Byung So Min

Long-term outcome of palliative therapy for malignant colorectal obstruction in patients with unresectable metastatic colorectal cancers: endoscopic stenting versus surgery

BACKGROUND Self-expandable metal stents (SEMSs) provide a promising alternative for initial palliation of malignant bowel obstruction. However, data on the long-term outcomes of SEMSs are limited. OBJECTIVE The aim of this study was to compare the long-term outcomes of endoscopic stenting with those of surgery for palliation in patients with incurable obstructive colorectal cancer. DESIGNS AND SETTING: A retrospective study. PATIENTS From January 2000 to December 2008, patients with incurable obstructive colorectal cancer who were treated with SEMSs (n = 71) or palliative surgery (n = 73) were reviewed. INTERVENTIONS SEMS placement by using through-the-endoscope methods or surgery. MAIN OUTCOME MEASUREMENTS Success rates and complication rates. RESULTS Early success rates in the SEMS group and those in the surgery group were not different (95.8% vs 100%, P = .12), and the SEMS group had fewer early complications than the surgery group (15.5% vs 32.9%, P = .015). Although the patency duration of the first stent in the SEMS group was shorter than that in the surgery group (P < .001), the median patency duration after a second stenting was comparable to that of the surgery group (P = .239). There were more late complications in the SEMS group than in the surgery group (P = .028), but the rates of major complications did not differ between the 2 groups (P = .074). LIMITATIONS Retrospective and single-center study. CONCLUSIONS SEMSs were not only an effective and acceptable therapy for initial palliation of malignant colorectal obstruction, but they also showed long-term efficacy comparable to that with surgery.

The differential impact of microsatellite instability as a marker of prognosis and tumour response between colon cancer and rectal cancer.

BACKGROUND Microsatellite instability (MSI) is a distinct molecular phenotype of colorectal cancer related to prognosis and tumour response to 5-fluorouracil (5-FU)-based chemotherapy. We investigated the differential impact of MSI between colon and rectal cancers as a marker of prognosis and chemotherapeutic response. METHODS PCR-based MSI assay was performed on 1125 patients. Six hundred and sixty patients (58.7%) had colon cancer and 465 patients (41.3%) had rectal cancer. RESULTS Among 1125 patients, 106 (9.4%) had high-frequency MSI (MSI-H) tumours. MSI-H colon cancers (13%) had distinct phenotypes including young age at diagnosis, family history of colorectal cancer, early Tumor, Node, Metastasis (TNM) stage, proximal location, poor differentiation, and high level of baseline carcinoembryonic antigen (CEA), while MSI-H rectal cancers (4.3%) showed similar clinicopathological characteristics to MSS/MSI-L tumours except for family history of colorectal cancer. MSI-H tumours were strongly correlated with longer disease free survival (DFS) (P=0.005) and overall survival (OS) (P=0.009) than MSS/MSI-L tumours in colon cancer, while these positive correlations were not observed in rectal cancers. The patients with MSS/MSI-L tumours receiving 5-FU-based chemotherapy showed good prognosis (P=0.013), but this positive association was not observed in MSI-H (P=0.104). CONCLUSION These results support the use of MSI status as a marker of prognosis and response to 5-FU-based chemotherapy in patients with colon cancers. Further study is mandatory to evaluate the precise role of MSI in patients with rectal cancers and the effect of 5-FU-based chemotherapy in MSI-H tumours.

Preoperative chemoradiotherapy effects on anastomotic leakage after rectal cancer resection: A propensity score matching analysis

Objective:To assess the effects of preoperative chemoradiotherapy (CRT) on anastomotic leakage (AL) after rectal cancer resection, using propensity score matching. Background:Conflicting data have emerged over the last decade regarding the effect of preoperative CRT on AL. Methods:We reviewed 1437 consecutive patients with rectal cancer who underwent low anterior resection (LAR) at our institution between 2005 and 2012. AL evaluated as grade C was the primary endpoint, as proposed by the International Study Group of Rectal Cancer in 2010. The patients were treated with (n = 360) or without (n = 1077) preoperative CRT. The total radiation dose was 50.4 Gy in 28 fractions. Multivariate and propensity score matching analyses were used to compensate for the differences in some baseline characteristics. Results:The preoperative CRT group contained more patients with the following characteristics, older age, male sex, smoker, advanced stage tumor, lower/mid rectal tumor location, ultra-LAR, and diverting stoma, than the non-preoperative CRT group (all Ps < 0.05). Postoperative AL occurred in 91 patients (6.3%). Before propensity score matching, the incidence of AL in patients with or without preoperative CRT was 7.5% and 5.9%, respectively (P = 0.293). After propensity score matching, the 2 groups were nearly balanced except for the initial stage and the length of the surgeons career, and the incidence of AL in patients with or without preoperative CRT was 7.5% and 8.1%, respectively (P = 0.781). Conclusions:We did not observe that preoperative CRT increased the risk of postoperative AL after LAR in patients with rectal cancer, using propensity score matching analysis.

Clear cell adenocarcinoma of the sigmoid colon.

Dear Editor, Clear cell adenocarcinoma generally develops in the kidney, ovaries, extra-ovarian endometriosis, uterine cervix, upper vagina or lower genital tract. Although pathological examinations and immunohistochemistry techniques have improved over the years, this tumor type has rarely been diagnosed in the colon. Therefore, isolated clear cell adenocarcinoma of the colon is considered to be a rare malignancy. In 1964, Hellstrom et al. described a case of a sigmoid colon adenocarcinoma composed of clear tumor cells, which resembled the physaliferous (clear) cells of chordomal tumors. Since this original description, nine other cases of clear cell adenocarcinoma of the large intestine have been reported despite the rarity of this tumor type. Most of the reported primary clear cell colonic adenocarcinomas were found exclusively in the left colon and generally in elderly men. This is in agreement with our presented case in which we found a clear cell colonic adenocarcinoma on the left side of an elderly man. A previously healthy 62-year-old man was admitted to our surgical department because of abdominal discomfort and intermittent melena for a duration of 6 months. A colonoscopy showed three descending colonic polyps and fungating masses approximately 2 cm in size that were below the level of polyps in the sigmoid colon. Endoscopic mucosal resections were performed on the three polyps and endoscopic biopsy was only applied to the fungating mass. The resected polyp specimens revealed hyperplastic polyps, tubular adenoma and chronic non-specific inflammation, respectively. Biopsy specimens of the fungating mass revealed intramucosal carcinomatous change resembled clear cell adenocarcinoma. No abnormal findings were noted in the liver, gallbladder or kidney and we found no evidence of pathologic lymphadenopathy. A low anterior resection was performed by using the double stapling method. Gross findings of the resected specimen showed a 1.2×1.5 cm-sized polypoid firm, solid mass. The histological examination showed a clear cell adenocarcinoma in the tubular adenoma. A clear cell adenocarcinoma had invaded the muscularis mucosa. Lymph node metastases were not found in eight regional lymph nodes and lymphovascular invasion was not identified. The tubules of the tubular adenoma of the colonic polyps were partly lined by clear cells. The clear cells were uniformly clear and grew in both acinar and papillary configurations. Both columnar and polygonal shapes were observed and the clear cytoplasm contained small, apparently unstructured vacuoles. The nuclei included one or more prominent Int J Colorectal Dis (2007) 22:1543–1544 DOI 10.1007/s00384-006-0257-8

The role of primary colectomy after successful endoscopic stenting in patients with obstructive metastatic colorectal cancer.

BACKGROUND: Although the initial clinical efficacy of self-expandable metal stents is acceptable, doubt still remains about long-term clinical outcomes and complications. OBJECTIVE: The aim of this study was to evaluate the stoma formation rate and risk factors for complications after successful stenting in patients with obstructive metastatic colorectal cancer. DESIGN: This was a tertiary-care center retrospective study. PATIENTS: From January 2000 to December 2010, 130 patients with unresectable obstructive colorectal cancer received successful self-expandable metal stent placement. Among them, 14 patients received primary colectomy after successful stenting. INTERVENTIONS: Self-expandable metal stent placement and primary colectomy were performed. MAIN OUTCOME MEASURES: The stoma formation rate and complications were measured. RESULTS: In patients with successful stenting, stoma formation rates at 1 and 2 years were 15.6% (95% CI, 8.74–22.4) and 24.4% (95% CI, 13.8–35.0), and the median patency duration was 157 days (range, 2–1590 days). However, long-term complications occurred in 58 patients (44.6%), including reobstruction (32.6%), stent migration (10.3%), and perforation (7.8%), and a large number of reinterventions (45.7%) and hospitalizations (37/9%) were needed to manage complications. In multivariate analysis, primary colectomy after successful endoscopic stenting was a negative predictive factor for reobstruction (OR, 0.12; 95% CI, 0.02–0.99; p = 0.04). LIMITATIONS: This was a retrospective, single-center study. CONCLUSIONS: To reduce stent-related late complications, primary colectomy after successful endoscopic stenting could be a therapeutic option in patients who have unresectable colorectal cancer with obstruction, especially in those who expect long-term survival.

Robotic interface for transabdominal division of the levators and pelvic floor reconstruction in abdominoperineal resection: a case report and technical description

Extralevator abdominoperineal resection (APR) in a prone jackknife position was developed to avoid a positive circumferential resection margin, and its application led to lower rates of local recurrence. The paper describes a technique of robotic extralevator APR with transabdominal levator division followed by pelvic floor reconstruction with bilayered composite mesh.

The magnetic resonance imaging-based approach for identification of high-risk patients with upper rectal cancer

Objective:To assess the efficacy of preoperative magnetic resonance imaging (MRI) in identifying upper rectal cancer patients who are at high risk for local recurrence. Methods:110 upper rectal cancer patients with locally advanced (pT3–4N0 or pTanyN+) tumors treated with tumor-specific mesorectal excision and no adjuvant radiotherapy were identified from an institutional database at a large academic medical center in Korea. Information on the extent of mesorectal invasion, sacral-side involvement was collected from preoperative MRI. Results:At a median follow-up of 47 months, 5 patients (4.5%) experienced local recurrence (LR). LR rates for patients with intermediate risk (T1–2/N1, T3N0), moderately high risk (T1–2/N2, T3N1, T4N0), and high risk (T3N2, T4/N1–2) were 3%, 4.8%, and 8.7%, respectively. Patients who did not have sacral-side involvement or mesorectal invasion of 5 mm or less did not experience LR. The patients with sacral-side involvement and intermediate risk, moderately high risk, and high risk had an LR rate of 4.2%, 5.6%, and 10%, respectively, or 11.1%, 33.3%, and 18.2%, respectively, when combined with those with mesorectal invasion of greater than 5 mm. Multivariate analyses demonstrated the presence of both sacral-side location and mesorectal invasion of greater than 5 mm was significantly associated with adverse disease-free and overall survival (P < 0.05). Conclusions:Patients with mesorectal invasion of greater than 5 mm and sacral-side involvement identified on MRI were at an increased risk of local recurrence. The detection of these features on MRI provides prognostic information that is not available in conventional risk classification systems. Improved identification of a high-risk subset of upper rectal cancer patients may guide indications for preoperative chemoradiotherapy in this subset.

Long-term oncologic outcomes of laparoscopic right hemicolectomy during the learning curve period: comparative study with cases after the learning curve period

Background: This study aimed to assess the learning curve in laparoscopic right hemicolectomy and compare the long-term oncologic outcomes of the learning curve period. Materials and Methods: We retrospectively reviewed 97 patients who underwent a laparoscopic right hemicolectomy by a single surgeon between July 2006 and January 2009. Among them, 87 patients, excluding patients with stage IV (n=10) disease, were evaluated for long-term oncologic outcomes. They were divided into 2 phases: phase 1 (the learning curve period) and phase 2 (the expert period). The cumulative sum method was used for estimating the learning curve. Results: The learning curve was determined at the 42nd case. Patient characteristics and postoperative clinicopathologic outcomes were similar in both groups except for the operation time (212.5±65.0 min vs. 146.4±37.1 min; P<0.001) and length of stay (10.7±5.4 d vs. 8.4±2.9 d; P=0.015). The 5-year overall survival rates were similar in both groups throughout all stages. The 5-year disease-free survival rate of stage III disease in phase 2 (85%) was better than that of phase 1 (53.3%; P=0.046). Conclusions: Laparoscopic right hemicolectomy during the learning curve period showed acceptable clinicopathologic outcomes. However, the 5-year disease-free survival rate was compromised in patients with stage III disease in phase I.

Twenty cases of restorative proctocolectomy for ulcerative colitis of Asian patients: analysis of operative safety and functional outcomes in single institution experience

Dear Editor, Since the first reports on restorative proctocolectomy, the procedure pioneered by Park and Nicholls in 1978, ileal pouch-anal anastomosis (IPAA) has become the gold standard for patients who require total proctocolectomy (TP) for ulcerative colitis. Although a high evacuation frequency with anal incontinence was recorded in the initial functional tests, the overall results improved gradually during the first 3–6 months, with further improvement over the next couple of years. Despite the high level of patient satisfaction with IPAA for postoperative fecal incontinence and stool consistency, the operation carries a high potential for complications; various pouch-related and unrelated complications have been reported postoperatively. Moreover, the young age of most of the IPAA patients warrants monitoring of the long-term complication rate and stability of function over time. In Korea, the incidence of ulcerative colitis has been steadily increasing since mid 1980s and so does the number of patients needing total proctocolectomy. Of the patients (n=24) who underwent TP for ulcerative colitis in our department between January 1996 and December 2005, 20 patients who underwent restorative proctocolectomy for ulcerative colitis were included in this study. We reviewed the medical records of the 20 patients and assessed their defecation, urinary, and sexual functions using a questionnaire. The procedures we performed were total proctocolectomy. The anastomosis method after TP was either hand-sewn IPAA with diverting ileostomy (n=17) or double-stapled IPAA without ileostomy, which remained 2 cm rectal mucosa from the dentate line (n=3). The mean age of the patients was 41.9 years (range, 24–63 years). The patients were 7 men and 13 women with an average disease duration of 47.70 months. The indications for surgery were medical intractability (n=18) and toxic megacolon (n=2). The mean duration for fecal diversion was 3.7 months, and the mean follow-up after the ileostomy take down was 59.1 months. Seven cases (35%) of postoperative complications developed, which included intestinal obstructions (n=3), pouchitis (n=2), pouch and stoma bleeding (n=1), and intractable fecal incontinence (n=1). The frequency of bowel movements was 10.1 times per day in the 3 months after ileostomy closure (period 1). It decreased to 8.1 times per day from 4 months to 1 year after ileostomy closure (period 2) and decreased further to 6.5 times per day 1 year more after ileostomy closure (period 3). Day and night fecal incontinence was seen in 4/20 and 17/20, respectively, during the period 1; 2/20 and 11/20 during the period 2; and 0/20 and 5/20 during the period 3. Consistency of the stool, expressed as the ratio of semisolid to loose stool, was 0:20 during the period 1, 10:10 during the period 2, and 14:6 Int J Colorectal Dis (2008) 23:131–132 DOI 10.1007/s00384-007-0278-y

Reduced pelvic field sparing anastomosis for postoperative radiotherapy in selected patients with mid–upper rectal cancer

Abstract The aim of this study was to report the clinical results of reduced pelvic field radiotherapy (RT), excluding the anastomotic site, after total mesorectal excision in selected patients with rectal cancer. Between 2011 and 2014, 99 patients underwent upfront surgery for clinically less-advanced tumors but were finally diagnosed as pT3/N+. Among them, 50 patients with mid–upper rectal cancer who received postoperative RT with a reduced pelvic field were included in this retrospective review. This group was composed of patients with high seated tumors, complete resection with a clear circumferential resection margin, and no complication during surgery. We investigated treatment outcomes, toxicity and the effect of RT-field reduction on organs-at risk in 5 randomly selected patients. During the median follow-up period of 42 months (range: 15−59 months), tumors recurred in 9 patients (18%). The 3-year overall and disease-free survival were 98% and 81%, respectively. Distant metastasis was the dominant failure pattern (n = 8, 16%), while no recurrences occurred at or near anastomotic sites. No anastomotic complications were found on pelvic examination, images and/or colonoscopy. Reported acute and late RT-related toxicities were mostly mild to moderate, with only small numbers of Grade 3 toxicities. None of the patients developed Grade 4−5 acute or late toxicity. With a caudally reduced field, 64% reduction in absolute anastomotic exposure at the maximum dose was achieved compared with the traditional whole-pelvic field (P = 0.008). The reduced pelvic field RT was able to minimize late anastomotic complication without increasing its recurrence in selected patients with mid–upper rectal cancer in the postoperative setting.