The influence of mechanical bowel preparation on long-term survival in patients surgically treated for colorectal cancer

High-intensity mechanical bowel preparation before curative colorectal surgery is associated with poor long-term prognosis

PURPOSE

Mechanical bowel preparation (MBP) has been widely used to reduce intestinal feces and bacteria and is considered necessary to prevent surgical infections. However, it is still controversial which intensity level of MBP is the most beneficial for patients before colorectal surgery. Our study aimed to determine the impact of different intensity levels of MBP on the progression-free survival (PFS) and overall survival (OS) for colorectal cancer (CRC) patients.

METHODS

We evaluated 694 patients pathologically diagnosed with CRC and underwent MBP before surgery at 4 general hospitals from January 2011 to December 2015. The survival status of patients, the disease progression, and the time of death or progression were obtained through telephone follow-up at the deadline October 10, 2018. Hazard ratios were estimated by Cox proportional hazard models. Survival was assessed using the Kaplan-Meier method followed by the log-rank test.

RESULTS

Of 694 patients included, 462 received low-intensity MBP and 232 received high-intensity MBP. A significantly higher PFS in low-intensity MBP was observed (p = 0.009). PFS at 2000 days was 69.331% in the low-intensity arm and 58.717% in the high-intensity arm. Patients who underwent low-intensity MBP also showed higher OS (p = 0.009). Nine patients in the low-intensity MBP group received secondary surgery, and two patients in the high-intensity MBP group received secondary surgery.

CONCLUSIONS

In this retrospective cohort, low-intensity MBP was associated with better PFS and OS, which could provide a reference for doctors when choosing the intensity of MBP.

Best practices in bowel preparation for colorectal surgery: a 2020 overview

INTRODUCTION

Cohort studies have recently initiated a paradigm shift in the field of preoperative bowel preparation. Indeed, the adjunction of oral antibiotics (OAB) to mechanical bowel preparation (MBP) is now the gold standard for the American guidelines. However, this strategy is highly controverted.

AREAS COVERED

This review was an up-to-date analysis of literature on bowel preparation. We conducted a systematic review for randomized controlled trials (RCTs) and meta-analyses published since 2009. A non-exhaustive overview of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) cohort studies and the international guidelines was also given, and future leads were discussed.

EXPERT OPINION

The methodology of the ACS NSQIP studies did not allow a strong conclusion in favor of the association MBP+OAB. Besides, guidelines were not univocal, with non-American guidelines promoting no preparation at all. RCTs favored OAB alone: indeed, MBP+OAB showed no benefits in terms of surgical site infection (SSI) except when compared to MBP alone, while OAB alone seemed superior to no preparation. Likewise, the meta-analyses also favored OAB alone in terms of overall SSI and organ space infection. Large RCTs are currently running and may change these conclusions. Finally, microbiota is a future lead for personalized OAB.

The Role of Bowel Preparation in Open, Minimally Invasive, and Converted-to-Open Colectomy

BACKGROUND

Bowel preparation before colectomy is considered an effective strategy to decrease postoperative complications. However, data regarding the effect of bowel preparation in patients undergoing minimally invasive colectomy are limited. The aim of this study was to investigate the role of different bowel preparation strategies in patients undergoing open, minimally invasive, and converted-to-open elective colectomies.

METHODS

We identified 39,355 patients who underwent elective colectomy from the American College of Surgeons National Surgical Quality Improvement Program colectomy-targeted database (2012-2016). Multivariate logistic regression models were used to assess the impact of different bowel preparation strategies on postoperative complications and mortality in three subapproach groups: open (n = 12,141), minimally invasive (n = 23,057), and converted to open (n = 4157).

RESULTS

Overall, a total of 10,066 (25.6%) patients received no preparation (NP), 11,646 (29.5%) mechanical bowel preparation (MBP) alone, 1664 (4.2%) antibiotic bowel preparation (ABP) alone, and 15,979 (40.6%) MBP + ABP. Compared with NP, MBP + ABP showed the strongest protective effects. MBP + ABP was associated with reduced risk of major complications (odds ratio [OR] = 0.60, 95% confidence interval [CI]: 0.55-0.66), infectious complications (OR = 0.50, 95% CI: 0.46-0.54), any complications (OR = 0.55, 95% CI: 0.51-0.60), 30-d mortality (OR = 0.68, 95% CI: 0.48-0.96), anastomotic leak (OR = 0.50, 95% CI: 0.43-0.58), and length of stay ≥ 4 d (OR = 0.64, 95% CI: 0.61-0.67) in overall population. These protective effects, except for 30-d mortality, were observed in open, minimally invasive, and converted-to-open groups. When the analysis was limited to robotic surgery only, MBP + ABP was only associated with reduced risk of major complications (OR = 0.61, 95% CI: 0.38-0.97) compared with NP. The protective effects remained similar over the study time period.

CONCLUSIONS

MBP + ABP is a preferred preoperative strategy in open, minimally invasive, and converted-to-open colectomy.

[Current view on variety of bowel preparation for elective colorectal surgery]

Mechanical bowel preparation used to be a standard procedure for a long time. Nowadays routine use of MBP seems to be debatable thus alternative approaches, e.g. avoiding any bowel preparation completely or using of MBP with oral antibiotics are considered. Data on performing different kinds of bowel preparation is reviewed in this article.

Routine preoperative mechanical bowel preparation with additive oral antibiotics is associated with a reduced risk of anastomotic leakage in patients undergoing elective oncologic resection for colorectal cancer

BACKGROUND

Anastomotic leakage (AL) following colorectal resection is a serious issue. AL in oncologic patients might negatively affect the overall survival. Recently, mechanical bowel preparation with additive oral antibiotics (MBP + AB) prior to surgery has been suggested as a means of reducing AL. However, it is unclear whether this positive effect is secondary to MBP alone or secondary to the additive oral antibiotic (MBP + AB). The aim of this study was to investigate the effect of mechanical bowel preparation with additive oral antibiotics (MBP + AB) and without additive oral antibiotics (MBP - AB) on the rate of AL following colorectal resection for cancer.

MATERIALS AND METHODS

Patients undergoing surgical management for colorectal cancer with anastomosis from January 2014 till September 2017 were included for analysis. Cases undergoing MBP + AB were included in the study group. Patients undergoing MBP - AB were included in the control group. Both groups were compared with regard to the rate of AL.

RESULTS

Four hundred and ninety-six patients: 125 undergoing MBP + AB and 371 undergoing MBP - AB were included for analysis. Significantly, more male patients were included in the MBP - AB group compared to the MBP + AB group: 60.1% vs. 45.6% respectively (p = 0.03). Both groups were similar with regard to age distribution and clinicopathological findings (p > 0.05). The rate of AL was significantly higher in the control group (MBP - AB) compared to study group (MBP + AB) (9.1% vs. 4.0%, p = 0.03).

CONCLUSION

Mechanical bowel preparation with additive oral antibiotics prior to elective colorectal resection with anastomosis significantly reduces the risk of AL. Therefore, mechanical bowel preparation with additive non-absorbable oral antibiotics should be recommended in all cases prior to elective colorectal surgery.

Gut microbiome influences on anastomotic leak and recurrence rates following colorectal cancer surgery

BACKGROUND

The pathogenesis of colorectal cancer recurrence after a curative resection remains poorly understood. A yet-to-be accounted for variable is the composition and function of the microbiome adjacent to the tumour and its influence on the margins of resection following surgery.

METHODS

PubMed was searched for historical as well as current manuscripts dated between 1970 and 2017 using the following keywords: 'colorectal cancer recurrence', 'microbiome', 'anastomotic leak', 'anastomotic failure' and 'mechanical bowel preparation'.

RESULTS

There is a substantial and growing body of literature to demonstrate the various mechanisms by which environmental factors act on the microbiome to alter its composition and function with the net result of adversely affecting oncological outcomes following surgery. Some of these environmental factors include diet, antibiotic use, the methods used to prepare the colon for surgery and the physiological stress of the operation itself.

CONCLUSION

Interrogating the intestinal microbiome using next-generation sequencing technology has the potential to influence cancer outcomes following colonic resection.

Dihydroartemisinin increases apoptosis of colon cancer cells through targeting Janus kinase 2/signal transducer and activator of transcription 3 signaling

As a derivative of artemisinin, dihydroartemisinin is effective in the treatment of malaria. Dihydroartemisinin has been identified to possess inhibitory effects in numerous types of animal model with tumors, indicating that it has an antineoplastic effect. The aim of the present study was to analyze the potential anticancer effects of dihydroartemisinin, particularly its effect on apoptosis of colon cancer cells. In the present study, it was identified that dihydroartemisinin inhibited cell viability, promoted cell apoptosis, increased B-cell lymphoma-2-associated X-protein expression, increased caspase-3/9 activities, decreased poly(ADP-ribose) polymerase levels, decreased phosphorylation of extracellular-signal-regulated kinase, and increased phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase in colon cancer cells. Conversely, the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) was suppressed by dihydroartemisinin in colon cancer cells. These results demonstrate that the potential anticancer effects of dihydroartemisinin may increase apoptosis of colon cancer cells through targeting JAK2/STAT3 signaling.