A review of controversies in the management of colorectal cancers

Intracorporeal anastomosis could be associated with a higher lymph node yield in right colon cancer surgery: Results of the ICA-LATAM study, a retrospective, multicentre, comparative analysis in Latin America

AIM

The aim of this work was to compare lymph node (LN) yield in patients operated on for right colon cancer (RCC) using a laparoscopic approach between those receiving an intracorporeal (ICA) or extracorporeal anastomosis (ECA).

METHOD

This is a retrospective multicentre study involving patients operated on for RCC in nine tertiary referral centres in Latin America during a 2-year period. The main comparative outcome between groups was the number of LNs harvested between groups.

RESULTS

The study included 416 patients, 261 (62.7%) in the ECA group and 155 (37.3%) in the ICA group. Patients in the ECA group were elderly (66 vs. 61 years, p < 0.001). Patients receiving an ICA achieved a significantly higher LN yield than those receiving an ECA (24 vs. 18, p < 0.001). This group also had a lower percentage of patients achieving a substandard LN yield (<12 LNs) (10% vs. 24.8%, p = 0.001) and more patients achieving a high number of harvested LNs (>32 LNs) (15.5% vs. 8.3%, p = 0.039). In the multivariate analysis, ICA was independently related to the primary outcome (LN yield) (OR 3.28, p = 0.027, 95% CI 1.14-9.38).

CONCLUSION

In this retrospective study, patients operated on for RCC who received an ICA achieved a higher LN yield. Further studies are needed to reconfirm these findings, and also to find an explanation for these results.

Augmented CD133 expression in distal margin correlates with poor prognosis in colorectal cancer

Pathological assessment of excised tumour and surgical margins in colorectal cancer (CRC) play crucial role in prognosis after surgery. Molecular assessment of margins could be more sensitive and informative than conventional histopathological analysis. Considering this view, we evaluated the distal surgical margins for expression of cancer stem cell (CSC) markers. Cellular and molecular assessment of normal, tumour and distal margin tissues were performed by flow cytometry, real-time q-PCR and immuno-histochemical analysis for CRC patients after tumour excision. CRC patients were evaluated for expression of CSC markers in their normal, tumour and distal tissues. Flow cytometry assay revealed CD133 and CD44 enriched cells in distal margin and tumour compared to normal colorectal tissues, which was further confirmed by immunohistochemistry. Most importantly, immunohistochemistry also revealed the enrichment of CSC markers expression in pathologically negative distal margins. Patients with distal margin enriched for CD133 expression showed an increased recurrence rate and decreased disease-free survival. This study proposes that although distal margin seems to be tumour free in conventional histopathological analysis, it could harbour cells enriched for CSC markers. Further CD133 could be a promising molecule to be used in molecular pathology for disease prognosis after surgery in CRC patients.

A Prospective Study of Distal Microscopic Spread in Rectal Cancer After Neoadjuvant Chemoradiation in Pinned and Unpinned Specimen

The most important margin in determining the prognosis of rectal cancer is circumferential resection margin (CRM). But, the type of surgery is determined by distal rectal margin (DRM), whether sphincter saving procedure is possible or patient needs an abdominoperineal resection. There are no standardized uniform guidelines for measurement of DRM. The purpose of this study is to assess the distal microscopic spread beyond gross margin after neoadjuvant concurrent chemoradiation (CCRT) in rectal cancers, the factors influencing the distal microscopic spread, the shrinkage of the distal margin in pinned and unpinned fresh and fixed specimen, and to find out the best method of measurement of distal rectal margin. A prospective analytical study was conducted from May 2013 through February 2015 in 47 cases of carcinoma rectum (both AR and APR) who had received neoadjuvant CCRT. Fresh specimen was collected within 30 min of specimen retrieval and a longitudinal cut was made in the distal margin of all specimens. One side of the specimen was pinned onto a cork board and the other side was left unpinned. Measurements were made from the distal end of clinical gross tumor. DRM was determined in both pinned and unpinned sides in fresh and fixed specimen. Of the 47 patients, 2 patients (4.2%) had small focus of tumor beyond gross margins, 1 at 6 mm and another at 3.5 mm on the unpinned side. The average margin for fresh and fixed pinned specimens was 3.67 and 3.47 cm, respectively, with percentage shrinkage of 5.4% for the pinned specimens. The average margin for fresh and fixed unpinned specimens was 3.32 and 2.84 cm, respectively, with percentage shrinkage of 14.4% for the unpinned specimens. Six patients (12.7%) had complete pathological response. Correlation of distal margin was better in pinned specimen. A correction factor of 15% for shrinkage needs to be taken into account while assessing unpinned specimen. Only in 4.2% of patients, there was distal submucosal spread beyond gross margin. Long-term follow up is required for assessing adequacy of DRM post neoadjuvant CCRT.

CXCR4 as a novel predictive biomarker for metastasis and poor prognosis in colorectal cancer

The clinical significance of CXCR4 expression in colorectal cancer remains unclear. The aim of this study was to investigate the expression and regulatory effects of CXCR4 in colorectal cancer and the association between CXCR4 protein expression and prognosis. The mRNA and protein expression levels of CXCR4 were determined using reverse-transcriptase polymerase chain reaction and immunohistochemistry staining, respectively, and the relationship between the CXCR4 protein level and clinicopathological parameters was analyzed in 720 cases of colorectal cancer. CXCR4 expression was elevated in colorectal cancer tissues compared to pericancerous tissues (P = 0.001). Of the 720 enrolled cases, 208 (28.89%) expressed CXCR4. In univariate analysis, CXCR4 was found to be associated with lymph node metastasis, TNM stage, and liver metastasis (P = 0.001, 0.001, and 0.012, respectively). Further multivariate analysis suggested that histological grade, TNM stage, and CXCR4 expression were related to liver metastasis (P = 0.020, 0.01, and 0.001, respectively). In the Cox regression test, the histological grade, lymph node metastasis, TNM stage, liver metastasis, and CXCR4 expression were found to be independent prognostic factors (P = 0.02, 0.045, 0.01, 0.001, and 0.001, respectively). CXCR4 protein may be a potential biomarker for liver metastasis and an independent marker for survival in colorectal cancer.