Nahm-Gun Oh

Three-fraction stereotactic body radiation therapy for isolated liver recurrence from colorectal cancer

AIMS To determine the feasibility and efficacy of 3-fraction stereotactic body radiation therapy for isolated colorectal cancer liver metastases. MATERIALS AND METHODS Ten patients with isolated inoperable liver metastasis from colorectal cancer with progression after salvage chemotherapy underwent stereotactic body radiation therapy. Follow-up was 7-49 months (median, 12). Six patients had a solitary lesion and 4 patients had 2 lesions. Internal target volumes of metastatic liver tumors ranged from 3.4 to 271 ml. Stereotactic body radiation therapy doses ranged from 36 to 51 Gy and were administered in three fractions. All patients demonstrated disease progression despite chemotherapy prior to stereotactic body radiation therapy. RESULTS Three-year overall survival and local control rates were 40% and 60%, respectively. Tumors with an internal target volume < 100 ml showed better local control rate than larger tumors. No severe complication was attributed to the therapy. CONCLUSION Our study suggests the potential feasibility of stereotactic body radiation therapy for selected patients with colorectal cancer liver metastasis and no treatment option. The study showed that excellent local control was achieved in patients with a total tumor volume of < 100 ml but failed to clarify the role of stereotactic body radiation therapy for larger tumors. Further large scale studies are needed to define the indications of such therapy.

Time-course of morphologic changes and peptide YY adaptation in ileal mucosa after loop ileostomy in humans.

PURPOSEThe secretion mechanism of peptide YY involves systemic factors, such as humoral and neural stimuli, and local factors, such as intestinal peristalsis and intraluminal nutrients. This study was designed to survey the impact of local stimuli on the secretion of peptide YY under circumstances in which systemic stimuli are identical.METHODSIleostomies were repaired within three months in a short-term group (14 patients) and after six months in a long-term group (14 patients). Mucosal peptide YY concentrations and cytomorphologic change, such as villus height, crypt depth, mucosal thickness, and villus index, were compared between proximal functioning ileum and a distal nonfunctioning ileal loop during ileostomy repair. In a control group of patients undergoing right hemicolectomy (21 cases), the normal distribution of peptide YY was measured in the mucosa throughout the distal ileum.RESULTSThe peak of peptide YY concentration in the terminal ileum was 307.4 ± 21 pmol/g, 25 cm from the ileocecal valve, with lower levels both proximally and distally. The mucosa of the functioning ileum in the short-term group showed hypertrophy, but had returned to preoperative levels in the long-term group. The nonfunctioning mucosa in both groups underwent atrophic changes. The mucosal peptide YY content in functioning ileum in the short-term group was higher than that of distal nonfunctioning mucosa (363.9 ± 25.5 pmol/g vs. 284.1 ± 13 pmol/g, P < 0.05), suggesting adaptive upregulation. The increments of mucosal peptide YY content in this short-term group compared with the control group were 45.6 and 4.7 percent in the proximal and distal segments, respectively. In the long-term group, proximal and distal mucosal peptide YY were similar (256.6 ± 31.9 pmol/g vs. 254.9 ± 27.1 pmol/g, P > 0.05), and there was no increment in either (1.3 vs. 4.4 percent, P > 0.05).CONCLUSIONSThe peak concentrations of PYY in the ileal mucosa are found 20 to 25 cm proximal to the ileocecal valve. In the short-term response of ileostomy, local stimulatory factors play a major role in the adaptation of mucosal PYY. In the defunctioned bowel without luminal stimulation, systemic stimulation was important for maintenance of mucosal PYY.

Patient-Performed Seton Irrigation for the Treatment of Deep Horseshoe Fistula

PURPOSE: Compared with total fistulotomy using a lay-open technique for treatment of deep horseshoe or deep posterior complex anal fistula, the seton drainage method has reduced damage of the external anal sphincter. However, conventional seton drainage is burdensome to patients, requiring frequent clinic visits for wound management during prolonged periods while the drainage tube is in place. To reduce the number of clinic visits and facilitate healing, we devised a patient-performed seton irrigation technique and compared the results with a conventional loose seton to determine its clinical usefulness. METHODS: We reviewed medical records of 24 patients who were diagnosed with deep horseshoe fistula and underwent surgery between January 1999 and December 2004. Twelve patients treated through December 2001 received a conventional loose seton. Twelve patients treated from January 2002 performed self-irrigation via the seton. These 2 groups were compared regarding duration of purulent discharge, length of time until seton removal, and recurrence rate. RESULTS: The mean duration of purulent discharge was 18.75 (range, 15–24) days for self-irrigation vs 29.75 (24–37) days for conventional loose seton treatment (P < .001). The mean time to removal of the seton was 21.58 (18–29) days for self-irrigation vs 32.58 (28–39) days for conventional treatment (P < .001). The recurrence rate after surgery was 8.3% for self-irrigation vs 16.7% for conventional treatment (P > .99). CONCLUSION: Patient-performed seton irrigation shortens the period of treatment and healing through more effective wound management, and we propose this technique as a useful new method of treating deep horseshoe fistula.

NTRK1 fusions for the therapeutic intervention of Korean patients with colon cancer

The identification and clinical validation of cancer driver genes are essential to accelerate the translational transition of cancer genomics, as well as to find clinically confident targets for the therapeutic intervention of cancers. Here we identified recurrent LMNA-NTRK1 and TPM3-NTRK1 fusions in Korean patients with colon cancer (3 out of 147, 2%) through next-generation RNA sequencing (RNA-seq). NTRK1 fusions were mutually exclusive oncogenic drivers of colon cancer that were accompanied with in vitro potential of colony formation and in vivo tumorigenicity comparable to KM12, a human colon cancer cell line harboring TPM3-NTRK1 fusion. NTRK1-encoded TrkA protein was prevalent in 11 out of 216 Korean (5.1%) and 28 out of 472 Chinese patients (5.9%) from independent cohorts, respectively. The expression level of TrkA was significantly correlated with NTRK1 fusion (p = 0.0192), which was verified by a fluorescence in situ hybridization (FISH). Korean patients with TrkA-positive colon cancer had a marginal but significant shorter overall survival time than TrkA-negative colon cancer [hazard ratio (HR) = 0.5346, 95% confidential interval (CI) = 0.2548-0.9722, p = 0.0411]. In addition, KM12 cell line was sensitive to selective TrkA inhibitors. These results demonstrate that NTRK1 fusion is granted as a clinically relevant target for therapeutic intervention of colon cancer.

Transcriptome analysis of paired primary colorectal carcinoma and liver metastases reveals fusion transcripts and similar gene expression profiles in primary carcinoma and liver metastases

BackgroundDespite the clinical significance of liver metastases, the difference between molecular and cellular changes in primary colorectal cancers (CRC) and matched liver metastases is poorly understood.MethodsIn order to compare gene expression patterns and identify fusion genes in these two types of tumors, we performed high-throughput transcriptome sequencing of five sets of quadruple-matched tissues (primary CRC, liver metastases, normal colon, and liver).ResultsThe gene expression patterns in normal colon and liver were successfully distinguished from those in CRCs; however, RNA sequencing revealed that the gene expression between primary CRCs and their matched liver metastases is highly similar. We identified 1895 genes that were differentially expressed in the primary carcinoma and liver metastases, than that in the normal colon tissues. A major proportion of the transcripts, identified by gene expression profiling as significantly enriched in the primary carcinoma and metastases, belonged to gene ontology categories involved in the cell cycle, mitosis, and cell division. Furthermore, we identified gene fusion events in primary carcinoma and metastases, and the fusion transcripts were experimentally confirmed. Among these, a chimeric transcript resulting from the fusion of RNF43 and SUPT4H1 was found to occur frequently in primary colorectal carcinoma. In addition, knockdown of the expression of this RNF43-SUPT4H1 chimeric transcript was found to have a growth-inhibitory effect in colorectal cancer cells.ConclusionsThe present study reports a high concordance of gene expression in the primary carcinoma and liver metastases, and reveals potential new targets, such as fusion genes, against primary and metastatic colorectal carcinoma.

Antiperistaltic ileostomy using the long terminal ileal segment

PURPOSE: This study was undertaken to determine whether reversed terminal ileal segments can be used to decrease ileostomy output in patients who have undergone total proctocolectomy and ileostomy for ulcerative colitis or familial adenomatous polyposis. METHODS: An approximately 25-cm length of terminal ileum was reversed in an antiperistaltic manner, and the new terminal ileal end was used for the ileostomy constructed in the usual manner. Six patients underwent this procedure and were compared with six patients who had conventional total proctocolectomy and ileostomy. Variables studied included weight of ileostomy output and the weight of the filtered fluid component. Data were obtained on seven different occasions during a two-month period beginning three months after the operation. Analysis was done using Studentst-test. RESULTS: There was a statistically significant decrease in the weight of the average 24-hour ileostomy effluent in those patients undergoing reversed antiperistaltic loop procedures. There was also a statistically significant decrease in the filterable liquid proportions. CONCLUSIONS: The antiperistaltic ileostomy is effective in reducing the daily amount of ileostomy effluent and facilitates stoma care, owing to its diminished liquid component.

Abdominopreanal proctocolectomy and ileal U-pouch in ulcerative colitis or familial adenomatous polyposis

In some cases of ulcerative colitis and familial adenomatous polyposis, cancerous changes frequently occur on the distal rectum, in which case a restorative proctocolectomy is not recommended because of the limitations of a radical resection. Even if rectal cancer is not confirmed preoperatively, a strong possibility of cancer in the rectum could afford some support for a radical pelvic dissection during the anus-sparing procedure. The author designed a new operative procedure for resolving this problem. It is an abdominopreanal extrasphincteric proctocolectomy with preileal-pouch positioning of the distal ileal segment including the ileocecal sphincter (ileal U-pouch) for the treatment of ulcerative colitis and familial adenomatous polyposis coli (restorative radical proctocolectomy). The author performed this restorative radical proctocolectomy on seven patients over the past 5 years at the Department of Surgery, Pusan National University Hospital, of which four cases were ulcerative colitis and three were familial adenomatous polyposis. The results obtained were as follows: (a) The most common sequela was nocturnal seepage, which lasted for 6 months in 4 patients after the final operation. (b) The mean frequency of defecation was six times per day at 6 months after the final operation. (c) The average amount of stool was about 460 g per day at 6 months after the final operation. Therefore, the ileal U-pouch is considered to be effective in reducing the daily amount of stool. A preanal extrasphincteric approach could be especially useful in the case of a difficult dissection of the anterectal space while also providing an effective dependent drainage of the ileoanal anastomotic space.

The significance of tumor budding in T1 colorectal carcinoma: The most reliable predictor of lymph node metastasis especially in endoscopically resected T1 colorectal carcinoma

Endoscopic resection is widely recognized as a first-line treatment for T1 colorectal cancers (CRC), although additional surgical intervention may be indicated based on the risk of lymph node (LN) metastasis. However, risk factors for LN metastasis in T1 CRC not fully established. We investigated the clinicopathological features of T1 CRC and evaluated their association with lymph node metastasis in 133 cases of T1 CRC, consisting of 87 cases with first-line endoscopic resection (EMR) followed by additional surgery and 46 cases with primary surgical resection. Among the total 133 cases, 16 cases (12.0%) showed LN metastasis; 13 cases (13/16, 81.25%) were included in endoscopic resection cohort. These were all of the non-pedunculated gross type and most of LN+ tumors invaded submucosa over 1000 μm (surgical cohort versus endoscopic resection cohort; 3 versus 11). However, there was no statistical difference in the depth of submucosal invasion between the LN+ and LN- in both surgical cohort (2799.42 μm ± 401.56 versus 3000.00 μm ± 721.69, P = .897) and endoscopic resection cohort (2066.55 μm ± 142.96 versus 2305.77 μm ± 345.62, P = .520). Conversely, presence of and a higher number of tumor budding foci were associated with an increase in the incidence of LN metastasis in both cohort (P < .0001). Positive resection margins as well as absence of adenoma component were also an independent predictive factor for lymph node metastasis in 87 cases with first-line endoscopic resection followed by additional surgery. We found that tumor budding was the most reliable LN metastasis predictor in T1 CRC in both surgically resected and endoscopic resection specimens.