 0.007) was the only independent risk factor for LR. CONCLUSION: Although long-term survival after TAE was comparable to that after TME, TAE had a greater recurrence risk than TME. Thus, TAE should only be considered as an alternative surgical option for early rectal cancer in selected patients.

Intestinal endometriosis: Diagnostic ambiguities and surgical outcomes.

BACKGROUND: Endometriosis is a common disease for women of reproductive age. However, when it involves intestines, it is difficult to diagnose preoperatively because its symptoms overlap with other diseases and the results of evaluations can be unspecific. Thus it is important to know the clinical characteristics of intestinal endometriosis and how to exactly diagnose. AIM: To analyze patients in whom intestinal endometriosis was diagnosed after surgical treatments, and to evaluate the clinical characteristics of preoperatively misdiagnosed cases. METHODS: We retrospectively reviewed the pathologic reports of 30 patients diagnosed as having intestinal endometriosis based on surgical specimens between January 2000 and December 2017. We reviewed their clinical characteristics and surgical outcomes. RESULTS: Twenty-three (76.6%) patients showed symptoms associated with endometriosis, with dysmenorrhea being the most common (n = 9, 30.0%). Thirteen patients (43.3%) had a history of pelvic surgeries. Ten patients (33.3%) had a history of treatment for endometriosis. Only 4 patients (13.3%) had a diagnosis of endometriosis based on endoscopic biopsy findings. According to preoperative evaluations, 13 patients (43.3%) had an initial diagnosis of pelvic endometriosis and 17 patients (56.6%) were misdiagnosed as having other diseases. The most common misdiagnosis was submucosal tumor in the large intestine (n = 8, 26.7%), followed by malignancies of the colon/rectum (n = 3, 10.0%) and ovary (n = 3, 10.0%). According to the Clavien-Dindo classification, 5 complications were grade I or II and 2 complications were grade IIIa. The median follow-up period was 26.9 (0.6-132.1) mo, and only 1 patient had a recurrence of endometriosis. CONCLUSION: Intestinal endometriosis is difficult to diagnose preoperatively because it mimics various intestinal diseases. Thus, if women of reproductive age have ambiguous symptoms and signs with nonspecific radiologic and/or endoscopic findings, intestinal endometriosis should be included in the differential diagnosis.

Does total regression of primary rectal cancer after preoperative chemoradiotherapy represent "no tumor" status?

PURPOSE: Insistence that total regression of primary tumor would not represent long-term oncologic outcomes has been raised. Therefore, this study aimed to evaluate the outcomes of these patients after preoperative chemoradiotherapy (PCRT) and radical surgery and to evaluate the associated risk factors. METHODS: We included 189 patients with rectal cancer who showed total regression of the primary tumor after PCRT, followed by radical resection, between 2001 and 2012. Recurrence-free survival (RFS) was calculated using the Kaplan-Meier method, and the results were compared with 77 patients with Tis rectal cancer who received only radical resection. Factors associated with RFS were evaluated using Cox regression analysis. RESULTS: Sphincter-saving resection was performed for 146 patients (77.2%). Adjuvant chemotherapy was administered to 168 patients (88.9%). During the follow-up period, recurrence occurred in 17 patients (9%). The 5-year RFS was 91.3%, which was significantly lower than that of patients with Tis rectal cancer without PCRT (P = 0.005). In univariate analysis, preoperative CEA and histologic differentiation were associated with RFS. However, no factors were found to be associated with RFS. CONCLUSION: RFS was lower in patients with total regression of primary rectal cancer after PCRT than in those with Tis rectal cancer without PCRT, and it would not be considered as the same entity with early rectal cancer or "disappeared tumor" status.

Transanal minimally invasive surgery as a treatment option for a completely occluded anastomosis after low anterior resection: A new approach to severe anastomotic stenosis.

New techniques have been developed to treat severe anastomotic strictures after rectal surgery. This report describes a new approach using transanal minimally invasive surgery for the treatment of complete anastomotic occlusion. A 49-year-old man presented with a completely occluded anastomosis after low anterior resection with temporary ileostomy for rectal cancer. The lumen was completely obstructed with a blind wall. A transanal surgical approach was used to treat the obstruction. Water-soluble radiopaque contrast medium was injected intraoperatively to identify the proximal lumen, and an incision was made by electrocautery until the luminal diameter was sufficient. There was no sign of bleeding or perforation after surgery. The patient underwent ileostomy takedown after all the chemotherapy sessions were completed. This report shows that transanal minimally invasive surgery is safe and feasible for the treatment of complete anastomotic occlusions requiring invasive interventions.

Comparison of Anthropometric Parameters after Ultralow Anterior Resection and Abdominoperineal Resection in Very Low-Lying Rectal Cancers.

BACKGROUND AND AIM: Ultralow anterior resection (uLAR) is a sphincter-saving procedure for very low-lying rectal cancers. This procedure, however, has complications related to defecation which can aggravate the patient's quality of life postoperatively. In this study, we compared the anthropometric and nutritional parameters after uLAR and abdominoperineal resection (APR). METHODS: We retrospectively reviewed the data of patients who underwent either uLAR or APR in 2012 for rectal cancers within 3 cm from the anal verge. Data including body weight, body mass index (BMI), levels of total protein, albumin, and hemoglobin and lymphocyte count were analyzed. We compared the changes of these parameters before operations to 3 years after discharge between uLAR and APR groups by ANOVA for repeated measures and Bonferroni comparison method. RESULTS: After 3 years of discharge, the body weight and BMI of the APR group were fully recovered to the preoperative levels; however, those of the uLAR group did not. The hemoglobin level in the APR group was recovered to the preoperative level within 3 months of discharge; however, that in the uLAR group was recovered after 1 year of discharge. CONCLUSIONS: Recovery of anthropometric and nutritional status of patients was more stable after APR than after uLAR. These findings might indirectly reflect the low anterior syndrome effect of uLAR and help colorectal surgeons in selecting better surgical methods and in better counseling patients with very low-lying rectal cancer.

Risk Factors and Adequate Management for Complications of Bevacizumab Treatment Requiring Surgical Intervention in Patients With Metastatic Colorectal Cancer.

BACKGROUND: Bevacizumab (BV) has been approved for treating colorectal cancer since 2004. Although BV use may lead to adverse effects, few studies have reported incidences requiring surgical intervention. We aimed to identify the risk factors and adequate interventions for complications requiring surgical intervention after BV treatment. PATIENTS AND METHODS: We retrospectively reviewed the records of patients with metastatic colorectal cancer treated with BV in our institute from January 2009 to December 2016. The baseline patient characteristics were used to evaluate the potential risk factors for complications requiring surgery. RESULTS: Of the 1008 patients recruited for this study, 60 (5.9%) experienced complications necessitating surgery after BV therapy. Gastrointestinal perforation was the most frequently observed complication, occurring in 36 patients (3.5%), and diverting colostomy was the most commonly performed intervention (22 patients, 36.6%). Multivariate analysis helped identify poor differentiation, signet ring cell carcinoma, stent insertion status, rectal location of the primary tumor, and intact primary tumor status as the risk factors. Survival time remained unchanged regardless of a complication that required surgery. CONCLUSION: Careful monitoring during BV treatment for metastatic colorectal cancer is essential for patients who have a predisposition to complications that may require surgery. After detection, adequate and timely surgical management is imperative for ensuring patient survival.