mFOLFIRINOX versus mFOLFOX 6 as adjuvant treatment for high-risk stage III colon cancer - the FROST trial: study protocol for a multicenter, randomized controlled, phase II trial

BACKGROUND

High-risk stage III colon cancer has a considerably poorer prognosis than stage II and low-risk stage III colon cancers. Nevertheless, most guidelines recommend similar adjuvant treatment approaches for all these stages despite the dearth of research focusing on high-risk stage III colon cancer and the potential for improved prognosis with intensive adjuvant treatment. Given the the proven efficacy of triplet chemotherapy in metastatic colorectal cancer treatment, the goal of this study is to evaluate the oncologic efficacy and safety of mFOLFIRINOX in comparison to those of the current standard of care, mFOLFOX 6, as an adjuvant treatment for patients diagnosed with high-risk stage III colon cancer after radical resection.

METHODS

This multicenter, randomized (1:1), open-label, phase II trial will assess and compare the effectiveness and toxicity of mFOLFIRINOX and mFOLFOX 6 in patients with high-risk stage III colon cancer after radical resection. The goal of the trial is to enroll 312 eligible patients, from 11 institutes, aged between 20 and 70 years, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, or between 70 and 75 with an ECOG performance status of 0. Patients will be randomized into two arms - Arm A, the experimental arm, and Arm B, the reference arm - and will receive 12 cycles of mFOLFIRINOX and mFOLFOX 6 every 2 weeks, respectively. The primary endpoint of this study is the 3-year disease-free survival, and secondary endpoints include the 3-year overall survival and treatment toxicity.

DISCUSSION

The Frost trial would help determine the oncologic efficacy and safety of adjuvant triplet chemotherapy for high-risk stage III colon cancers and ultimately improve prognoses.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05179889, registered on 17 December 2021.

Clinical and Genetic Characteristics of Early and Advanced Gastric Cancer

Gastric cancer (GC) persists as the fourth most prevalent cause of global cancer-related mortality, presenting a challenge due to the scarcity of available therapeutic strategies. Precision medicine is crucial not only in the treatment but also in the management of GC. We performed gene panel sequencing with Oncomine focus assay comprising 52 cancer-associated genes and MSI analysis in 100 case-matched gastric cancer cases. A comprehensive analysis of clinical and genetic characteristics was conducted on these genetic results and clinicopathological findings. Upon comparison of clinicopathological characteristics, significant differences between early gastric cancer (EGC) and advanced gastric cancer (AGC) were observed in tumor location (p = 0.003), Lauren classification (p = 0.015), T stage (p = 0.000), and N stage (p = 0.015). The six most frequently mutated genes were PIK3CA (29%, 10/35), ERBB2 (17%, 6/35), KRAS (14%, 5/35), ALK (6%, 2/35), ESR1 (6%, 2/35), and FGFR3 (6%, 2/35). Regarding genetic variation, there was a tendency for the N stage to be higher in GC patients with mutated genes (p = 0.014). The frequency of mutations in GC patients was statistically significantly higher in AGC (n = 24) compared to EGC (n = 11) (odds ratio, 2.792; 95% confidence interval, 1.113 to 7.007; p = 0.026). Six of the ten GC patients carrying mutated genes and exhibiting MSI were classified into intestinal-type and undifferentiated GC, with the location of the tumor being in the lower-third. Among these patients, five harbored mutated PIK3CA, while the remaining patient had a mutation in ALK. Conclusions: AGC patients more frequently exhibited alterations of PIK3CA, KRAS, and ERBB2 as somatic oncogenic drivers, and displayed a higher prevalence of cumulative genetic events, including increased rates of PIK3CA mutations, enhanced detection of immunotherapy biomarkers, and mutations of the ESR1 gene.

Short-term and long-term oncologic outcomes of self-expandable metallic stent compared with tube decompression for obstructive colorectal cancer: a systematic review and meta-analysis

Purpose

Patients with obstructive colorectal cancer managed by emergency surgery show high morbidity, mortality, and stoma formation rates. Decompression modalities, including the self-expandable metallic stent (SEMS) and tube drainage (TD), have been used to improve surgical outcomes. However, there have been limited studies comparing the 2 modalities. We performed a meta-analysis on short- and long-term outcomes between SEMS and TD.

Methods

PubMed, EMBASE, Cochrane Library, and Google Scholar were searched. Data were pooled, and the overall effect size was calculated using random effect models. Outcome measures were perioperative short-term and 3-year survival outcomes.

Results

We included 20 nonrandomized studies that examined 2,047 patients in the meta-analysis. The meta-analysis showed SEMS had better short-term outcomes in clinical success rate, decompression-related complications, laparoscopic surgery rate, stoma formation rate, and postoperative complication rate with a relative risk (RR) of 0.36 (95% confidence interval [CI], 0.24-0.54; I2 = 20%), 0.32 (95% CI, 0.20-0.50; I2 = 0%), 0.47 (95% CI, 0.34-0.66; I2 = 87%), 0.34 (95% CI, 0.24-0.49; I2 = 52%), and 0.70 (95% CI, 0.54-0.89, I2 = 28%), respectively. However, there was no significant difference between the 2 groups in 3-year overall survival (RR, 0.99; 95% CI, 0.77-1.27; I2 = 0%).

Conclusion

Although the long-term oncologic impact of SEMS is still unclear compared with TD, the results of this meta-analysis may suggest that SEMS insertion can be performed more successfully and safely and may have benefits for short-term perioperative outcomes compared with TD. Further studies are warranted to provide more definitive survival results.

Preoperative sequential short-course radiation therapy and FOLFOX chemotherapy versus long-course chemoradiotherapy for locally advanced rectal cancer: a multicenter, randomized controlled trial (SOLAR trial)

BACKGROUND

Preoperative (chemo)radiotherapy has been widely used as an effective treatment for locally advanced rectal cancer (LARC), leading to a significant reduction in pelvic recurrence rates. Because early administration of intensive chemotherapy for LARC has more advantages than adjuvant chemotherapy, total neoadjuvant therapy (TNT) has been introduced and evaluated to determine whether it can improve tumor response or treatment outcomes. This study aims to investigate whether short-course radiotherapy (SCRT) followed by intensive chemotherapy improves oncologic outcomes compared with traditional preoperative long-course chemoradiotherapy (CRT).

METHODS

A multicenter randomized phase II trial involving 364 patients with LARC (cT3-4, cN+, or presence of extramural vascular invasion) will be conducted. Patients will be randomly assigned to the experimental or control arm at a ratio of 1:1. Participants in the experimental arm will receive SCRT (25 Gy in 5 fractions, daily) followed by four cycles of FOLFOX (oxaliplatin, 5-fluorouracil, and folinic acid) as a neoadjuvant treatment, and those in the control arm will receive conventional radiotherapy (45-50.4 Gy in 25-28 fractions, 5 times a week) concurrently with capecitabine or 5-fluorouracil. As a mandatory surgical procedure, total mesorectal excision will be performed 2-5 weeks from the last cycle of chemotherapy in the experimental arm and 6-8 weeks after the last day of radiotherapy in the control arm. The primary endpoint is 3-year disease-free survival, and the secondary endpoints are tumor response, overall survival, toxicities, quality of life, and cost-effectiveness.

DISCUSSION

This is the first Korean randomized controlled study comparing SCRT-based TNT with traditional preoperative LC-CRT for LARC. The involvement of experienced colorectal surgeons ensures high-quality surgical resection. SCRT followed by FOLFOX chemotherapy is expected to improve disease-free survival compared with CRT, with potential advantages in tumor response, quality of life, and cost-effectiveness.

TRIAL REGISTRATION

This trial is registered at Clinical Research Information under the identifier Service KCT0004874 on April 02, 2020, and at Clinicaltrial.gov under the identifier NCT05673772 on January 06, 2023.

Clinical Effectiveness of Fluorescence Lymph Node Mapping Using ICG for Laparoscopic Right Hemicolectomy: A Prospective Case-Control Study

BACKGROUND

The distinction between D3 lymph nodes and actual lymphatic pathways in primary tumors can be difficult during surgery, making it challenging to confirm the completeness of D3 lymph node dissection. Fluorescence lymph node mapping (FLNM) is a promising method for lymph node visualization.

PURPOSE

This study aimed to assess whether FLNM enhances the effectiveness of D3 lymph node dissection in patients with right-sided colon cancer.

METHODS

Endoscopic submucosal indocyanine green injection were performed on the distal margin of the colon cancer. In an FLNM group, the lymphatic drainage pathway and distribution of D3 lymph nodes were explored. Pathological evaluations were conducted for the fluorescent D3 and non-fluorescent D3 lymph nodes.

RESULTS

The FLNM group showed a significantly higher number of harvested lymph nodes in the D3 area. In stage III patients, the proportion of D3 lymph node metastasis was significantly higher in the FLNM group. The harvested D3 lymph node count showed a proportional correlation with a metastatic lymph node count of up to 15.

CONCLUSION

FLNM could be considered a promising new strategy to potentially increase harvested D3 lymph node counts in colon cancer surgery.

The effect on incisional hernia of absorbable barbed suture for midline fascial closure in minimally invasive surgery for colorectal and gastric cancers: study protocol for a randomized controlled trial

BACKGROUND

Incisional hernia following abdominal surgery is a frequent complication of midline laparotomy. This complication is strongly associated with the technique and material used for suture. While a monofilament absorbable suture is recommended to prevent incisional hernia, it can lead to suture loosening or surgical-knot breakage. Although barbed sutures can be an alternative suture material in abdominal fascial closure, evidence for its safety and effectiveness is lacking. Therefore, we designed a prospective randomized trial to evaluate the safety and efficacy of absorbable barbed sutures for midline fascia closure in minimally invasive surgery for colorectal and gastric cancers in comparison with conventional absorbable monofilament sutures.

METHODS

A total of 312 patients who underwent minimally invasive surgery for colorectal and gastric cancers will be randomly allocated to either the absorbable barbed or monofilament suture group for abdominal fascia closure in a 1:1 ratio. The primary outcome is incisional hernia rate within 3 years after surgery, as verified by physical examination and computed tomography. Postoperative complications, including surgical site infection, postoperative pain, and quality of life, will be compared between two groups as secondary outcomes. The investigator will examine the patients until discharge and at 6, 12, 18, 24, and 36 months postoperatively.

DISCUSSION

This is the first randomized controlled trial to compare absorbable barbed sutures with monofilament sutures for midline fascia closure in minimally invasive surgery. If absorbable barbed sutures demonstrate superior results to those of monofilament sutures, this type of suture material may be recommended as an alternative option for abdominal fascia closure.

TRIAL REGISTRATION

KCT0007069. Registered on January 30, 2023.

Anastomotic leak after minimally invasive anterior resection for rectal cancer with high versus low ligation of the inferior mesenteric artery: a study protocol for a multicentre randomized clinical trial

BACKGROUND

Although many efforts have been made to decrease the incidence of anastomotic leak (AL), it remains one of the most serious complications of rectal cancer surgery. Many previous studies have reported an association between the ligation level of the inferior mesenteric artery (IMA) (high or low) and the incidence of AL after rectal cancer surgery. However, we cannot draw a solid conclusion because of the low quality and heterogeneity of those studies. Therefore, this study aims to investigate the impact of the IMA ligation level on the occurrence of AL after minimally invasive anterior resection of rectal cancer.

METHODS/DESIGN

Patients with primary rectal cancer without distant metastases will be included after screening. They will be randomly assigned (1:1) to receive high or low ligation of the IMA. The primary endpoint is AL incidence; secondary endpoints are quality of life; urinary, sexual, and defecatory functions; and 3-year disease-free survival. We hypothesized that the incidence rate of AL would be 15% and 5% in the high- and low-ligation groups, respectively. With a two-sided α of 0.05 and a power of 0.8, the sample size is calculated to be 314 patients (157 per group), considering a 10% dropout rate.

DISCUSSION

Although many studies have compared the short- and long-term outcomes of high and low ligation of the IMA in rectal cancer surgery, it is still debatable. This trial aims to help draw a more solid conclusion regarding the association between the IMA ligation level and AL incidence after rectal cancer surgery. We also hope to contribute to standardizing the method of rectal cancer surgery in this trial.

TRIAL REGISTRATION

Clinical Research Information Service KCT0003523. Registered on February 18, 2019.

Colo-colonic intussusception with post-polypectomy electrocoagulation syndrome: A case report

BACKGROUND

Post-polypectomy electrocoagulation syndrome (PPES) can occur after colonoscopic polypectomy and is usually treated conservatively with a positive prognosis. Nevertheless, there can be cases with complications developing.

CASE SUMMARY

A 58-year-old woman, who had no previous medical history, visited the Emergency Department of another hospital with symptoms of abdominal pain and fever, 1 d after multiple colonoscopic polypectomies. An abdominopelvic computed tomography (CT) scan demonstrated colo-colonic intussusception, and she was transferred to our hospital to consider an operation. CT showed colo-colonic intussusception with PPES and no evidence of obstruction. The physical examination showed localized mild tenderness on the right sided abdomen. The patient fasted and was admitted for treatment with intravenous antibiotics (piperacillin/tazobactam 4.5 g each 8 h, ornidazole 500 mg each 12 h). After admission, the symptoms got better and a follow-up CT scan demonstrated resolution of the PPES and intussusception. The patient was discharged on hospital day 9.

CONCLUSION

Colo-colic intussusception can occur with PPES, and it can be properly treated conservatively.

Clinical significance of p53 protein expression and TP53 variation status in colorectal cancer

In human colorectal cancer (CRC), TP53 is one of the most important driver genes. Immunohistochemistry (IHC) has been used most often to assess the variational status of TP53. Recently, next-generation sequencing (NGS) of the TP53 gene has increased. However, to our knowledge, a comparison between TP53 status evaluated by IHC and NGS has not been studied. Therefore, the primary aim of this study was to compare the clinical effect of TP53 status evaluated by IHC and NGS in patients with CRC. The secondary aim was to investigate the correlation between expression of p53 by IHC and variational status of TP53 by NGS. We performed immunohistochemical staining of p53 and sequencing of TP53 by NGS in 204 human samples of CRC. We then analyzed the correlation between variational status of TP53 and p53 expression, along with their prognostic impact in CRC patients. There was significant correlation between p53 expression and TP53 variation, TP53 variation and higher N stage, and positive p53 expression and higher N stage. Positive IHC expression of p53 was significantly associated with overall survival (OS) of CRC patients by univariate analysis and was revealed as an independent prognostic factor by multivariate analysis. Additionally, the nonsense/frameshift p53 expression pattern showed a significantly better prognosis than the wild type and missense p53 expression patterns. However, the variational status of TP53 was not significant in OS of CRC patients. These results suggest that IHC expression of p53 protein correlates with variation status of TP53 and expression of p53 protein rather than variation status of TP53 has more significant impact on the OS of CRC patients.

Effects of angiotensin peptides on colonic motility in rats

Purpose

Renin-angiotensin system (RAS) is involved in the pathophysiology of colonic inflammation. The aim of this study was to investigate whether small angiotensins (Angs) peptides play a role in the regulation of colonic motility and their roles are modulated in colitis.

Methods

Experimental colitis was induced by an intake of 5% dextran sulfate sodium (DSS) dissolved in tap water for 7 days in Sprague-Dawley rats. After sacrifice, plasma hormone concentrations and messenger RNAs (mRNAs) for RAS were measured. Functional analysis of colonic motility in response to Angs peptides was performed using Taenia coli.

Results

DSS-treated colon showed an increased necrosis with massive infiltration of inflammatory cells. The mRNA level of colonic angiotensin II receptor type 2 (AT2R) in DSS-treated rats was higher than that in control rats whereas the mRNA levels of angiotensin II converting enzyme (ACE), ACE2, AT1R, AT4R, and Mars receptor were not different from those in control rats. Ang III, Ang IV, and Ang-(1-9) (1, 3 μM) increased the frequency of basal colonic motility. Ang-(1-7) did not cause any significant changes in frequency and amplitude of basal motility. The order of potency for an increased frequency of basal motility seems to be Ang II>>Ang IV>Ang III=Ang-(1-9). The increased frequency of basal motility by Ang-(1-9) but not Ang IV was significantly enhanced in DSS-treated rat colon.

Conclusion

In conclusion, these data suggest that small Angs peptides are partly involved in the pathophysiological regulation of colonic motility in experimental colitis.

Prognostic value of tumor deposits for long-term oncologic outcomes in patients with stage III colorectal cancer: a systematic review and meta-analysis

PURPOSE

The presence of tumor deposits (TDs) in colorectal cancer is associated with a poor prognosis. In patients with the concomitant presence of both TDs and lymph nodes (LNs), there is no staging option except for the number of positive LNs alone. Therefore, to determine the prognostic value of TDs in patients with stage III colorectal cancer, meta-analyses of survival outcomes of patients with TDs were performed comparing different subgroups based on the lymph node status.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effect models. Outcome measures were 5-year overall survival (OS) and 5-year disease-free survival (DFS).

RESULTS

We included in the analysis 18 nonrandomized studies and 1 prospective study that examined 90,455 patients. N1c patients (TD + LN-) had worse 5-year DFS than TDs-negative stage III patients (TD-LN +) with a RR of 1.30 (95% CI 1.06-1.61, I² = 47%). In subgroup analysis, N1c patients had worse 5-year DFS (RR = 1.60, 95% CI = 1.25-2.05, I² = 40%) compared with TDs-negative N1 patients (TD-N1) whereas N1c patients had better 5-year OS (RR = 0.72, 95% CI = 0.62-0.83, I² = 0%) and 5-year DFS (RR = 0.75, 95% CI = 0.57-0.99, I² = 0%) compared with TDs-negative N2 patients (TD-N2).

CONCLUSIONS

These results may suggest that current nodal staging for colorectal cancer needs modification. The presence of TDs may have more adverse oncologic outcomes than TDs-negative N1 patients. More studies are warranted to further verify these results.

Correlation of PIK3CA mutation with programmed death ligand-1 (PD-L1) expression and their clinicopathological significance in colorectal cancer

Background

The prognostic significance of PIK3CA mutations in colorectal cancer (CRC) remains controversial. Recently, an association between programmed death ligand-1 (PD-L1) and PIK3CA mutations has been reported. The study presented here was conducted to investigate the effect of PIK3CA mutations on the prognosis of CRC patients and the association between PIK3CA mutations and PD-L1.

Methods

PIK3CA mutations were analyzed by targeted next-generation sequencing using formalin-fixed paraffin-embedded specimens from 224 primary CRC patients. PD-L1 expression was evaluated by immunohistochemical staining.

Results

PIK3CA mutations and PD-L1 expression were detected in 21.4% and 10.3% of CRC patients, respectively. PIK3CA mutations were significantly correlated with right-side colon cancer (P=0.011) and were correlated inversely with lymph node metastasis (P=0.026), distant metastasis (P=0.047), and high TNM stage (P=0.036). In univariate analysis, PIK3CA mutations were correlated with longer relapse-free survival in CRC patients. PD-L1 expression was correlated significantly with PIK3CA mutations (P<0.001).

Conclusions

PIK3CA mutations were associated with favorable prognostic factors, longer relapse-free survival, and expression of PD-L1. Further investigation is needed to identify whether PIK3CA mutations are a good prognostic factor. Additionally, further studies are needed to understand the mechanisms behind the correlation between PIK3CA mutations and PD-L1 expression.

Long-term oncologic outcomes of transanal TME compared with transabdominal TME for rectal cancer: a systematic review and meta-analysis

Background

Transanal total mesorectal excision (TaTME) appears to have favorable surgical and pathological outcomes. However, the evidence on survival outcomes remains unclear. We performed a meta-analysis to compare long-term oncologic outcomes of TaTME with transabdominal TME for rectal cancer.

Methods

PubMed, EMBASE, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random-effects models. Outcome measures were overall survival (OS), disease-free survival (DFS), and local and distant recurrence.

Results

We included 11 nonrandomized studies that examined 2,143 patients for the meta-analysis. There were no significant differences between the two groups in OS, DFS, and local and distant recurrence with a RR of 0.65 (95% CI 0.39–1.09, I² = 0%), 0.79 (95% CI 0.57–1.10, I² = 0%), 1.14 (95% CI 0.44–2.91, I² = 66%), and 0.75 (95% CI 0.40–1.41, I² = 0%), respectively.

Conclusion

In terms of long-term oncologic outcomes, TaTME may be an alternative to transabdominal TME in patients with rectal cancer. Well-designed randomized trials are warranted to further verify these results.

Multifunctional Indocyanine Green Applications for Fluorescence-Guided Laparoscopic Colorectal Surgery

Indocyanine green (ICG) could be applied for multiple functions such as fluorescent tumor localization, fluorescence lymph node mapping (FLNM), and intraoperative angiography in colorectal cancer surgery. With the near-infrared (NIR) systems, colonoscopic ICG tattooing can be used to define the early colorectal cancer that cannot be easily distinguished through the serosal surface. The lymphatic pathways can be visualized under the NIR system when ICG is injected through the submucosal or subserosal layer around the tumor. Intraoperative ICG angiography can be applied to find a favorable perfusion segment before the colon transection. Although all fluorescence functions are considered essential steps in image-guided surgery, it is difficult to perform multifunctional ICG applications in a single surgical procedure at once because complex protocols could interfere with each other. Therefore, we review the multifunctional ICG applications for fluorescent tumor localization, FLNM, and ICG angiography. We also discuss the optimal protocol for fluorescence-guided colorectal surgery.

Fournier Gangrene in a Patient With Type 2 Diabetes Mellitus Treated With Dapagliflozin: A Case Report

Rare cases of Fournier gangrene (FG) possibly associated with sodium-glucose cotransporter 2 inhibitors have been reported. We present a case of a 66-year-old male patient with type 2 diabetes mellitus on oral metformin, glimepiride, and dapagliflozin therapy. He presented with pain in the perineum and scrotum for 5 days. The clinical finding, computed tomography finding, and laboratory data were matched with FG. Emergency surgical drainage, debridement of necrotic tissue, and diverting loop ileostomy formation were performed by a urologist and a surgeon. The patient had no complications from diabetes before the onset of FG, and serum glucose management was good at the onset of FG. This case shows an FG patient with good glucose management taking dapagliflozin and suggests a possible association between dapagliflozin and FG. Further evaluation and additional research on this relationship are needed.

Oncologic effects of adjuvant chemotherapy in patients with ypT0-2N0 rectal cancer after neoadjuvant chemoradiotherapy and curative surgery: a meta-analysis

Purpose

The role of adjuvant chemotherapy for patients with ypT0–2N0 rectal cancer following neoadjuvant chemoradiotherapy (nCRT) and curative surgery is uncertain. We performed a meta-analysis using selected studies to compare adjuvant chemotherapy with observation for this cohort of patients.

Methods

PubMed, Embase, and the Cochrane Library were searched. Data were pooled, and overall effect size was calculated using random effect models. Outcome measures were 5-year overall survival (OS), disease-free survival (DFS), local, and distant recurrence.

Results

We included 17 nonrandomized studies for qualitative analysis and 16 nonrandomized studies that examined 4,747 patients for the meta-analysis. In analysis of patients with ypT0N0 rectal cancer, adjuvant chemotherapy had no significant effect on OS (odds ratio [OR], 1.53; 95% confidence interval [CI], 0.86–2.72; I² = 27%), DFS (OR, 1.22; 95% CI, 0.61–2.42; I² = 5%), local recurrence (OR, 0.78; 95% CI, 0.08–7.37; I² = 0%), and distant recurrence (OR, 1.04; 95% CI, 0.41–2.62; I² = 0%). In analysis of patients with ypT1–2N0 rectal cancer, adjuvant chemotherapy also had no significant effect on OS (OR, 2.15; 95% CI, 0.59–7.80; I² = 26%), DFS (OR, 1.66; 95% CI, 0.35–7.85; I² = 44%), local recurrence (OR, 2.56; 95% CI, 0.72–9.13; I² = 0%), and distant recurrence (OR, 1.15; 95% CI, 0.23–5.87; I² = 0%).

Conclusion

Adjuvant chemotherapy may have no oncologic benefits in patients with ypT0–2N0 rectal cancer after nCRT and radical surgery. Routine use of adjuvant chemotherapy for those patients may be avoided.

Meta-analysis of oncologic effect of primary tumor resection in patients with unresectable stage IV colorectal cancer in the era of modern systemic chemotherapy

Purpose

The management of primary tumors in patients with stage IV colorectal cancer remains unclear. This meta-analysis evaluated the survival benefits of primary tumor resection (PTR) in patients with unresectable stage IV colorectal cancer in the era of modern chemotherapy.

Methods

Multiple comprehensive databases were searched for studies comparing survival outcomes in patients with metastatic colorectal cancer who did and did not undergo PTR. Outcome data were pooled, and overall effect size was calculated using random effect models.

Results

Seventeen nonrandomized studies involving 18,863 patients met the inclusion criteria. Meta-analysis showed that PTR significantly improved overall survival (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.56–0.71; P < 0.001) and progression free survival (HR, 0.76; 95% CI, 0.67–0.87; P < 0.001). Subgroup analyses and sensitivity analyses, performed by predefined methods, also indicated that PTR improved overall patient survival.

Conclusion

Palliative resection of the primary tumor may have survival benefits in patients with unresectable stage IV colorectal cancer. Randomized controlled trials are needed to determine the optimal treatment for these patients.

Management of Colonic Diverticulitis Tailored to Location and Severity: Comparison of the Right and the Left Colon

Purpose

This study assessed optimal management of colonic diverticulitis as functions of disease location and severity and factors associated with complicated diverticulitis.

Methods

This retrospective review analyzed 202 patients diagnosed between 2007 and 2014 at Chonbuk National University Hospital, South Korea, with colonic diverticulitis by using abdominopelvic computed tomography. Diverticulitis location was determined, and disease severity was categorized using the modified Hinchey classification.

Results

Patients included 108 males (53.5%) and 94 females (46.5%); of these, 167 patients (82.7%) were diagnosed with right-sided and 35 (17.3%) with left-sided colonic diverticulitis. Of the 167 patients with right-sided colonic diverticulitis, 12 (7.2%) had complicated and 155 (92.8%) had uncomplicated diverticulitis; of these, 157 patients (94.0%) were successfully managed conservatively. Of the 35 patients with left-sided colonic diverticulitis, 23 (65.7%) had complicated and 12 (34.3%) had uncomplicated diverticulitis; of these, 23 patients (65.7%) were managed surgically. Among patients with right-sided diverticulitis, those with complicated disease were significantly older (54.3 ± 12.7 years vs. 42.5 ± 13.4 years, P = 0.004) and more likely to be smokers (66.7% vs. 32.9%, P = 0.027) than those with uncomplicated disease. However, among patients with left-sided diverticulitis, those with complicated disease had significantly lower body mass index (BMI; 21.9 ± 4.7 kg/m² vs. 25.8 ± 4.3 kg/m², P = 0.021) than those with uncomplicated disease.

Conclusion

Conservative management may be effective in patients with right-sided diverticulitis and patients with uncomplicated left-sided colonic diverticulitis. Surgical management may be required for patients with complicated left-sided diverticulitis. Factors associated with complicated diverticulitis include older age, smoking and lower BMI.

Adhesive small bowel obstruction after laparoscopic and open colorectal surgery: a systematic review and meta-analysis

BACKGROUND

It is considered that laparoscopic surgery is associated with a much lower rate of postoperative formation of adhesions than open surgery. This meta-analysis assessed the incidence of adhesion-related readmissions and surgery for adhesive small bowel obstruction (SBO) in patients who underwent laparoscopic or open colorectal surgery.

METHODS

Multiple comprehensive databases were searched systematically to identify relevant studies and meta-analysis was done.

RESULTS

Meta-analysis showed that laparoscopic surgery was associated with a lower rate of adhesive SBO, both for randomized clinical trials (relative risk [RR] .26, 95% confidence interval [CI] .10 to .67, I(2)=41%) and nonrandomized studies (RR .49, 95% CI .32 to .76, I(2)=91%). Laparoscopic surgery was also associated with a lower rate of subsequent surgery for adhesive SBO, both for randomized clinical trials (RR .25, 95% CI .06 to .96, I(2)=0%) and nonrandomized studies (RR .56, 95% CI .33 to .94, I(2)=77%).

CONCLUSIONS

Laparoscopic colorectal surgery significantly reduced the rates of adhesive SBO and subsequent surgery for adhesive SBO, compared with open surgery.

Modulation in Natriuretic Peptides System in Experimental Colitis in Rats

BACKGROUND

Renin-angiotensin system is involved in the pathophysiology of colonic inflammation. However, there are a few reports about modulation of natriuretic peptide system.

AIMS

This study investigates whether a local atrial natriuretic peptide (ANP) system exists in rat colon and whether ANP plays a role in the regulation of colonic motility in experimental colitis rat model.

METHODS

Experimental colitis was induced by an intake of 5 % dextran sulfate sodium (DSS) dissolved in tap water for 7 days. After rats were killed, plasma hormone concentrations and mRNAs for natriuretic peptide system were measured. Functional analysis of colonic motility in response to ANP was performed using taenia coli.

RESULTS

DSS-treated colon showed an increased necrosis with massive infiltration of inflammatory cells. The colonic natriuretic peptide receptor-A mRNA level and particulate guanylyl cyclase activity in response to ANP from colonic tissue membranes were higher, and the mRNA levels of ANP and natriuretic peptide receptor-B were lower in DSS-treated rats than in control rats. ANP decreased the frequency of basal motility in a dose-dependent manner but did not change the amplitude. The inhibitory responses of frequency of basal motility to ANP and 8-bromo-cGMP were enhanced in DSS-treated rat colon.

CONCLUSION

In conclusion, augmentation of inhibitory effect on basal motility by ANP in experimental colitis may be due an increased expression of colonic natriuretic peptide receptor-A mRNA. These data suggest that local natriuretic peptide system is partly involved in the pathophysiology of experimental colitis.

Transanal tube placement for prevention of anastomotic leakage following low anterior resection for rectal cancer: a systematic review and meta-analysis

Purpose

Anastomotic leakage following low anterior resection (LAR) for rectal cancer is a serious complication that increases morbidity and mortality rates. Transanal tube placement may reduce postoperative anastomotic leakage rate by reducing intraluminal pressure and preventing fecal extrusion through the staple line. This meta-analysis evaluated the effectiveness of transanal tube placement to prevent anastomotic leakage after LAR for rectal cancer using a stapling technique.

Methods

A systematic review of the literature was consistent with the recommendations of the PRISMA (preferred reporting items for systematic reviews and meta-analyses) statement. Multiple comprehensive databases, including PubMed, Embase, Cochrane Library and KoreaMed, were searched. The main study outcomes were anastomotic leakage.

Results

Two randomized clinical trials and 4 nonrandomized studies involving 1,118 patients were included. Subgroup analyses of randomized clinical trials found that transanal tube placement had no effect on study outcomes. Meta-analysis of nonrandomized studies showed that transanal tube placement was associated with a lower incidence of anastomotic leakage (relative risk, 0.32; 95% CI, 0.15-0.67; I² = 0%).

Conclusion

Transanal tube placement may be effective in preventing or reducing the occurrence of anastomotic leakage after LAR for rectal cancer using a stapling technique. Randomized clinical trials with sufficient power are needed to confirm the benefit of transanal tube placement.

Surgical repair of intractable chylous ascites following laparoscopic anterior resection

Chylous ascites is the accumulation of a milk-like peritoneal fluid rich in triglycerides and it is an unusual complication following surgical treatment of colorectal cancer. Conservative management is usually sufficient in patients with chylous ascites after surgery. However, we describe a patient with intractable chylous ascites after laparoscopic anterior resection for sigmoid colon cancer who failed initial conservative treatment. This patient was successfully managed by surgery.

Cholecystocolic fistula caused by gallbladder carcinoma: Preoperatively misdiagnosed as hepatic colon carcinoma

Cholecystocolic fistula secondary to gallbladder carcinoma is extremely rare and has been reported in very few studies. Most cholecystocolic fistulae are late complications of gallstone disease, but can also develop following carcinoma of the gallbladder when the necrotic tumor penetrates into the adjacent colon. Although no currently available imaging technique has shown great accuracy in recognizing cholecystocolic fistula, abdominopelvic computed tomography may show fistulous communication and anatomical details. Herein we report an unusual case of cholecystocolic fistula caused by gallbladder carcinoma, which was preoperatively misdiagnosed as hepatic flexure colon carcinoma.

Efficacy of conservative management in patients with right colonic diverticulitis

BACKGROUND

Although right colonic diverticulitis is more common than sigmoid diverticulitis, and its incidence has been increasing in Asian countries, there is no definitive treatment strategy for right colonic diverticulitis. This retrospective clinical study assessed the effect of conservative management in patients with right colonic diverticulitis.

METHODS

Of the 169 patients who were diagnosed with right colonic diverticulitis at Chonbuk National University Hospital, South Korea, from 2005 to 2012, 152 patients evaluated by abdominopelvic computed tomography (CT) and managed conservatively were included. CT findings were categorized by modified Hinchey classification, with stages Ib, II, III and IV, as well as fistula and obstruction defined as complicated diverticulitis. Factors associated with recurrence of diverticulitis were determined.

RESULTS

The mean age of 152 patients (87 males, 65 females) was 42.9 ± 13.8 years, median follow-up interval was 61 months (range, 17-113 months). At diagnosis, five patients (3.3%) had complicated diverticulitis. After treatment of first attack, 15 patients (9.9%) experienced recurrence of right colonic diverticulitis, including 10 (6.6%) within 12 months. Fourteen of these patients were successfully treated conservatively, whereas one failed conservative management and required surgical resection. Statistical analysis found no variables related to recurrence of right colonic diverticulitis.

CONCLUSION

Right colonic diverticulitis has a low rate of complicated diverticulitis at first attack and a low recurrence rate, with most recurrences being uncomplicated. Therefore, conservative management is effective in patients with right colonic diverticulitis. Close follow-up of patients for 12 months is required because most recurrences may occur within 12 months.

Hepatitis C virus E2 protein purified from mammalian cells is frequently recognized by E2-specific antibodies in patient sera

The envelope protein of hepatitis C virus (HCV) is composed of two membrane-associated glycoproteins, E1 and E2. To obtain HCV E2 protein as a secretory form at a high level, we constructed a recombinant chinese hamster ovary (CHO) cell line expressing a C-terminal truncated E2 (E2t) fused to human growth hormone (hGH), CHO/hGHE2t. The hGHE2t fusion protein was purified from the culture supernatant using anti-hGH mAb affinity chromatography at approximately 80% purity. The purified hGHE2t protein appeared to be assembled into oligomers linked by intermolecular disulfide bond(s) when density gradient centrifugation and SDS-polyacrylamide gel electrophoresis were employed. When the purified fusion protein was used for testing its ability to bind to antibodies specific for HCV by enzyme-linked immunosorbent assay, the protein was recognized by antibodies in sera from 90% of HCV-positive patients. Treatment of hGHE2t protein by beta-mercaptoethanol, but not by heat and SDS, significantly reduced its reactivity to the antibodies of patient sera, suggesting that intermolecular and/or intramolecular disulfide bonds are important for its ability to recognize its specific antibody and that the E2 protein contains discontinuous antigenic epitope(s).

Alterations of p53 gene in primary gastric cancer tissues

This study was conducted to investigate the p53 gene alterations in 25 surgically-resected gastric adenocarcinomas in the Korea Cancer Center Hospital by polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) for exons 4-8 and immunohistochemical staining (IHCS) with anti-p53 antibody, DO-7. p53 mutations were detected in nine (36%) out of 25 cancer tissues by PCR-SSCP in exon 4-8: 0,1,1,6 and 1 mutations in exons 4,5,6,7 and 8, respectively. All tissues were also tested by IHCS, and positive staining was observed in 11 cases (44%). A discrepancy of the results between the two methods was observed in four cases. In one which showed positivity by PCR-SSCP a negative reaction by IHCS, the two base deletion was observed in exon 7. On the other hand, in three cases the mutation was detected only in IHCS but not in PCR-SSCP. The exact mechanism by which this discrepancy develops is not clear at present, although it may be due to the mutation of other exons not tested in this study or the relatively low sensitivity of the PCR-SSCP method. The incidence of p53 gene mutations was analysed according to pathologic stage and histological differentiation, but no significant difference was observed between the p53 alterations and these factors. By combined use of PCR-SSCP and IHCS, 48% of the 25 primary gastric cancer were considered to have mutations of the p53 gene. These results suggest that p53 mutation is not an infrequent event in primary gastric cancer and the p53 gene plays an important role in the carcinogenesis process of gastric cancer.