The KRAS-Mutant Consensus Molecular Subtype 3 Reveals an Immunosuppressive Tumor Microenvironment in Colorectal Cancer.

Colorectal cancers (CRC) with KRAS mutations (KRASmut) are frequently included in consensus molecular subtype 3 (CMS3) with profound metabolic deregulation. We explored the transcriptomic impact of KRASmut, focusing on the tumor microenvironment (TME) and pathways beyond metabolic deregulation. The status of KRASmut in patients with CRC was investigated and overall survival (OS) was compared with wild-type KRAS (KRASwt). Next, we identified CMS, and further investigated differentially expressed genes (DEG) of KRASmut and distinctive pathways. Lastly, we used spatially resolved gene expression profiling to define the effect of KRASmut in the TME regions of CMS3-classified CRC tissues. CRC patients with KRASmut were mainly enriched in CMS3. Their specific enrichments of immune gene signatures in immunosuppressive TME were associated with worse OS. Activation of TGFß signaling by KRASmut was related to reduced pro-inflammatory and cytokine gene signatures, leading to suppression of immune infiltration. Digital spatial profiling in TME regions of KRASmut CMS3-classified tissues suggested up-regulated genes, CD40, CTLA4, ARG1, STAT3, IDO, and CD274, that could be characteristic of immune suppression in TME. This study may help to depict the complex transcriptomic profile of KRASmut in immunosuppressive TME. Future studies and clinical trials in CRC patients with KRASmut should consider these transcriptional landscapes.

Impact of Washing Processes on RNA Quantity and Quality in Patient-Derived Colorectal Cancer Tissues.

Background: Colorectal cancer (CRC) is a common and lethal cancer worldwide. Extraction of high-quality RNA from CRC samples plays a key role in scientific research and translational medicine. Specimen collection and washing methods that do not compromise RNA quality or quantity are needed to ensure high quality specimens for gene expression analysis and other RNA-based downstream applications. We investigated the effect of tissue specimen collection and different preparation processes on the quality and quantity of RNA extracted from surgical CRC tissues. Materials and Methods: After surgical resection, tissues were harvested and prepared with various washing processes in a room adjacent to the operating room. One hundred fourteen tissues from 36 CRC patients were separately washed in either cold phosphate-buffered saline reagent (n = 34) or Dulbecco's modified Eagle's medium (DMEM; n = 34) for 2-3 minutes until the stool was removed, and unwashed specimens served as controls (n = 34). Six tissue specimens were washed and immersed in DMEM for up to 1 hour at 4°C. Before RNA extraction, all specimens were kept in the stabilizing reagent for 3 months at -80°C. RNA was extracted, and the concentration per milligram of tissue was measured. RNA quality was assessed using the RNA integrity number (RIN) value. Results: Different washing processes did not result in significant differences in RNA quantity or RIN values. In the six tissues that were washed and immersed in DMEM for 1 hour, RIN values significantly decreased. The quality of the extracted RNA from most specimens was excellent with the average RIN greater than 7. Conclusions: RNA is stable in specimens washed in different processes for short periods, but RIN values may decrease with prolonged wash times.

Current status of IBD and surgery of Crohn's disease in Thailand.

Inflammatory bowel disease (IBD) consists of two diseases: ulcerative colitis (UC) and Crohn's disease (CD). The incidence of IBD is much higher in Western countries compared to Asian countries, especially in Thailand. The incidence of UC in Thailand is quite low and seems less aggressive than in Western countries. Over the past two decades, the evolution of UC management in Thailand has led to a reduction in hospitalization and colectomy rate. Regarding CD, the majority of patients have an inflammatory phenotype at diagnosis. Diagnosis of CD remains challenging in Thailand as the time from onset of symptoms to diagnosis is quite delayed, possibly due to unawareness and difficulty in the differential diagnosis between CD and other infectious entero-colitis such as intestinal tuberculosis. With a significant trend to early initiation of immunomodulators and biologics, the cumulative rate of surgery after diagnosis has been improved. To improve the outcomes of CD treatment in Thailand, physicians need more awareness to recognize the disease, which results in early diagnosis, prevention of long-term complications, and reduction in the rate of surgery.

Implementation of enhanced recovery after surgery and its increasing compliance improved 5-year overall survival in resectable stage III colorectal cancer.

PURPOSE: Enhanced recovery after surgery (ERAS) improves short-term outcomes after colorectal cancer (CRC) surgery, but its benefits on oncological results remain unclear. The objectives of this study are (1) to compare 5-year overall survival (OS) following non-metastatic CRC surgery between ERAS and conventional care (CC), and (2) to evaluate the association between ERAS compliance and OS. METHODS: Patients undergoing curative resection for stage I-III CRC in a university hospital were reviewed. Utilizing the 2010-2012 CRC registry, 5-year OS of surgical patients between ERAS and CC were compared. Utilizing the 2010-2016 ERAS registry, 5-year OS between patients with high ERAS compliance (≥ 70%) and their counterparts were compared. RESULTS: Between 2010 and 2012, 349 patients had curative surgery: 70 (20%) with ERAS and 279 (80%) with CC. The 5-year OS was 80.3% in ERAS and 65.6% in CC (HR 0.54, 95%CI 0.33-0.88, p = 0.014). After adjustment with other variables, ERAS was associated with better 5-year OS for stage III CRC only (72.6% vs. 57.2%, adjusted HR 0.54, 95%CI 0.30-0.98, p = 0.041). Regarding ERAS compliance, 320 patients were reviewed: 232 (73%) with high compliance. The 5-year OS was 83.9% in high compliance and 69.6% in low compliance (HR 0.49, 95% CI 0.29-0.83, p = 0.007). After adjustment with cancer staging, high compliance had better 5-year OS in stage III CRC only (80.5% vs. 60.7%, adjusted HR 0.44, 95%CI 0.23-0.84, p = 0.013). CONCLUSION: ERAS was associated with improved 5-year OS following non-metastatic CRC surgery (especially stage III disease) than CC. High ERAS compliance had better OS than its counterpart.

Outcomes of local excision for early rectal cancer: a 6-year experience from the largest university hospital in Thailand.

BACKGROUND: This study aimed to determine clinical outcomes of local excision for early rectal cancer from a University Hospital in Thailand. MATERIALS AND METHODS: We performed a retrospective review of 22 consecutive patients undergoing local excision for early rectal cancer (clinical and radiological T1/T2) from 2005-2010 at the Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok. Data were collected from patients' medical records, including demographic and clinical characteristics, pathological report and surgical outcomes. RESULTS: This study included 10 males and 12 females, with average age of 68 years. Nineteen patients (86%) underwent transanal excision and the others had trans-sacral excision. Median operative time was 45 minutes. Postoperative complications occurred in 2 patients (9%); 1 fecal fistula and 1 wound infection following trans-sacral excision. There was no 30-day postoperative mortality. Median hospital stay was 5 days. Pathological reports revealed T1 lesion in 12 cases (55%), T2 lesion in 8 cases (36%) and T3 lesion in 2 cases (9%). Eight patients received additional treatment; one re-do transanal excision, two proctectomies, and five adjuvant chemoradiation. During the median follow-up period of 25 months, local recurrence was detected in 4 patients (18%); two cases of T2 lesions with close or positive margins, and two cases of T3 lesions. Three patients with local recurrence underwent salvage abdominoperineal resection. No local recurrence was found in T1/T2 lesions with free surgical margins. CONCLUSIONS: Local excision is a feasible and acceptable alternative to radical resection only in early rectal cancer with free resection margins and favorable histopathology.

Comparison of perineal operations with abdominal operations for full-thickness rectal prolapse.

BACKGROUND: We can divide surgery for rectal prolapse into two broad categories: abdominal and perineal. However, few studies compare the long-term outcomes and quality of life among operations for full-thickness rectal prolapse. The purpose of this study was to compare abdominal (AO) versus perineal (PO) procedures for the treatment of full-thickness rectal prolapse regarding recurrence rate, incontinence, constipation, and quality of life. METHODS: Records of 177 operations from 1995 to 2001 were reviewed retrospectively. A telephone survey was attempted for all. Seventy-five (42%) responded to the Cleveland Clinic Incontinence Score (CCIS), KESS Constipation Score (KESS-CS), and SF-36 Quality of Life Score. Appropriate statistical analysis was performed. RESULTS: For the 122 AO and 55 PO, there were no deaths. Mean follow-up was similar (PO 3.1 vs. AO 3.9 years; P = 0.306). As expected the PO patients were older (mean 69 vs. 55 years) and had higher ASA scores. Those undergoing PO had less procedural blood loss, operative time, hospital stay, and dietary restriction. The PO group also scored worse on the physical component of SF-36 (PO 33 vs. AO 39.6; P = 0.034). However, the rate of recurrent prolapse was significantly higher for the PO (PO 26.5% vs. AO 5.2%; P < 0.001). Complications, CCIS, KESS-CS, and SF-36 mental component were similar in both groups. CONCLUSIONS: In full-thickness rectal prolapse, elderly, sick patients are selected for a perineal operation. The morbidity, functional outcomes, and quality of life are acceptable. However, the high recurrence rates make the perineal operation a second-best choice for younger, healthy patients.

Nonreversal of Hartmann's procedure for diverticulitis: derivation of a scoring system to predict nonreversal.

PURPOSE: A Hartmann's procedure is performed in perforated diverticulitis, but in some patients the colostomy is never closed. Identification of patients at risk for Hartmann's nonreversal would be helpful to determine the extent of resection. The aim of this study was to quantify the risk of nonclosure by deriving a predictive score. METHODS: Patients undergoing a Hartmann's procedure for diverticulitis were identified from database. They were separated into those who underwent Hartmann's reversal within one year of the initial operation, and those who did not. The data were analyzed in univariable and multivariable logistic regression. A predictive scoring system of Hartmann's reversal was created. The predictive power of the multivariable models, the predictive scoring system, and colorectal POSSUM physiology scores were compared. RESULTS: Eighty of 117 patients (68.4%) had their colostomy reversed. Multivariate analysis identified age, American Society of Anesthesiologists' score, pulmonary comorbidity, preoperative blood transfusion, perforation, and anticoagulants as the factors of failure for stoma reversal. All 36 patients with a predictive score of less than 14 had their stoma reversed. Twenty-two of 25 patients (88%) with scores greater than 18 did not have a reversal. Predictive power was similar when using only colorectal POSSUM physiology scores alone, or with preoperative data. CONCLUSIONS: More than 30% of patients undergoing a Hartmann's procedure for diverticulitis will not have their stoma reversed within a year. If this scoring system can be validated in an independent group of patients, it will be useful in allowing surgeons to strategize accurately and to counsel patients realistically.

Outcomes of sphincter-saving operation for rectal cancer without protective stoma and pelvic drain, and risk factors for anastomotic leakage.

BACKGROUND/AIMS: To evaluate the outcomes of sphincter-saving operation for rectal cancer without protective stoma and pelvic drain and to determine factors influencing anastomotic leakage. METHODS: We investigated 170 patients undergoing elective sphincter-saving operation without protective stoma and pelvic drain during 2003-2006 in a single institution. Early postoperative outcomes were evaluated. 17 independent patient-, tumor-, and treatment-related variables were analyzed by a multivariate model to determine their association with anastomotic leakage. RESULTS: The patients' median age was 64 years. Median tumor height was 8 cm (range 3-15) from the anal verge. Overall 30-day mortality rate was 1.2%. Postoperative complications were diagnosed in 38 patients (22%) including 14 cases of anastomotic leakage (8.2%), of which 10 cases (71%) required surgical intervention. Tumor height within 5 cm from the anal verge was the only independent factor for leakage (OR 4.04; 95% CI 1.25-13.08). CONCLUSION: A sphincter-saving operation without a protective stoma and pelvic drain can be performed safely in the vast majority of rectal cancer patients. Tumor height within 5 cm from the anal verge is an independent risk factor for anastomotic leakage. Thus, the routine use of a protective stoma and pelvic drainage might be unnecessary.