The effectiveness and safety of rectal modular dissection for male middle and low rectal cancer after neoadjuvant chemoradiation therapy: the short-term outcome.

Background: The purpose of this study was to assess the efficacy and safety of rectal modular dissection (RMD) in male patients with middle and low rectal cancer. RMD is a technique used to guide the surgical procedure for rectal mobilization, with the ultimate goal of achieving total mesorectal excision. In order to evaluate the effectiveness of RMD, a single-center, non-inferiority randomized clinical trial was carried out. Methods: Eligible patients were randomly assigned into two groups: the RMD group and the traditional rectal mobilization (TRM) group. Demographic characteristics, perioperative data and pathological results of the surgical specimens were collected for analysis. additionally, assessments of urogenital function and defecation function were conducted for all participants. Results: A total of 103 patients (RMD group 53 patients and TRM group 50 patients) were included to analyzed. There were no significant differences in age, body mass index, ASA classification, and tumor characteristics between two groups. The RMD group had significantly lower blood loss (P = 0.00), shorter operative duration (P = 0.00), and shorter hospital stay (P = 0.04) compared to the TRM group. The complete rate of mesorectal excision was higher in the RMD group (98.1%) compared to the TRM group (86.0%, P = 0.02). In terms of functional outcomes, the RMD group had better evaluation scores for urethral function (IPSS score, P = 0.01), erectile function (IIEF-5 score, P = 0.00) and defecation function (LARS score, P = 0.00) at the one-year postoperative follow-up. The 1-year disease-free survival rate was similar between the two groups (P = 0.28). Conclusions: These results suggest that RMD is an effective and safe approach for achieving total mesorectal excision while promoting better functional outcomes for patients. The trial was registered in Chinese Clinical Trial Registry (ChiCTR2100052094).

Long-course chemoradiation plus concurrent/sequential PD-1 blockade as neoadjuvant treatment for MMR-status-unscreened locally advanced rectal cancer: protocol of a multicentre, phase 2, randomised controlled trial (the POLAR-STAR trial).

INTRODUCTION: Recent preclinical studies have discovered unique synergism between radiotherapy and immune checkpoint inhibitors, which has already brought significant survival benefit in lung cancer. In locally advanced rectal cancer (LARC), neoadjuvant radiotherapy plus immune checkpoint inhibitors have also achieved surprisingly high pathological complete response (pCR) rates even in proficient mismatch-repair patients. As existing researches are all phase 2, single-cohort trials, we aim to conduct a randomised, controlled trial to further clarify the efficacy and safety of this novel combination therapy. METHODS AND ANALYSIS: Eligible patients with LARC are randomised to three arms (two experiment arms, one control arm). Patients in all arms receive long-course radiotherapy plus concurrent capecitabine as neoadjuvant therapy, as well as radical surgery. Distinguishingly, patients in arm 1 also receive anti-PD-1 (Programmed Death 1) treatment starting at Day 8 of radiation (concurrent plan), and patients in arm 2 receive anti-PD-1 treatment starting 2 weeks after completion of radiation (sequential plan). Tislelizumab (anti-PD-1) is scheduled to be administered at 200 mg each time for three consecutive times, with 3-week intervals. Randomisation is stratified by different participating centres, with a block size of 6. The primary endpoint is pCR rate, and secondary endpoints include neoadjuvant-treatment-related adverse event rate, as well as disease-free and overall survival rates at 2, 3 and 5 years postoperation. Data will be analysed with an intention-to-treat approach. ETHICS AND DISSEMINATION: This protocol has been approved by the institutional ethical committee of Beijing Friendship Hospital (the primary centre) with an identifying serial number of 2022-P2-050-01. Before publication to peer-reviewed journals, data of this research will be stored in a specially developed clinical trial database. TRIAL REGISTRATION NUMBER: NCT05245474.

Mesenteric Castleman Disease Misdiagnosed as Lymph Node Metastasis of Rectal Cancer on 18 F-FDG PET/CT.

ABSTRACT: Two years ago, a 64-year-old man underwent an 18 F-FDG PET/CT for staging rectal cancer. Besides the hypermetabolic rectal lesion, the image revealed a mesenteric lymph node with intense activity and multiple lung nodules with slight FDG uptake, which were highly suspected of metastases. After surgery and multiple cycles of chemotherapy, the follow-up 18 F-FDG PET/CT showed remission of all lesions except for the enlarged mesenteric lymph node with higher metabolic activity. Serum CEA remained normal during the follow-up. Postoperative pathology of the mesenteric lymph node confirmed Castleman disease.

The Effectiveness and Safety of Rectal Modular Resection in Low Rectal Cancer: A Retrospective Study.

Background: Described by Heald in 1982, total mesorectal excision (TME) is now routinely performed as the standard procedure for mid-low rectal cancer, with remarkable decrease in local recurrence and improved oncology outcome. However, the integrity of the resected mesentery and damage to autonomic nerves still remain challenging for general surgeons, especially in the cohort of neoadjuvant therapy patients. The concept of rectal modular resection (RMR), based on an integral understanding of the regional anatomy, was proposed as a surgical skill for dissociation of the rectum with shorter surgical duration, function preservation, and improved oncology outcome. Methods: This was a retrospective trial. Patients with resectable rectal lesions, ranging between 3 and 7 cm from the anal verge, were enrolled and grouped by TME surgery based on RMR or classical procedure resection (CPR). We estimated perioperative outcomes, including surgery complications such as anastomotic leak, urine retention, and others. Pathological properties, including distal clearance, harvested lymph nodes, tumor differentiation, and specimen grading, were also taken into account. Patients were followed postoperatively and functional evaluation was recorded at the 3-month and 1-year postoperation visits. Results: From January 2019 to December 2021, a total of 92 patients were enrolled in this study. TME surgery complying with the RMR methodology was performed with a back-to-bilateral-to-front modular proceeding. Duration of operation was significantly shortened in the RMR group, without increase in blood loss or failure rate of anus preservation. The quality of the specimen, graded according to integrity of the mesorectum, stands out in the RMR group. Functional evaluation revealed no statistical difference between RMR and CPR groups regarding sexual ability impairment and defecation disorder since follow-up is still ongoing. Conclusions: RMR-based TME was efficient with compressed operation duration compared with CPR and its safety was well validated with regard to the occurrence of complications and function loss.

Comparison of safety of loop ileostomy and loop transverse colostomy for low-lying rectal cancer patients undergoing anterior resection: A retrospective, single institution, propensity score-matched study.

INTRODUCTION: This study was to compare the prevalence of stoma-related complications and stoma reversal perioperative complications of patients with low-lying rectal cancer who received preventative loop ileostomy and those who underwent loop transverse colostomy. METHODS: This retrospective single-center study analyzed the clinicopathologic and surgical data of 288 patients with pathologically proven primary rectal cancer who underwent anterior resection with either preventative loop ileostomy (n = 82) or loop transverse colostomy. To achieve comparability of a propensity score matching method was used to match patients from each group in a 1:2 ratio. Determinants of stoma-related complications were analyzed by multivariate logistic regression analysis. RESULTS: Forty-nine (74.3%) patients in the loop ileostomy group experienced stoma-related complications versus 48.7% in the loop transverse colostomy group (P < 0.01). Irritant dermatitis was the most frequent complication in both groups. The loop ileostomy group had a significantly higher rate (24.24%) of stoma reversal perioperative complications than the loop transverse colostomy group. Multivariate logistic regression analysis showed that ileostomy versus loop transverse colostomy was a significant independent risk for stoma-related complications and stoma reversal perioperative complications. Furthermore, by Clavien-Dindo classification, patients receiving loop ileostomy had an overall higher rate of complications and stoma reversal perioperative complications versus those undergoing loop transverse colostomy (P < 0.01). The rate of grade II complications was significantly higher in the loop ileostomy group (43.9%) than that of loop transverse colostomy group (13.5%, P < 0.01), whereas the rate of grade I, and grade IIIa and IIIb complications and stoma reversal perioperative complications was comparable between the two groups. CONCLUSION: The study has demonstrated that loop transverse colostomy is associated with significantly lower rates of stoma-related complications and stoma reversal perioperative complications compared to loop transverse colostomy.

Construction and validation of a novel Ferroptosis-related gene signature predictive model in rectal Cancer.

BACKGROUND: Rectal cancer (RC) is one of the most common malignant tumors. Ferroptosis is an iron-dependent form of cell death, which plays an important role in various cancers. However, the correlation between ferroptosis-related genes (FRGs) and prognosis in RC remains unclear. METHODS: Gene expression data from The Cancer Genome Atlas Rectum adenocarcinoma (TCGA-READ) and GSE87211 were downloaded. Clustering and functional enrichment were evaluated. A FRGs risk score was established based on the univariate Cox analysis and the Least absolute shrinkage and selection operator (LASSO) analysis. K-M analysis and ROC analysis were conducted to determine prognostic values. qRT-PCR was performed to validate levels of mRNA expression. Multivariate Cox analysis was used to build a prognostic prediction model based on the risk score. RESULTS: Based on FRGs, RC patients were grouped into two clusters. In the functional enrichment of differentially expressed genes between the two clusters, immune-related pathways dominated. A novel FRGs signature with 14 genes related to the overall survival (OS) of RC was established. qRT-PCR of the 14 genes identified TP63, ISCU, PLIN4, MAP3K5, OXSR, FANCD2 and ATM were overexpressed in RC tissue; HSPB1, MAPK1, ABCC1, PANX1, MAPK9 and ATG7 were underexpressed; TUBE1 had no difference. The high-risk group had a significantly lower OS than the low-risk group (P < 0.001), and ROC curve analysis confirmed the signature's predictive capacity. Multivariate analysis demonstrated that the risk score and age were independent prognostic factors. CONCLUSION: A novel FRGs model can be used to predict the prognosis in RC, as well as to guide individual treatment.

Long-term outcomes of transanal endoscopic microsurgery for the treatment of rectal neuroendocrine tumors.

BACKGROUND: Transanal endoscopic microsurgery (TEM) has been accepted worldwide for the treatment of local rectal lesions. We aimed to assess the efficacy and safety of TEM in the treatment of rectal neuroendocrine tumors (RNET). METHODS: A retrospective study of patients who had undergone TEM for RNET at our institution between December 2006 and June 2019 was performed. Demographic and tumor characteristics, operative and pathological details, complications, anal function questionnaires, and follow-up data were included. RESULTS: A total of 144 patients was included. TEM was performed as primary excision in 54 patients, after endoscopic forceps biopsy in 57 patients, and after incomplete resection by endoscopic excision in 33 patients. The median size of all primary tumors was 0.6 cm (range, 0.3-2.0 cm), and the negative resection margin was achieved in 142 (98.6%) patients. Postoperative complications (referring to only bleeding) occurred in 3 (2.1%) patients and was successfully managed with conservative method. After a median follow-up of 75.5 months after surgery, 3 patients died of other causes, and 2 patients suffered metastasis. An anal function questionnaire was posted 24 months after TEM. Among the results, 3 (2.1%) patients complained of major low anterior resection syndrome (LARS), including 1 (0.7%) who suffered from complete incontinence, while 6 (4.2%) patients had minor LARS. CONCLUSIONS: TEM has satisfying long-term outcomes and relatively low anal function disturbance as for the treatment of small RNET. TEM also acts as a preferred salvage treatment for incomplete endoscopic excision.

Comparing the techniques and outcomes of laparoscopic transverse colectomy to laparoscopic hemicolectomy in mid-transverse colon cancer resection.

Introduction: The mid-transverse colon cancer is relatively uncommon in all colon cancers and the optimal surgical approach of mid-transverse colon cancer remains debatable. Aim and Objectives: Our study aimed to depict the techniques and outcomes of laparoscopic transverse colectomy in one single clinical center and compare this surgical approach to traditional laparoscopic right hemicolectomy and laparoscopic left hemicolectomy. Method: This was a retrospective cohort study of patients with mid-transverse colon cancer in one single clinical center from February 2012 to October 2020. The enrolled patients were divided into two groups undergoing laparoscopic transverse colectomy and laparoscopic right/left hemicolectomy, respectively. The intraoperative, postoperative complications, oncological outcomes and functional outcomes were compared between the two groups. The primary endpoint was disease free survival (DFS). Results: The study enrolled 70 patients with 40 patients undergoing laparoscopic transverse colectomy and 30 patients undergoing laparoscopic hemicolectomy. The intraoperative accidental hemorrhage and multiple organ resection occurred similarly in the two groups. In transverse colectomy, caudal-to-cephalic approach was likely to harvest more lymph nodes although require more operation time than cephalic-to-caudal approach (23.1 ± 14.3 vs. 13.4 ± 5.4 lymph nodes, P = 0.004; 184.3 ± 37.1 min vs. 146.3 ± 44.4 min, P = 0.012). The laparoscopic transverse colectomy was marginally associated with lower incidence of overall postoperative complications and shorter postoperative hospital stay although without statistical significance (8(20.0%) vs. 12(40.0%), P = 0.067; 7(5-12) vs. 7(5-18), P = 0.060). The 3-year DFS showed no significant difference (3-year DFS 89.7% in transverse colectomy vs. 89.9% in hemicolectomy, P = 0.688) between the two groups. The alternating consistency of defecation occurred significantly less after laparoscopic transverse colectomy than laparoscopic hemicolectomy (15(51.7%) vs. 20(80.0%), P = 0.030). Conclusion: The laparoscopic transverse colectomy is technically feasible with satisfactory oncological and functional outcomes for mid-transverse colon cancer. Performing the caudal-to-cephalic approach might be more advantageous in lymphadenectomy.

Clinicopathological and Molecular Characteristics of Colorectal Signet Ring Cell Carcinoma: A Review.

Colorectal signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC) with unique characteristics. Due to the limited researches on it, a comprehensive and in-depth understanding of this subtype is still lacking. In this article, we summarize the clinicopathological features and molecular characteristics of colorectal SRCC based on a literature review. Clinically, SRCC has been associated with young age, proximal site preference, advanced tumor stage, high histological grade, high rate of lymph node involvement, frequent peritoneal metastasis, and a significantly poor prognosis. Regarding molecular characteristics, in SRCC, the mutation burden of the classic signaling pathways that include WNT/ß-catenin, RAS/RAF/MAPK, and PI3K/AKT/mTOR signaling pathways are generally reduced. In contrast, some genes related to the "epithelial-mesenchymal transition (EMT) process" and the "stem cell properties", including RNF43, CDH1, and SMAD4, as well as the related TGF-ß signaling pathway have been observed more frequently altered in SRCC than in conventional adenocarcinoma (AC). In many studies but not in others, SRCC showed a higher frequency of BRAF mutation, microsatellite instability-high (MSI-H) and CpG island methylator phenotype (CIMP) positive status compared to AC. It has been proposed that colorectal SRCC consists of two subtypes, in which the MSI+/CIMP+/BRAF +/CD3+/PD-L1+ hypermethylated genotype is more common in the proximal colon, and may represent the potential candidate for immunotherapy. Understanding the special molecular mechanisms related to the aggressive biology of SRCC is of great importance, which may provide a theoretical basis for the development of more targeted and effective treatments for this refractory disease.

Efficacy and Safety of Sirolimus for Blue Rubber Bleb Nevus Syndrome: A Prospective Study.

INTRODUCTION: Blue rubber bleb nevus syndrome (BRBNS) is a rare systemic venous malformation (VM) disease. The characteristic gastrointestinal (GI) bleeding from multiple VM lesions causes severe chronic anemia which renders most patients depend on lifelong blood transfusion and frequent endoscopic treatment with dismayed outcomes. Although recent case reports suggest that oral sirolimus (rapamycin) is effective, a comprehensive evaluation of its efficacy and safety is in need. METHODS: A prospective study was conducted for both pediatric and adult BRBNS patients with administration of sirolimus at the dose of 1.0 mg/m2 to maintain a trough concentration of 3-10 ng/mL. Laboratory tests including complete blood count, biochemical profile, D-dimer, and whole-body magnetic resonance imaging were performed at baseline and 3, 6, and 12 months after treatment. Clinical indicators such as hemoglobin level, lesion size, and transfusion need were evaluated. Adverse effects were recorded regularly. RESULTS: A total of 11 patients (4 males and 7 females) with median age of 14 (range, 5-49) years were recruited. The average lesion size was reduced by 7.4% (P < 0.001), 9.3% (P < 0.001), and 13.0% (P < 0.05) at 3, 6, and 12 months of sirolimus treatment, respectively. Hemoglobin increased significantly after 6- and 12-month treatment (P = 0.006 and 0.019, respectively). Only 1 patient received blood transfusion once during the study. Patients' quality of life and coagulation function were improved. Grade 1-2 adverse effects including oral ulcers (81.8%), acne (27.3%), transient elevation of liver enzymes (18.2%), and hair loss (9.1%) were observed. DISCUSSION: Sirolimus reduces the size of VMs, alleviates GI bleeding, and eliminates transfusion dependence of patients with BRBNS. The drug-related adverse effects are mild and mostly self-limited. These findings support sirolimus as a first-line treatment for GI and cutaneous VMs of BRBNS (see Visual abstract, Supplementary Digital Content, http://links.lww.com/AJG/B819).

Risk factors for perioperative complications in laparoscopic surgeries of retrorectal cystic lesions.

BACKGROUND: The incidence of retrorectal lesions is low, and no consensus has been reached regarding the most optimal surgical approach. Laparoscopic approach has the advantage of minimally invasive. The risk factors influencing perioperative complications of laparoscopic surgery are rarely discussed. AIM: To investigate the risk factors for perioperative complications in laparoscopic surgeries of retrorectal cystic lesions. METHODS: We retrospectively reviewed the medical records of patients who underwent laparoscopic excision of retrorectal cystic lesions between August 2012 and May 2020 at our hospital. All surgeries were performed in the general surgery department. Patients were divided into groups based on the lesion location and diameter. We analysed the risk factors like type 2 diabetes mellitus, hypertension, the history of abdominal surgery, previous treatment, clinical manifestation, operation duration, blood loss, perioperative complications, and readmission rate within 90 d retrospectively. RESULTS: Severe perioperative complications occurred in seven patients. Prophylactic transverse colostomy was performed in four patients with suspected rectal injury. Two patients underwent puncture drainage due to postoperative pelvic infection. One patient underwent debridement in the operating room due to incision infection. The massive-lesion group had a significantly longer surgery duration, higher blood loss, higher incidence of perioperative complications, and higher readmission rate within 90 d (P < 0.05). Univariate analysis, multivariate analysis, and logistic regression showed that lesion diameter was an independent risk factor for the development of perioperative complications in patients who underwent laparoscopic excision of retrorectal cystic lesions. CONCLUSION: The diameter of the lesion is an independent risk factor for perioperative complications in patients who undergo laparoscopic excision of retrorectal cystic lesions. The location of the lesion was not a determining factor of the surgical approach. Laparoscopic surgery is minimally invasive, high-resolution, and flexible, and its use in retrorectal cystic lesions is safe and feasible, also for lesions below the S3 level.

Serial Circulating Tumor DNA in Predicting and Monitoring the Effect of Neoadjuvant Chemoradiotherapy in Patients with Rectal Cancer: A Prospective Multicenter Study.

PURPOSE: We investigated the value of circulating tumor DNA (ctDNA) in predicting tumor response to neoadjuvant chemoradiotherapy (nCRT), monitoring tumor burden, and prognosing survival in patients with locally advanced rectal cancer (LARC). EXPERIMENTAL DESIGN: This prospective multicenter trial recruited 106 patients with LARC for treatment with nCRT followed by surgery. Serial ctDNAs were analyzed by next-generation sequencing at four timepoints: at baseline, during nCRT, presurgery, and postsurgery. RESULTS: In total, 1,098 mutations were identified in tumor tissues of the 104 patients being analyzed (median, seven mutations/patient). ctDNA was detected in 75%, 15.6%, 10.5%, and 6.7% of cases at the four timepoints, respectively. None of the 29 patients with pathologic complete response (ypCR) had preoperative ctDNA detected. The preoperative ctDNA-positive rate was significantly lower in the well-responded patients with pathologic tumor regression grade of ypCAP 0-1 than ypCAP 2-3 group (P < 0.001), lower in ypCR than non-ypCR group (P = 0.02), and lower in pathologic T stage (ypT) 0-2 than ypT 3-4 group (P = 0.002). With a median follow-up of 18.8 months, 13 patients (12.5%) experienced distant metastasis. ctDNA positivity at all four timepoints was associated with a shorter metastasis-free survival (MFS; P < 0.05). Multivariate analyses showed that the median variant allele frequency (VAF) of mutations in baseline ctDNA was a strong independent predictor of MFS (HR, 1.27; P < 0.001). CONCLUSIONS: We show that ctDNA is a real-time monitoring indicator that can accurately reflect the tumor burden. The median VAF of baseline ctDNA is a strong independent predictor of MFS.

Multiple polypoid colonic metastases from rectal adenocarcinoma with signet ring cells features: a case report.

BACKGROUND: Multiple polypoid colonic metastases are very rare which mainly originated from gastric carcinoma or melanoma. For rectal cancers, liver, lung and peritoneum are the most common metastatic sites. Here we present an unusual case with rectal adenocarcinoma and metachronous multiple colonic polypoid metastases. CASE PRESENTATION: A 53-year-old man who underwent radical resection for rectal cancer 2 years ago was admitted to our department for an elevation of CEA level of 18.4 ng/ml. Colonoscopy revealed ten ivory rubbery colonic polypoid lesions (about 5 mm in diameters) in the large bowel which were confirmed as signet ring cell carcinomas (SRCC) by biopsy, but full-body contrast enhanced CT and PET-CT showed no other suspicious lesion. Seven weeks later, a laparoscopic total colectomy was performed and more than 50 polypoid lesions were observed throughout the mucosal surface of the large intestine which were confirmed as metastatic SRCC by postoperative pathological examination. All the 34 paracolic lymph nodes retrieved were involved. After 4 months, diffuse abdominopelvic and multiple bone metastases were identified by CT and the patient died of the disease 1 month later. CONCLUSION: Here we present an unusual case of multiple colonic polypoid metastases of rectal adenocarcinoma. For SRCC that is prone to have disseminated micrometastases, colonic 'polyps' may be the early noticeable sign of undetectable and extensive tumor spread. Instead of surgical resection of 'the confined disease in colon', systemic treatment maybe a more appropriate choice.

Laparoscopic resection of large retrorectal developmental cysts in adults: Single-centre experiences of 20 cases.

Context: Retrorectal tumours are rare with developmental cysts being the most common type. Conventionally, large retrorectal developmental cysts (RRDCs) require the combined transabdomino-sacrococcygeal approach. Aims: This study aims to investigate the surgical outcomes of the laparoscopic approach for large RRDCs. Settings and Design: A retrospective case series analysis. Subjects and Methods: Data of patients with RRDCs of 10 cm or larger in diameter who underwent the laparoscopic surgery between 2012 and 2017 at our tertiary centre were retrospectively analyzed. Statistical Analysis Used: Results are presented as median values or mean ± standard deviation for continuous variables and numbers (percentages) for categorical variables. Results: Twenty consecutive cases were identified (19 females; median age, 36 years). Average tumour size was 10.9 ± 1.1 cm. Cephalic ends of lesions ranged from S1/2 junction to S4 level. Caudally, 18 cysts extended to the sacrococcygeal hypodermis. Seventeen patients underwent the pure laparoscopy; three patients received a combined laparoscopic-posterior approach. The operating time was 167.1 ± 57.3 min for the pure laparoscopic group and 212.0 ± 24.5 min for the combined group. The intraoperative haemorrhage was 68.2 ± 49.7 and 66.7 ± 28.9 (mL), respectively. Post-operative complications included one trocar site hernia, one wound infection and one delayed rectal wall perforation. The median post-operative hospital stay was 7 days. With a median follow-up period of 36 months, 1 lesions recurred. Conclusions: The laparoscopic approach can provide a feasible and effective alternative for large RRDCs, with advantages of the minimally invasive surgery. For lesions with ultra-low caudal ends, especially those closely clinging to the rectum, a combined posterior approach is still necessary.

Genotyping of Circulating Tumor DNA Reveals the Clinically Actionable Mutation Landscape of Advanced Colorectal Cancer.

Circulating tumor DNA (ctDNA) enables genomic profiling of colorectal cancer. We investigated therapeutic targets by performing ctDNA panel-captured sequencing of 152 blood samples from advanced stage patients, from which somatic mutations and potentially actionable targets were evaluated. An additional 11 matched tissue samples were retrospectively obtained to verify target validity. The mutation frequencies of 1,127 collective genetic variants identified in our study strongly correlated with those of multiple public databases (Pearson R 2 = 0.92, P < 0.0001). The clonal fraction of driver genes was 90.3%, which was significantly higher than that of potential passenger genes (58.12%). Totally, 90 drug-sensitive genes from 56 patients (36.84%) were identified, including recurring targets PIK3CA, FBXW7, EGFR, BRAF, and NRAS Various resistance mechanisms of anti-EGFR antibodies were revealed via ctDNA profiling, with 29 patients individually exhibiting multiple mechanisms, suggesting considerable resistance heterogeneity in our study population. Of the matched tissue/blood pairs, 88.14% of tissue-derived mutations were detected in ctDNA, and 88.9% of actionable targets were validated. The mutational landscape of ctDNA was highly consistent with tissue databases, and ctDNA profiling showed favorable concordance with tumor tissues in our matched analysis. Thus, comprehensive ctDNA genotyping is a promising noninvasive alternative to biopsy-derived analysis for determining targeted therapy in advanced colorectal cancer.

Comparison of safety of loop ileostomy and loop transverse colostomy for low-lying rectal cancer patients undergoing anterior resection: A retrospective, single institute, propensity score-matched study.

PURPOSE: To compare the prevalence of stoma-related complications and stoma reversal perioperative complications of patients with low-lying rectal cancer who received preventative loop ileostomy and those who underwent loop transverse colostomy. METHODS: This retrospective single-center study analyzed the clinicopathologic and surgical data of 288 patients with pathologically proven primary rectal cancer who underwent anterior resection of rectal cancer with preventative loop ileostomy or loop transverse colostomy between January 2012 and July 2017 at the Department of General Surgery, Peking Union College Hospital. The patients were allocated to the ileostomy group (n=82) and the loop transverse colostomy group (n=206). To achieve comparability of the ileostomy group and the loop transverse colostomy group with regard to potential confounding variables, a propensity score-matching method was used to match patients from each group in a 1:2 ratio. Determinants of stoma-related complications were analyzed by multivariate logistic regression analysis. RESULTS: The propensity score-matched loop ileostomy group (n=66) and the loop transverse colostomy group (n=111) were comparable in patient demographic and baseline characteristics. Forty-nine (74.3%) patients in the loop ileostomy group experienced stoma-related complications vs 48.7% in the loop transverse colostomy group (p<0.001). Irritant dermatitis was the most frequent complication in both groups. The loop ileostomy group had a significantly higher rate (24.24%) of stoma reversal perioperative complications than the loop transverse colostomy group (9.01%, p=0.008). Multivariate logistic regression analysis showed that ileostomy vs loop transverse colostomy was a significant independent risk for stoma-related complications (Odds ratio/OR 3.495; 95%CI 1.741, 7.018; p<0.001) and stoma reversal perioperative complications (OR 2.124; 95%CI 1.010, 4.512; p< 0.05). CONCLUSION: This study has demonstrated that loop transverse colostomy is associated with significantly lower rates of stoma-related complications and stoma reversal perioperative complications compared to loop transverse colostomy. Prospective controlled studies with a larger patient population are warranted to examine the efficacy and safety of loop ileostomy and loop transverse colostomy.

[Transanal endoscopic microsurgery for local excision of rectal gastrointestinal stromal tumors].

OBJECTIVE: To investigate the efficacy of transanal endoscopic microsurgery (TEM) combined with imatinib for rectal gastrointestinal stromal tumors(GIST). METHODS: Clinical data of 35 patients with rectal GIST undergoing TEM at Peking Union Medical College Hospital from February 2008 to May 2017 were analyzed retrospectively. Operation details, postoperative recovery condition, and follow-up information were reviewed. The differences in clinicopathological features and perioperative parameters were compared between patients who received neoadjuvant therapy (12 patients, imatinib mesylate, oral, 400 mg daily for 6 months before surgery) and those without neoadjuvant therapy (23 patients). RESULTS: Of 35 patients, 18 were males and 17 were females with the mean age of (49.3±13.3) years. Mean tumor diameter was (1.8±1.1) cm and mean distance from lower tumor margin to anal verge was (4.0±1.8) cm. Mean operative time was (82.4±21.1) minutes and mean blood loss was (11.7±7.5) ml. No conversion to laparotomy occurred. Complete resection with negative margins was achieved in all cases. Complications were classified according to Clavien-Dindo system: 4 cases of grade I, 3 of grade II and 1 of grade IIIb. The tumor size in patients who received neoadjuvant therapy reduced from (3.1±1.2) cm to (2.6±1.2) cm, though it was still larger than the tumor size in patients without neoadjuvant therapy[(1.5±0.8) cm, P<0.01]. No significant difference in operative time was found between patients with and without neoadjuvant therapy [(76.7±24.8) minutes vs. (85.4±18.8) minutes, P>0.05]. Thirty patients (85.7%) were followed up for (50.3±36.6) months, and no local recurrence or metastasis was observed. CONCLUSIONS: TEM is safe and effective in the treatment of rectal GIST. Preoperative neoadjuvant therapy is beneficial to TEM in treating larger tumors without increasing operating time. Satisfactory follow-up result is observed.

Endometriosis-associated recto-sigmoid cancer: a case report.

BACKGROUND: Endometriosis is a relatively common condition in women of reproductive age. Malignant transformation of intestinal endometriosis is a very rare event. We report a case in which a patient with a history of endometriosis underwent surgery for malignant intestinal endometriosis. CASE PRESENTATION: A 55-year-old woman complained of rectorrhagia and intermittent abdominal pain. A neoplasm was revealed by colonoscopy, CT scan and F18-FDG PET/CT of the recto-sigmoidal colon. The patient underwent a rectal anterior resection, hysterectomy and bilateral salpingo-oophorectomy for treatment. According to the histological and immunohistochemical presentation, the diagnosis of endometriosis-associated recto-sigmoid cancer was confirmed. The patient was treated with adjuvant chemotherapy for 6 months. During the follow-up appointment 22 months later, there was clinical and radiographic evidence of recurrence in the rectum. The patient received chemotherapy again and will receive another surgery after two more cycles of chemotherapy. CONCLUSION: We report a case of malignant intestinal endometriosis. Although there is no standard therapy for malignant intestinal endometriosis due to the rarity of this disease, surgery and adjuvant chemotherapy seemed to be rational. This case indicates that local recurrence may be a common situation after standard therapy.