Utility of KRAS mutation detection using circulating cell-free DNA from patients with colorectal cancer.

In this study, we evaluated the clinical utility of detecting KRAS mutations in circulating cell-free (ccf)DNA of metastatic colorectal cancer patients. We prospectively recruited 94 metastatic colorectal cancer patients. Circulating cell-free DNA was extracted from plasma samples and analyzed for the presence of seven KRAS point mutations. Using the Invader Plus assay with peptide nucleic acid clamping method and digital PCR, KRAS mutations were detected in the ccfDNA in 35 of 39 patients previously determined to have primary tumors containing KRAS mutations using the Luminex method, and in 5 of 55 patients with tumors containing wild-type KRAS. Curative resection was undertaken in 7 of 34 patients with primary and ccfDNA KRAS mutations, resulting in the disappearance of the mutation from the cell-free DNA in five of seven patients. Three of these patients had tumor recurrence and KRAS mutations in their ccfDNA reappeared. Epidermal growth factor receptor blockade was administered to 24 of the KRAS tumor wild-type patients. Of the 24 patients with wild-type KRAS in their primary tumors, three patients had KRAS mutations in their ccfDNA and did not respond to treatment with epidermal growth factor receptor (EGFR) blockade. We also detected a new KRAS mutation in five patients during chemotherapy with EGFR blockade, before disease progression was detectable with imaging. The detection of KRAS mutations in ccfDNA is an attractive approach for predicting both treatment response and acquired resistance to EGFR blockade, and for detecting disease recurrence.

Segmental Hypoganglionosis of the Colon: A Case Report.

A 64-year-old woman was admitted to hospital with persistent abdominal pain. She had been hospitalized with similar symptoms on five occasions during a period of 2 years. Computed tomography revealed dilatation and fecal impaction from the ileum to the transverse colon. A barium enema and simultaneous ileus tube radiography showed a narrow segment of descending-sigmoid colon. Colonoscopy showed no mucosal change. Her symptoms did not improve with conservative therapy, so descending and sigmoid colectomy was performed. Histologic examination showed disappearance of ganglion cells; axon of Meissner's plexuses was present, and the number of Auerbach's plexuses was decreased. The definitive diagnosis was segmental hypoganglionosis (SH) of the colon. The postoperative course was uneventful, and the functional result was positive at 1 year postoperatively. SH is extremely rare; however, surgical intervention is expected to be of benefit. Therefore, it is important to keep SH in mind when treating patients with chronic obstruction of the left side of the colon.

Usefulness of a Colonic Stent for Colonic Obstruction Caused by Lung Cancer Metastasis.

The gastrointestinal tract is not a common site for metastasis from lung cancer, and colonic metastases are especially rare. Although surgical intervention can improve colonic obstruction, perioperative mortality is high in patients with advanced malignancy, and these patients experience a significant deterioration in quality of life postoperatively. This report describes an uncommon case of colonic metastasis from non-small cell lung cancer (NSCLC), in which colonic obstruction was improved with a self-expanding metallic stent. A 62-year-old man was admitted to our hospital for progressively worsening abdominal pain. He had been treated with immunotherapy and chemotherapy after being diagnosed with NSCLC (T4N2M1) 1.5 years earlier. Enhanced computed tomography showed intestinal obstruction and a mass in the colon at the hepatic flexure. Histopathological analysis of a biopsy specimen confirmed NSCLC metastasis. Considering his general condition, endoscopic stenting was chosen as an urgent decompression procedure. He was discharged 45 days after stenting and was able to resume immunotherapy. Emergency stenting could be offered at experienced centers when operative intervention is not part of the treatment plan, as it is safe and improves the efficiency of care along with the quality of life.

Modified Marionette Technique for Laparoscopic Colorectal Surgery.

INTRODUCTION: Single-port laparoscopic surgery has some technical limitations with respect to control of the forceps inserted through the single-access site, which results in increased internal collisions due to coaxial alignment of the instruments, as well as and decreased range of motion and visualization. To overcome these limitations, we employ a "modified marionette technique" as a way to carry out laparoscopic colorectal surgery. Materials and Surgical Technique: The procedures for the modified marionette technique are performed as follows: An Internal Organ Retractor (IOR)™ and an atraumatic clip designed to firmly grasp tissue, with 1-0 nylon thread, are inserted through a 12-mm trocar and secured in place where adequate visualization and traction for cutting with a radio knife is required. A looped 1-0 nylon thread put through an 18-gauge injection needle is pierced through the abdominal wall, the looped nylon extruded, and the nylon attached to the IOR is pulled out by threading the looped nylon thread. This allows for adequate traction from outside the body through the abdominal wall and appropriate placing adjustments. CONCLUSION: The "modified marionette technique" using IOR introduced here is an easy, economical, effective and safe traction technique for colorectal surgeries. This technique will be a useful tool for performing both reduced port and multiport laparoscopic colorectal surgeries.

Chylous ascites associated with intestinal obstruction from volvulus due to Petersen's hernia: report of a case.

BACKGROUND: Chylous ascites is an uncommon finding which is usually associated with recent abdominal/oncologic or retroperitoneal surgery. It is not usually seen in cases of acute obstruction. CASE PRESENTATION: A patient who had previously undergone a laparoscopy-assisted distal gastrectomy with Roux-en-Y reconstruction for early gastric cancer presented with acute abdominal pain and epigastric fullness. Computed tomography suggested small bowel obstruction due to volvulus. We were able to reduce the volvulus and close a Petersen's hernia without resecting the bowel; a large amount of chylous ascites was an incidental finding. CONCLUSIONS: We present a case of chylous ascites occurring in a setting of small bowel obstruction due to Petersen's hernia, 3 years after successful distal gastrectomy for early gastric cancer, with no evidence of tumor recurrence.

Rechallenge with 5-fluorouracil in a patient who developed encephalopathy caused by 5-fluorouracil for colon cancer.

We report a case involving a patient with colon cancer who underwent 5-fluorouracil (5-FU) rechallenge and maintained an oncological effect for a long period after encephalopathy caused by 5-FU. Our patient was a 61-year-old man who was diagnosed with adenocarcinoma of the ascending colon with direct liver invasion. He underwent right hemicolectomy with partial liver resection followed by adjuvant chemotherapy with modified FOLFOX6 (mFOLFOX6). Ten months after completion of mFOLFOX6, his carcinoembryonic antigen concentration increased, and ascites was revealed by computed tomography 2 months later. We started FOLFIRI, and he was taken to our hospital by ambulance because of loss of consciousness 10 days after the start of the third cycle of FOLFIRI. Laboratory investigations showed hyperammonemia and elevations of his serum creatinine and blood urea nitrogen concentrations. Brain computed tomography demonstrated no abnormalities. Transfusion of 1500 ml of crystalloid fluid resulted in gradual recovery over the next 12 h. His ammonia concentration decreased to a normal level. Twelve days after onset of the encephalopathy, we restarted FOLFIRI, but the dose of continuous 5-FU was decreased by 20 %. The patient's carcinoembryonic antigen concentration considerably decreased from 376.5 to 19.9 ng/ml, and his ascites disappeared. Nineteen months after the resumption of FOLFIRI, he underwent 34 courses of FOLFIRI and maintained stable disease. The encephalopathy did not recur.

A Case of Portal Venous Gas after Rectal Surgery without Anastomotic Leakage or Bowel Necrosis.

Portal venous gas has traditionally been considered an indicator of a poor prognosis due to bowel necrosis. Portal venous gas has recently been detected in patients with various clinical conditions, such as Crohn's disease, chemotherapy, and blunt abdominal injury without bowel necrosis. We herein report the first case of a patient with rectal cancer in whom portal venous gas developed after low anterior resection without anastomotic leakage or bowel necrosis. A 66-year-old man who had undergone low anterior resection started having severe diarrhea the day after the operation. A fever was present for 2 days after the operation but resolved on postoperative day 3. The patient complained of abdominal pain 5 days postoperatively. Computed tomography showed portal venous gas. Emergency open laparotomy was performed, but only limited ascites fluid without leakage or bowel necrosis was found. We irrigated the abdominal cavity and performed an ileostomy with insertion of a drainage tube in the rectovesical pouch. Only serous ascites was discharged through the drainage tube. The portal venous gas disappeared 3 days after the second operation. The patient was discharged in good condition 21 days after the first operation. Portal venous gas can develop after rectal surgery without anastomotic leakage or bowel necrosis. Conservative treatment is reasonable for patients without signs of bowel necrosis or panperitonitis. However, patients with portal venous gas must be carefully observed because portal venous gas may be life threatening.

Surgical Specimens of Colorectal Cancer Fixed with PAXgene Tissue System Preserve High-Quality RNA.

BACKGROUND: RNA analysis of surgical specimens is one of the most useful methods for exploring biomarkers of advanced cancer. The most readily available source for RNA is formalin-fixed, paraffin-embedded (FFPE) specimens, but RNA isolated from FFPE tissue is of limited use. The PAXgene Tissue (PAX) system is a formalin-free system designed to improve the quality of molecular analysis without diminishing the quality of histopathological analysis. In this human colorectal cancer tissue study, we aimed to evaluate whether surgical specimens fixed with PAX can preserve high-quality RNA in comparison with FFPE and fresh-frozen tissue specimens. METHODS: Ten consecutive advanced colorectal cancer patients undergoing colectomy were examined. Each specimen was processed in three ways: as frozen tissue, as PAX-fixed tissue, and as formalin-fixed tissue. RNA integrity numbers (RINs) were assessed using an Agilent Bioanalyzer. RNA transcript levels and stability were investigated by quantitative real-time PCR. We also evaluated the immunohistochemical intensity of Ki-67, CEA, and EGFR in the PAX samples. RESULTS: The average RINs of RNA extracted from frozen and PAX samples were significantly higher than those from FFPE samples (p < 0.001). The cycle threshold (Ct) values were similar in PAX and frozen samples, but significantly increased in FFPE samples (p < 0.001). Most of the ΔCt values in the PAX samples did not differ significantly from those in the matched frozen samples. On the other hand, most of the ΔCt values in the FFPE samples differed significantly from those in the matched frozen samples. The immunohistochemical intensity in the PAX samples was well preserved. CONCLUSIONS: The quality of RNA extracted from PAX samples may be slightly inferior to that from frozen samples, but is greatly superior to that from FFPE samples.

Gene profiling and bioinformatics analyses reveal time course differential gene expression in surgically resected colorectal tissues.

It has previously been reported that gene profiles in surgically-resected colorectal cancer tissues are altered over time possibly due to the different tissue-acquisition methods and sample extraction timing that were used. However, the changes that occur are still not clearly understood. In the present study, time-dependent changes in gene expression profiling in colorectal surgical specimens were analyzed. Normal and tumor tissues at several time-points (0, 30, 60 and 120 min) were extracted, and RNA quality, microarray experiments, quantitative PCR and bioinformatics clustering were performed. Although RNA integrity was preserved 2 h after resection, inherent increased/decreased gene expression was observed from 30-120 min in approximately 10% of genes. Bioinformatics clustering could not distinguish case-by-case, probably due to gene profiling changes. Irregular changes in gene expression after surgical resection were found, which could be a crucial confounding factor for quantitative analyses.