Risk Factor Analysis of Lymph Node Metastasis for Rectal Neuroendocrine Tumors: Who Needs a Radical Resection in Rectal Neuroendocrine Tumors Sized 1-2 cm?

BACKGROUND

Rectal neuroendocrine tumors (NETs) have malignant potential, and lymph node (LN) or distant metastases can occur; however, treatment of NETs 1-2 cm in size is controversial.

OBJECTIVE

This study aimed to identify predictive factors for LN metastasis and prognostic factors for recurrence of rectal NETs, especially tumors 1‒2 cm in size.

METHODS

Between October 2004 and November 2020, 453 patients underwent endoscopic or surgical treatment for rectal NETs in Seoul National University Hospital. The data on these patients were prospectively collected in our database and reviewed retrospectively. In cases of local excision, we evaluated LN metastasis with radiologic imaging, including computed tomography or magnetic resonance imaging before treatment and during the follow-up periods.

RESULTS

LN metastasis was observed in 40 patients (8.8%). A higher rate of LN metastasis was observed in larger-sized tumors, advanced T stage, lymphovascular invasion (LVI), perineural invasion (PNI), and high tumor grade. In multivariable analysis, the significant risk factors for LN metastasis were tumor size (1 ≤ size < 2 cm: hazard ratio [HR] 64.07; size ≥2 cm: HR 102.37, p < 0.001) and tumor grade (G2: HR 3.63, p = 0.034; G3: HR 5.09, p = 0.044). In multivariable analysis for tumors 1-2 cm in size, the risk factor for LN metastasis was tumor grade (G2: HR 6.34, p = 0.013).

CONCLUSIONS

Tumor grade and size are important predictive factors for LN metastasis. In NETs 2 cm in size, tumor grade is also important for LN metastasis, and radical resection should be considered.

Glycemic traits and colorectal cancer survival in a cohort of South Korean patients: A Mendelian randomization analysis

BACKGROUND

Clinical diabetic traits have been reported to be associated with increased colorectal cancer (CRC) risk in observational studies. Using the Mendelian randomization (MR) analysis method, we examined the causal association between glycemic traits, such as fasting glucose (FG), fasting insulin (FI), and glycosylated hemoglobin A1c (HbA1c), and survival in a cohort of CRC patients.

METHODS

We conducted a two-sample MR analysis among a cohort of patients with locally advanced CRC at Seoul National University Hospital. Single-nucleotide polymorphisms robustly associated (p < 5 × 10-8 ) with the three glycemic traits were obtained from the Meta-Analyses of Glucose and Insulin-related traits Consortium, Asian Genetic Epidemiology Network, and Korea Biobank Array. Three-year and 5-year overall survival (OS) and progression-free survival (PFS) were used as outcomes. Survival analysis was conducted using subgroup analysis by cancer stage and subsite in a multivariate Cox proportional hazards model adjusted for age and sex to examine whether glycemic traits affected survival.

RESULTS

A total of 509 patients were included in our final analysis. MR analysis showed that HbA1c levels were associated with poor 3-year OS (β = 4.20, p = 0.02). Sensitivity analyses did not show evidence of any violations of the MR assumptions. In the cancer subgroup analysis of the Cox proportional hazards model, pooled hazard ratios for FG were significantly associated with poor 3-year OS and PFS regardless of cancer stage. FI was not significantly associated with any 3-year survival endpoints. Among Stage III patients, three glycemic traits were significantly associated with both 5-year OS and PFS. Location-specific subgroup analysis showed a significant association between three glycemic traits and 5-year PFS in patients with left-sided colon cancer. FG was associated with poor 3-year survival for colon cancer but not rectal cancer.

CONCLUSIONS

Our results suggest that FG and HbA1c could be used to predict prognosis in CRC patients. Lifestyle and/or pharmacological interventions targeting glycemic traits could help improve survival for CRC patients.

Three-dimensional body composition parameters using automatic volumetric segmentation allow accurate prediction of colorectal cancer outcomes

BACKGROUND

Parameters obtained from two-dimensional (2D) cross-sectional images have been used to determine body composition. However, data from three-dimensional (3D) volumetric body images reflect real body composition more accurately and may be better predictors of patient outcomes in cancer. This study aimed to assess the 3D parameters and determine the best predictive factors for patient prognosis.

METHODS

Patients who underwent surgery for colorectal cancer (CRC) between 2010 and 2016 were included in this study. Preoperative computed tomography images were analysed using an automatic segmentation program. Body composition parameters for muscle, muscle adiposity, subcutaneous fat (SF) and abdominal visceral fat (AVF) were assessed using 2D images at the third lumbar (L3) level and 3D images of the abdominal waist (L1-L5). The cut-off points for each parameter were determined using X-tile software. A Cox proportional hazards regression model was used to identify the association between the parameters and the treatment outcomes, and the relative influence of each parameter was compared using a gradient boosting model.

RESULTS

Overall, 499 patients were included in the study. At a median follow-up of 59 months, higher 3D parameters of the abdominal muscles and SF from the abdominal waist were found to be associated with longer overall survival (OS) and disease-free survival (all P < 0.001). Although the 3D parameters of AVF were not related to survival outcomes, patients with a high AVF volume and mass experienced higher rate of postoperative complications than those with low AVF volume (27.4% vs. 18.7%, P = 0.021, for mass; 27.1% vs. 19.0%, P = 0.028, for volume). Low muscle mass and volume (hazard ratio [HR] 1.959, P = 0.016; HR 2.093, P = 0.036, respectively) and low SF mass and volume (HR 1.968, P = 0.008; HR 2.561, P = 0.003, respectively), both in the abdominal waist, were identified as independent prognostic factors for worse OS. Along with muscle mass and volume, SF mass and volume in the abdominal waist were negatively correlated with mortality (all P < 0.001). Both AVF mass and volume in the abdominal waist were positively correlated with postoperative complications (P < 0.05); 3D muscle volume and SF at the abdominal waist were the most influential factors for OS.

CONCLUSIONS

3D volumetric parameters generated using an automatic segmentation program showed higher correlations with the short- and long-term outcomes of patients with CRC than conventional 2D parameters.

A 3 mm Port Reduces Postoperative Pain After Laparoscopic Colon Cancer Surgery: A Case-control Matched Study

BACKGROUND

Recently, smaller-size trocars and instruments have been developed for laparoscopic colon cancer surgery; however, their effectiveness and safety have not been elucidated. This study aimed to investigate whether 3 mm trocars and instruments have benefits compared with conventional trocars and instruments.

PATIENTS AND METHODS

Patients with colon cancer who underwent laparoscopic anterior resection or right hemicolectomy were included. Patients who underwent combined resections of other organs and those with conversion to open surgery were excluded. In the 3 mm group, three 5 mm trocars were replaced by 3 mm trocars. The numeric rating scale (NRS) immediately postoperatively at 24, 48, and 72 hours, respectively, after surgery and the use of additional analgesics and perioperative outcomes were analyzed. Case-control matched analysis was used to reduce bias according to the type of surgery.

RESULTS

A total of 207 patients (conventional: n = 158, 3 mm: n = 49) were included. Before matching, NRS 48 hours postoperatively ( P = 0.049), proportion of patients using additional intravenous (IV) analgesics ( P = 0.007), postoperative hospital stay ( P < 0.001), and blood loss ( P < 0.001) were lower in the 3 mm group. In multivariable analysis, trocar type significantly impacted the proportion of patients using additional IV analgesics (odds ratio: 0.330; 95% CI: 0.153-0.712; P = 0.005). After case-control matching, NRS immediately postoperatively ( P = 0.015) and 24 hours postsurgery ( P = 0.043), patients using additional IV analgesics ( P = 0.019), postoperative hospital stay ( P = 0.010), intraoperative blood loss ( P < 0.001), and postoperative complication rate ( P = 0.028) were significantly lower in the 3 mm group compared with the 5 mm group.

CONCLUSIONS

The use of 3 mm trocars and instruments in laparoscopic colon cancer surgery can effectively reduce postoperative pain while maintaining perioperative safety.

Cystic lymphangioma causing intussusception of the right colon: a case report and review of current literature

Among intraabdominal lymphangiomas, colonic lymphangiomas are rare. These cystic tumors are generally asymptomatic and incidentally found but may present with bleeding or obstructive symptoms. Intussusception by such tumors is scarcely reported, with only nine previously reported cases listed in Pubmed. We report a case of a 41-year-old female Asian patient who presented with acute abdomen and was diagnosed with colonic intussusception caused by lymphangioma. She received emergent right hemicolectomy, recovered well without complications, and was discharged on the 5th postoperative day.

Postoperative NSAIDs use and the risk of anastomotic leakage after restorative resection for colorectal cancer

BACKGROUND

Although non-steroidal anti-inflammatory drugs (NSAIDs) are useful options for multimodal opioid-sparing analgesia, their effect on anastomotic leakage (AL) after colorectal surgery remains unclear. We aimed to investigate the association between early postoperative NSAID use and AL occurrence in patients who underwent colorectal cancer surgery at a high-volume tertiary care center.

METHODS

This retrospective observational study included all adult patients who underwent elective colorectal cancer resection surgery during 2011-2021 at a tertiary teaching hospital. Based on NSAID use within five postoperative days, patients were classified into either NSAID or no NSAID groups. We performed multivariable logistic regression analysis for the primary outcome, AL, within the first 30 postoperative days, before and after propensity score analysis using stabilized inverse probability of treatment weighting (sIPTW).

RESULTS

Among the 7928 patients analyzed, 0.6% experienced AL after surgery. The occurrence rates of AL were 1.7% (12/714) and 0.5% (37/7214) in the NSAID and no NSAID groups, respectively. Multivariable logistic regression analysis revealed that early postoperative NSAID use was significantly associated with AL [odds ratio (OR), 3.41; 95% confidence interval (CI), 1.76-6.60; P < 0.001]. Significance was maintained after sIPTW (OR, 3.65; 95% CI, 1.86-6.72; P < 0.001).

CONCLUSION

Early postoperative NSAID use was significantly associated with AL in patients undergoing colorectal cancer surgery at a high-volume tertiary care center. Further prospective studies are required to investigate NSAIDs' clinically meaningful unfavorable effects following colorectal cancer surgery.

Real-world survival after colorectal surgery for malignancy in Korean patients with chronic kidney disease: an analysis of Korean healthcare big data, 2002-2019

Purpose

Globally, chronic kidney disease (CKD) is common and has been associated with an increased risk of colorectal cancer (CRC). There is a dearth of literature on the real-world morbidity and mortality associated with CKD comorbid with CRC. This study was performed to evaluate real-world survival outcomes of colorectal malignancy in Korean CKD patients.

Methods

The National Health Insurance Service of Korea provided data on patients who underwent surgical resection among patients diagnosed with CRC from 2002 to 2019.

Results

A total of 219,550 patients were included: 6,181 patients with underlying CKD and 213,369 patients without it. Each morbidity was significantly higher in the CKD-CRC group, and the postoperative mortality rates for the 30-day (3.11% vs. 1.78%, P < 0.001), 60-day (5.95% vs. 3.83%, P < 0.001), and 90-day mortality rate (8.12% vs. 5.32%, P < 0.001) were significantly higher in the CKD group. The median survival time (MST, year) was significantly lower in the CKD-CRC group (5.63; interquartile range [IQR], 5.26-5.91) than in the non-CKD-CRC group (8.71; IQR, 8.37-8.93). MST was significantly lower among CKD patients who received chemotherapy after adjustment by multivariate analysis (adjusted hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.37-1.49; P < 0.001]). Subgroup analysis showed that in the CKD-CRC group, MST was lower in patients who received dialysis than in those who did not, even after multivariate analysis (adjusted HR, 2.38; 95% CI, 2.20-2.58; P < 0.001).

Conclusion

Prevention of CKD-to-end-stage renal disease progression should be adopted as a strategy to increase postoperative survival, along with active surveillance and cancer treatment.

Epigenetic insights into colorectal cancer: comprehensive genome-wide DNA methylation profiling of 294 patients in Korea

DNA methylation regulates gene expression and contributes to tumorigenesis in the early stages of cancer. In colorectal cancer (CRC), CpG island methylator phenotype (CIMP) is recognized as a distinct subset that is associated with specific molecular and clinical features. In this study, we investigated the genomewide DNA methylation patterns among patients with CRC. The methylation data of 1 unmatched normal, 142 adjacent normal, and 294 tumor samples were analyzed. We identified 40,003 differentially methylated positions with 6,933 (79.8%) hypermethylated and 16,145 (51.6%) hypomethylated probes in the genic region. Hypermethylated probes were predominantly found in promoter-like regions, CpG islands, and N shore sites; hypomethylated probes were enriched in open-sea regions. CRC tumors were categorized into three CIMP subgroups, with 90 (30.6%) in the CIMP-high (CIMP-H), 115 (39.1%) in the CIMP-low (CIMP-L), and 89 (30.3%) in the non-CIMP group. The CIMP-H group was associated with microsatellite instabilityhigh tumors, hypermethylation of MLH1, older age, and rightsided tumors. Our results showed that genome-wide methylation analyses classified patients with CRC into three subgroups according to CIMP levels, with clinical and molecular features consistent with previous data. [BMB Reports 2023; 56(10): 563-568].

Total neoadjuvant therapy with short-course radiotherapy Versus long-course neoadjuvant chemoradiotherapy in Locally Advanced Rectal cancer, Korean trial (TV-LARK trial): study protocol of a multicentre randomized controlled trial

BACKGROUND

For locally advanced rectal cancer (LARC), total neoadjuvant therapy (TNT) may enhance tumour response, reduce recurrence, and improve patient compliance compared to upfront surgery. Recent studies have shown that chemoradiotherapy (CRT) followed by consolidation chemotherapy leads to higher rate of pathologic complete response (pCR) than induction chemotherapy followed by CRT. However, an optimal TNT regimen that maximise the pCR rate and minimise toxicity has not been established. Therefore, the aim of this trial was to investigate whether preoperative short-course radiotherapy followed by chemotherapy with four cycles of CAPOX can double the pCR rate compared to a standard schedule of long-course preoperative CRT in patients with LARC.

METHODS

This is a multi-centre, prospective, open label, randomised controlled trial. Patients with clinical primary tumour stage 3 and higher or regional node-involved rectal cancer located within 10 cm from the anal verge were randomly assigned equally to short-course radiotherapy (25 Gy in 5 fractions over 1 week) followed by four cycles of CAPOX (intravenous oxaliplatin [130 mg/m2, once a day] on day 1 and capecitabine [1,000 mg/m2, twice a day] from days 1 to 14) (TNT) or CRT (50.4 Gy in 28 fractions over 5 weeks, concurrently with concomitant oral capecitabine 825 mg/m2 twice a day). After preoperative treatment, total mesorectal excision was performed 2-4 weeks in the TNT group and 6-10 weeks in the CRT group, followed by optional additional adjuvant chemotherapy. The primary endpoint is the pCR rate, and secondary endpoints include disease-related treatment failure, quality of life, and cost-effectiveness. Assuming a pCR rate of 28% and 15% in the TNT and CRT groups, respectively, and one-side alpha error rate of 0.025 and power of 80%, 348 patients will be enrolled considering 10% dropout rate.

DISCUSSION

The TV-LARK trial will evaluate the superiority of employed TNT regimen against the standard CRT regimen for patients with LARC. We aimed to identify a TNT regimen that will improve the pCR rate and decrease systemic recurrence in these patients.

TRIAL REGISTRATION

Cris.nih.go.kr ID: KCT0007169 (April 08, 2022). The posted information will be updated as needed to reflect the protocol amendments and study progress.

Personalised circulating tumour DNA assay with large-scale mutation coverage for sensitive minimal residual disease detection in colorectal cancer

BACKGROUND

Postoperative minimal residual disease (MRD) detection using circulating-tumour DNA (ctDNA) requires a highly sensitive analysis platform. We have developed a tumour-informed, hybrid-capture ctDNA sequencing MRD assay.

METHODS

Personalised target-capture panels for ctDNA detection were designed using individual variants identified in tumour whole-exome sequencing of each patient. MRD status was determined using ultra-high-depth sequencing data of plasma cell-free DNA. The MRD positivity and its association with clinical outcome were analysed in Stage II or III colorectal cancer (CRC).

RESULTS

In 98 CRC patients, personalised panels for ctDNA sequencing were built from tumour data, including a median of 185 variants per patient. In silico simulation showed that increasing the number of target variants increases MRD detection sensitivity in low fractions (<0.01%). At postoperative 3-week, 21.4% of patients were positive for MRD by ctDNA. Postoperative positive MRD was strongly associated with poor disease-free survival (DFS) (adjusted hazard ratio 8.40, 95% confidence interval 3.49-20.2). Patients with a negative conversion of MRD after adjuvant therapy showed significantly better DFS (P < 0.001).

CONCLUSION

Tumour-informed, hybrid-capture-based ctDNA assay monitoring a large number of patient-specific mutations is a sensitive strategy for MRD detection to predict recurrence in CRC.

2022 Seoul Consensus on Clinical Practice Guidelines for Functional Constipation

Chronic constipation is one of the most common digestive diseases encountered in clinical practice. Constipation manifests as a variety of symptoms, such as infrequent bowel movements, hard stools, feeling of incomplete evacuation, straining at defecation, a sense of anorectal blockage during defecation, and use of digital maneuvers to assist defecation. During the diagnosis of chronic constipation, the Bristol Stool Form Scale, colonoscopy, and a digital rectal examination are useful for objective symptom evaluation and differential diagnosis of secondary constipation. Physiological tests for functional constipation have complementary roles and are recommended for patients who have failed to respond to treatment with available laxatives and those who are strongly suspected of having a defecatory disorder. As new evidence on the diagnosis and management of functional constipation emerged, the need to revise the previous guideline was suggested. Therefore, these evidence-based guidelines have proposed recommendations developed using a systematic review and meta-analysis of the treatment options available for functional constipation. The benefits and cautions of new pharmacological agents (such as lubiprostone and linaclotide) and conventional laxatives have been described through a meta-analysis. The guidelines consist of 34 recommendations, including 3 concerning the definition and epidemiology of functional constipation, 9 regarding diagnoses, and 22 regarding managements. Clinicians (including primary physicians, general health professionals, medical students, residents, and other healthcare professionals) and patients can refer to these guidelines to make informed decisions regarding the management of functional constipation.

Gut microbiome associated with low anterior resection syndrome after rectal cancer surgery

This study aimed to assess the likely association of gut microbiome with low anterior resection syndrome (LARS) symptoms. Postoperative stool samples from patients with minor or major LARS after sphincter-preserving surgery (SPS) for rectal cancer were collected and analyzed using 16S ribosomal RNA sequencing method. The symptom patterns of LARS were classified into two groups (PC1LARS, PC2LARS) using principal component analysis. The dichotomized sum of questionnaire items (sub1LARS, sub2LARS) was used to group patients according to the main symptoms. According to microbial diversity, enterotype, and taxa, PC1LARS and sub1LARS were associated with frequency-dominant LARS symptoms and patients, while PC2LARS and sub2LARS were grouped as incontinence-dominant LARS symptoms and patients. Butyricicoccus levels decreased while overall LARS scores increased. The α-diversity richness index Chao1 showed a significantly negative correlation in sub1LARS and a positive correlation in sub2LARS. In sub1LARS, the severe group showed a lower Prevotellaceae enterotype and higher Bacteroidaceae enterotype than the mild group. Subdoligranulum and Flavonifractor showed a negative and a positive correlation with PC1LARS, respectively, while showing a negative relationship with PC2LARS. Lactobacillus and Bifidobacterium were negatively correlated to PC1LARS. Frequency-dominant LARS had decreased diversity of gut microbiome and showed lower levels of lactic acid-producing bacteria.

Mutational evolution after chemotherapy-progression in metastatic colorectal cancer revealed by circulating tumor DNA analysis

Emerging new mutations after treatment can provide clues to acquired resistant mechanisms. Circulating tumor DNA (ctDNA) sequencing has enabled noninvasive repeated tumor mutational profiling. We aimed to investigate newly emerging mutations in ctDNA after disease progression in metastatic colorectal cancer (mCRC). Blood samples were prospectively collected from mCRC patients receiving palliative chemotherapy before treatment and at radiological evaluations. ctDNA from pretreatment and progressive disease (PD) samples were sequenced with a next-generation sequencing panel targeting 106 genes. A total of 712 samples from 326 patients were analyzed, and 381 pretreatment and PD pairs (163 first-line, 85 second-line and 133 later-line [≥third-line]) were compared. New mutations in PD samples (mean 2.75 mutations/sample) were observed in 49.6% (189/381) of treatments. ctDNA samples from later-line had more baseline mutations (P = .002) and were more likely to have new PD mutations (adjusted odds ratio [OR] 2.27, 95% confidence interval [CI]: 1.40-3.69) compared to first-line. RAS/BRAF wild-type tumors were more likely to develop PD mutations (adjusted OR 1.87, 95% CI: 1.22-2.87), independent of cetuximab treatment. The majority of new PD mutations (68.5%) were minor clones, suggesting an increasing clonal heterogeneity after treatment. Pathways involved by PD mutations differed by the treatment received: MAPK cascade (Gene Ontology [GO]: 0000165) in cetuximab and regulation of kinase activity (GO: 0043549) in regorafenib. The number of mutations revealed by ctDNA sequencing increased during disease progression in mCRC. Clonal heterogeneity increased after chemotherapy progression, and pathways involved were affected by chemotherapy regimens.

Optimal surgical management of duodenal fistula in Crohn's disease: a Korean multicenter cohort study

PURPOSE

Duodenal fistula in Crohn's disease (CDF) is a rare condition with an unclear optimal surgical management approach. We reviewed a Korean multicenter cohort of CDF surgery cases and assessed their perioperative outcomes to evaluate the effectiveness of the surgical interventions.

METHODS

The medical records of patients who underwent CD surgery between January 2006 and December 2021 from three tertiary medical centers were retrospectively reviewed. Only CDF cases were included in this study. The demographic and preoperative characteristics, perioperative details, and postoperative outcomes were analyzed.

RESULTS

Among the initial population of 2149 patients who underwent surgery for CD, 23 cases (1.1%) had a CDF operation. Fourteen of these patients (60.9%) had a history of previous abdominal surgery, and 7 had duodenal fistula at the previous anastomosis site. All duodenal fistulas were excised and primarily repaired via a resection of the originating adjacent bowel. Additional procedures such as gastrojejunostomy, pyloric exclusion, or T-tube insertion were performed in 8 patients (34.8%). Eleven patients (47.8%) experienced postoperative complications including for anastomosis leakages. Fistula recurrence was noted in 3 patients (13%) of which one patient required a re-operation. Biologics administration was associated with fewer adverse events by multivariable analysis (P = 0.026, odds ratio = 0.081).

CONCLUSION

Optimal perioperative conditioning of patients receiving a primary repair of a fistula and resection of the original diseased bowel can successfully cure CDF. Along with primary repair of the duodenum, other complementary additional procedures should be considered for better postoperative outcomes.

Prokinetic Activity of Mulberry Fruit, Morus alba L

The fruit of Morus alba L. (MAF) has been consumed as a food worldwide. MAF has also been widely used in traditional medicine for thousands of years in East Asia, and its diverse bioactivities have been reported in numerous publications. However, no prokinetic activity has been reported for MAF or its components. In the present study, therefore, we investigated the effects of MAF on gastrointestinal motor function by measuring the intestinal transit rate (ITR) of Evans blue in mice in vivo. The ITR values accelerated by MAF were significantly higher than those accelerated by cisapride or metoclopramide, suggesting that MAF has potential as a new prokinetic agent to replace cisapride and metoclopramide. We also investigated the effects of MAF on myogenic and neurogenic contractions in human intestinal smooth muscles by measuring spontaneous contractions of smooth muscle strips, smooth muscle contractions induced by neural stimulation, and migrating motor complexes from intestinal segments in the human ileum and sigmoid colon in situ. MAF increased both myogenic and neurogenic contractions to enhance ileal and colonic motility in the human intestine. Taken together, these results indicate that MAF enhanced intestinal motility by increasing both myogenic and neurogenic contractions, thereby accelerating the ITR.

Circulating Tumor DNA Dynamics and Treatment Outcome of Regorafenib in Metastatic Colorectal Cancer

Purpose

Circulating tumor DNA (ctDNA) is emerging as a valuable non-invasive tool to identify tumor heterogeneity and tumor burden. This study investigated ctDNA dynamics in metastatic colorectal cancer patients treated with regorafenib.

Materials and Methods

In this prospective biomarker study, plasma cell-free DNA (cfDNA) samples obtained at baseline, at the first response evaluation after 2 cycles of treatment, and at the time of progressive disease (PD) were sequenced using a targeted next-generation sequencing platform which included 106 genes.

Results

A total of 285 blood samples from 110 patients were analyzed. Higher baseline cfDNA concentration was associated with worse progression-free survival (PFS) and overall survival (OS). After 2 cycles of treatment, variant allele frequency (VAF) in the majority of ctDNA mutations decreased with a mean relative change of -31.6%. Decreases in the VAF of TP53, APC, TCF7L2, and ROS1 after 2 cycles of regorafenib were associated with longer PFS. We used the sum of VAF at each time point as a surrogate for the overall ctDNA burden. A reduction in sum (VAF) of ≥ 50% after 2 cycles was associated with longer PFS (6.1 vs. 2.7 months, p=0.002), OS (11.3 vs. 5.9 months, p=0.001), and higher disease control rate (86.3% vs. 51.1%, p<0.001). VAF of the majority of the ctDNA mutations increased at the time of disease progression, and VAF of BRAF increased markedly.

Conclusion

Reduction in ctDNA burden as estimated by sum (VAF) could be used to predict treatment outcome of regorafenib.

Carbohydrate antigen 19-9 plus carcinoembryonic antigen for prognosis in colorectal cancer: An observational study

AIM

Carcinoembryonic antigen (CEA) is a primary prognostic marker and can detect colorectal cancer (CRC) recurrence; however, it has low sensitivity. Carbohydrate antigen 19-9 (CA 19-9) can be used as a supplemental tumour marker along with CEA. The purpose of this study was to determine whether preoperative CA 19-9 added to CEA helped predict long-term prognosis and whether follow-up CA 19-9 added to CEA had additional benefits in diagnosing the recurrence of CRC.

METHOD

We retrospectively assessed patients who underwent surgery for primary CRC between January 2004 and December 2015 at Seoul National University Hospital. Data on demographics, preoperative and follow-up CEA and CA 19-9 levels, recurrence and survival were obtained and analysed with respect to tumour marker levels to ascertain their prognostic and diagnostic values.

RESULTS

A total of 4972 and 1530 patients were included to analyse preoperative and follow-up tumour marker levels, respectively. The 5-year relapse-free survival rates were 72.2% ± 0.8%, 52.5% ± 2.2%, 55.5% ± 3.2% and 32.1% ± 2.3% in the normal CEA and CA 19-9, high CEA, high CA 19-9, and high CEA and high CA 19-9 groups, respectively (all P < 0.001). Patients whose elevated CEA or CA 19-9 levels reduced to normal levels had better survival outcomes than those with postoperatively elevated levels. Elevated follow-up CA 19-9 and CEA levels were related to higher incidences of distant metastasis (CA 19-9, 14.0% vs. 23.1%, P = 0.004; CEA, 12.6% vs. 30.1%, P < 0.001) but not to local recurrence. Combined follow-up CEA and CA 19-9 increased the sensitivity for recurrence to 31.4%, with a 5% difference from the sensitivity of CEA alone. In the subgroup with high preoperative CA 19-9 levels, sensitivity increased by 18.2% overall.

CONCLUSION

CA 19-9 is a valuable prognostic and diagnostic marker for CRC when used adjunctively with CEA and can be a supplementary marker with CEA to improve sensitivity, especially with elevated preoperative CA 19-9.

Regional Differences in Intestinal Contractile Responses to Radial Stretch in the Human Lower Gastrointestinal Tract

Background/Aims

Radial stretch evokes an increase or decrease in contractions in the lower gastrointestinal tract via mechanosensory enteric neurons that project into the muscle layers. We aim to elucidate the differences in stretch reflexes according to their location in the human colon.

Methods

We used healthy intestinal smooth muscle tissue excised during elective colon cancer surgery. Conventional intracellular recordings from colonic muscle cells and tension recordings of colonic segments were performed. Radial stretch was evoked through balloon catheter inflation. Changes in the membrane potential and frequency, amplitude, and area under the curve of muscle contractions were recorded before and after the radial stretch at proximal and distal segment sites.

Results

In intracellular circular muscle recordings, hyperpolarization was noted at the distal site of sigmoid colonic segments after radial stretch, in contrast to depolarization at all other sites. In tension recordings at proximal ascending or sigmoid colonic segment sites, contractile activation was observed with statistically significant increases in the frequency, amplitude, and area under the curve after radial stretch. Distal sites of ascending and sigmoid colonic segments showed increase and decrease in contraction, respectively.

Conclusion

Radial stretch in the human colon (in vitro) evokes excitatory activity at both proximal and distal sites of the ascending colon and at the proximal site of the sigmoid colon, whereas it elicits inhibitory activity at the distal site of the sigmoid colon.

Korean clinical practice guidelines on biologics and small molecules for moderate-to-severe ulcerative colitis

Ulcerative colitis (UC), a relapsing-remitting chronic inflammatory bowel disease (IBD), has a variable natural course but potentially severe disease course. Since the development of anti-tumor necrosis factor (TNF) agents has changed the natural disease course of moderate-to-severe UC, therapeutic options for patients who failed conventional treatments are expanding rapidly. IBD clinical trials have demonstrated the potential efficacy and safety of novel biologics such as anti-integrin α4β7 and anti-interleukin-12/23 monoclonal antibodies and small molecules such as a Janus kinase inhibitor. Anti-TNF biosimilars also have been approved and are widely used in IBD patients. Wise drug choices should be made considering evidence-based efficacy and safety. However, the best position of these drugs remains several questions, with limited data from direct comparative trials. In addition, there are still concerns to be elucidated on the effect of therapeutic drug monitoring and combination therapy with immunomodulators. The appropriate treatment regimens in acute severe UC and the risk of perioperative use of biologics are unclear. As novel biologics and small molecules have been approved in Korea, we present the Korean guidelines for medical management of adult outpatients with moderate-to-severe UC and adult hospitalized patients with acute severe UC, focusing on biologics and small molecules.

Enterotypical Prevotella and three novel bacterial biomarkers in preoperative stool predict the clinical outcome of colorectal cancer

BACKGROUND

A significant proportion of colorectal cancer (CRC) patients suffer from early recurrence and progression after surgical treatment. Although the gut microbiota is considered as a key player in the initiation and progression of CRC, most prospective studies have been focused on a particular pathobionts such as Fusobacterium nucleatum. Here, we aimed to identify novel prognostic bacteria for CRC by examining the preoperative gut microbiota through 16S ribosomal RNA gene sequencing.

RESULTS

We collected stool samples from 333 patients with primary CRC within 2 weeks before surgery and followed up the patients for a median of 27.6 months for progression and 43.6 months for survival. The sequence and prognosis data were assessed using the log-rank test and multivariate Cox proportional hazard analysis. The gut microbiota was associated with the clinical outcomes of CRC patients (P_progress = 0.011, P_decease = 0.007). In particular, the high abundance of Prevotella, a representative genus of human enterotypes, indicated lower risks of CRC progression (P = 0.026) and decease (P = 0.0056), while the occurrence of Alistipes assigned to Bacteroides sp., Pyramidobacter piscolens, Dialister invisus, and Fusobacterium nucleatum indicated a high risk of progression. A microbiota-derived hazard score considering the five prognostic bacteria accurately predicted CRC progression in 1000 random subsamples; it outperformed widely accepted clinical biomarkers such as carcinoembryonic antigen and lymphatic invasion, after adjustment for the clinicopathological stage (adjusted HR 2.07 [95% CI, 1.61-2.64], P = 7.8e-9, C-index = 0.78). PICRUSt2 suggested that microbial pathways pertaining to thiamine salvage and L-histidine degradation underlie the different prognoses.

CONCLUSIONS

The enterotypical genus Prevotella was demonstrated to be useful in improving CRC prognosis, and combined with the four pathobionts, our hazard score based on the gut microbiota should provide an important asset in predicting medical outcomes for CRC patients. Video Abstract.

Distribution and Function of Platelet-derived Growth Factor Receptor Alpha-positive Cells and Purinergic Neurotransmission in the Human Colon: Is It Different Between the Right and Left Colon?

Background/Aims

Platelet-derived growth factor receptor alpha-positive (PDGFRα⁺) cells function in the purinergic regulation of gastrointestinal motility, and purines are reportedly inhibitory neurotransmitters in the enteric nervous system. We explore the distribution and function of PDGFRα⁺ cells related to purinergic inhibitory neurotransmission in human right and left colons.

Methods

Human colonic segments were prepared with mucosa and submucosa intact, and the circular muscle tension and longitudinal muscle tension were recorded. Purinergic neurotransmitters were administered after recording the regular contractions. Immunohistochemistry was performed on the circular muscle layers. Intracellular recording was performed on the colonic muscular layer. SK3, P2RY1, and PDGFR-α mRNA expression was tested by quantitative real-time polymerase chain reaction (qPCR).

Results

Adenosine triphosphate (ATP) treatment significantly decreased the frequency and area under the curve (AUC) of the segmental contraction in right and left colons. Beta-nicotinamide adenine dinucleotide (β-NAD) decreased the frequency in the right colon and the amplitude, frequency and AUC in the left colon. Apamin significantly increased frequency and AUC in the left colon, and after apamin pretreatment, ATP and β-NAD did not change segmental contractility. Through intracellular recordings, a resting membrane potential decrease occurred after ATP administration; however, the degree of decrease between the right and left colon was not different. PDGFRα⁺ cells were distributed evenly in the circular muscle layers of right and left colons. SK3, P2RY1, and PDGFRα expression was not different between the right and left colon.

Conclusion

Purines reduce right and left colon contractility similarly, and purinergic inhibitory neurotransmission can be regulated by PDGFRα⁺ cells in the human colon.

Standard versus longer interval of radical resection after neoadjuvant chemoradiotherapy in locally advanced rectal cancer: A 20-year single-center experience & propensity-score matching

BACKGROUND AND OBJECTIVES

Despite the standard interval of 6-8 weeks between neoadjuvant chemoradiotherapy (nCRT) and surgery, it is debated whether an interval of >8 weeks increases the pathologic complete response (pCR) rate. We investigated the interval between nCRT and surgery, and its impact on oncological outcomes and postoperative complications in patients with locally advanced rectal cancer.

METHODS

We retrospectively reviewed patients with rectal cancer who underwent total mesorectal excision after long-course nCRT between 2000 and 2020. They were divided into two groups-those who underwent surgery at 6-8 and >8 weeks after nCRT. Surgical outcomes (stoma rate and postoperative complications), pCR, tumor regression grade (TRG), recurrence-free survival (RFS), and overall survival (OS) were compared.

RESULTS

We selected 770/1153 patients with rectal cancer, including 502 and 268 patients surgically treated at 6-8 and >8 weeks after nCRT, respectively. The pCR rates were similar between the two groups (14.7% vs. 15.3%, p = 0.836), while the TRG was significantly better in the >8 weeks group (p = 0.267). Additionally, the postoperative complications, recurrence, 5-year RFS, and OS rates were not significantly different between the two groups.

CONCLUSIONS

Although tumor regression increased in the >8 weeks group, the oncological benefits of surgery >8 weeks after nCRT remain uncertain.

Composite scoring system and optimal tumor budding cut-off number for estimating lymph node metastasis in submucosal colorectal cancer

BACKGROUND

Tumor budding is associated with lymph node (LN) metastasis in submucosal colorectal cancer (CRC). However, the rate of LN metastasis associated with the number of tumor buds is unknown. Here, we determined the optimal tumor budding cut-off number and developed a composite scoring system (CSS) for estimating LN metastasis of submucosal CRC.

METHODS

In total, 395 patients with histologically confirmed T1N0-2M0 CRC were evaluated. The clinicopathological characteristics were subjected to univariate and multivariate analyses. The Akaike information criterion (AIC) values of the multivariate models were evaluated to identify the optimal cut-off number. A CSS for LN metastasis was developed using independent risk factors.

RESULTS

The prevalence of LN metastasis was 13.2%. Histological differentiation, lymphatic or venous invasion, and tumor budding were associated with LN metastasis in univariate analyses. In multivariate models adjusted for histological differentiation and lymphatic or venous invasion, the AIC value was lowest for five tumor buds. Unfavorable differentiation (odds ratio [OR], 8.16; 95% confidence interval [CI], 1.80-36.89), lymphatic or venous invasion (OR, 5.91; 95% CI, 2.91-11.97), and five or more tumor buds (OR, 3.01; 95% CI, 1.21-7.69) were independent risk factors. In a CSS using these three risk factors, the rates of LN metastasis were 5.6%, 15.5%, 31.0%, and 52.4% for total composite scores of 0, 1, 2, and ≥ 3, respectively.

CONCLUSIONS

For the estimation of LN metastasis in submucosal CRC, the optimal tumor budding cut-off number was five. Our CSS can be utilized to estimate LN metastasis.

Abstract 5157: ctDNA change predicts treatment outcome of regorafenib in metastatic colorectal cancer

Introduction: Regorafenib is a multikinase inhibitor which showed clinical benefit in patients with treatment refractory metastatic colorectal cancer. However, as only a subset of patients derives clinical benefit from regorafenib, it is essential to identify biomarker to predict therapeutic response. Circulating tumor DNA (ctDNA) is emerging as a valuable non-invasive tool to identify tumor heterogeneity and tumor burden. This study investigated ctDNA dynamics in patients with metastatic colorectal cancer treated with regorafenib.

Methods: This is a prospective biomarker study including patients with refractory metastatic colorectal cancer treated with regorafenib (ClinicalTrial.gov Identifier: NCT01996969). Patients with metastatic colorectal cancer who were refractory to standard therapies (fluoropyrimidine, oxaliplatin, and irinotecan) were eligible for the current study. Patients received oral regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle and were treated until disease progression, death, unacceptable toxicity, or decision by the treating physicians. Blood samples were obtained prior to regorafenib treatment and after every two cycles of regorafenib treatment until disease progression. ctDNA was detected by AlphaLiquid® 100 target capture panel (IMBdx, Inc., Seoul, South Korea). Alphaliquid® 100 is a tumor agnostic panel consist of 106 genes, including 10 gene fusion and MSI. Variant allele frequency (VAF) amount was calculated by adding the VAF value of all altered genes.

Results: A total of 110 patients were included in the present study. Baseline blood samples were successfully acquired in 107 patients (97.3%) with a total of 713 genetic alteration. Mutation was most frequently found in TP53 (76.6%) followed by APC (75.7%), KRAS (43.0%), PIK3CA (17.8%), and SMAD4 (17.8%). BRAF mutation was found in 8.4% of patients and NRAS was detected in 3.7% of patients. Blood samples after two cycle of regorafenib was acquired in 106 patients, and was acquired in 95 patients after disease progression. Among 104 patients with baseline and follow-up cfDNA, the mean VAF at baseline was 12.8% and 7.2% in follow-up. This resulted in a mean VAF change of -5.61% (absolute value) and -43.7% (relative change). VAF decreased markedly after 2 cycles of regorafenib in several genes, including CSF1R, JAK3, KIT, ROS1, and TERT. Although, VAF change of specific gene was not associated with regorafenib outcome, VAF change of whole gene was an early predictive marker for regorafenib. Reduction in VAF amount of ≥ 50% after two cycles of regorafenib were associated with a significantly improved PFS (6.1 vs. 2.7 months, p = 0.002), OS (11.3 vs. 5.9 months, p = 0.001), and higher disease control rate (86.3% vs. 51.1%, p &lt; 0.001).

Conclusions: Serial ctDNA could be used as an early predictive biomarker in metastatic colorectal cancer treated with regorafenib.

Citation Format: Dae-Won Lee, Sae-Won Han, Yoojoo Lim, Hwang-Phill Kim, Hanseong Roh, Min Jung Kim, Seung-Bum Ryoo, Ji Won Park, Seung-Yong Jeong, Kyu Joo Park, Gyeong Hoon Kang, Tae-You Kim. ctDNA change predicts treatment outcome of regorafenib in metastatic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5157.

Development and validation of a novel strong prognostic index for colon cancer through a robust combination of laboratory features for systemic inflammation: a prognostic immune nutritional index

BACKGROUND

Systemic inflammation is associated with survival outcomes in colon cancer. However, it is not well-known which systemic inflammatory marker is a powerful prognostic marker in patients with colon cancer.

METHODS

A total of 4535 colon cancer patients were included in this study. We developed a novel prognostic index using a robust combination of seven systemic inflammation-associated blood features of the discovery set. The predictability and generality of the novel prognostic index were evaluated in the discovery, validation and replication sets.

RESULTS

Among all combinations, the combination of albumin and monocyte count was the best candidate expression. The final formula of the proposed novel index is named the Prognostic Immune and Nutritional Index (PINI). The concordance index of PINI for overall and progression-free survival was the highest in the discovery, validation and replication sets compared to existing prognostic inflammatory markers. PINI was found to be a significant independent prognostic factor for both overall and progression-free survival.

CONCLUSIONS

PINI is a novel prognostic index that has improved discriminatory power in colon cancer patients and appears to be superior to existing prognostic inflammatory markers. PINI can be utilised for decision-making regarding personalised treatment as the complement of the TNM staging system.

Propulsive colonic contractions are mediated by inhibition-driven poststimulus responses that originate in interstitial cells of Cajal

The peristaltic reflex is a fundamental behavior of the gastrointestinal (GI) tract in which mucosal stimulation activates propulsive contractions. The reflex occurs by stimulation of intrinsic primary afferent neurons with cell bodies in the myenteric plexus and projections to the lamina propria, distribution of information by interneurons, and activation of muscle motor neurons. The current concept is that excitatory cholinergic motor neurons are activated proximal to and inhibitory neurons are activated distal to the stimulus site. We found that atropine reduced, but did not block, colonic migrating motor complexes (CMMCs) in mouse, monkey, and human colons, suggesting a mechanism other than one activated by cholinergic neurons is involved in the generation/propagation of CMMCs. CMMCs were activated after a period of nerve stimulation in colons of each species, suggesting that the propulsive contractions of CMMCs may be due to the poststimulus excitation that follows inhibitory neural responses. Blocking nitrergic neurotransmission inhibited poststimulus excitation in muscle strips and blocked CMMCs in intact colons. Our data demonstrate that poststimulus excitation is due to increased Ca2+ transients in colonic interstitial cells of Cajal (ICC) following cessation of nitrergic, cyclic guanosine monophosphate (cGMP)-dependent inhibitory responses. The increase in Ca2+ transients after nitrergic responses activates a Ca2+-activated Cl− conductance, encoded by Ano1, in ICC. Antagonists of ANO1 channels inhibit poststimulus depolarizations in colonic muscles and CMMCs in intact colons. The poststimulus excitatory responses in ICC are linked to cGMP-inhibited cyclic adenosine monophosphate (cAMP) phosphodiesterase 3a and cAMP-dependent effects. These data suggest alternative mechanisms for generation and propagation of CMMCs in the colon.

Coring-out fistulectomy for perianal cryptoglandular fistula: a retrospective cohort study on 20 years of experience at a single center

Purpose

Cryptoglandular fistula is one of the common anal diseases requiring surgical treatment. Various surgical techniques have been introduced; however, there is no known standard technique. Coring-out fistulectomy is a surgical technique that accurately resects only the fistula tract. However, only a few cases of this procedure have been reported. We aimed to analyze the surgical outcomes of coring-out fistulectomy for cryptoglandular anal fistulas.

Methods

We retrospectively reviewed the medical records of patients who underwent coring-out fistulectomy for a cryptoglandular fistula between 1999 and 2019. Primary outcomes were the treatment success rate (recurrence and healing rates) and incidence of fecal incontinence.

Results

A total of 184 patients were included in our study. The average age of the patients was 44 years (range, 16–75 years), and 88.0% were male. Twenty-four (13.0%), 13 (7.1%), and 68 patients (37.0%) underwent operation for recurrent fistula, multiple tracts, and complex type fistula, respectively. The healing rate was 92.4%, and recurrence occurred in 15 of 170 healed patients (8.8%). Thus, the treatment success rate was 84.2%. There was no fecal incontinence except in 1 patient who had preoperative fecal incontinence because of cauda equine syndrome. In multivariable analysis of the factors affecting the treatment success rate, the complex fistula (odds ratio [OR], 14.2; 95% confidence interval [CI], 4.7–43.0; P < 0.001) and undetected internal opening during the operation (OR, 4.0; 95% CI, 1.4–11.6; P = 0.012) were significant factors.

Conclusion

Coring-out fistulectomy is a simple and feasible technique for sphincter-preserving anal fistula surgery.

OUP accepted manuscript

Background

Method

Results

Conclusion

Role of Dedicated Subspecialized Radiologists in Multidisciplinary Team Discussions on Lower Gastrointestinal Tract Cancers

Objective

To determine the impact of dedicated subspecialized radiologists in multidisciplinary team (MDT) discussions on the management of lower gastrointestinal (GI) tract malignancies.

Materials and Methods

We retrospectively analyzed the data of 244 patients (mean age ± standard deviation, 61.7 ± 11.9 years) referred to MDT discussions 249 times (i.e., 249 cases, as five patients were discussed twice for different issues) for lower GI tract malignancy including colorectal cancer, small bowel cancer, GI stromal tumor, and GI neuroendocrine tumor between April 2018 and June 2021 in a prospective database. Before the MDT discussions, dedicated GI radiologists reviewed all imaging studies again besides routine clinical reading. The referring clinician’s initial diagnosis, initial treatment plan, change in radiologic interpretation compared with the initial radiology report, and the MDT’s consensus recommendations for treatment were collected and compared. Factors associated with changes in treatment plans and the implementation of MDT decisions were analyzed.

Results

Of the 249 cases, radiologic interpretation was changed in 73 cases (29.3%) after a review by dedicated GI radiologists, with 78.1% (57/73) resulting in changes in the treatment plan. The treatment plan was changed in 92 cases (36.9%), and the rate of change in the treatment plan was significantly higher in cases with changes in radiologic interpretation than in those without (78.1% [57/73] vs. 19.9% [35/176], p < 0.001). Follow-up records of patients showed that 91.2% (227/249) of MDT recommendations for treatment were implemented. Multiple logistic regression analysis revealed that the nonsurgical approach (vs. surgical approach) decided through MDT discussion was a significant factor for patients being managed differently than the MDT recommendations (Odds ratio, 4.48; p = 0.017).

Conclusion

MDT discussion involving additional review of radiology examinations by dedicated GI radiologists resulted in a change in the treatment plan in 36.9% of cases. Changes in treatment plans were significantly associated with changes in radiologic interpretation.

Clinical outcomes of surgical management for recurrent rectal prolapse: a multicenter retrospective study

Purpose

Methods

Results

Conclusion

A Novel Scoring System for Response of Preoperative Chemoradiotherapy in Locally Advanced Rectal Cancer Using Early-Treatment Blood Features Derived From Machine Learning

Background

Preoperative chemoradiotherapy (CRT) is a standard treatment for locally advanced rectal cancer (LARC). However, individual responses to preoperative CRT vary from patient to patient. The aim of this study is to develop a scoring system for the response of preoperative CRT in LARC using blood features derived from machine learning.

Methods

Patients who underwent total mesorectal excision after preoperative CRT were included in this study. The performance of machine learning models using blood features before CRT (pre-CRT) and from 1 to 2 weeks after CRT (early-CRT) was evaluated. Based on the best model, important features were selected. The scoring system was developed from the selected model and features. The performance of the new scoring system was compared with those of systemic inflammatory indicators: neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and the prognostic nutritional index.

Results

The models using early-CRT blood features had better performances than those using pre-CRT blood features. Based on the ridge regression model, which showed the best performance among the machine learning models (AUROC 0.6322 and AUPRC 0.5965), a novel scoring system for the response of preoperative CRT, named Response Prediction Score (RPS), was developed. The RPS system showed higher predictive power (AUROC 0.6747) than single blood features and systemic inflammatory indicators and stratified the tumor regression grade and overall downstaging clearly.

Conclusion

We discovered that we can more accurately predict CRT response by using early-treatment blood data. With larger data, we can develop a more accurate and reliable indicator that can be used in real daily practices. In the future, we urge the collection of early-treatment blood data and pre-treatment blood data.

Circulating tumor DNA sequencing in colorectal cancer patients treated with first-line chemotherapy with anti-EGFR

Circulating tumor DNA (ctDNA) may reveal dynamic tumor status during therapy. We conducted serial ctDNA analysis to investigate potential association with clinical outcome in metastatic colorectal cancer (mCRC) patients receiving chemotherapy. Tissue KRAS/NRAS wild-type mCRC patients were enrolled and treated with first-line cetuximab-containing chemotherapy. ctDNA isolated from plasma were analyzed by next generation sequencing (NGS) with 16 targeted gene panel. Among 93 patients, 84 (90.3%) had at least 1 somatic mutation in baseline ctDNA samples (average 2.74). Five patients with KRAS or NRAS hotspot mutation in the ctDNA showed significantly worse progression-free survival (PFS) (p = 0.029). Changes in average variant allele frequency (VAF) in ctDNA showed significant correlation with tumor size change at the time of first response evaluation (p = 0.020) and progressive disease (PD) (p = 0.042). Patients whose average VAF decreased below cutoff (< 1%) at the first evaluation showed significantly better PFS (p < 0.001), and the average VAF change further discriminated the PFS in the patients in partial response (p = 0.018). At the time of PD, 54 new mutations including KRAS and MAP2K1 emerged in ctDNA. ctDNA sequencing can provide mutation profile that could better reflect tumor mutation status and predict treatment outcome.

Molecular and functional characterization of detrusor PDGFRα positive cells in spinal cord injury-induced detrusor overactivity

Volume accommodation occurs via a novel mechanism involving interstitial cells in detrusor muscles. The interstitial cells in the bladder are PDGFRα⁺, and they restrain the excitability of smooth muscle at low levels and prevents the development of transient contractions (TCs). A common clinical manifestation of spinal cord injury (SCI)-induced bladder dysfunction is detrusor overactivity (DO). Although a myogenic origin of DO after SCI has been suggested, a mechanism for development of SCI-induced DO has not been determined. In this study we hypothesized that SCI-induced DO is related to loss of function in the regulatory mechanism provided by PDGFRα⁺ cells. Our results showed that transcriptional expression of Pdgfra and Kcnn3 was decreased after SCI. Proteins encoded by these genes also decreased after SCI, and a reduction in PDGFRα⁺ cell density was also documented. Loss of PDGFRα⁺ cells was due to apoptosis. TCs in ex vivo bladders during filling increased dramatically after SCI, and this was related to the loss of regulation provided by SK channels, as we observed decreased sensitivity to apamin. These findings show that damage to the mechanism restraining muscle contraction during bladder filling that is provided by PDGFRα⁺ cells is causative in the development of DO after SCI.

The oncologic safety of left colectomy with modified complete mesocolic excision for distal transverse colon cancer: Comparison with descending colon cancer

BACKGROUND

The optimal surgical approach for distal transverse colon cancer has not been well established. This study aimed to evaluate the oncologic safety of left colectomy with a modified complete mesocolic excision for distal transverse colon cancer as compared with descending colon cancer.

MATERIAL AND METHODS

This study involved 383 patients who underwent left colectomy with modified complete mesocolic excision for non-metastatic distal transverse and splenic flexure colon (transverse group, N = 110) and descending colon cancer (descending group, N = 237) from 3 institutions. Recurrence-free survival (RFS) and overall survival (OS) were compared between the two groups.

RESULTS

Baseline characteristics between the two groups were similar except for the length of the distal margin (transverse group = 11.0 cm vs descending group = 9.0 cm, p = 0.004). During a median follow-up of 47.0 months, RFS and OS were not different between the transverse and descending groups (5-year RFS: 82% vs 71%, p = 0.139; 5-year OS: 83% vs 79%, p = 0.416, respectively). In multivariable analysis, RFS and OS were not different between the two groups (transverse group vs. descending group: adjusted hazard ratio [aHR] = 1.557, 95% CI = 0.786-3.084, p = 0.204; aHR = 1.251, 95% CI = 0.530-2.952, p = 0.609).

CONCLUSION

The oncologic outcomes of left colectomy with a modified complete mesocolic excision of distal transverse colon cancer were comparable to those of descending colon cancer. Left colectomy with a modified complete mesocolic excision can be an acceptable surgical treatment for distal transverse colon cancer.

Laparoscopic removal of mesh migrating into the sigmoid colon after totally extraperitoneal (TEP) laparoscopic inguinal hernia repair with positive faecal occult blood test

A 76-year-old man was referred to our clinic after a foreign body seen in his sigmoid colon during a colonoscopy. He had undergone three operations for a left inguinal hernia within the previous 8 years, and the first procedure was a laparoscopic totally extraperitoneal approach. Four years later, removal of migrated and infected mesh was conducted by open approach. He then had a positive stool occult blood test for routine check-up 4 years after the remnant mesh removal. An ill-defined lesion was identified on colonoscopy. CT revealed a 2.7 cm diameter enhancing lesion in the sigmoid colon. Laparoscopic sigmoidectomy was performed, and remnant mesh fragment was found in the sigmoid colon and removed. The migrated mesh could not be wholly removed by open abdominal approach and the remnant mesh fragment migrated to sigmoid colon. It suggests the importance of a laparoscopic approach to remove the entire mesh.

Surgical Management of Sigmoid Volvulus: A Multicenter Observational Study

Purpose: This study aimed to evaluate real-world clinical outcomes from surgically treated patients for sigmoid volvulus.Methods: Five tertiary centers participated in this retrospective study with data collected from October 2003 through September 2018, including demographic information, preoperative clinical data, and information on laparoscopic/open and elective/emergency procedures. Outcome measurements included operation time, postoperative hospitalization, and postoperative morbidity.Results: Among 74 patients, sigmoidectomy was the most common procedure (n = 46), followed by Hartmann’s procedure (n = 23), and subtotal colectomy (n = 5). Emergency surgery was performed in 35 cases (47.3%). Of the 35 emergency patients, 34 cases (97.1%) underwent open surgery, and a stoma was established for 26 patients (74.3%). Elective surgery was performed in 39 cases (52.7%), including 21 open procedures (53.8%), and 18 laparoscopic surgeries (46.2%). Median laparoscopic operation time was 180 minutes, while median open surgery time was 130 minutes (P < 0.001). Median postoperative hospitalization was 11 days for laparoscopy and 12 days for open surgery. There were 20 postoperative complications (27.0%), and all were resolved with conservative management. Emergency surgery cases had a higher complication rate than elective surgery cases (40.0% vs. 15.4%, P = 0.034).Conclusion: Relative to elective surgery, emergency surgery had a higher rate of postoperative complications, open surgery, and stoma formation. As such, elective laparoscopic surgery after successful sigmoidoscopic decompression may be the optimal clinical option.

Surgical Management of Sigmoid Volvulus: A Multicenter Observational Study

Purpose

This study aimed to evaluate real-world clinical outcomes from surgically treated patients for sigmoid volvulus.

Methods

Five tertiary centers participated in this retrospective study with data collected from October 2003 through September 2018, including demographic information, preoperative clinical data, and information on laparoscopic/open and elective/emergency procedures. Outcome measurements included operation time, postoperative hospitalization, and postoperative morbidity.

Results

Among 74 patients, sigmoidectomy was the most common procedure (n = 46), followed by Hartmann’s procedure (n = 23), and subtotal colectomy (n = 5). Emergency surgery was performed in 35 cases (47.3%). Of the 35 emergency patients, 34 cases (97.1%) underwent open surgery, and a stoma was established for 26 patients (74.3%). Elective surgery was performed in 39 cases (52.7%), including 21 open procedures (53.8%), and 18 laparoscopic surgeries (46.2%). Median laparoscopic operation time was 180 minutes, while median open surgery time was 130 minutes (P < 0.001). Median postoperative hospitalization was 11 days for laparoscopy and 12 days for open surgery. There were 20 postoperative complications (27.0%), and all were resolved with conservative management. Emergency surgery cases had a higher complication rate than elective surgery cases (40.0% vs. 15.4%, P = 0.034).

Conclusion

Relative to elective surgery, emergency surgery had a higher rate of postoperative complications, open surgery, and stoma formation. As such, elective laparoscopic surgery after successful sigmoidoscopic decompression may be the optimal clinical option.

Quality of life after sphincter preservation surgery or abdominoperineal resection for low rectal cancer (ASPIRE): A long-term prospective, multicentre, cohort study

Background

The long-term effects of radical resection on quality of life may influence the treatment selection. The objective of this study was to determine whether abdominoperineal resection has a better effect on the quality of life than sphincter preservation surgery at 3 years after surgery

Methods

This prospective, cohort study included patients who underwent radical resection for low rectal cancer. The primary outcomes were European Organisation for Research and Treatment of Cancer QLQ-C30 and CR38 quality of life scores 3 years after surgery, which were compared with linear generalised estimating equations, after adjustment for baseline values, a time effect, and an interaction effect between time and treatment. The secondary outcomes included sexual-urinary functions and oncological outcomes. The study was registered with ClinicalTrials.gov (NCT01461525).

Findings

Between December 2011 and August 2016, 342 patients were enrolled: 268 (78•4%) underwent sphincter preservation surgery and 74 (21•6%) underwent abdominoperineal resection. The global quality of life scores did not differ between sphincter preservation surgery and abdominoperineal resection groups (adjusted mean difference, 4•2 points on a 100-point scale; 95% confidence interval  [CI], −1•3 to 9•7, p = 0•1316). Abdominoperineal resection was associated with a worse body image (9•8 points; 95% CI, 2•9 to 16•6, p = 0•0052), micturition symptoms (−8•0 points; 95% CI, -14•1 to −1•8, p = 0•0108), male sexual problems (−19•9 points; 95% CI, -33•1 to -6•7, p = 0•0032), less confidence in getting and maintaining an erection in males (0•5 points on a 5-point scale; 95% CI, 0•1 to 0•8, p = 0•0155), and worse urinary symptoms (−5•4 points on a 35-point scale; 95% CI, −8•0 to −2•7, p < 0•0001). The 5-year overall survival was worse with abdominoperineal resection in unadjusted (92•2% vs 80•9%; difference 11•3%, hazard ratio 2•38; 95% CI, 1•27 to 4•46, p = 0•0052), but did not differ after adjustment.

Interpretation

In this long-term prospective study, abdominoperineal resection failed to meet the superiority to sphincter preservation surgery in terms of quality of life. Although the global quality of life scores did not differ between groups, this study suggests that sphincter preservation surgery can be an acceptable alternative to abdominoperineal resection for low rectal cancer, offering a better quality of life and sexual-urinary functions, with no increased oncological risk even after 3 years.

Funding

Seoul National University Bundang Hospital, Korea

A survey investigating the current situation of the international visiting scholar program at the department of surgery in Korea

Purpose

The number of international visiting scholars has been on the increase in Korea and we aim to investigate the program's current situation.

Methods

This cross-sectional study is based on an online survey questionnaire responded by international visiting scholars in surgical departments of 8 Korean hospitals between 2014 and 2018 about their experiences and satisfaction with the visiting scholar program.

Results

A total of 1,496 international scholars from 80 countries visited various surgical departments in 8 Korean hospitals between 2014 and 2018. The numbers have been on the increase over the years. Out of 355 visiting scholars in 2018, 71 replied to the online survey, of whom 52 were male and 19 female, and mostly in their 30s and 40s. Information about the program was accessed mostly through friends or colleagues (42.3%) and international conferences (36.6%). The commonest funding source was private (35.2%) and more than half stayed for less than 3 months. The visiting scholar's main roles were mostly observation or participation in surgery and clinical research. All but 1 were satisfied with the program (98.6%) and would recommend it to friends and colleagues, although the language barrier was identified as an inconvenience. Those aged 20–39 years with governmental or institutional funding were associated with stays of more than 1 year.

Conclusion

The number of international visiting scholars at surgical departments in Korean hospitals has been on the increase with high satisfaction levels. Improvements need to be made on funding sources and lengthening visiting period to maximize the benefits of the program.

The prognoses and postoperative outcomes of patients with both colorectal cancer and liver cirrhosis based on a nationwide cohort in Korea

Purpose

The management of patients with colorectal cancer (CRC) who have liver cirrhosis (LC) requires a thorough understanding of both diseases; however, the prognoses and postoperative outcomes of such patients remain understudied. We investigated the effect of LC on surgical and oncologic outcomes in patients with CRC, and identified prognostic factors.

Methods

We analyzed 453 patients with CRC and LC (CRC-LC group), 906 with CRC only (CRC group), 906 with LC only (LC group), and 1,812 healthy subjects using health insurance claim data (2008–2013).

Results

The CRC-LC group had a higher frequency of intensive care unit admission than the CRC group; there were no differences between the 2 groups in terms of early and late postoperative small bowel obstruction and incisional hernia. However, the 30-day, 60-day, and 90-day mortality rates were all significantly higher in the CRC-LC group. The higher Charlson comorbidity index (hazard ratio [HR], 1.127) and the lower socioeconomic status (HR, 0.985) were significant worse predictors of 5-year survival. Patients with underlying LC had a significantly higher HR in both the advanced CRC (HR, 1.858) and nonadvanced CRC (HR, 1.799) subgroups. However, the nonadvanced CRC subgroup showed a lower HR than the LC group (HR, 0.730).

Conclusion

Patients with CRC who had underlying LC had a lower survival rate than did those without LC, although the incidence rates of postoperative complications were not significantly different. The presence of LC was associated with a significantly lower survival rate regardless of CRC presence.

ERRATUM: Correction of Figure 1: Outcomes of surgical treatments for rectovaginal fistula and prognostic factors for successful closure: a single-center tertiary hospital experiences

[This corrects the article on p. 149 in vol. 97, PMID: 31508396.].

Oncologic Risk of Rectal Preservation Against Medical Advice After Chemoradiotherapy for Rectal Cancer: A Multicenter Comparative Cross-Sectional Study with Rectal Preservation as Supported by Surgeon

BACKGROUND

Rectal preservation against medical advice after neoadjuvant chemoradiotherapy for rectal cancer may increase oncologic uncertainty. This study aimed to compare the oncologic outcomes of patients undergoing rectal preservation as intended by the surgeon, and the outcomes of patients refusing rectal resection against medical advice.

METHODS

The study population consisted of patients in whom the rectum was preserved after neoadjuvant chemoradiotherapy for clinical stage I-III mid or low rectal cancer between May 2003 and August 2017 (n = 2883); these patients were divided into those in whom rectal preservation was intended by their surgeon (intended rectal preservation, group A, n = 41) and those in whom the rectum was not resected against medical advice (unintended rectal preservation, group B, n = 101), defined as non-operative management or local excision.

RESULTS

The tumor distance, age, and performance status of patients were not significantly different between the groups, while the clinical T stage before chemoradiotherapy was lower in group A than in group B (P < 0.001). During the median follow-up period of 34 months (interquartile range 18.0-72.0 months), the 3-year overall survival in group B (59.7%) was worse than that in group A (90.1%; P < 0.001), and 80.2% of group B patients had residual or unknown disease status.

CONCLUSIONS

This study showed that unintended rectal preservation increases oncologic risk after neoadjuvant chemoradiotherapy for rectal cancer regardless of short-term follow-up. Therefore, these findings could be shared with rectal cancer patients who choose to ignore medical advice after chemoradiotherapy to preserve their rectum.

Impacts of anemia and transfusion on oncologic outcomes in patients undergoing surgery for colorectal cancer

PURPOSE

This study aimed to evaluate the prevalence of preoperative anemia and impacts of anemia and transfusion on survival in patients undergoing surgery for colorectal cancer.

METHODS

This study included patients who underwent surgery for primary colorectal cancer between 2011 and 2012. The influence of preoperative anemia and postoperative transfusion on recurrence-free survival and overall survival were retrospectively investigated. Anemia was defined as hemoglobin level < 13 g/dL in males and < 12 g/dL in females. The primary outcome was the prevalence of preoperative anemia in patients with colorectal cancer. Secondary outcomes included preoperative anemia management, postoperative 30-day mortality and morbidity, tumor recurrence, and overall survival.

RESULTS

Among a total of 1899 patients, 823 patients (43.3%) were anemic preoperatively, and 264 patients (13.9%) received postoperative transfusions. Postoperative transfusion was associated with 30-day postoperative complications (OR = 1.514, 95% CI = 1.020 ~ 2.247) but not preoperative anemia (OR = 1.143, 95% CI, 0.811 ~ 1.611). Preoperative anemia (HR = 1.459, 95% CI = 1.104 ~ 1.929) and postoperative transfusion (HR = 1.566, 95% CI = 1.089 ~ 2.252) were significantly associated with worse recurrence-free survival in multivariable analysis. Preoperative anemia (HR = 1.572, 95% CI = 1.274 ~ 1.940) and postoperative transfusion (HR = 1.381, 95% CI = 1.076 ~ 1.773) were significant independent risk factors for worse overall survival.

CONCLUSIONS

Preoperative anemia and postoperative transfusion were associated with worse survival in patients undergoing surgery for colorectal cancer. An alternative therapy to treat anemia and reduce transfusions should be introduced to improve oncologic outcomes.

Efficacy of health coaching and a web-based program on physical activity, weight, and distress management among cancer survivors: A multi-centered randomised controlled trial

OBJECTIVES

To investigate the efficacy of health coaching and a web-based program on survivor physical activity (PA), weight, and distress management among stomach, colon, lung and breast cancer patients.

METHODS

This randomised, controlled, 1-year trial conducted in five hospitals recruited cancer survivors within 2 months of completing primary cancer treatment who had not met ≥1 of these behavioural goals: (i) conducting moderate PA for at least 150 minutes/week or strenuous exercise for over 75 minutes per week or, in the case of lung cancer patients, low or moderate intensity exercise for over 12.5 MET per week, (ii) maintaining normal weight, and (iii) attaining a score >72 in the Post Traumatic Growth Inventory (PTGI). Participants were randomly assigned to one of three groups: the control group, a web-only group, or a health coaching + web group. The primary endpoint was based on a composite of PA, weight, and PTGI score at 12 months.

RESULTS

Patients in the health coaching + web group (difference = 6.6%, P = .010) and the web-only group (difference = 5.9%, P = .031) had greater overall improvements across the three-outcome composite than the control group. The health coaching + web group had greater overall improvement in PTGI (difference = 12.6%; P < .001) than the control group, but not in PA and weight.

CONCLUSION

The web-based program, with or without health coaching, may improve health behaviours including PA, weight, and distress management among cancer survivors within 2 months of completing primary cancer treatment. The web-based program with health coaching was mainly effective for reducing psychological distress.

Initial M Staging of Rectal Cancer: FDG PET/MRI with a Hepatocyte-specific Contrast Agent versus Contrast-enhanced CT

BackgroundThe performance of PET/MRI in the determination of distant metastases (M stage) in rectal cancer relative to the current practice with contrast material-enhanced CT is largely unknown.PurposeTo compare the staging of clinical M stage rectal cancer with fluorine 18 fluorodeoxyglucose (FDG) PET/MRI (including dedicated liver and rectal MRI) to that of chest and abdominopelvic CT and dedicated rectal MRI.Materials and MethodsFrom January 2016 to August 2017, patients with newly diagnosed advanced mid to low rectal cancers were recruited for this prospective study (clinicaltrials.gov identifier: NCT0265170). Participants underwent both FDG PET/MRI with dedicated liver and rectal MRI and chest and abdominopelvic CT (the standard-of-care protocol) within 3 weeks of each other. Thereafter, M stage assessment performance was determined by using findings from 6-month clinical follow-up or biopsy as the reference standard. Performance was compared between protocols. Agreement in M stage classification was also assessed. Nonparametric statistical analyses were performed, and P < .05 indicated a significance difference.ResultsSeventy-one participants (28 women; mean age ± standard deviation, 61 years ± 9; age range, 39-79 years) were enrolled. The M stage could not be determined with the standard-of-care protocol in 22 of the 71 participants (31%; 95% confidence interval [CI]: 20.5%, 43.1%) because of indeterminate lesions. However, among these participants, PET/MRI correctly helped identify all 14 (100%; 95% CI: 76.8%, 100%) without metastases and seven of eight (88%; 95% CI: 47.4%, 99.7%) who were later confirmed to have metastases. PET/MRI showed high specificity for ruling out metastatic disease compared with the standard-of-care protocol (98% [54 of 55 participants] vs 72% [40 of 55 participants], respectively; P < .001), without increasing the number of participants with missed metastasis (6% [one of 16 participants] vs 6% [one of 16 participants]; P > .99).ConclusionPET/MRI with dedicated rectal and liver MRI can facilitate the staging work-up of newly diagnosed advanced rectal cancers by helping assess indeterminate lesions, metastases, and incidental findings better than contrast-enhanced CT, obviating for additional imaging work-up.© RSNA, 2019Online supplemental material is available for this article.Clinical trial registration no. NCT02651701.

Outcomes of surgical treatments for rectovaginal fistula and prognostic factors for successful closure: a single-center tertiary hospital experiences

Purpose

Rectovaginal fistula can result from various causes and diverse surgical procedures have developed as a result. We investigated the outcomes of surgical treatments for rectovaginal fistula according to causes and procedures.

Methods

Between 1998 and 2016, 92 patients underwent 128 operations for rectovaginal fistula. Prospectively collected data were recorded, and a retrospective review was conducted.

Results

The median age was 49 years, and low fistula occurred in 58 patients (63.0%). The most common cause was radiation therapy, followed by pelvic operation, birth injury, perineal operation, cancer invasion, and trauma. The most common procedure during the first operation was diverting ostomy alone, followed by transanal rectal advancement flap, sphincteroplasty with perineoplasty, bowel resection, fistulectomy with seton placement, and Martius flap. Thirty-one patients (33.7%) experienced successful closure after the first operation. Repeated operations were performed in 16 patients (17.4%), including gracilis muscle transpositions, stem cell injections, and Martius flaps. The overall success rate was 42.4% (n = 39). Radiation therapy and pelvic operation as cause of fistula were significantly poor prognostic factors (P = 0.010, P = 0.045) and Crohn disease had a tendency for poor prognostic factors (P = 0.058).

Conclusion

Radiation therapy and pelvic operation for cancer were more common causes than birth injury, and these causes of rectovaginal fistula were the most important prognostic factors. An individualized approach and repeated surgeries with complex or newly developed procedures, even among high-risk causes of fistula, may be necessary to achieve successful closure.

Oncologic Outcomes in Patients Who Undergo Neoadjuvant Chemoradiotherapy and Total Mesorectal Excision for Locally Advanced Rectal Cancer: A 14-Year Experience in a Single Institution

PURPOSE

This study evaluated the oncologic outcomes of locally advanced rectal cancer patients who underwent preoperative neoadjuvant chemoradiotherapy (CRT) followed by surgery and determined the prognostic significance of pathologic complete response (pCR).

METHODS

Between January 2002 and December 2015, 580 patients with rectal cancer who underwent surgery after neoadjuvant CRT were identified. Survival according to tumor response to CRT and pathologic stage was analyzed using the Kaplan-Meier method, and the Cox proportional hazard model was used to identify factors associated with survival outcomes.

RESULTS

A total of 111 patients (23.7%) achieved pCR while the other 469 patients showed residual disease. Patients with pCR had a lower pretreatment carcinoembryonic antigen level and earlier cT classification than those with residual disease. With a median follow-up of 78 months, disease-free survival (DFS) and overall survival (OS) were significantly better in the pCR group than in the residual disease group. The 5-year DFS and 5-year OS for patients with ypStage 0, I, II, or III were 92.5%, 85.1%, 72.2%, 54.3% (P < 0.001) and 94.5%, 91.0%, 83.1%, 69.3%, respectively (P < 0.001). Pathologic AJCC stage after CRT was the most statistically significant independent predictor of OS (HR, 6.97 [95% confidence interval, 3.16-15.39] for stage III vs. stage 0) and DFS (HR, 7.30 [95% confidence interval, 3.63-14.67] for stage III vs. stage 0).

CONCLUSION

Rectal cancer patients who achieved pCR showed improved survival compared to those with residual disease after preoperative CRT. Moreover, pCR was an independent indicator of OS and DFS, and pathologic AJCC stage was correlated with survival after preoperative CRT.

Inflammatory Myofibroblastic Tumor of the Retroperitoneum Including Chronic Granulomatous Inflammation Suggesting Tuberculosis: A Case Report

An inflammatory myofibroblastic tumor (IMT) is a solid tumor of unknown etiology frequently affecting children and young adults and commonly affecting the lung or orbital region. We present a case involving a 41-year-old man who had an IMT combined with Mycobacterium tuberculosis infection in the retroperitoneum. He presented with only pain in the right lower abdomen without accompanying symptoms; a retroperitoneal mass was found on computed tomography. The tumor had invaded the end of the ileum and was attached to the omentum, so mass excision could not be performed. The tumor was completely excised surgically and had histological features diagnostic of an IMT. Histologic findings of the omentum were positive for Ziehl-Nielsen staining for acid-fast bacilli and for a positive polymerase chain reaction for M. tuberculosis. The patient had no apparent immune disorder. These findings made this case exceptional because IMTs, which are mostly due to atypical mycobacteria, have been found mainly in immunocompromised patients.

Prognostic significance of sealed-off perforation in colon cancer: a prospective cohort study

Background

Perforated colon cancer is a rare complication, but has a high risk of recurrence. However, most studies have not distinguished sealed-off perforation from free perforation, and the prognosis is unclear. The aim of this study was to evaluate the oncologic outcome of colon cancer with sealed-off perforation.

Methods

Eighty-six consecutive patients who underwent resection for colon cancer with sealed-off or free perforation were included. We defined sealed-off perforation as a colon perforation with localized abscess identified on operative, computed tomography, or pathologic findings, with no evidence of free perforation, including fecal contamination and dirty fluid collection in the peritoneal cavity. Oncologic outcomes were compared between patients with colon cancer with sealed-off perforation and free perforation using a log-rank test and Cox regression analysis.

Results

The sealed-off perforation group included 62 patients, and 24 patients were in the free perforation group. TNM stage and lymphatic, venous, and perineural invasion were similar between the groups. The median follow-up period was 28.9 months (range 0–159). The sealed-off perforation group had better prognosis compared with the free perforation group in terms of progression-free survival (PFS) and overall survival (OS), although there were no statistically significant differences in PFS (5-year PFS 53.7% vs. 40.5%, p = 0.148; 5-year OS 53.6% vs. 22.9%, p = 0.001). However, in multivariable analysis using the Cox progression test, sealed-off perforation did not show a significant effect on cancer progression (p = 0.138) and OS (p = 0.727).

Conclusions

Colon cancer with sealed-off perforation showed no difference in prognosis compared with free perforation.

Electronic supplementary material

The online version of this article (10.1186/s12957-018-1530-3) contains supplementary material, which is available to authorized users.