Metastasis causes most cancer deaths, yet this process remains one of the most enigmatic aspects of the disease. Building on new mechanistic insights emerging from recent research, we offer our perspective on the metastatic process and reflect on possible paths of future exploration. We suggest that metastasis can be portrayed as a two-phase process: The first phase involves the physical translocation of a cancer cell to a distant organ, whereas the second encompasses the ability of the cancer cell to develop into a metastatic lesion at that distant site. Although much remains to be learned about the second phase, we feel that an understanding of the first phase is now within sight, due in part to a better understanding of how cancer cell behavior can be modified by a cell-biological program called the epithelial-to-mesenchymal transition.

http://science.sciencemag.org/content/sci/331/6024/1559.full.pdf

A Perspective on Cancer Cell Metastasis

Stem cells are defined as cells able to both extensively self-renew and differentiate into progenitors. Research data show that more resistant stem cells than common cancer cells exist in cancer patients.To identify unrecognized differences between cancer stem cells and cancer cells might be able to develope effective classification,diagnose and treat ment for cancer.

Stem Cells,Cancer and Cancer Stem Cells

Emerging Biological Principles of Metastasis

The success of anticancer therapy is usually limited by the development of drug resistance. Such acquired resistance is driven, in part, by intratumoural heterogeneity - that is, the phenotypic diversity of cancer cells co-inhabiting a single tumour mass. The introduction of the cancer stem cell (CSC) concept, which posits the presence of minor subpopulations of CSCs that are uniquely capable of seeding new tumours, has provided a framework for understanding one dimension of intratumoural heterogeneity. This concept, taken together with the identification of the epithelial-to-mesenchymal transition (EMT) programme as a critical regulator of the CSC phenotype, offers an opportunity to investigate the nature of intratumoural heterogeneity and a possible mechanistic basis for anticancer drug resistance. In fact, accumulating evidence indicates that conventional therapies often fail to eradicate carcinoma cells that have entered the CSC state via activation of the EMT programme, thereby permitting CSC-mediated clinical relapse. In this Review, we summarize our current understanding of the link between the EMT programme and the CSC state, and also discuss how this knowledge can contribute to improvements in clinical practice.

EMT, CSCs, and drug resistance: the mechanistic link and clinical implications

Cancer stem cells: current status and evolving complexities.

https://www.cell.com/cell-stem-cell/pdf/S1934-5909(10)00156-6.pdf

A Subpopulation of CD26+ Cancer Stem Cells with Metastatic Capacity in Human Colorectal Cancer

OBJECTIVES: This study aimed to identify the risk factors of surgical site infection (SSI) in elective colorectal resection and the strategy for prevention of SSI in modern era of colorectal surgery. BACKGROUND: The practice of colorectal surgery has undergone remarkable evolution recently because of application of laparoscopic resection. This could affect SSI in colorectal patients. An updated investigation of SSI under current practice of colorectal surgery would provide valuable information. METHODS: This was a prospective study of SSI on 1011 patients, who had elective colorectal resection in a university teaching hospital, during January 2002 to December 2006. Standard definition and postoperation follow-up of SSI were adopted through collaboration between surgeons and wound surveillance program of Infection Control Unit. Risk factors of SSI were evaluated. Logistic regression was used to perform multivariate analysis and decide independent risk factors of SSI. RESULTS: The overall rate of incisional SSI and organ/space SSI was 4.8% and 1.7%, respectively. Rate of incisional SSI in open and laparoscopic colorectal resection was 5.7% and 2.7%, respectively. Anastomotic leakage was the only factor that predicted organ/space SSI (P < 0.01). Independent risk factors of incisional SSI included blood transfusion [P = 0.047; odds ratio (OR) = 2.43; 95% confidence interval (CI): 1.0-5.9], anastomotic leakage (P < 0.01; OR = 6.5; 95% CI: 2.3-18.6), and open colorectal resection (P = 0.037; OR = 2.36; 95% CI: 1.1-5.3). CONCLUSION: In current practice of colorectal surgery, operative factors are more important than patient factors for SSI. Good surgical technique to reduce anastomotic leakage and reduce blood transfusion has paramount importance in SSI prevention. Laparoscopic surgery was associated with reduction of rate of SSI by more than 50% when compared with open surgery and would have a strong impact on the prevention of surgical infection.

Impact of Laparoscopic Colorectal Resection on Surgical Site Infection

Aim

This study aimed to evaluate both the short- and long-term outcomes associated with colonic stenting as a bridge to surgery in patients with obstructing adenocarcinoma of the colon.



Method

Patients with potentially curable acute left-sided colonic obstruction treated with stenting as a bridge to surgery (n = 28) or with emergency surgical resection (n = 39) from January 1998 to December 2008 were identified from a prospectively maintained database. Short-term data on postoperative mortality, morbidity, necessity of intensive care and length of hospital stay were compared. Overall survival and disease-free survival were also analysed.



Results

Patients in the two study arms had similar demographic profiles. Those receiving preoperative stenting had a higher likelihood of a laparoscopic resection (P < 0.001). The emergency surgery group had a higher rate of postoperative complications (P = 0.024), rate of intensive care unit admission (P = 0.013) and longer total length of hospital stay (9 vs 12 days, P = 0.001). With a median follow-up of 26.5 and 31.3 months for the stenting and surgical resection groups, there was no difference in overall and disease-free survival (overall survival 30 vs 31 months, P = 0.858; disease-free survival 13 vs 12 months, P = 0.989). There was no difference in the rate of systemic recurrence (8 vs 13, P = 0.991).



Conclusion

Stenting as a bridge to surgery is a safe strategy for acute left-sided colonic obstruction with improved short-term outcome and comparable long-term oncological results.

Long-term outcome of stenting as a bridge to surgery for acute left-sided malignant colonic obstruction.

Objective We report a single-incision laparoscopic left colectomy for a patient with a distal transverse colon cancer.

Method  A 78-year-old man with carcinoma of the transverse colon close to the splenic flexure underwent a single-incision laparoscopic left colectomy with full mobilization of splenic flexure using the TriPort™ Access System and ordinary laparoscopic instruments.

Results  The operation was successfully performed. The patient recovered uneventfully and was discharged after 3 days. Histopathological examination showed a T3N1 tumour with clear resection margins.

Conclusion  This case demonstrates that single-incision laparoscopic colectomy can be applied safely to large bowel cancer close to the splenic flexure. The technique warrants further investigation.

Single incision laparoscopic left colectomy for carcinoma of distal transverse colon

Aim The aim of this study was to evaluate the outcomes of self-expanding metallic stent (SEMS) placement in acute left-sided large-bowel obstruction.



Method  From 1997 to 2008, 130 patients [mean 67 (SD 14.7)] underwent SEMS insertion for acute left-sided large-bowel obstruction. One-hundred and one procedures were palliative, and 29 patients underwent stent insertion as a bridge for surgery. The success rate and the outcome were analysed.



Results  The chief causes of obstruction were primary (67%) and recurrent (16%) colorectal carcinoma. The success rate was 88% after insertion of the first stent. In nine patients, insertion of a second stent was required. Complications occurred in 20% of the insertions, with migration (10.8%) being the most common. Perforation occurred in two patients and one developed a colovesical fistula. In patients with palliative stenting, 14 (13.9%) required subsequent surgery, with a stoma placed in all except three. Among the 29 patients who underwent SEMS insertion as a bridge to surgery, subsequent surgical resection was performed in 26 patients at a mean interval of 12 days (SD 18.0). Primary anastomosis was performed in 24 patients. The mean survival for those who underwent SEMS insertion as a bridge to surgery was 40 (95% confidence interval: 24–55) months.



Conclusion  SEMS placement is safe and effective in relieving acute left-sided colonic obstruction. It allows subsequent definitive surgery on an elective setting and also serves as good palliation for advanced or disseminated disease.

J. T. C. Poon

Papers

A Subpopulation of CD26+ Cancer Stem Cells with Metastatic Capacity in Human Colorectal Cancer

Impact of Laparoscopic Colorectal Resection on Surgical Site Infection

Long-term outcome of stenting as a bridge to surgery for acute left-sided malignant colonic obstruction.

Single incision laparoscopic left colectomy for carcinoma of distal transverse colon

Self-expanding metallic stents for acute left-sided large-bowel obstruction: a review of 130 patients.