Tumor mutation burden in blood predicts benefit from neoadjuvant chemo/radiotherapy in locally advanced rectal cancer.

Distant metastasis has been the major concern of prognosis in patients with locally advanced rectal cancer (LARC). The purpose of this study was to investigate the prognostic value of TMB in blood (bTMB) in LARC patients after receiving neoadjuvant chemoradiotherapy (nCRT) and surgery. Using targeted ctDNA sequencing, we revealed that bTMB level at baseline was positively correlated with recurrence-free survival (RFS). Following nCRT, the patients with decreasing TMB tends to have a longer median RFS. bTMB level after surgery was negatively correlated with RFS. The serum cytokines including IFNγ, IFNα2, IL-1ß, IL-2 and MIP-1ß were significantly higher in pre-nCRT serum with higher bTMB group than that of lower bTMB group. Clonal evolution analysis showed that the pre- and post-nCRT ctDNAs of most cases had shared mutations. In conclusion, we presume that bTMB could potentially improve pre- and post-treatment risk assessment and facilitate individualized therapy for patients with LARC.

Glycan analysis of colorectal cancer samples reveals stage-dependent changes in CEA glycosylation patterns.

BACKGROUND: Carcinoembryonic antigen (CEA) is a glycoprotein associated with colorectal cancer (CRC). While the functions of its gene and protein have been fully characterized, its post-translational modifications in the context of CRC development remain undefined. METHODS: To show the correlation between the different stages of CRC development and changes in the glycosylation patterns of CEA, we analyzed CEA in tumor tissues (CEA-T) and paired tumor-adjacent normal tissues (CEA-A) from 53 colorectal cancer patients using a high-density lectin microarray containing 56 plant lectins. RESULTS: We detected higher expression levels of fucose, mannose and Thomsen-Friedenreich antigen, and lower expression levels of N-acetylgalactosamine, N-acetylglucosamine, galactose, branched and bisecting N-glycans on CEA in the tumor tissues relative to the tumor-adjacent normal tissues. Furthermore, a combinatorial assessment of 9 lectins is sufficient to distinguish CRC tumor tissues from tumor-adjacent normal tissues with 83% sensitivity and ~ 90% specificity. Moreover, the levels of N-acetylgalactosamine, mannose, galactose, N-acetylglucosamine on CEA showed a downward trend after first experiencing an increase at Stage II with the stages of CRC. CONCLUSIONS: Our insights into the changing CEA glycosylation patterns and their role in the development of CRC highlight the importance of glycan variants on CEA for early clinical detection and staging of CRC.

Risk Factors for Nonclosure of a Temporary Defunctioning Ileostomy Following Anterior Resection of Rectal Cancer.

BACKGROUND: In patients with colorectal cancer, a defunctioning ileostomy is commonly constructed to reduce anastomotic complications. However, many patients do not undergo a subsequent procedure to have their temporary stoma closed. OBJECTIVE: This study investigated the incidence of nonclosure of ileostomies and identified factors associated with nonclosure. DESIGN: This study is a retrospective analysis of prospectively collected data. SETTING: This study was conducted at a tertiary referral cancer hospital. PATIENTS: A total of 296 patients who received anterior resection with a defunctioning ileostomy with protective intention from 2006 to 2013 were included. MAIN OUTCOME MEASURES: The primary outcomes measured were the incidence of nonclosure of ileostomy and associated risk factors. RESULTS: Patients were followed for a median time of 29 months (range, 21-100 months). At the end of the study, 51 (17.2%) patients were left with a permanent ileostomy. The median time interval from the creation of a defunctioning ileostomy to closure was 192 days (range, 14-865 days). Multivariate analyses using a logistic regression model showed that metastatic diseases (OR, 0.179, p < 0.001), Charlson Comorbidity Index score >1 (OR, 0.268; p < 0.01), and complications from the index surgery (OR, 0.391; p = 0.013) were significant independent risk factors for failing to close a defunctioning ileostomy. LIMITATIONS: Although our study has a large patient cohort, it is limited by its retrospective nature. It is difficult to fully evaluate stoma complications after hospital discharge, and the prevalence may be underestimated. CONCLUSION: One in 6 temporary ileostomies constructed during an elective anterior resection for rectal cancer was not closed. Patients should be told before the index surgery that there is a risk of nonclosure and possible complications associated with permanent ileostomy.

Glycomic profiling of carcinoembryonic antigen isolated from human tumor tissue.

BACKGROUND: Carcinoembryonic antigen (CEA) is a protein commonly found in human serum, with elevated CEA levels being linked to the progression of a wide range of tumors. It is currently used as a biomarker for malign tumors such as lung cancer and colorectal cancer [Urol Oncol: Semin Orig Invest 352: 644-648, 2013 and Lung Cancer 80: 45-49, 2013]. However, due to its low specificity in clinical applications, CEA can be used for monitoring only, rather than tumor diagnosis. The function of many glycoproteins is critically dependent on their glycosylation pattern, which in turn has the potential to serve in tumor detection. However, little is known about the detailed glycan patterns of CEA. METHODS: To determine these patterns, we isolated and purified CEA proteins from human tumor tissues using immunoaffinity chromatography. The glycan patterns of CEA were then analyzed using a Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry(3) (MALDI-TOF-MS(3)) approach. RESULTS: We identified 61 glycoforms in tumor tissue, where CEA is upregulated. These glycosylation entities were identified as bi-antennary, tri-antennary and tetra-antennary structures carrying sialic acid and fucose residues, and include a multitude of glycans previously not reported for CEA. CONCLUSION: Our findings should facilitate a more precise tumor prediction than currently possible, ultimately resulting in improved tumor diagnosis and treatment.

Subcutaneous vacuum drains reduce surgical site infection after primary closure of defunctioning ileostomy.

PURPOSE: Surgical site infection (SSI) is the most common complication after primary closure of defunctioning ileostomy. We use a subcutaneous vacuum drain (SVD) in our institution to prevent infection. This study aimed to analyze the risk factors of SSI and to assess the utility of an SVD for preventing SSI in patients undergoing primary closure of ileostomy. METHODS: Patients undergoing ileostomy closure in the Department of Colorectal Surgery, Peking University Cancer Hospital, from September 2006 to March 2013, were included in this study. The clinical features of these patients with or without a subcutaneous drain were reviewed, and the complication rate of SSI was analyzed. The primary endpoints were the incidence and risk factors of SSI, and the secondary endpoints were the rate of overall complications and their management. RESULTS: A total of 245 consecutive patients were enrolled in the study. The overall incidence of SSI was 8.6%. Eighty-five (34.7%) patients received placement of an SVD. The use of SVDs was associated with a significantly lower incidence of SSI compared with primary closure (PC) without an SVD (1.2 vs. 12.5%, p = 0.001). Multivariate analyses showed that the presence of an SVD (odds ratio (OR) 0.063, p = 0.012), total operation time >90 min (OR 4.862, p = 0.002), and postoperative complications (OR 10.576, p < 0.001) were independent risk factors of SSI. CONCLUSIONS: This study shows that an SVD is effective for reducing SSI in patients undergoing PC of ileostomy. Further randomized trials are required to confirm our findings and to compare SVDs with purse-string sutures.

[Retrospective analysis of 856 cases with stage 0 to III rectal cancer underwent curative surgery combined modality therapy].

OBJECTIVE: To investigate the survival and prognostic factors of stage 0 to III rectal cancer in 10 years. METHODS: Clinical data and follow-up of 856 rectal cancer patients with stage 0-III underwent curative surgery from January 2000 to December 2010 were retrospective analyzed. There were 470 male and 386 female patients, with a mean age of (58 ± 12) years. Kaplan-Meier method was used to analyze the overall survival and disease free survival. Log-rank test was used to compare the survival between groups. Cox regression was used to analyze the independent prognostic factors of rectal cancer. RESULTS: The patients in each stage were stage 0 with 18 cases, stage I with 209 cases, stage II with 235 cases, and stage III with 394 cases. All patients received curative surgery. There were 296 patients evaluated as cT3, cT4 and any T with N+ received preoperative radiotherapy. 5.4% patients got pathological complete response (16/296), and the recurrence rate was 4.7% (14/296). After a median time of 41.7 months (range 4.1 to 144.0 months) follow-up, the 5-year overall survival rate in stage 0 to I of was 91.0%, stage II 86.2%, and stage III 60.0%, with a significant difference (P=0.000). The cumulative local recurrence rate was 4.8% (41/856), of which 70.7% (29/41) occurred within 3 years postoperatively, 97.6% (40/41) in 5 years. The cumulative distant metastasis rate was 16.4% (140/856), of which 82.9% (129/140) occurred within 3 years postoperatively, 96.4% (135/140) in 5 years. The incidence of abnormal imaging findings was significantly higher in pulmonary than liver and other sites metastases (75.0% vs. 21.7%, χ² =25.691, P=0.000). The incidence of CEA elevation was significantly higher in liver than lung and other sites metastases (56.8% vs. 37.8%, χ² =25.691, P=0.000). Multivariable analysis showed that age (P=0.015, HR=1.385, 95% CI: 1.066 to 1.801), surgical approach (P=0.029, HR=1.337, 95% CI: 1.030 to 1.733), differentiation (P=0.000, HR=1.535, 95% CI: 1.222 to 1.928), TNM stage (P=0.000, HR=1.349, 95% CI: 1.260 to 1.444) and lymphovascular invasion (P=0.001, HR=1.715, 95% CI: 1.258 to 2.342) are the independent prognostic factors for rectal cancer. CONCLUSIONS: Age, surgical approach, differentiation, TNM stage and lymphovascular invasion are independent prognostic factors for rectal cancer. Preoperative evaluation and combined modality therapy can significant reduce the local recurrence and improve overall survival for rectal cancer patients.

MicroRNA-181a promotes tumor growth and liver metastasis in colorectal cancer by targeting the tumor suppressor WIF-1.

BACKGROUND: Given the emerging role of microRNA in tumor disease progression, we investigated the association between microRNA expression, liver metastasis and prognosis of colorectal cancer. METHODS: Colorectal cancer tissues from patients with or without liver metastases were profiled to identify differentially expressed microRNA. Expression profile was further assessed using quantitative reverse transcription PCR and in situ hybridization. Correlation between miR-181a expression, the most differentially expressed microRNA, between patients with and without liver metastasis, and its downstream target genes were investigated using qRT-PCR. Luciferase reporter assay was conducted to establish functional association between miR-181a and its target genes. Manipulation of miR-181a expression and its consequences in tumor growth and metastasis were demonstrated in various in vitro and in vivo models. RESULTS: miR-181a was revealed being the most elevated in CRC with liver metastases. miR-181a expression correlated with advanced stage, distant metastasis, and served as an independent prognostic factor of poor overall survival. Stable transfection of CRC cell lines with miR-181a promoted cell motility and invasion, as well as tumor growth and liver metastasis,while silencing its expression resulted in reduced migration and invasion. Additionally, we identified WIF-1 as direct and functional targets of miR-181a. Ectopic expression of miR-181a suppressed the epithelial markers E-cadherin and ß-catenin, while enhanced the mesenchymal markers vimentin. CONCLUSION: Our data demonstrate that miR-181a expression is associated with CRC liver metastasis and survival. miR-181a has strong tumor-promoting effects through inhibiting the expression of WIF-1, and its potential role in promoting epithelial-mesenchymal transition.

Zebrafish live imaging: a strong weapon in anticancer drug discovery and development.

Developing anticancer drugs is a complex and time-consuming process. The inability of current laboratory models to reflect important aspects of the tumor in vivo limits anticancer medication research. Zebrafish is a rapid, semi-automated in vivo screening platform that enables the use of non-invasive imaging methods to monitor morphology, survival, developmental status, response to drugs, locomotion, or other behaviors. Zebrafish models are widely used in drug discovery and development for anticancer drugs, especially in conjunction with live imaging techniques. Herein, we concentrated on the use of zebrafish live imaging in anticancer therapeutic research, including drug screening, efficacy assessment, toxicity assessment, and mechanism studies. Zebrafish live imaging techniques have been used in numerous studies, but this is the first time that these techniques have been comprehensively summarized and compared side by side. Finally, we discuss the hypothesis of Zebrafish Composite Model, which may provide future directions for zebrafish imaging in the field of cancer research.

Total Neoadjuvant Therapy With PD-1 Blockade for High-Risk Proficient Mismatch Repair Rectal Cancer.

Importance: Total neoadjuvant therapy (TNT) is the standard treatment for locally advanced rectal cancer, especially for patients with high-risk factors. However, the efficacy of TNT combined with immunotherapy for patients with proficient mismatch repair (pMMR) rectal cancer is unknown. Objectives: To evaluate the safety and efficacy of TNT with induction chemoimmunotherapy followed by long-course chemoradiation in patients with high-risk, pMMR rectal cancer and to identify potential molecular biomarkers associated with treatment efficacy. Design, Setting, and Participants: This cohort study was a single-arm phase 2 trial conducted at Gastrointestinal Cancer Center, Peking University Cancer Hospital & Institute, from June 2020 to October 2021. Biopsies and plasma were collected before treatment for whole-exome sequencing and cell-free DNA sequencing, respectively. Data were analyzed from May 2022 to September 2022. Interventions: Participants received 3 cycles of induction oxaliplatin and capecitabine combined with camrelizumab and radiotherapy (50.6 Gy in 22 fractions) with concurrent capecitabine. Patients without disease progression received 2 cycles of consolidation oxaliplatin/capecitabine. Main Outcomes and Measures: The primary end point was pathologic complete response rate. Results: Of 25 patients enrolled (19 men [76%]; 6 women [24%]; median [IQR] age, 58 [48-64] years), 22 patients (88%) completed the TNT schedule. The pathologic complete response rate was 33.3% (7/21). Twelve patients (48%) achieved clinical complete response, and 4 patients (16%) chose to watch and wait. R0 resection was achieved in 21 of 21 patients, and the major pathologic response rate was 38.1% (8/21). The most common adverse event was nausea (80%, 20/25); grade 3 toxic effects occurred in 9 of 25 patients (36%). Patients with tumor shrinkage of 50% or greater after induction oxaliplatin/capecitabine and camrelizumab or clinical complete response had higher percentages of LRP1B mutation. Mutation of LRP1B was associated with high tumor mutation burden and tumor neoantigen burden. Patients with high tumor mutation burden all benefited from therapy. Conclusions and Relevance: This study found that TNT with induction chemoimmunotherapy followed by long-course chemoradiation was safe and effective for patients with high-risk rectal cancer with pMMR status. Longer follow-up and larger clinical studies are needed to validate this innovative regimen. There is also an urgent need to further validate the predictive value of LRP1B and discover other novel biomarkers with potential predictive value for rectal cancer.

Prognostic role of serum AZGP1, PEDF and PRDX2 in colorectal cancer patients.

This study was designed to develop novel and better reliable serum prognostic biomarkers for colorectal cancer (CRC). A 50 sample set including CRC, adenoma and healthy control sera was used to identify the serum proteins involved in CRC carcinogenesis using serum proteomic approach. Alpha-2-glycoprotein 1, zinc-binding (AZGP1), pigment epithelium derived factor (PEDF) and peroxiredoxin 2 (PRDX2) were selected as good candidates. Two independent cohorts of 868 individuals were enrolled. The expression of selected proteins in serum from cohort 1 (n = 534) was quantified with enzyme-linked immunosorbent assays. CRC sera of this cohort (n = 405) were assigned to training and test sets, which were used to identify and verify the prognostic markers. The prognostic values of identified proteins were further validated in cohort 2 (n = 334) using quantitative reverse transcription PCR and immunohistochemical staining. Our data showed that the elevated AZGP1 and decreased PEDF and PRDX2 expressions in CRC serum and tissues were correlated with liver metastases. In the training set, higher AZGP1 and lower PEDF levels in sera were significantly associated with a poorer overall survival (OS), higher AZGP1 was also associated with a poorer disease-free survival (DFS). This association was verified in the testing set and further validated in patients in cohort 2. Patients with lower PEDF or PRDX2 levels in their CRC tissues had a significantly poorer DFS or OS than patients with high levels of these proteins in cohort 2. Univariate and multivariate analyses indicated that the prognostic performance of serum AZGP1 and PEDF was independent of other clinicopathological factors. We propose that they may serve as prognostic markers and potential therapeutic targets in CRC.

Intermediate-fraction neoadjuvant radiotherapy for rectal cancer.

BACKGROUND: In China, standard neoadjuvant chemoradiation therapy has not been well accepted, not only because of financial constraints but also because of the poorly-tolerated long duration of the regimen. OBJECTIVE: The current study aimed to evaluate the impact of a modified neoadjuvant radiation regimen on the prognosis of rectal cancer patients in China. DESIGN: This was a nonrandomized cohort study evaluating outcomes of patients who chose to undergo preoperative radiotherapy compared with those who chose not to undergo preoperative radiotherapy (controls). SETTINGS: The study was carried out in Peking University Cancer Hospital, a tertiary care cancer center in China. PATIENTS: Records of patients with locally advanced, mid-to-low rectal cancer who underwent total mesorectal excision at Peking University Cancer Hospital from 2001 through 2005 were analyzed in this study. INTERVENTION: Patients who chose preoperative radiotherapy received a total dose of 30 Gy delivered in 10 once-daily fractions of 3.0 Gy each, with at least a 14-day delay of surgery after delivery of the last fraction. MAIN OUTCOME MEASURES: Tumor downstaging was evaluated. Local recurrence, distant metastases, and disease-free and overall survival were analyzed with the Kaplan-Meier method. RESULTS: A total of 101 patients accepted and 162 patients declined the modified preoperative radiotherapy regimen. Of the 101 patients receiving preoperative radiotherapy, 5 (5%) had a complete response, and 50 (50%) achieved TNM downstaging. The local recurrence rate was 5% with preoperative radiotherapy and 18% in the control groups (p = 0.02). Within the preoperative radiotherapy group, 5-year disease-free survival and overall survival rates were significantly higher in patients with T-, N-, or TNM-downstaging than in patients without downstaging. Evaluation of literature reports indicated that clinical safety and effectiveness of the modified protocol are comparable to results of standard neoadjuvant procedures. LIMITATIONS: The allocation to study groups was not randomized, and patient self-selection may have introduced bias, particularly because patients with greater financial means were more likely to choose to undergo the preoperative radiotherapy regimen. CONCLUSIONS: Compared with surgery alone, this modified preoperative radiotherapy regimen is associated with significantly reduced local recurrence and complication rates, with improved survival in patients who show downstaging. The modified protocol offers a clinical outcome equivalent to standard preoperative radiotherapy regimens while offering an alternative for increasing the flexibility of preoperative radiation regimens in China.

UVRAG Promotes Tumor Progression through Regulating SP1 in Colorectal Cancer.

Colorectal cancer (CRC) is the third most common type of cancer. The ultraviolet radiation resistance-associated gene (UVRAG) plays a role in autophagy and has been implicated in tumor progression and prognosis. However, the role of UVRAG expression in CRC has remained elusive. In this study, the prognosis was analyzed via immunohistochemistry, and the genetic changes were compared between the high UVRAG expression group and the low UVRAG expression group using RNA sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq) data, and genetic changes were then identified by in vitro experiments. It was found that UVRAG could enhance tumor migration, drug resistance, and CC motif chemokine ligand 2 (CCL2) expression to recruit macrophages by upregulating SP1 expression, resulting in poor prognosis of CRC patients. In addition, UVRAG could upregulate the expression of programmed death-ligand 1 (PD-L1). In summary, the relationship between UVRAG expression and the prognosis of CRC patients as well as the potential mechanisms in CRC were explored, providing evidence for the treatment of CRC.

Total neoadjuvant treatment for MRI-stratified high-risk rectal cancer: a single-center, single-arm, prospective Phase II trial (PKUCH-R02).

Background: Induction chemotherapy combined with neoadjuvant chemoradiotherapy has been recommended for patients with high-risk, locally advanced rectal cancer. However, the benefit of more intensive total neoadjuvant treatment (TNT) is unknown. This study aimed to assess the safety and efficacy of induction chemotherapy combined with chemoradiotherapy and consolidation chemotherapy for magnetic resonance imaging-stratified high-risk rectal cancer. Methods: This was a single-center, single-arm, prospective Phase II trial in Peking University Cancer Hospital (Beijing, China). Patients received three cycles of induction oxaliplatin and capecitabine (CapeOX) followed by chemoradiotherapy and two cycles of consolidation CapeOX. The primary end point was adverse event rate and the second primary end points were 3-year disease-free survival rate, completion of TNT, and pathological downstaging rate. Results: Between August 2017 and August 2018, 68 rectal cancer patients with at least one high risk factor (cT3c/3d/T4a/T4b, cN2, mesorectal fascia involvement, or extramural venous invasion involvement) were enrolled. The overall compliance of receiving the entire treatment was 88.2% (60/68). All 68 patients received induction chemotherapy, 65 received chemoradiotherapy, and 61 received consolidation chemotherapy. The Grade 3-4 adverse event rate was 30.8% (21/68). Nine patients achieved clinical complete response and then watch and wait. Five patients (7.4%) developed distant metastasis during TNT and received palliative chemotherapy. Fifty patients underwent surgical resection. The complete response rate was 27.9%. After a median follow-up of 49.2 months, the overall 3-year disease-free survival rate was 69.7%. Conclusions: For patients with high-risk rectal cancer, this TNT regimen can achieve favorable survival and complete response rates but with high toxicity. However, it is necessary to pay attention to the possibility of distant metastasis during the long treatment period.

LGR4 cooperates with PrPc to endow the stemness of colorectal cancer stem cells contributing to tumorigenesis and liver metastasis.

Cancer stem cells (CSCs) are a subpopulation of cancer cells that drive tumour progression and metastasis. Anti-CSC strategies represent new targets for cancer therapies. However, CSCs are highly plastic and heterogeneous, making validation and targeting difficult without bona fide markers that define their identity, especially in a clinical setting. Here, we report that a leucine-rich repeat containing G protein-coupled receptor 4 (LGR4) cooperates with CD44 and PrPc; the latter contributes significantly to metastatic capacity and defines the stemness characteristics of colorectal CSCs. CD44+PrPc+LGR4+ cells effectively developed into organoids and, when transplanted, generated orthotopic and metastatic tumours. Importantly, targeting LGR4 and PrPc with lentiviral shRNAs inhibited organoid development and the growth of orthotopic tumours by inhibiting Wnt/ß-catenin signalling. Thus, our study offers a novel therapeutic strategy that simultaneously targets CSC stemness and metastatic properties.

Surgery may not benefit patients with locally advanced rectal cancer who achieved clinical complete response following neoadjuvant chemoradiotherapy.

PURPOSE: We compared the long-term outcome of the watch and wait (WW) strategy and surgery in patients with locally advanced rectal cancer. PATIENTS AND METHODS: This prospective cohort study included 84 patients who achieved clinical complete response (cCR) after neoadjuvant chemoradiotherapy (NCRT). They were divided into the WW group (n = 58) and surgery group (SG, n = 26). Patients in the SG underwent total mesorectal excision. The study site was the Peking University Cancer Hospital. RESULTS: Eighty-four patients were included (58 and 26 in the WW group and SG, respectively). A total of 76·9% of the patients in the SG achieved pathological complete response (pCR) and 23·1% of the patients had a residual tumor. The total recurrence and metastasis rate was 15·4% (4/26) in the SG and 18·9% (11/58) in the WW group. There was no significant difference in the recurrence and metastasis rate between the two groups. In the WW group, 9 cases developed tumor regrowth during follow-up and underwent salvage surgery. The overall survival rate of the WW group (96·6% vs 92·3%) was not significantly different from that of the SG (P > 0·05). The WW patients also retained their anal sphincter function and avoided surgery-related complications. CONCLUSION: The WW strategy is a feasible treatment option in patients with cCR after NCRT. Surgery may not bring benefits to these cCR patients.

Surgical treatment of massive stoma site tumors after a curative operation for rectal cancer.

OBJECTIVE: This study aimed to evaluate the clinical and oncological outcomes of selected rectal cancer patients with massive stoma site tumors who underwent radical resection and reconstruction. METHODS: We reviewed 8 cases of massive stoma site tumors in patients who had permanent gastrointestinal stoma in the abdominal wall following radical resection of rectal cancer between March 2013 and May 2018 at the Peking University Cancer Hospital and Peking University Shougang Hospital. RESULTS: There were seven males and one female patient, with a median age of 50.6 years. The average time between the initial surgery and the development of a malignant tumor at the stoma site was 5 years (range, 0.5-14 years). The average diameter of the stoma site tumors was 8.1 cm, and the diameter of the largest tumor was 12 cm. After tumor resection, the area of the largest abdominal wall defect was about 15 × 14 cm2. Abdominal wall repair included the use of a tensor fasciae latae muscle flap, local fasciocutaneous rotational flap, and pedicled anterolateral thigh flap. No patient died in the 30 days following surgery. The longest follow-up period was 81 months, and 5 patients died. CONCLUSIONS: Multidisciplinary clinical management fosters positive outcomes in treating massive stoma site tumors. Local R0 resection and abdominal wall reconstruction are safe and feasible, and function to removes local disease, allowing patients to live a higher quality of life.

Surgical complications after different therapeutic approaches for locally advanced rectal cancer.

BACKGROUND: Preoperative radiochemotherapy is widely used in locally advanced rectal cancer. It can improve local control of rectal cancer. However, some researchers believe it increases the incidence of surgical complications. They doubt its safety. Patients with locally advanced rectal cancer receive three different treatments in our hospital, including long-course radiochemotherapy, short-course radiotherapy, and surgery directly. We can compare their differences in postoperative complications. AIM: To investigate surgical complications caused by different preoperative radiotherapy regimens. METHODS: We retrospectively analyzed 1197 patients admitted between 2008 and 2010 with locally advanced rectal cancer. Three hundred and forty-six patients were treated with preoperative long-course radiochemotherapy (25 × 2 Gy) followed by total mesorectal excision (TME) 6-8 wk later, and 259 patients received short-course radiotherapy (10 × 3 Gy) and subsequently TME 7-10 d later. The remaining 592 patients underwent TME alone without neoadjuvant therapy. According to Clavien-Dindo classification, surgical complications were evaluated for up to 30 d after discharge from hospital. RESULTS: There were no deaths in 30 d in all groups after treatment. The major complications were anastomotic leakage and perineal wound complications. The results suggested that both long-course [odds ratio (OR) = 3.624, 95% confidence interval (CI): 1.689-7.775, P = 0.001] and short-course (OR = 5.150, 95%CI: 1.828-14.515, P = 0.002) radiotherapy were associated with anastomotic leakage. Temporary ileostomy was a protective factor for anastomotic leakage (OR = 6.211, 95%CI: 2.525-15.385, P < 0.001). The severity of anastomotic leakage did not increase in patients following preoperative radiotherapy (P = 0.411). Compared with TME alone, short-course radiotherapy was associated with an increase in perineal wound complications (OR = 5.565, 95%CI: 2.203-14.057, P < 0.001), but long-course radiotherapy seemed safe regarding this complication (OR = 1.692, 95%CI: 0.651-4.394, P = 0.280). Although the severity of perineal wound complications increased in patients following short-course radiotherapy (P < 0.001), additional intervention was not necessary. CONCLUSION: Radiotherapy increased the incidence but not severity of anastomotic leakage. Short-course radiotherapy was also accompanied with perineal wound complications, but intervention appeared unnecessary to ameliorate the complications.

Somatic Mutations and Immune Alternation in Rectal Cancer Following Neoadjuvant Chemoradiotherapy.

Checkpoint blockade therapy triggers tumor-specific immune responses in a variety of cancer types. We presumed that rectal cancer patients could have become sensitive to immunotherapy after receiving neoadjuvant chemoradiotherapy (nCRT). In this study, we report immune alternation in post-nCRT patients compared with pretreatment conditions from gene-expression omnibus (GEO) data. Whole-exome sequencing of 14 locally advanced rectal cancer (LARC) patient samples showed that nCRT induced new mutations compared with the paired pretreatment biopsies, evidenced by appearance of a neoantigen landscape. An association was identified between mutation burden and enrichment of immune activation-related pathways. Animal experiment results further demonstrated that radiotherapy enhanced the efficacy of anti-PD-1. Mutation burden and the neoantigens of LARC patients were associated with response to nCRT. The mRNA expression profiling of 66 pretreatment biopsy samples from LARC patients showed that immune activation-related pathways were enriched in response to nCRT. PD-L1 expression was negatively correlated with disease-free survival in the CD8-low expression patient group who received nCRT in a cohort of 296 samples. Thus, nCRT was able to alter immune function in LARC patients, which may be associated with the appearance of neoantigens. Neoantigens could make rectal cancer patients potential candidates to receive checkpoint blockade immunotherapy, and mutation burden could be a useful biomarker to stratify patients into responding and nonresponding groups for immunotherapy. Cancer Immunol Res; 6(11); 1401-16. ©2018 AACR.

Enhancement of Sensitivity to Chemo/Radiation Therapy by Using miR-15b against DCLK1 in Colorectal Cancer.

Chemo-/radiotherapy resistance is the main cause accounting for most treatment failure in colorectal cancer (CRC). Tumor-initiating cells (TICs) are the culprit leading to CRC chemo-/radiotherapy resistance. The underlying regulation mechanism of TICs in CRC remains unclear. Here we discovered that miR-15b expression positively correlated with therapeutic outcome in CRC. Expression of miR-15b in pretreatment biopsy tissue samples predicted tumor regression grade (TRG) in rectal cancer patients after receiving neoadjuvant radiotherapy (nRT). Expression of miR-15b in post-nRT tissue samples was associated with therapeutic outcome. DCLK1 was identified as the direct target gene for miR-15b and its suppression was associated with self-renewal and tumorigenic properties of DCLK1+ TICs. We identified B lymphoma Mo-MLV insertion region l homolog (BMI1) as a downstream target regulated by miR-15b/DCLK1 signaling. Thus, miR-15b may serve as a valuable marker for prognosis and therapeutic outcome prediction. DCLK1 could be a potential therapeutic target to overcome chemo-/radioresistance in CRC.

[Long-term prognostic analysis on complete/near-complete clinical remission for mid-low rectal cancer after neoadjuvant chemoradiotherapy].

OBJECTIVE: To investigate the long-term outcome of organ preservation with local excision or "watch and wait" strategy for mid-low rectal cancer patients evaluated as clinical complete remission (cCR) or near-cCR following neoadjuvant chemoradiotherapy (NCRT). METHODS: Clinical data of 62 mid-low rectal cancer patients evaluated as cCR/near-cCR after NCRT undergoing organ preservation surgery with local excision or receiving "watch and wait" strategy at Department of Gastrointestinal Surgery, Peking University Cancer Hospital and Institute from March 2011 to August 2017 were retrospectively analyzed. According to the approximate 1:2 pairing, 123 patients who underwent radical resection with complete pathological remission(ypCR) after neoadjuvant chemotherapy during the same period were selected for prognosis comparison. The primary endpoint of the study was 3-year non-regrowth disease-free survival (NR-DFS) and tumor specific survival (CSS). Survival analysis was performed using the Kaplan-Meier curve (Log-rank method). The secondary endpoint of the study was 3-year organ preservation and sphincter preservation. RESULTS: The retrospective study included 38 male and 24 female patients. The median age was 60 (31-79) years and the median distance from tumor to anal verge was 4(1-8) cm. The ratio of cCR and near-cCR was 79.0%(49/62) and 21.0%(13/62) respectively. Local regrowth rate was 24.2%(15/62). Of 15 with tumor regrowth, 9 patients received salvage radical rectal resection and no local recurrence was found during follow-up; 4 patients received salvage local excision among whom one patient had a local recurrence occurred patient; 2 patients refused further surgery. The overall metastasis rate was 8.1%(5/62), including resectable metastasis(4.8%,3/62) and unresectable metastasis (3.2%,2/62). The valid 3-year organ preservation rate and sphincter preservation rate were 85.5%(53/62) and 95.2%(59/62) respectively. The median follow-up was 36.2(8.6-89.0) months. The 3-year NR-DFS of patients with cCR and near-cCR was 88.6% and 83.1% respectively, which was not significantly different to that of patients with ypCR (94.7%, P=0.217). The 3-year CSS of patients with cCR and near-cCR was both 100%, which was not significantly different to that of patients with ypCR(93.4%, P=0.186). CONCLUSIONS: Mid-low rectal cancer patients with cCR or near-cCR after NCRT undergoing organ preservation with local excision or receiving "watch and wait" strategy have good long-term prognosis with low rates of local tumor regrowth and distant metastasis, which is similar to those with ypCR after radical surgery. This treatment mode may be used as an option for organ preservation in mid-low rectal cancer patients with good tumor remission after NCRT.