Meta-analysis of the prognostic value of CpG island methylator phenotype in rectal cancer

Serrated Colorectal Lesions: An Up-to-Date Review from Histological Pattern to Molecular Pathogenesis

Until 2010, colorectal serrated lesions were generally considered as harmless lesions and reported as hyperplastic polyps (HPs) by pathologists and gastroenterologists. However, recent evidence showed that they may bear the potential to develop into colorectal carcinoma (CRC). Therefore, the World Health Organization (WHO) classification has identified four categories of serrated lesions: hyperplastic polyps (HPs), sessile serrated lesions (SSLs), traditional serrated adenoma (TSAs) and unclassified serrated adenomas. SSLs with dysplasia and TSAs are the most common precursors of CRC. CRCs arising from serrated lesions originate via two different molecular pathways, namely sporadic microsatellite instability (MSI) and the CpG island methylator phenotype (CIMP), the latter being considered as the major mechanism that drives the serrated pathway towards CRC. Unlike CRCs arising through the adenoma-carcinoma pathway, APC-inactivating mutations are rarely shown in the serrated neoplasia pathway.

[Epidural block associated with improved long-term survival after surgery for colorectal cancer: A retrospective cohort study with propensity score matching]

OBJECTIVE

To investigate the effect of epidural anesthesia on the long-term prognosis of patients after selective colorectal cancer resection surgery.

METHODS

This was a retrospective cohort study and approved by local institution review board. Patients who underwent selective colorectal cancer resection surgery from August 2011 to December 2012 in Peking University First Hospital were enrolled. The patients were divided into general anesthesia (GA) group and combined epidural-general anesthesia (EGA) group according to anesthesia type. Primary outcome was patient's long-term survival status. Secondary outcome included the overall incidence of in-hospital complications and length of postoperative in-hospital stay. Propensity score was used to match cases between the two groups based on the probability of receiving EGA. Survival was analyzed by Kaplan-Meier analysis and compared by Log-rank test between the two groups. Multivariate Cox regression analysis was used to investigate the relationship between epidural anesthesia and other variables with long-term survival status.

RESULTS

A total of 264 patients were entered into final analysis, including 166 cases in GA group and 98 cases in EGA group. Mean age of the patients was (63.3±12.1) years and mean survival time was 47.2 (95%CI 45.7-48.7) months. Before the propensity score match, the mortality in EGA group was 16.9% (28/166) and 9.2% (9/98) in GA group. But comparison between the two groups had no statistical significance (P=0.091). After the propensity score match, 87 paired cases were matched and analyzed. The risk of long-term mortality in EGA group was lower than that of GA group by Kaplan-Meier analysis (5.7% vs.16.1%, HR=0.344, 95%CI 0.124-0.955, P=0.041). Mean survival time of EGA group was longer than that of GA group (50.3 months vs. 42.9 months, P=0.032). Multivariate Cox regression ana-lysis showed that EGA, in comparison with GA, was related with lower risk of long-term mortality (HR=0.326, 95%CI 0.117-0.909, P=0.032). Age (HR=1.042, 95%CI 1.001-1.085, P=0.046) and preoperative lymph node metastasis (HR=2.924, 95%CI 1.162-7.356, P=0.023) were also related with increased risk of long-term mortality.

CONCLUSION

Present study found that perioperative use of epidural anesthesia and analgesia was associated with improvement of the patient's long-term survival. Well-designed studies are needed to verify this hypothesis.

[Epidural block associated with improved long-term survival after surgery for colorectal cancer: A retrospective cohort study with propensity score matching]

OBJECTIVE

To investigate the effect of epidural anesthesia on the long-term prognosis of patients after selective colorectal cancer resection surgery.

METHODS

This was a retrospective cohort study and approved by local institution review board. Patients who underwent selective colorectal cancer resection surgery from August 2011 to December 2012 in Peking University First Hospital were enrolled. The patients were divided into general anesthesia (GA) group and combined epidural-general anesthesia (EGA) group according to anesthesia type. Primary outcome was patient's long-term survival status. Secondary outcome included the overall incidence of in-hospital complications and length of postoperative in-hospital stay. Propensity score was used to match cases between the two groups based on the probability of receiving EGA. Survival was analyzed by Kaplan-Meier analysis and compared by Log-rank test between the two groups. Multivariate Cox regression analysis was used to investigate the relationship between epidural anesthesia and other variables with long-term survival status.

RESULTS

A total of 264 patients were entered into final analysis, including 166 cases in GA group and 98 cases in EGA group. Mean age of the patients was (63.3±12.1) years and mean survival time was 47.2 (95%CI 45.7-48.7) months. Before the propensity score match, the mortality in EGA group was 16.9% (28/166) and 9.2% (9/98) in GA group. But comparison between the two groups had no statistical significance (P=0.091). After the propensity score match, 87 paired cases were matched and analyzed. The risk of long-term mortality in EGA group was lower than that of GA group by Kaplan-Meier analysis (5.7% vs.16.1%, HR=0.344, 95%CI 0.124-0.955, P=0.041). Mean survival time of EGA group was longer than that of GA group (50.3 months vs. 42.9 months, P=0.032). Multivariate Cox regression ana-lysis showed that EGA, in comparison with GA, was related with lower risk of long-term mortality (HR=0.326, 95%CI 0.117-0.909, P=0.032). Age (HR=1.042, 95%CI 1.001-1.085, P=0.046) and preoperative lymph node metastasis (HR=2.924, 95%CI 1.162-7.356, P=0.023) were also related with increased risk of long-term mortality.

CONCLUSION

Present study found that perioperative use of epidural anesthesia and analgesia was associated with improvement of the patient's long-term survival. Well-designed studies are needed to verify this hypothesis.

The Molecular Hallmarks of the Serrated Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a leading cause of cancer death worldwide. It includes different subtypes that differ in their clinical and prognostic features. In the past decade, in addition to the conventional adenoma-carcinoma model, an alternative multistep mechanism of carcinogenesis, namely the “serrated pathway”, has been described. Approximately, 15 to 30% of all CRCs arise from neoplastic serrated polyps, a heterogeneous group of lesions that are histologically classified into three morphologic categories: hyperplastic polyps, sessile serrated adenomas/polyps, and the traditional serrated adenomas/polyps. Serrated polyps are characterized by genetic (BRAF or KRAS mutations) and epigenetic (CpG island methylator phenotype (CIMP)) alterations that cooperate to initiate and drive malignant transformation from normal colon mucosa to polyps, and then to CRC. The high heterogeneity of the serrated lesions renders their diagnostic and pathological interpretation difficult. Hence, novel genetic and epigenetic biomarkers are required for better classification and management of CRCs. To date, several molecular alterations have been associated with the serrated polyp-CRC sequence. In addition, the gut microbiota is emerging as a contributor to/modulator of the serrated pathway. This review summarizes the state of the art of the genetic, epigenetic and microbiota signatures associated with serrated CRCs, together with their clinical implications.

Meta-analysis of the molecular associations of mucinous colorectal cancer

BACKGROUND

Mucinous differentiation occurs in 5-15 per cent of colorectal adenocarcinomas. This subtype of colorectal cancer responds poorly to chemoradiotherapy and has a worse prognosis. The genetic aetiology underpinning this cancer subtype lacks consensus. The aim of this study was to use meta-analytical techniques to clarify the molecular associations of mucinous colorectal cancer.

METHODS

This study adhered to MOOSE guidelines. Databases were searched for studies comparing KRAS, BRAF, microsatellite instability (MSI), CpG island methylator phenotype (CIMP), p53 and p27 status between patients with mucinous and non-mucinous colorectal adenocarcinoma. A random-effects model was used for analysis.

RESULTS

Data from 46 studies describing 17 746 patients were included. Mucinous colorectal adenocarcinoma was associated positively with KRAS (odds ratio (OR) 1·46, 95 per cent c.i. 1·08 to 2·00, P = 0·014) and BRAF (OR 3·49, 2·50 to 4·87; P < 0·001) mutation, MSI (OR 3·98, 3·30 to 4·79; P < 0·001) and CIMP (OR 3·56, 2·85 to 4·43; P < 0·001), and negatively with altered p53 expression (OR 0·46, 0·31 to 0·67; P < 0·001).

CONCLUSION

The genetic origins of mucinous colorectal adenocarcinoma are predominantly associated with BRAF, MSI and CIMP pathways. This pattern of molecular alterations may in part explain the resistance to standard chemotherapy regimens seen in mucinous adenocarcinoma.