OUP accepted manuscript

Background

Diverting ileostomy during resection of rectal cancer is frequently performed in patients at risk of anastomotic failure. Clostridium difficile infection (CDI) is reported to be frequent in patients who receive ileostomy closure with a questionable association to postoperative anastomosis leak. The primary aim of this study was to determine the incidence of CDI following ileostomy closure in patients who underwent rectal cancer surgery; the secondary aim was to assess the rate of postileostomy closure CDI in patients who presented with leakage at the original colorectal anastomosis site.

Methods

Medical records of patients with rectal cancer who underwent ileostomy closure between January 2015 and December 2019 were retrospectively reviewed. All patients had previously received resection and anastomosis for primary rectal cancer with diverting ileostomy. Data regarding CDI incidence, preoperative status, perioperative management, and clinical outcomes were collected. CDI positivity was determined by direct real-time PCR and enzyme-linked fluorescent assays for detecting toxin A and B.Statistical analyses were computed for CDI risk factors.

Results

A total of 1270 patients were included and 208 patients were tested for CDI owing to colitis-related symptoms. The incidence of CDI was 3.6 per cent (46 patients). Multivariable analysis for CDI risk factors identified adjuvant chemotherapy (hazard ratio (HR) 2.28; P = 0.034) and colorectal anastomosis leakage prior to CDI (HR 3.75; P = 0.008). Finally, patients with CDI showed higher colorectal anastomosis leakage risk in multivariable analysis after ileostomy closure (HR 6.922; P = 0.001).

Conclusion

Patients with CDI presented with a significantly higher rate of colorectal anastomosis leakage prior to ileostomy closure.

Re-evaluation of controversial issues in the treatment of cT3N0-2 rectal cancer: a 10-year cohort analysis using propensity-score matching

BACKGROUND

Although neoadjuvant treatment is thought to provide optimal local control for stage II and III rectal cancers, many patients have been reported cured by total mesorectal excision (TME), alone or with additional chemotherapy (CTX).

METHODS

This study retrospectively evaluated outcomes in 2643 patients with cT3N0-2 rectal cancers undergoing curative TME during 2005-2015. Recurrence and survival outcomes were measured in three propensity-score matched groups, consisting of patients who underwent preoperative chemoradiotherapy (CRT) with postoperative CTX (NAPOC), postoperative CRT (POCRT), and exclusively postoperative CTX (EPOCT).

RESULTS

Near-complete or complete TME was conducted in more than 95.9% of patients and 80% of scheduled dose of postoperative CTX was completed in 99%. Except for higher SR rate in the POCRT group than the NAPOC group (p = 0.008), 5-year cumulative local and systemic recurrence (LR and SR) rates were 4.9% and 15.2% for cT3N0, and 4.2% and 21% for cT3N1-2 patients (LR, p = 0.703; SR, 0.065), respectively, with no significant differences associated with treatment exposure (p = 0.11-1). The 5-year cumulative disease-free (75.6% vs 65.7%, p = 0.018) and overall survival (87.1% vs 79.4%, p = 0.018 each) rates were higher in the NAPOC group than the POCRT group with cT3N1-2. However, any significant survival differences were not identified between the NAPOC and EPOCT groups according to tumor sub-stages or locations (p = 0.395-0.971).

CONCLUSIONS

We found any treatment modalities including competent TME and postoperative adjuvant CTX efficiently reducing LR generating robust survival outcome in the propensity-matched cohorts, demanding further randomized controlled trials by clinical sub-stages II-III.

Molecular Characterization of Dysplasia-Initiated Colorectal Cancer With Assessing Matched Tumor and Dysplasia Samples

Purpose

Ulcerative colitis (UC) is known to have an association with the increased risk of colorectal cancer (CRC), and UC-associated CRC does not follow the typical progress pattern of adenoma-carcinoma. The aim of this study is to investigate molecular characteristics of UC-associated CRC and further our understanding of the association between UC and CRC.

Methods

From 5 patients with UC-associated CRC, matched normal, dysplasia, and tumor specimens were obtained from formalin-fixed paraffin-embedded (FFPE) samples for analysis. Genomic DNA was extracted and whole exome sequencing was conducted to identify somatic variations in dysplasia and tumor samples. Statistical analysis was performed to identify somatic variations with significantly higher frequencies in dysplasia-initiated tumors, and their relevant functions were investigated.

Results

Total of 104 tumor mutation genes were identified with higher mutation frequencies in dysplasia-initiated tumors. Four of the 5 dysplasia-initiated tumors (80.0%) have TP53 mutations with frequent stop-gain mutations that were originated from matched dysplasia. APC and KRAS are known to be frequently mutated in general CRC, while none of the 5 patients have APC or KRAS mutation in their dysplasia and tumor samples. Glycoproteins including mucins were also frequently mutated in dysplasia-initiated tumors.

Conclusion

UC-associated CRC tumors have distinct mutational characteristics compared to typical adenoma-carcinoma tumors and may have different cancer-driving molecular mechanisms that are initiated from earlier dysplasia status.

Short-term and long-term outcomes of laparoscopic vs open ileocolic resection in patients with Crohn's disease: Propensity-score matching analysis

BACKGROUND

Laparoscopic ileocolic resection (LICR) is the preferred surgical approach for primary ileocolic Crohn’s disease (CD) because it has greater recovery benefits than open ICR (OICR).

AIM

To compare short- and long-term outcomes in patients who underwent LICR and OICR.

METHODS

Patients who underwent ICR for primary CD from 2006 to 2017 at a single tertiary center specializing in CD were included. Patients who underwent LICR and OICR were subjected to propensity-score matching analysis. Patients were propensity-score matched 1:1 by factors potentially associated with 30-d perioperative morbidity. These included demographic characteristics and disease- and treatment-related variables. Factors were compared using univariate and multivariate analyses. Long-term surgical recurrence-free survival (SRFS) in the two groups was determined by the Kaplan-Meier method and compared by the log-rank test.

RESULTS

During the study period, 348 patients underwent ICR, 211 by the open approach and 137 laparoscopically. Propensity-score matching yielded 102 pairs of patients. The rate of postoperative complication was significantly lower (14% versus 32%, P = 0.003), postoperative hospital stay significantly shorter (8 d versus 13 d, P = 0.003), and postoperative pain on day 7 significantly lower (1.4 versus 2.3, P < 0.001) in propensity-score matched patients who underwent LICR than in those who underwent OICR. Multivariate analysis showed that postoperative complications were significantly associated with preoperative treatment with biologics [odds ratio (OR): 3.14, P = 0.01] and an open approach to surgery (OR: 2.86, P = 0.005). The 5- and 10-year SRFS rates in the matched pairs were 92.9% and 83.3%, respectively, with SRFS rates not differing significantly between the OICR and LICR groups. The performance of additional procedures was an independent risk factor for surgical recurrence [hazard ratio (HR): 3.28, P = 0.02].

CONCLUSION

LICR yielded better short-term outcomes and postoperative recovery than OICR, with no differences in long-term outcomes. LICR may provide greater benefits in selected patients with primary CD.

Effects of anchoring sutures at diverting ileostomy after rectal cancer surgery on peritoneal adhesion at following ileostomy reversal

Purpose

During diverting ileostomy reversal for rectal cancer patients who underwent previous sphincter-saving surgery, the extent of adhesion formation around the ileostomy site affects operative and postoperative outcomes. Anchoring sutures placed at the time of the ileostomy procedure may reduce adhesions around the ileostomy. This study aimed to evaluate the effects of anchoring sutures on the degree of adhesion formation and the postoperative course at the time of ileostomy reversal.

Methods

Patients who underwent sphincter-saving surgery with diverting ileostomy for rectal cancer between January 2013 and December 2017 were enrolled. Variables including the peritoneal dhesion index (PAI) score, operation time, the length of resected small bowel, operative complications, and postoperative hospital stay were collected prospectively and compared between the anchoring group (AG) and non-anchoring group (NAG).

Results

A total of 90 patients were included in this study, with 60 and 30 patients in the AG and NAG, respectively. The AG had shorter mean operation time (46.88 ± 16.37 minutes vs. 61.53 ± 19.36 minutes, P = 0.001) and lower mean PAI score (3.02 ± 2.53 vs. 5.80 ± 2.60, P = 0.001), compared with the NAG. There was no significant difference in the incidence of postoperative complications between the AG and NAG (5.0% vs. 13.3%, respectively; P = 0.240).

Conclusion

Anchoring sutures at the formation of a diverting ileostomy could decrease the adhesion score and operation time at ileostomy reversal, thus may be effective in improving perioperative outcomes.

Radiofrequency Ablation versus Stereotactic Body Radiation Therapy in the Treatment of Colorectal Cancer Liver Metastases

Purpose

This study aimed to compare the treatment outcomes of radiofrequency ablation (RFA) and stereotactic body radiation therapy (SBRT) for colorectal cancer liver metastases (CRLM) and to determine the favorable treatment modality according to tumor characteristics.

Materials and Methods

We retrospectively analyzed the records of 222 colorectal cancer patients with 330 CRLM who underwent RFA (268 tumors in 178 patients) or SBRT (62 tumors in 44 patients) between 2007 and 2014. Kaplan-Meier method and Cox models were used by adjusting with inverse probability of treatment weighting (IPTW).

Results

The median follow-up duration was 30.5 months. The median tumor size was significantly smaller in the RFA group than in the SBRT group (1.5 cm vs 2.3 cm, p < 0.001). In IPTW-adjusted analysis, difference in treatment modality was not associated with significant differences in 1-year and 3-year recurrence-free survival (35% vs. 43%, 22% vs. 23%; p=0.198), overall survival (96% vs. 91%, 58% vs. 56%; p=0.508), and freedom from local progression (FFLP; 90% vs. 72%, 78% vs. 60%; p=0.106). Significant interaction effect between the treatment modality and tumor size was observed for FFLP (p=0.001). In IPTW-adjusted subgroup analysis of patients with tumor size > 2 cm, the SBRT group had a higher FFLP compared with the RFA group (hazard ratio, 0.153; p < 0.001).

Conclusion

SBRT and RFA showed similar local control in the treatment of patients with CRLM. Tumor size was an independent prognostic factor for local control and SBRT may be preferred for larger tumors.

Evaluating the benefit of adjuvant chemotherapy in patients with ypT0–1 rectal cancer treated with preoperative chemoradiotherapy

BACKGROUND

Adjuvant chemotherapy (ACTx) is recommended in rectal cancer patients after preoperative chemoradiotherapy (PCRT), but its efficacy in patients in the early post-surgical stage who have a favorable prognosis is controversial.

AIM

To evaluate the long-term survival benefit of ACTx in patients with ypT0–1 rectal cancer after PCRT and surgical resection.

METHODS

We identified rectal cancer patients who underwent PCRT followed by surgical resection at the Asan Medical Center from 2005 to 2014. Patients with ypT0–1 disease and those who received ACTx were included. The 5-year overall survival (OS) and 5-year recurrence-free survival (RFS) were analyzed according to the status of the ACTx.

RESULTS

Of 520 included patients, 413 received ACTx (ACTx group) and 107 did not (no ACTx group). No significant difference was observed in 5-year RFS (ACTx group, 87.9% vs no ACTx group, 91.4%, P = 0.457) and 5-year OS (ACTx group, 90.5% vs no ACTx group, 86.2%, P = 0.304) between the groups. cT stage was associated with RFS and OS in multivariate analysis [hazard ratio (HR): 2.57, 95% confidence interval (CI): 1.07–6.16, P = 0.04 and HR: 2.27, 95%CI: 1.09–4.74, P = 0.03, respectively]. Furthermore, ypN stage was associated with RFS and OS (HR: 4.74, 95%CI: 2.39–9.42, P < 0.00 and HR: 4.33, 95%CI: 2.20–8.53, P < 0.00, respectively), but only in the radical resection group.

CONCLUSION

Oncological outcomes of patients with ypT0–1 rectal cancer who received ACTx after PCRT showed no improvement, regardless of the radicality of resection. Further trials are needed to evaluate the efficacy of ACTx in these group of patients.

Optimal postoperative surveillance strategies for stage III colorectal cancer

BACKGROUND

Optimal surveillance strategies for stage III colorectal cancer (CRC) are lacking, and intensive surveillance has not conferred a significant survival benefit.

AIM

To examine the association between surveillance intensity and recurrence and survival rates in patients with stage III CRC.

METHODS

Data from patients with pathologic stage III CRC who underwent radical surgery between January 2005 and December 2012 at Asan Medical Center, Seoul, Korea were retrospectively reviewed. Surveillance consisted of abdominopelvic computed tomography (CT) every 6 mo and chest CT annually during the 5 year follow-up period, resulting in an average of three imaging studies per year. Patients who underwent more than the average number of imaging studies annually were categorized as high intensity (HI), and those with less than the average were categorized as low intensity (LI).

RESULTS

Among 1888 patients, 864 (45.8%) were in HI group. Age, sex, and location were not different between groups. HI group had more advanced T and N stage (P = 0.002, 0.010, each). Perineural invasion (PNI) was more identified in the HI group (21.4% vs 30.3%, P < 0.001). The mean overall survival (OS) and recurrence-free interval (RFI) was longer in the LI group (P < 0.001, each). Multivariate analysis indicated that surveillance intensity [odds ratio (OR) = 1.999; 95% confidence interval (CI): 1.680-2.377; P < 0.001], pathologic T stage (OR = 1.596; 95%CI: 1.197-2.127; P = 0.001), PNI (OR = 1.431; 95%CI: 1.192-1.719; P < 0.001), and circumferential resection margin (OR = 1.565; 95%CI: 1.083-2.262; P = 0.017) in rectal cancer were significantly associated with RFI. The mean post-recurrence survival (PRS) was longer in patients who received curative resection (P < 0.001). Curative resection rate of recurrence was not different between HI (29.3%) and LI (23.8%) groups (P = 0.160). PRS did not differ according to surveillance intensity (P = 0.802).

CONCLUSION

Frequent surveillance with CT scan do not improve OS in stage III CRC patients. We need to evaluate role of other surveillance method rather than frequent CT scans to detect recurrence for which curative treatment was possible because curative resection is the important to improve post-recurrence survival.

Long-term oncologic and complication outcomes in anal cancer patients treated with radiation therapy

Aim

The aim of the study is to analyze prognostic factors for tumor control, survival, and late toxicity in patients with anal cancer treated with chemoradiation.

Materials and Methods

Anal cancer patients treated between 1996 and 2010 were analyzed. Patients received radiotherapy and concurrent 5-fluorouracil and mitomycin-C.

Results

Data from 70 patients were analyzed. With a median follow-up of 6.4 years, 5-year overall survival and progression-free survival were 88% and 84%, respectively. Female gender and total radiation dose (≥54 Gy) were significantly associated with better local control. For survival, female gender, patient age, and tumor size were significant prognostic factors. The most common late toxicity was lymphedema. Possible prognosticators were examined, and only radiation dose to the inguinal area was significant.

Conclusion

Despite moderately high radiation doses, local recurrence, and late complications were problems in treating anal cancer. In the intensity-modulated radiotherapy era, consensus on accurate target volume based on the pattern of failure analysis is required.

Cost-effective screening using a two-antibody panel for detecting mismatch repair deficiency in sporadic colorectal cancer

BACKGROUND

The microsatellite instability (MSI) test and immunohistochemistry (IHC) are widely used to screen DNA mismatch repair (MMR) deficiency in sporadic colorectal cancer (CRC). For IHC, a two-antibody panel of MLH1 and MSH2 or four-antibody panel of MLH1, MSH2, PMS2, and MSH6 are used. In general, MSI is known as a more accurate screening test than IHC.

AIM

To compare two- and four-antibody panels of IHC in terms of accuracy and cost benefit on the basis of MSI testing for detecting MMR deficiency.

METHODS

We retrospectively analyzed patients with CRC who underwent curative surgery between 2015 and 2017 at a tertiary referral center. Both IHC with four antibodies and MSI tests were routinely performed. The sensitivity and specificity of a four- and two types of two-antibody panels (PMS2/MSH6 and MLH1/MSH2) were compared on the basis of MSI testing for detecting MMR deficiency.

RESULTS

High-frequency MSI was found in 5.5% (n = 193) of the patients (n = 3486). The sensitivities of the four- and two types of two-antibody panels were 97.4%, 92.2%, and 87.6%, respectively. The specificities of the three types of panels did not differ significantly (99.6% for the four-antibody and PMS2/MSH6 panels, 99.7% for the MLH1/MSH2 panel). Based on Cohen's kappa statistic (κ), four- and two-antibody panels were in almost perfect agreement with the MSI test (κ > 0.9). The costs of the MSI test and the four- and two-antibody panels of IHC were approximately $200, $160, and $80, respectively.

CONCLUSION

Considering the cost of the four-antibody panel IHC compared to that of the two-antibody panel IHC, a two-antibody panel of PMS2/MSH6 might be the best choice in terms of balancing cost-effectiveness and accuracy.

Comparison of long-term recurrence-free survival between primary surgery and endoscopic resection followed by secondary surgery in T1 colorectal cancer

BACKGROUND AND AIMS

We aimed to investigate whether endoscopic resection of T1 colorectal cancer (CRC) before surgery (secondary surgery) unfavorably affects long-term recurrence-free survival (RFS) compared with surgery without prior endoscopic resection (primary surgery).

METHODS

We reviewed the medical records of patients who underwent radical surgery for T1 CRC with high-risk histologic features at a tertiary referral hospital in Korea between 2011 and 2016. The primary outcome was RFS. We performed 2 types of propensity score (PS) analyses to control for confounders.

RESULTS

Of 852 patients, 388 underwent primary surgery and 464 secondary surgery. During the median follow-up period of 57.0 months (range, 41.0-63.0), cancer recurred in 18 patients (2.1%). The 5-year RFS rates did not differ between the primary and secondary surgery groups (97.0 vs 98.5%, P = .194). Further analyses of RFS rates according to nodal stages and number of high-risk histologic features showed no difference between groups. Moreover, RFS rates were not different between the groups after PS matching. In multivariable Cox proportional regression analysis, baseline serum carcinoembryonic antigen level was an independent risk factor for cancer recurrence (hazard ratio, 1.464; 95% confidence interval, 1.242-1.725; P < .001) but prior endoscopic resection of T1 CRC was not (P = .201). Both PS analyses consistently showed no increase in cancer recurrence risk in the secondary surgery group.

CONCLUSIONS

Our data showed no additional cancer recurrence risk by endoscopic resection before surgery of T1 CRC with high-risk histologic features.

Intra-Abdominal Gauze Packing for Uncontrolled Hemorrhage in Non-Trauma Patients

Purpose: The outcomes of non-trauma patients requiring intra-abdominal gauze packing for the management of uncontrollable hemorrhage following surgery, and the evaluation of survival risk factors were examined. Methods: Data from patients who underwent intra-abdominal gauze packing to control bleeding during abdominal surgery between September 2012 and March 2019 were retrospectively reviewed. Results: A total of 28 patients were included in the study population analysis. There were 9 patients who died during hospitalization. One patient died as a result of uncontrolled bleeding. In spite of gauze packing, 2 patients who had increasing blood transfusion requirements (> 4 packs/4 hours) were found to have arterial bleeding. Univariate analysis for hospital death showed that immunocompromised status, emergency surgery, a thrombocytopenic state prior to initial surgery, and a longer duration until gauze removal had a negative association with survival outcomes. Among these factors, only time to gauze removal > 36 hours was identified as an independent risk factor for survival outcome in the multivariate analysis. Conclusions: Gauze packing could be considered as an effective method for the management of uncontrolled hemorrhage, in non-trauma patients. In cases of persistent bleeding after gauze packing, arterial bleeding should be suspected. Gauze removal after > 36 hours may indicate a poor survival outcome.

Comparative perianal fistula closure rates following autologous adipose tissue-derived stem cell transplantation or treatment with anti-tumor necrosis factor agents after seton placement in patients with Crohn's disease: a retrospective observational study

Background

Perianal fistula is one of the most common complications in Crohn’s disease, and various medical and surgical treatments are being tried. The aim of this study was to compare the perianal fistula closure rates following treatment with anti-tumor necrosis factor (TNF) agents or autologous adipose tissue-derived stem cell (auto-ASC) transplantation with Crohn’s disease (CD).

Methods

CD patients who underwent seton placement for perianal fistula from January 2015 to December 2019 at a tertiary referral center were retrospectively reviewed. Patients were divided into two groups, one that received sequential treatments with anti-TNF agents (anti-TNF group) and the other that underwent auto-ASC transplantation (stem cell group). Clinical variables and fistula closure rates were compared in the two groups.

Results

Of the 69 patients analyzed, 39 were treated with anti-TNF agents and 30 underwent auto-ASC transplantation. Compared with the stem cell group, patients in the anti-TNF group were older (p=0.028), were more frequently male (p=0.019), had fistulas with more penetrating behavior (p=0.002), had undergone surgery more frequently (p=0.010), and had a shorter interval from seton placement to intended treatment (p<0.001). During a median follow-up of 46 months (range, 30–52.5 months), fistula closure rates were significantly faster (83.3% vs. 23.1%, p<0.001), and the mean interval from seton placement to fistula closure significantly shorter (14 vs. 37 months, p<0.001) in the stem cell than in the anti-TNF group. Three patients experienced fistula recurrence, all in the stem cell group.

Conclusions

Medical treatment using anti-TNF agents and auto-ASC transplantation are feasible treatment options after seton placement for Crohn’s perianal fistula. However, the closure rate was significantly faster and the time to closure significantly shorter in patients who underwent auto-ASC transplantation than medical treatment.

Trial registration

This study was retrospectively registered and approved by the Institutional Review Board of Asan Medical Center, number 2020-1059.

Immuno-genomic classification of colorectal cancer organoids reveals cancer cells with intrinsic immunogenic properties associated with patient survival

Background

The intrinsic immuno-ge7nomic characteristics of colorectal cancer cells that affect tumor biology and shape the tumor immune microenvironment (TIM) are unclear.

Methods

We developed a patient-derived colorectal cancer organoid (CCO) model and performed pairwise analysis of 87 CCOs and their matched primary tumors. The TIM type of the primary tumor was classified as immuno-active, immuno-exhausted, or immuno-desert.

Results

The gene expression profiles, signaling pathways, major oncogenic mutations, and histology of the CCOs recapitulated those of the primary tumors, but not the TIM of primary tumors. Two distinct intrinsic molecular subgroups of highly proliferative and mesenchymal phenotypes with clinical significance were identified in CCOs with various cancer signaling pathways. CCOs showed variable expression of cancer-specific immune-related genes such as those encoding HLA-I and HLA-II, and molecules involved in immune checkpoint activation/inhibition. Among these genes, the expression of HLA-II in CCOs was associated with favorable patient survival. K-means clustering analysis based on HLA-II expression in CCOs revealed a subgroup of patients, in whom cancer cells exhibited Intrinsically Immunogenic Properties (Ca-IIP), and were characterized by high expression of signatures associated with HLA-I, HLA-II, antigen presentation, and immune stimulation. Patients with the Ca-IIP phenotype had an excellent prognosis, irrespective of age, disease stage, intrinsic molecular type, or TIM status. Ca-IIP was negatively correlated with intrinsic E2F/MYC signaling. Analysis of the correlation between CCO immuno-genotype and TIM phenotype revealed that the TIM phenotype was associated with microsatellite instability, Wnt/β-catenin signaling, APC/KRAS mutations, and the unfolded protein response pathway linked to the FBXW7 mutation in cancer cells. However, Ca-IIP was not associated with the TIM phenotype.

Conclusions

We identified a Ca-IIP phenotype from a large set of CCOs. Our findings may provide an unprecedented opportunity to develop new strategies for optimal patient stratification in this era of immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02034-1.

Improvement in the Assessment of Response to Preoperative Chemoradiotherapy for Rectal Cancer Using Magnetic Resonance Imaging and a Multigene Biomarker

The response to preoperative chemoradiotherapy (PCRT) is correlated with oncologic outcomes in patients with locally advanced rectal cancer. Accurate prediction of PCRT response before surgery can provide crucial information to aid clinicians in further treatment planning. This study aimed to develop an evaluation tool incorporating a genetic biomarker and magnetic resonance imaging (MRI) to improve the assessment of response in post-CRT patients with locally advanced rectal cancer. A total of 198 patients who underwent PCRT followed by surgical resection for locally advanced rectal cancer between 2010 and 2016 were included in this study. Each patient's response prediction index (RPI) score, a multigene biomarker developed in our previous study, and magnetic resonance tumor regression grade (mrTRG) score were added to create a new predictive value for pathologic response after PCRT, called the combined radiation prediction value (cRPV). Based on the new value, 121 and 77 patients were predicted to be good and poor responders, respectively, showing significantly different cRPV values (p = 0.001). With an overall predictive accuracy of 84.8%, cRPV was superior to mrTRG and RPI for the prediction of pathologic chemoradiotherapy response (mrTRG, 69.2%; RPI, 77.3%). In multivariate analysis, cRPV was found to be the sole predictor of tumor response (odds ratio, 32.211; 95% confidence interval, 14.408-72.011; p = 0.001). With its good predictive value for final pathologic regression, cRPV may be a valuable tool for assessing the response to PCRT before surgery.

Long non-coding RNA OIP5-AS1 serves as a competing endogenous RNA to modulate X-linked inhibitor of apoptosis protein expression via adsorbing miR-429 in papillary thyroid cancer

Papillary thyroid cancer (PTC) is currently one of the most common endocrine tumors worldwide. Long non-coding RNA (LncRNA) is a vital regulator in the biological processes of diverse tumors. Hence, this work aimed to clarify the role and mechanism of lncRNA OIP5-AS1 in PTC progression. OIP5-AS1 and miR-429 expression levels in PTC tissues and cells were examined using qRT-PCR. Immunohistochemical staining (IHC) was applied to detect X-linked inhibitors of apoptosis protein (XIAP) expression in PTC tissues. A dual-luciferase reporter gene experiment was employed to validate the relationship for miR-429 and XIAP, miR-429 and OIP5-AS1. The regulatory effects of OIP5-AS1 on PTC cell proliferation, migration, and invasion was detected using the MTT, BrdU, Transwell and Western blot assays. In this work we reported that OIP5-AS1 expression was up-modulated in PTC tissues and cell lines. OIP5-AS1 overexpression enhanced the proliferation and metastasis of PTC cells, but the transfection of miR-429 mimics reversed the functions of OIP5-AS1 on the proliferation, migration, and invasion of PTC cells. Additionally, OIP5-AS1 was identified as a competitive endogenous RNA (ceRNA) that repressed miR-429, thereby increasing the expression level of XIAP. Taken together, the findings confirm that OIP5-AS1 accelerates PTC progression via modulating the miR-429/XIAP axis and imply that OIP5-AS1 is likely to be a therapeutic target for PTC.

How to Combine Diffusion-Weighted and T2-Weighted Imaging for MRI Assessment of Pathologic Complete Response to Neoadjuvant Chemoradiotherapy in Patients with Rectal Cancer?

OBJECTIVE

Adequate methods of combining T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) to assess complete response (CR) to chemoradiotherapy (CRT) for rectal cancer are obscure. We aimed to determine an algorithm for combining T2WI and DWI to optimally suggest CR on MRI using visual assessment.

MATERIALS AND METHODS

We included 376 patients (male:female, 256:120; mean age ± standard deviation, 59.7 ± 11.1 years) who had undergone long-course CRT for rectal cancer and both pre- and post-CRT high-resolution rectal MRI during 2017-2018. Two experienced radiologists independently evaluated whether a tumor signal was absent, representing CR, on both post-CRT T2WI and DWI, and whether the pre-treatment DWI showed homogeneous hyperintensity throughout the lesion. Algorithms for combining T2WI and DWI were as follows: 'AND,' if both showed CR; 'OR,' if any one showed CR; and 'conditional OR,' if T2WI showed CR or DWI showed CR after the pre-treatment DWI showed homogeneous hyperintensity. Their efficacies for diagnosing pathologic CR (pCR) were determined in comparison with T2WI alone.

RESULTS

Sixty-nine patients (18.4%) had pCR. AND had a lower sensitivity without statistical significance (vs. 62.3% [43/69]; 59.4% [41/69], p = 0.500) and a significantly higher specificity (vs. 87.0% [267/307]; 90.2% [277/307], p = 0.002) than those of T2WI. Both OR and conditional OR combinations resulted in a large increase in sensitivity (vs. 62.3% [43/69]; 81.2% [56/69], p < 0.001; and 73.9% [51/69], p = 0.008, respectively) and a large decrease in specificity (vs. 87.0% [267/307]; 57.0% [175/307], p < 0.001; and 69.1% [212/307], p < 0.001, respectively) as compared with T2WI, ultimately creating additional false interpretations of CR more frequently than additional identification of patients with pCR.

CONCLUSION

AND combination of T2WI and DWI is an appropriate strategy for suggesting CR using visual assessment of MRI after CRT for rectal cancer.

Oncological outcomes according to the treatment modality based on the size of rectal neuroendocrine tumors: a single-center retrospective study

BACKGROUND

Owing to an increased number of colonoscopy screenings, the incidence of diagnosed rectal neuroendocrine tumors (NETs) has also increased. Tumor size is one of the most frequently regarded factors when selecting treatment; however, it may not be the determinant prognostic variable. We aimed to evaluate oncological outcomes according to the treatment modality based on the size of rectal NETs.

METHODS

A retrospective analysis was performed on patients who were treated for rectal NETs between March 2000 and January 2016 at the Asan Medical Center, Seoul, Korea. Patients who underwent endoscopic removal, local surgical excision, and radical resection were included. The primary outcome was recurrence-free survival (RFS). Data were specified and analyzed following the 2019 World Health Organization classification (WHO).

RESULTS

A total of 644 patients were categorized under three groups according to the treatment modality used: endoscopic removal (n = 567), surgical local excision (n = 56), and radical resection (n = 21). Of a total of 35 recurrences, 27 were local, whereas eight were distant. The RFS rate did not differ significantly between the treatment groups in the same tumor-size group ([Formula: see text]1 cm group: P = .636, 1-2 cm group: P = .160). For T1 tumors, RFS rate was not different between local excision and radical resection ([Formula: see text]1 cm group: P = .452, 1-2 cm group: P = .700). Depth of invasion, a high Ki-67 index, and margin involvement were confirmed as independent risk factors for recurrence. Among patients treated with endoscopic removal, endoscopic biopsy was a significant factor for worse RFS (P < .001), while tumor size did not affect the RFS.

CONCLUSION

The current guideline recommends treatment options according to tumor size. However, more oncologically important prognostic factors include muscularis propria invasion and a higher Ki-67 index.

Surgical options for perianal fistula in patients with Crohn's disease: A comparison of seton placement, fistulotomy, and stem cell therapy

OBJECTIVE

This study was designed to assess the demographic characteristics of patients with Crohn's perianal fistula (CPF) who were treated at a tertiary referral institution. Surgical outcomes were compared in groups of patients who underwent seton placement, fistulotomy, and stem cell therapy.

METHODS

Patients who underwent surgery for CPF between 2015 and 2017 at Asan Medical Center, Seoul, Korea, were retrospectively evaluated. Patients were divided into groups who underwent seton placement, fistulotomy, and stem cell therapy. Their clinical variables and closure rates were compared.

RESULTS

This study included 156 patients who underwent a total of 209 operations. More than half of the operations consisted of seton placement (67%), followed by stem cell therapy (18%) and fistulotomy (15%) patients. Of the 209 fistulas, 153 (73%) were complex, with an overall closure rate of 38% during a median follow-up of 29 months. Closure rates following fistulotomy, stem cell therapy, and seton placement were 90%, 70%, and 18%. Seton placement was more significantly frequently used than the other procedures in patients with complex fistula and those with abscesses. Of the 79 fistulas that achieved complete closure, 11 (14%) recurred. The recurrence rates did not differ among the various techniques.

CONCLUSION

Surgical treatment of CPF is dependent on lesion type. Seton placement was the primary draining procedure for complex fistulas and abscesses, resulting in low closure rates. Fistulotomy was the definite procedure for low type and simple fistula. Stem cell therapy showed high closure rates as definitive treatment, even for complex fistulas.

Impact of the COVID-19 Pandemic on Surgical Treatment Patterns for Colorectal Cancer in a Tertiary Medical Facility in Korea

Simple Summary

The COVID-19 pandemic is threatening to public health, including malignant disease. Fear of viral infection has influenced the diagnosis and treatment of colorectal cancer and may result in impairment of surgical and oncologic outcomes. Therefore, we need to analyze the influence of COVID-19 on surgical outcomes of colorectal cancer and provide guidance on proper diagnosis and treatment, including public messaging regarding appropriate healthcare.

Abstract

Because of their reluctance to visit the hospital due to concerns about contracting coronavirus disease 2019 (COVID-19), patients with colorectal cancer have been affected by delays in care during the pandemic. This study assessed the effects of the pandemic on the clinical characteristics and surgical treatment patterns of colorectal cancer patients at a tertiary medical facility in Korea. Patients who underwent colorectal cancer surgery at our institution between March and September 2020 were analyzed. Clinicopathological and treatment characteristics were compared with those of patients who underwent surgery in 2018 and 2019. The patients who did not undergo tumor resection (4.1% vs. 1.8%, p < 0.001) and who received neoadjuvant treatment (16.7% vs. 14.7%, p = 0.039) were significantly higher during the COVID period. The minimally invasive approach was performed less during the COVID period (81.2% vs. 88%, p < 0.001). More patients in the COVID period required combined resection of organs adjacent to the tumor (4.8% vs. 2.8%, p = 0.017). Surgical aggressiveness, as shown by the proportion of patients undergoing minimally invasive surgery and adjacent organ resection, was significantly influenced by the pandemic. In addition, resectability decreased during the COVID period. These characteristics will likely influence long-term oncological outcomes, indicating the need for long-term monitoring of this cohort.

Clinicopathological Characteristics and Surgical Outcomes of Crohn Disease-Associated Colorectal Malignancy

PURPOSE

Carcinoma arising from Crohn disease (CD) is rare, and there is no clear guidance on how to properly screen for at-risk patients and choose appropriate care. This study aimed to evaluate the clinicopathological characteristics, treatment, and oncologic outcomes of CD patients diagnosed with colorectal cancer (CRC).

METHODS

Using medical records, we retrospectively enrolled a single-center cohort of 823 patients who underwent abdominal surgery for CD between January 2006 and December 2015. CD-associated CRC patients included those with adenocarcinoma, lymphoma, or neuroendocrine tumors of the colon and rectum.

RESULTS

Nineteen patients (2.3%) underwent abdominal surgery to treat CD-associated CRC. The mean duration of CD in the CD-associated CRC group was significantly longer than that in the benign CD group (124.7 ± 77.7 months vs. 68.9 ± 60.2 months, P = 0.006). The CD-associated CRC group included a higher proportion of patients with a history of perianal disease (73.7% vs. 50.2%, P = 0.035) and colonic location (47.4% vs. 6.5%, P = 0.001). Among 19 CD-associated CRC patients, 17 (89.5%) were diagnosed with adenocarcinoma, and of the 17 cases, 15 (88.2%) were rectal adenocarcinoma. On multivariable analyses for developing CRC, only colonic location was a risk factor (relative risk, 7.735; 95% confidence interval, 2.862-20.903; P = 0.001).

CONCLUSION

Colorectal malignancy is rare among CD patients, even among patients who undergo abdominal surgery. Rectal adenocarcinoma accounted for most of the CRC, and colonic location was a risk factor for developing CRC.

Treatment Strategy for Perianal Fistulas in Crohn Disease Patients: The Surgeon's Point of View

Perianal fistula is a frequent complication and one of the subclassifications of Crohn disease (CD). It is the most commonly observed symptomatic condition by colorectal surgeons. Accurately classifying a perianal fistula is the initial step in its management in CD patients. Surgical management is selected based on the type of perianal fistula and the presence of rectal inflammation; it includes fistulotomy, fistulectomy, seton procedure, fistula plug insertion, video-assisted ablation of the fistulous tract, stem cell therapy, and proctectomy with stoma creation. Perianal fistulas are also managed medically, such as antibiotics, immunomodulators, and biologics including anti-tumor necrosis factor-alpha agents. The current standard treatment of choice for perianal fistula in CD patients is the multidisciplinary approach combining surgical and medical management; however, the rate of long-term remission is low and is reported to be 50% at most. Therefore, the optimum management strategy for perianal fistulas associated with CD remains controversial. Currently, the goal of management for CD-related perianal fistulas are controlling symptoms and maintaining long-term anal function without proctectomy, while monitoring progression to anorectal carcinoma. This review evaluates perianal fistula in CD patients and determines the optimal surgical management strategy based on recent evidence.

Effect of anaemia on the response to preoperative chemoradiotherapy for rectal cancer

BACKGROUNDS

Radiation therapy with concurrent chemotherapy is an important treatment for rectal cancer, especially for advanced stage disease. Low serum haemoglobin levels are accepted as a negative indicator in the response to radiation therapy. This study aimed to evaluate the relationship between anaemia and the response to preoperative chemoradiotherapy for rectal cancer and its effect on oncologic outcomes.

METHODS

We retrospectively reviewed medical records of primary rectal cancer patients who were treated with preoperative chemoradiotherapy followed by total mesorectal excision between January 2011 and December 2015. Anaemia was defined as serum haemoglobin levels ≤9 g/dL before or during radiotherapy. Patients were divided into good and poor responders according to pathologic tumour regression grades. The effect of anaemia on the response to radiation therapy, recurrence-free survival and overall survival were analysed after subgroup analysis.

RESULTS

Overall, 301 and 394 patients were categorized into good and poor responder groups, respectively. Proportions of anaemia patients were higher in the poor responder group than in the good responder group (7.6% versus 4.0%, P = 0.042). Anaemia was associated with less pathologic complete regression but was not a risk factor for worse recurrence-free or overall survival. There was no significant difference in survival between patients with and without anaemia.

CONCLUSION

Haemoglobin levels ≤9 g/dL before or during radiotherapy were risk factors for achieving pathologic complete regression after preoperative chemoradiotherapy for rectal cancer. However, anaemia was not independently associated with worse survival outcomes.