New Strategies in Rectal Cancer

Development and validation of comprehensive nomograms from the SEER database for predicting early mortality in metastatic rectal cancer patients

BACKGROUND

Metastatic rectal cancer is an incurable malignancy, which is prone to early mortality. We aimed to establish nomograms for predicting the risk of early mortality in patients with metastatic rectal cancer.

METHODS

In this study, clinical data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database.We utilized X-tile software to determine the optimal cut-off points of age and tumor size in diagnosis. Significant independent risk factors for all-cause and cancer-specific early mortality were determined by the univariate and multivariate logistic regression analyses, then we construct two practical nomograms. In order to assess the predictive performance of nomograms, we performed calibration plots, time-dependent receiver-operating characteristic curve (ROC), decision curve analysis (DCA) and clinical impact curve (CIC).

RESULTS

A total of 2570 metastatic rectal cancer patients were included in the study. Multivariate logistic regression analyses revealed that age at diagnosis, CEA level, tumor size, surgical intervention, chemotherapy, radiotherapy, and metastases to bone, brain, liver, and lung were independently associated with early mortality of metastatic rectal cancer patients in the training cohort. The area under the curve (AUC) values of nomograms for all-cause and cancer-specific early mortality were all higher than 0.700. Calibration curves indicated that the nomograms accurately predicted early mortality and exhibited excellent discrimination. DCA and CIC showed moderately positive net benefits.

CONCLUSIONS

This study successfully generated applicable nomograms that predicted the high-risk early mortality of metastatic rectal cancer patients, which can assist clinicians in tailoring more effective treatment regimens.

Surgical anatomy and clinical variation of the left colonic artery in laparoscopic anterior rectal resection

Objectives

This study aims to investigate the surgical anatomy and clinical variation of the left colonic artery (LCA) during laparoscopic anterior rectal resection.

Methods

We conducted a retrospective analysis of 87 patients diagnosed with colorectal cancer who underwent laparoscopic anterior rectal resection with preserved LCA at the Department of Gastroenterology, Sichuan Cancer Hospital, between March 2018 and April 2022, aiming to observe the emanation location, anatomical typing, and travel trajectory of the LCA, as well as its relationship with the inferior mesenteric vein (IMV).

Results

In all observed cases, we observed that the LCA emanated from the left side of the inferior mesenteric artery (IMA), and the average distance from the root of the IMA to the emanation of the LCA was approximately 3.5 ± 1.1 cm. Specifically, 35 of these cases had the LCA branching from the IMA alone (Type I, 40.2%),16 cases had the LCA cotruncating with the sigmoid artery (SA) (Type II, 18.4%), 30 cases had the LCA cotruncating with the superior rectal artery (SRA) and SA (Type III, 34.5%), and six cases had the LCA cotruncating with four or more branches of the SRA and SA (Type IV, 6.9%). No LCA agenesis cases were found in this group. In addition, we also observed the occurrence of LCA alignment. Specifically, there were 25 cases where the LCA crossed the IMV in a diagonal upward direction (Type A, 28.7%), 36 cases where the LCA crossed the IMV in an upward arched manner (Type B, 41.4%), 18 cases where the LCA crossed the IMV in a vertical outward direction (Type C, 20.7%), and eight cases where the LCA crossed the IMV in a diagonal downward manner (Type D, 9.2%). Among them, two cases developed anastomotic fistula, one case had chyle leakage 1 week after surgery, and four cases experienced urinary retention; all of the patients successfully recovered and were discharged after receiving conservative treatment.

Conclusion

The anatomy and variation of the LCA can be clearly and accurately observed during laparoscopic surgery. Understanding the type and variation of the LCA helps to dissect the vessels in the IMA region during surgery, particularly in cases when the LCA is preserved, and reduce the incidence of vascular injury and its complications.

Immunotherapy in rectal cancer patients-a propensity score matched analysis of the National Cancer Database

BACKGROUND

Rectal cancer patients with microsatellite instability (MSI-H) are candidates for immunotherapy. However, there is little evidence on its effect on overall survival (OS).

METHODS

Retrospective analysis of stage II-IV rectal adenocarcinoma patients in the National Cancer Database (NCDB) between 2010 and 2019. Propensity score matching was adjusted for baseline and treatment confounders. The cohort was divided into patients who received immunotherapy and matched controls. The primary outcome was OS.

RESULTS

5175/206,615 (2.5%) patients with rectal adenocarcinoma underwent immunotherapy. These patients were younger (58 vs 62 years; p < 0.001), more often male (64.4% vs 61.7%; p < 0.001), were more likely to have private insurance (50.8% vs 43.4%; p < 0.001), more metastatic disease at presentation (clinical TNM stage IV-80.8% vs 23.3%; p < 0.001), presented with larger tumors (median: 5 cm vs. 4.2 cm; p < 0.001) and less often underwent surgery (33.7% vs. 69.9%; p < 0.001), radiation therapy (21.5% vs 57.4%; p < 0.001), and standard chemotherapy (38.1% vs 61%; p < 0.001) than controls. After matching, 488 patients were in each group. OS was significantly shorter in the immunotherapy group (mean survival: 56.4 months (95% CI: -53.03-59.86)) compared to controls (mean survival: 70.5 months (95% CI: -66.15-74.92) (p = 0.004)). Cox regression analysis of factors associated with OS demonstrated that immunotherapy was associated with increased mortality (HR 2.16; 95% CI: 2.09-2.24; p < 0.001). After clinical staging stratification, immunotherapy was associated with improved OS in stage IV (HR 0.91, 95% CI: 0.88-0.95; p < 0.001) but lower survival in stage II (HR 2.38; 95% CI: 2.05-2.77; p < 0.001) and stage III (HR 2.43; 95% CI: 2.18-2.7; p < 0.001) patients.

CONCLUSION

Immunotherapy showed modest increase in OS in stage IV metastatic rectal cancer. OS was significantly lower in stage II-III disease treated with immunotherapy.

Applying interpretable machine learning algorithms to predict risk factors for permanent stoma in patients after TME

Objective

The purpose of this study was to develop a machine learning model to identify preoperative and intraoperative high-risk factors and to predict the occurrence of permanent stoma in patients after total mesorectal excision (TME).

Methods

A total of 1,163 patients with rectal cancer were included in the study, including 142 patients with permanent stoma. We collected 24 characteristic variables, including patient demographic characteristics, basic medical history, preoperative examination characteristics, type of surgery, and intraoperative information. Four machine learning algorithms including extreme gradient boosting (XGBoost), random forest (RF), support vector machine (SVM) and k-nearest neighbor algorithm (KNN) were applied to construct the model and evaluate the model using k-fold cross validation method, ROC curve, calibration curve, decision curve analysis (DCA) and external validation.

Results

The XGBoost algorithm showed the best performance among the four prediction models. The ROC curve results showed that XGBoost had a high predictive accuracy with an AUC value of 0.987 in the training set and 0.963 in the validation set. The k-fold cross-validation method was used for internal validation, and the XGBoost model was stable. The calibration curves showed high predictive power of the XGBoost model. DCA curves showed higher benefit rates for patients who received interventional treatment under the XGBoost model. The AUC value for the external validation set was 0.89, indicating that the XGBoost prediction model has good extrapolation.

Conclusion

The prediction model for permanent stoma in patients with rectal cancer derived from the XGBoost machine learning algorithm in this study has high prediction accuracy and clinical utility.

The pattern and treatment outcomes for rectal cancer with concurrent locoregional recurrence and distant metastases after total mesorectal excision

Background

To study the pattern and treatment outcome of rectal cancer (RC) with concurrent locoregional recurrence (LR) and distant metastasis (DM) after total mesorectal excision (TME) and to identify patient-, disease-, and treatment-related factors associated with differences in prognosis after concurrent LR and DM.

Methods

RC patients who were diagnosed with concurrent LR and DM after TME from May 2015 to June 2019 were included in our study. All patients received single or multiple treatment modalities under the guidance of multidisciplinary team (MDT) of colorectal cancer in Fudan University Shanghai Cancer Center. The prognostic value of various clinicopathological factors for survival were calculated by Kaplan–Meier curves and Cox regression analyses.

Results

A total of 74 RC patients with concurrent LR and DM who had undergone TME with a median follow-up of 27 months were eligible for analysis. The median survival of the included patients was 34 months, and 30 patients (41%) died. Fifty-nine patients (80%) underwent comprehensive treatments. Patients with oligometastatic disease (OMD) achieved no evidence of disease (NED) status more frequently than those with multiple metastases (P = 0.003). In the univariate analysis, patients achieving NED, diagnosed with OMD and five or less peritoneal metastases tended to have longer survival after LR and DM diagnosis (P < 0.05). In the multivariate analysis, attaining NED status was the only independent factor for survival (hazard ratio (HR), 2.419; P = 0.032). Survival after concurrent LR and DM in the non-NED group was significantly shorter than that in the NED group (median survival, 32 vs. 46 months; HR, 2.7; P = 0.014).

Conclusions

The pattern and treatment outcome of RC with concurrent LR and DM after TME has changed with the development of multiple treatment modalities. Although the prognosis remains poor, pursuing NED status through comprehensive treatments may improve the survival of RC patients with concurrent LR and DM after TME.

Prognostic and clinical significance of subcellular CDC27 for patients with rectal adenocarcinoma treated with adjuvant chemotherapy

Rectal adenocarcinoma (READ) constitutes one-third of newly diagnosed colorectal cancer cases. Surgery, chemotherapy and concurrent chemoradiotherapy are the main treatments to improve patient outcomes for READ. However, patients with READ receiving these treatments eventually relapse, leading to a poor survival outcome. The present study collected surgical specimens from patients with READ and determined that cytoplasmic cell division cycle 27 (CDC27) expression was associated with the risk of lymph node metastasis and distant metastasis. Nuclear CDC27 expression was negatively associated with 5-year disease-free survival (DFS) and 5-year overall survival (OS) rates. Multivariate Cox proportional regression analysis showed that nuclear CDC27 was an independent prognostic factor in the patients with READ, especially in those treated with adjuvant chemotherapy. High nuclear CDC27 expression was significantly associated with poorer 5-year DFS (HR, 2.106; 95% CI, 1.275-3.570; P=0.003) and 5-year OS (HR, 2.369; 95% CI, 1.270-4.6810; P=0.005) rates. The data indicated that cytoplasmic CDC27 expression could affect tumor progression and that it plays an important role in metastasis. Nuclear CDC27 expression was markedly associated with poorer survival outcomes and was an independent prognostic factor in patients with postoperative adjuvant chemotherapy-treated READ. Thus, CDC27 expression serves as a potential prognostic marker for rectal tumor progression and chemotherapy treatment.

Constructing and Validating a Prognosis Predictive Nomogram for Cancer-Specific Survival in Rectal Cancer Patients Receiving Preoperative Radiotherapy

Background A predictive tool is required to identify the cancer-specific survival in rectal cancer (RC) patients who have opted to receive preoperative radiotherapy.Methods A database containing the data on RC patients' records of Surveillance, Epidemiology, and End Results (SEER) receiving surgery during 2000-2014 was selected. All patients received neoadjuvant radiotherapy (NR). The correlation of clinicopathological parameters was analyzed using the Chi-square test and the survival risk factors were analyzed using the Cox proportional hazards analysis (univariate and multivariate). Finally, the nomogram was developed and validated to visually represent an accurate prediction of the probability of 3- and 5-year cancer-specific survival (CSS) based on the screened variables of the cohort.Results 11,499 rectal cancer patients were included in our cohort. Patients' records were randomly allocated to either the development or validation cohorts based on an equal ratio (1:1). Performing the multivariate Cox regression analysis incorporating these variables in the development cohort determined 11 independent prognostic factors. Statistically significant differences were recorded among subgroups using log-rank tests, which confirmed the appropriateness and acceptability of factor stratifications. Then, the nomogram was constructed and its concordance index (C-index) values in the development cohort (0.720) and validation cohort (0.717) were evaluated to be higher (P<0.05) than those of the AJCC stage (0.631 and 0.633 respectively). Also, the 3-year AUC values of this nomogram were higher than those of the AJCC stage in both the development cohort (0.746 vs. 0.631) and the validation cohort (0.745 vs. 0.640). Using DCA curves, the predictive potential of the currently developed nomogram outperformed the conventional AJCC staging system.Conclusion The nomogram model might be a more reliable tool to predict prognosis accurately in rectal cancer patients receiving preoperative radiotherapy.

Deep-learning model for predicting the survival of rectal adenocarcinoma patients based on a surveillance, epidemiology, and end results analysis

Background

We collected information on patients with rectal adenocarcinoma in the United States from the Surveillance, Epidemiology, and EndResults (SEER) database. We used this information to establish a model that combined deep learning with a multilayer neural network (the DeepSurv model) for predicting the survival rate of patients with rectal adenocarcinoma.

Methods

We collected patients with rectal adenocarcinoma in the United States and older than 20 yearswho had been added to the SEER database from 2004 to 2015. We divided these patients into training and test cohortsat a ratio of 7:3. The training cohort was used to develop a seven-layer neural network based on the analysis method established by Katzman and colleagues to construct a DeepSurv prediction model. We then used the C-index and calibration plots to evaluate the prediction performance of the DeepSurv model.

Results

The 49,275 patients with rectal adenocarcinoma included in the study were randomly divided into the training cohort (70%, n = 34,492) and the test cohort (30%, n = 14,783). There were no statistically significant differences in clinical characteristics between the two cohorts (p > 0.05). We applied Cox proportional-hazards regression to the data in the training cohort, which showed that age, sex, marital status, tumor grade, surgery status, and chemotherapy status were significant factors influencing survival (p < 0.05). Using the training cohort to construct the DeepSurv model resulted in a C-index of the model of 0.824, while using the test cohort to verify the DeepSurv model yielded a C-index of 0.821. Thesevalues show that the prediction effect of the DeepSurv model for the test-cohort patients was highly consistent with the prediction resultsfor the training-cohort patients.

Conclusion

The DeepSurv prediction model of the seven-layer neural network that we have established can accurately predict the survival rateand time of rectal adenocarcinoma patients.

MicroRNA-199b Deregulation Shows Oncogenic Properties and Promising Clinical Value as Circulating Marker in Locally Advanced Rectal Cancer Patients

The identification of robust prognostic markers still represents a need in locally advanced rectal cancer (LARC). MicroRNAs (miRs) have progressively emerged as promising circulating markers, overcoming some limitations that traditional biopsy comprises. Tissue miR-199b deregulation has been reported to predict outcome and response to neoadjuvant chemoradiotherapy (nCRT) in LARC, and was also found to be associated with disease progression in colorectal cancer. However, its biological and clinical relevance remains to be fully clarified. Thus, we observed here that miR-199b regulates cell migration, aggressiveness, and cell growth, and inhibits colonosphere formation and induces caspase-dependent apoptosis. Moreover, miR-199b expression was quantified by real-time PCR in plasma samples from LARC patients and its downregulation was observed in 22.7% of cases. This alteration was found to be associated with higher tumor size (p = 0.002) and pathological stage (p = 0.020) after nCRT. Notably, we observed substantially lower global miR-199b expression associated with patient downstaging (p = 0.009), as well as in non-responders compared to those cases who responded to nCRT in both pre- (p = 0.003) and post-treatment samples (p = 0.038). In concordance, we found that miR-199b served as a predictor marker of response to neoadjuvant therapy in our cohort (p = 0.011). Altogether, our findings here demonstrate the functional relevance of miR-199b in this disease and its potential value as a novel circulating marker in LARC.

Total Neoadjuvant Therapy Is a Predictor for Complete Pathological Response in Patients Undergoing Surgery for Rectal Cancer

INTRODUCTION

Total neoadjuvant therapy (TNT) is a new therapeutic strategy in patients with rectal cancer. We examined the role of TNT, in addition to other pre-operative factors, as a predictor for pathologic complete response (pCR).

METHODS

A retrospective analysis of all rectal cancer patients who underwent surgery between 2016 and 2021 was conducted. Patients were classified into two groups-pCR group and residual tumor group. Patient data were reviewed and entered into univariate and multivariate analyses to determine predictors of pCR.

RESULTS

A total of 172 patients were treated with neoadjuvant therapy and underwent surgery during the study period. Sixty patients (34.9%) were treated with TNT while 112 (65.1%) were treated with traditional neoadjuvant chemoradiation. The overall pCR rate was 25.6% (44 patients), with 31.6% (19 patients) in patients who received TNT compared to 22.3% (25 patients) in patients who received neoadjuvant chemoradiation (NCRT). Univariate analysis of clinical and radiological factors correlated with pCR demonstrated no significant differences between the two groups in cT stage (p = 0.46), cN stage (p = 0.52), positive circumferential resection margin (CRM) (p = 0.72), tumor location (p = 0.35), symptomatic presentation (p = 0.09), and anal sphincter involvement (p = 0.68). Multivariate logistic analysis demonstrated that only pre-operative TNT (OR:2.35; 95% CI 1.06-5.25; p = 0.03) was predictive of pCR, while extramural vascular invasion (EMVI) was a predictor for lower rates of pCR (OR: 0.28; 95% CI 0.09-0.9; p = 0.03).

CONCLUSION

Rectal cancer patients undergoing TNT prior to surgery have a higher chance of developing a complete pathologic response. Evaluation of this therapy should be continued and extended to larger numbers of patients to see if the differences we observed are real.

Prognostic Factors and Treatment of Recurrence after Local Excision of Rectal Cancer

PURPOSE

Indications for local excision in patients with rectal cancer remain controversial. We reviewed factors affecting survival rate and treatment effectiveness in cancer recurrence after local excision among patients with rectal cancer.

MATERIALS AND METHODS

A total of 831 patients was enrolled. Of these, 391 patients were diagnosed with primary rectal cancer and underwent local excision. A retrospective observational study was performed on patients who underwent full-thickness local excision for rectal cancer.

RESULTS

The median duration of follow-up was 61 months. The overall recurrence rate was 11.5%. The rate of local recurrence was 5.1%. Five-year overall survival rate among recurrent patients was 66.8%; the rate among patients who underwent salvage operation due to recurrence was 84.7%, compared with 44.2% among patients treated with non-operative management (p<0.001). Multivariate analysis of disease-free survival identified distance from the anal verge (p=0.038) and histologic grade (p=0.047) as factors predicting poor prognosis. Multivariate analysis of overall survival showed that age (p<0.001), serum carcinoembryonic antigen (CEA) levels (p=0.001), and histologic grade (p=0.013) also affected poor prognosis. In subgroup analysis of patients with recurrence, 25 patients underwent reoperation, while 20 patients did not. For 5-year overall survival rate, there was a significant difference between 84.7% of the reoperation group and 44.2% of the non-operation group (p<0.001).

CONCLUSION

The risk factors affecting overall survival rate after local excision were age 65 years or older, preoperative CEA level 5 or higher, and high histologic grade. In cases of recurrence after local excision of rectal cancer, salvage operation might improve overall survival.

Racial Disparities in the Management of Locoregional Colorectal Cancer

Racial disparities pervade nearly all aspects of management of locoregional colorectal cancer, including time to treatment, receipt of resection, adequacy of resection, postoperative complications, and receipt of neoadjuvant and adjuvant multimodality therapies. Disparate gaps in treatment translate into enduring effects on survivorship, recurrence, and mortality. Efforts to reduce these gaps in care must be undertaken on a multilevel basis and focus on modifiable factors that underlie racial disparity.

The efficacy and safety of different radiotherapy doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer

Background

This study aimed to evaluate efficacy and adverse effects of different radiotherapy (RT) doses in neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Methods

Fifty-nine patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy in hospital between January 2015 and May 2017 were enrolled in retrospective analysis. The patients were divided into the 56-Gy group and the 50-Gy group. The concurrent chemotherapy regimen was based on capecitabine. All patients received one cycle of oxaliplatin combined with capecitabine induction chemotherapy. All patients completed neoadjuvant chemoradiotherapy and received radical surgery.

Results

Of the patients in this study, 29 patients and 30 patients received a radiation dose of 56- and 50-Gy, respectively. All clinical characteristics were matched between the two groups. All patients received surgery 6 to 8 weeks after completing RT. The therapeutical effective rate in the 56-Gy group was 93.10% (27/29), compared with 66.67% in the 50-Gy group (20/30); the difference between the two groups was statistically significant (χ²=6.36, P=0.01). The pathological complete remission (pCR) rate in the 56-Gy group (37.93%, 11/29) was statistically significantly higher than that in the 50-Gy group (13.33%, 4/30) (χ²=4.71, P=0.030). The anal preservation rate in the 56-Gy group (65.5%, 19/29) was statistically significantly higher than that in the 50-Gy group (33.33%, 10/30) (χ²=6.11, P=0.01). The 56-Gy group had a local recurrence rate of 0% (0/29) and a distant metastasis rate of 10.34% (3/29), while the 50-Gy group had a local recurrence rate of 6.67% (2/30) and a distant metastasis rate of 16.67% (5/30); no significant difference existed between the two groups (χ²=2.00, 0.50, P=0.16, 0.48). The incidence of adverse reactions (gastrointestinal reactions, bone marrow suppression, and perianal skin reactions) in the 56-Gy group was not significantly different from that in the 50-Gy group (P>0.05).

Conclusions

Increasing the radiation dose can significantly improve the anal preservation and pCR rates of patients with locally advanced rectal cancer, thus improving their life quality. Moreover, it does not increase the rates of recurrence or adverse reactions. Our findings have certain clinical significance, but further prospective study is needed.

The Clinical Value of the Combined Detection of Enhanced CT, MRI, CEA, and CA199 in the Diagnosis of Rectal Cancer

Background

To explore the clinical value of enhanced computed tomography (enhanced CT), magnetic resonance imaging (MRI), carcinoembryonic antigen (CEA), and cancer antigen 199 (CA199) in the diagnosis of rectal cancer (RC).

Methods

A total of 156 patients with RC confirmed by postoperative pathology admitted to the Affiliated Yantai Yuhuangding Hospital of Qingdao University from March 2018 to November 2020 were included in the malignant group, and 52 patients with chronic proctitis in the benign control group. All patients underwent preoperative enhanced CT, MRI scans, and serum CEA and CA199 tests. The accuracy, sensitivity, and specificity of single and combined enhanced CT, MRI, CEA, and CA199 tests for the clinical staging of RC were calculated.

Results

The postoperative pathological diagnosis showed that 35 cases of 156 RC patients were at T1 stage, 29 cases were at T2 stage, 24 cases were at T3 stage, 11 cases were at T4 stage, 23 cases were at N0 stage, 21 cases were at N1 stage, 8 cases were at N2 stage, 3 cases were at M0 stage, and 2 cases were at M1 stage. The positive rate of MRI in the diagnosis of RC was higher than that of enhanced CT. Serum CEA and CA199 levels in the malignant group were significantly increased compared with the benign group. The sensitivity, specificity, and accuracy of the combined detection were significantly higher than those of the single detection.

Conclusion

Compared with enhanced CT, MRI has a higher detection rate of T and N stage in patients with RC. Combined enhanced CT, MRI, CEA, and CA199 can provide more accurate diagnosis and preoperative staging of RC patients.

The effect of demographic, clinical, and pathological data on quality of life in rectum cancer

PURPOSE

The aims of the current study are to describe the quality of life among patients with rectal cancer and to determine the clinical and demographic correlation that influences the quality of life of rectal cancer patients.

METHOD

In this study, 50 patients with rectal cancer treated in the Radiation Oncology Department of Kayseri City Education and Research Hospital were included. Ethics committee approval was received for the study. Data collection form was used to determine the demographic and clinicopathological characteristics of the patients. To assess the quality of life, the European Committee of Cancer Treatment and Organization Quality of Life Scale (EORTC QLQ-C30) question-answer scale was used. The data were collected by interviewing the patients face to face. Mann-Whitney U and Kruskal-Wallis tests were used to analyze the data. Spearman correlation analysis was performed to reveal the relationship between dependent variables.

RESULTS

As a result of this study, 52% of patients were 65 years and older and 54% were male patients. The most common surgery was low anterior resection and the most common type of pathology was adenocarcinoma. According to American Cancer Committee (AJCC) 7th edition 2009 staging, 80% stage 3 was the most common. In EORTC C30 Cancer Quality of Life Scale Functional Scale Subscale, the highest score is from the physical function and the lowest score is from the emotional function. In the symptom scale subscale, the most common symptom was nausea/vomiting. Performance status (ECOG) was found to be significantly associated with T stage, N stage, TNM stage, and symptom scores. There was a moderately significant positive correlation between symptom scales and global health status scales (ρ = 0.51; p < 0.001). There was a perfectly positive and significant relationship between symptom scales and functional scales (ρ = 0.83; p < 0.001).

CONCLUSIONS

As a result of this study we conducted, it was observed that rectal cancer patients decreased performance status and increased symptoms in the presence of advanced disease. Accordingly, it was found that the quality of life of the patient decreased.

Rectal operative bed: ?tumor? post-management changes … positron emission tomography/computed tomography (PET/CT) can answer

Background

Rectal cancer is a common malignancy that continues to have a highly variable outcome. Local pelvic recurrence following surgery is usually leading to incurable disease. Surgical resection with stage-appropriate combined-modality therapy is the mainstay in the treatment of rectal cancer. A difficulty has been reported in distinguishing the benign post-management findings from tumor recurrence. By adding the metabolic changes to the post-operative morphologic changes, combined positron emission tomography (PET) and computed tomography (CT) may offer clinically useful addition in operative bed evaluation.

Results

The study included 30 patients, 17 males (56.6%) and 13 females (43.3%). Suspicious operative bed findings included pre-sacral soft tissue density noted in 20 patients (66%), anastomotic site mural thickening in five patients (16.6%), and post-operative loco-regional nodes in five patients (16.6%). Moreover, pre-sacral soft tissue focal avid uptake was noted in 17 patients (17/20, 85%), and no uptake noted in three patients (3/20, 15%). Anastomotic site mural thickening was seen in five patients with positive uptake noted in three patients (3/5, 60%), and no uptake seen in two patients (2/5, 40%). Loco-regional nodes were seen in five patients with positive uptake in five patients. The most accurate SUV max cut-off value among studied cases was 3.5. Confirmation of PET/CT results was done by histopathological assessment in ten patients (33.3%) and by follow up after 6 months in 20 patients (66.6%) with recurrence noted in 15 patients (75%) and normal post-operative findings noted in five patients (25%).

Conclusion

PET/CT study is an effective tool for evaluation of suspicious colorectal oncologic operative bed findings noted in the routine CT studies. PET/CT fusion images affect the clinical management by guiding further procedures (surgery and radiation therapy).

MYL6B drives the capabilities of proliferation, invasion, and migration in rectal adenocarcinoma through the EMT process

Objective

This study was designed to explore the biological significance of myosin light chain 6B (MYL6B) in rectal adenocarcinoma.

Methods

Profiles on the Oncomine dataset, GEPIA website, and UALCAN-TCGA database were searched to assess the MYL6B expression level in rectal adenocarcinoma tissues and normal tissues. After MYL6B knockdown using siRNA strategy, cell counting kit-8 (CCK-8) and transwell assays were conducted to measure cell proliferation, migration and invasion, respectively. Flow cytometry analysis was conducted to assess cell apoptosis. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot were performed to detect the expression level of mRNAs and proteins.

Results

The data showed that overexpression of MYL6B was observed in rectal adenocarcinoma tissues and correlated with a poor prognosis of patients. Functional in vitro experiments revealed that MYL6B knockdown could inhibit proliferation, migration, and invasion of rectal adenocarcinoma cells, while promote cell apoptosis. Moreover, western blot analysis suggested that increased expression of E-cadherin and decreased expression of N-cadherin and Vimentin were induced by si-MYL6B.

Conclusion

In summary, this study elaborated on the promoting effect of MYL6B in rectal adenocarcinoma progression, thus providing novel insight for strategies of clinical diagnosis and drug application in the future clinical study.

A bibliometric analysis of 23,492 publications on rectal cancer by machine learning: basic medical research is needed

BACKGROUND AND AIMS

The aim of this study was to analyse the landscape of publications on rectal cancer (RC) over the past 25 years by machine learning and semantic analysis.

METHODS

Publications indexed in PubMed under the Medical Subject Headings (MeSH) term 'Rectal Neoplasms' from 1994 to 2018 were downloaded in September 2019. R and Python were used to extract publication date, MeSH terms and abstract from the metadata of each publication for bibliometric assessment. Latent Dirichlet allocation was applied to analyse the text from the articles' abstracts to identify more specific research topics. Louvain algorithm was used to establish a topic network resulting in identifying the relationship between the topics.

RESULTS

A total of 23,492 papers published were identified and analysed in this study. The changes of research focus were analysed by the changing of MeSH terms. Studied contents extracted from the publications were divided into five areas, including surgical intervention, radiotherapy and chemotherapy intervention, clinical case management, epidemiology and cancer risk as well as prognosis studies.

CONCLUSIONS

The number of publications indexed on RC has expanded rapidly over the past 25 years. Studies on RC have mainly focused on five areas. However, studies on basic research, postoperative quality of life and cost-effective research were relatively lacking. It is predicted that basic research, inflammation and some other research fields might become the potential hotspots in the future.

Robotic- vs laparoscopic-assisted proctectomy for locally advanced rectal cancer based on propensity score matching: Short-term outcomes at a colorectal center in China

BACKGROUND

Reports in the field of robotic surgery for rectal cancer are increasing year by year. However, most of these studies enroll patients at a relatively early stage and have small sample sizes. In fact, studies only on patients with locally advanced rectal cancer (LARC) and with relatively large sample sizes are lacking.

AIM

To investigate whether the short-term outcomes differed between robotic-assisted proctectomy (RAP) and laparoscopic-assisted proctectomy (LAP) for LARC.

METHODS

The clinicopathological data of patients with LARC who underwent robotic- or laparoscopic-assisted radical surgery between January 2015 and October 2019 were collected retrospectively. To reduce patient selection bias, we used the clinical baseline characteristics of the two groups of patients as covariates for propensity-score matching (PSM) analysis. Short-term outcomes were compared between the two groups.

RESULTS

The clinical features were well matched in the PSM cohort. Compared with the LAP group, the RAP group had less intraoperative blood loss, lower volume of pelvic cavity drainage, less time to remove the pelvic drainage tube and urinary catheter, longer distal resection margin and lower rates of conversion (P < 0.05). However, the time to recover bowel function, the harvested lymph nodes, the postoperative length of hospital stay, and the rate of unplanned readmission within 30 days postoperatively showed no difference between the two groups (P > 0.05). The rates of total complications and all individual complications were similar between the RAP and LAP groups (P > 0.05).

CONCLUSION

This retrospective study indicated that RAP is a safe and feasible method for LARC with better short-term outcomes than LAP, but we have to admit that the clinically significant of part of indicators are relatively small in the practical situation.

Risk factor analysis for inaccurate pre-operative MRI staging in rectal cancer

BACKGROUND

Various tumor characteristics might lead to inaccurate local MRI-defined stage of rectal cancer and the purpose of this study was to explore the clinicopathological factors that impact on the precision pre-treatment MRI-defined stage of rectal cancer.

METHODS

A retrospectively analysis was conducted in non-metastatic rectal cancer patients who received radical tumor resection without neoadjuvant treatment during 2007-2015 in the Sixth Affiliated Hospital of Sun Yat-sen University. Clinical T stage and N stage defined by pelvic enhanced MRI and pathological stage were compared and patients were subdivided into accurate-staging, over-staging and under-staging subgroups. Logistic regressions were used to explore risk factors for over-staging or under-staging.

RESULTS

Five hundred fifty-one cases of patients were collected. Among them, 109 cases (19.4%) of patients were over-T-staged and 50 cases (8.9%) were under-T-staged, while 78 cases (13.9%) were over-N-staged and 75 cases (13.3%) were under-N-staged. Logistic regression suggested that pre-operative bowel obstruction was risk factor for over-T-staging (OR = 3.120, 95%CI: 1.662-5.857, P < 0.001) as well as over-N-staging (OR = 3.494, 95%CI: 1.797-6.794, P < 0.001), while mucinous adenocarcinoma was a risk factor for under-N-staging (OR = 4.049, 95%CI: 1.876-8.772, P < 0.001). Patients with larger tumor size were at lower risk for over-T-staging (OR = 0.837, 95%CI: 0.717-0.976, P = 0.024) and higher risk for over-N-staging (OR = 1.434, 95%CI: 1.223-1.680, P < 0.001).

CONCLUSION

Bowel obstruction, mucinous adenocarcinoma and tumor size might have impact on the pre-operative MRI T staging or N staging of rectal cancer. Our results reminded clinicians to assess clinical stage individually in such rectal cancer patients.

Management of rectal cancer in Canada: an evidence-based comparison of clinical practice guidelines

Background

Rectal cancer requires a multidisciplinary and multimodality treatment approach. Clinical practice guidelines (CPGs) provide a framework for delivering consistent, evidence-based health care. We compared provincial/territorial CPGs across Canada to identify areas of variability and evaluate their quality.

Methods

We retrieved CPGs from Canadian organizations responsible for cancer care oversight and evaluated their quality and developmental methodology using the AGREE-II instrument. Recommendations for diagnostic and staging investigations, treatment by stage, and post-treatment surveillance of stage I–III rectal cancers were abstracted and compared.

Results

We identified 7 sets of CPGs for analysis, varying in content, presentation, quality, and year last updated. Differences were noted in locoregional staging: 4 recommended magnetic resonance imaging over endorectal ultrasonography, 2 recommended either modality, and 3 specified scenarios for one over the other. Recommendations also varied for use of staging computed tomography of the chest versus chest radiography and for surgical management and indications for transanal excision. Recommendations for neoadjuvant therapy in stage II/III disease also differed: 3 guidelines recommended long-course chemoradiation over short-course radiation therapy alone, while 3 others recommended short-course radiation in specific clinical scenarios. Adjuvant chemotherapy for stage II/III disease was uniformly recommended, with variable protocols. The use of proctosigmoidoscopy and interval/duration of endoscopic post-treatment surveillance varied among guidelines.

Conclusion

Canadian CPGs vary in their recommendations for staging, treatment, and surveillance of rectal cancer. Some of these differences reflect areas with limited definitive evidence. Consistent guidelines with uniform implementation across provinces/territories may lead to more equitable care to patients.

PET/MRI and PET/CT hybrid imaging of rectal cancer - description and initial observations from the RECTOPET (REctal Cancer trial on PET/MRI/CT) study

Purpose

The role of hybrid imaging using ¹⁸F-fluoro-2-deoxy-D-glucose positron-emission tomography (FDG-PET), computed tomography (CT) and magnetic resonance imaging (MRI) to improve preoperative evaluation of rectal cancer is largely unknown. To investigate this, the RECTOPET (REctal Cancer Trial on PET/MRI/CT) study has been launched with the aim to assess staging and restaging of primary rectal cancer. This report presents the study workflow and the initial experiences of the impact of PET/CT on staging and management of the first patients included in the RECTOPET study.

Methods

This prospective cohort study, initiated in September 2016, is actively recruiting patients from Region Västerbotten in Sweden. This pilot study includes patients recruited and followed up until December 2017. All patients had a biopsy-verified rectal adenocarcinoma and underwent a minimum of one preoperative FDG-PET/CT and FDG-PET/MRI examination. These patients were referred to the colorectal cancer multidisciplinary team meeting at Umeå University Hospital. All available data were evaluated when making management recommendations. The clinical course was noted and changes consequent to PET imaging were described; surgical specimens underwent dedicated MRI for anatomical matching between imaging and histopathology.

Results

Twenty-four patients have so far been included in the study. Four patients were deemed unresectable, while 19 patients underwent or were scheduled for surgery; one patient was enrolled in a watch-and-wait programme after restaging. Consequent to taking part in the study, two patients were upstaged to M1 disease: one patient was diagnosed with a solitary hepatic metastasis detected using PET/CT and underwent metastasectomy prior to rectal cancer surgery, while one patient with a small, but metabolically active, lung nodulus experienced no change of management. PET/MRI did not contribute to any recorded change in patient management.

Conclusions

The RECTOPET study investigating the role of PET/CT and PET/MRI for preoperative staging of primary rectal cancer patients will provide novel data that clarify the value of adding hybrid to conventional imaging, and the role of PET/CT versus PET/MRI.

Trial registration

NCT03846882.

Pathophysiological Role of Histamine H4 Receptor in Cancer: Therapeutic Implications

Cancer is a leading cause of death in both developed and developing countries. Although advances in cancer research lead to improved anti-neoplastic therapies, they continue to have unfavorable outcomes, including poor response and severe toxicity. Thus, the challenge for the new therapeutic approaches is to increase anti-tumor efficacy by targeting different molecules encompassed in the tumor and its microenvironment, as well as their specific interactions. The histamine H4 receptor (H4R) is the last discovered histamine receptor subtype and it modulates important immune functions in innate and in adaptive immune responses. Several ligands have been developed and some of them are being used in clinical trials for immune disorders with promising results. When searched in The Cancer Genome Atlas (TCGA) database, human H4R gene was found to be expressed in bladder cancer, kidney cancer, breast cancer, gastrointestinal cancers, lung cancer, endometrial cancer, and skin cancer. In the present work, we aimed to briefly summarize current knowledge in H4R's pharmacology and in the clinical use of H4R ligands before focusing on recent data reporting the expression of H4R and its pathophysiological role in cancer, representing a potential molecular target for cancer therapeutics. H4R gene and protein expression in different types of cancers compared with normal tissue as well as its relationship with patient prognosis in terms of survival will be described.

Organ Preservation Strategies After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

Standard use of neoadjuvant chemoradiotherapy, total mesorectal excision, and postoperative adjuvant chemotherapy in locally advanced rectal cancer has tremendously improved oncologic outcomes over the past several decades. However, these improvements come with costs of significant morbidity and poor quality of life. Along with developments in imaging techniques, clinical experience and evidence have identified a certain subgroup of patients that have exceptionally good clinical outcomes while preserving quality of life. Driven by patient demand and interest in preserving quality of life, numerous organ preservation treatment strategies for managing rectal cancer are rapidly evolving. Herein, the flow of research in organ preservation strategies and counter arguments are discussed.

Novelties in treatment of locally advanced rectal cancer

Treatment of locally advanced rectal cancer is evolving through surgical innovation and paradigm shifts in neoadjuvant treatment. Whereas local recurrence was a significant concern before the systematic implementation of neoadjuvant chemoradiation therapy and surgery according to total mesorectal excision principles, distant relapse remains a major drawback. Hence, efforts in recent years have focused on delivering preoperative chemotherapy regimens to overcome compliance issues with adjuvant administration. In parallel, new surgical techniques, including transanal video-assisted total mesorectal excision and robot-assisted surgery, emerged to face the challenge to navigate in the deep and narrow spaces of the pelvis. Furthermore, patients experiencing a complete response after neoadjuvant treatment might even escape surgery within a close surveillance strategy. This novel "watch and wait" concept has gained interest to improve quality of life in highly selected patients. This review summarizes recent evidence and controversies and provides an overview on timely and innovative aspects in the treatment of locally advanced rectal cancer.

Clinical and molecular diagnosis of pathologic complete response in rectal cancer: an update

INTRODUCTION

The standard of care for locally advanced rectal cancer includes neoadjuvant chemoradiation with subsequent total mesorectal excision. This approach has shown various degrees of response to neoadjuvant chemoradiation (ranging from complete response to further tumor growth), which have substantial prognostic and therapeutic implications. A total regression of the tumor is a predictor of superior oncologic outcomes compared with partial responders and non-responders. Further, this concept has opened the possibility of nonoperative strategies for complete responders and explains the widespread research interest in finding clinical, radiographic, pathologic, and biochemical parameters that allow for identification of these patients. Areas covered: The present review evaluates the most recent efforts in the literature to identify predictors of patients likely to achieve a complete response following neoadjuvant treatment for the management of rectal cancer. This includes clinical predictors of pathologic complete response such as tumor location, size, and stage, molecular predictors such as tumor biology and microRNA, serum biomarkers such as carcinoembryogenic antigen and nomograms. Expert commentary: There has been significant progress in our ability to predict pathological complete response. However, more high-quality research is still needed to use this concept to confidently dictate clinical management.

Progress in neoadjuvant drug therapy of rectal cancer

Rectal cancer is one of the most common malignant tumors of the digestive system. A portion of patients have had locally advanced disease at the time of diagnosis and have lost the chance of radical surgery. How to increase the R0 resection rate has always been a major difficulty in clinical practice. Some studies have shown that for some patients, neoadjuvant drug therapy can achieve reduction of clinical stage, increase the R0 resection rate and anus-preserving rate, reduce the local recurrence and micro-metastasis, and prolong the survival time of patients. This article mainly reviews the progress in neoadjuvant drug therapy of rectal cancer.

Critical and Challenging Issues in the Surgical Management of Low-Lying Rectal Cancer

Despite innovative advancements, the management of distally located rectal cancer (RC) remains a formidable endeavor. The critical location of the tumor predisposes it to a circumferential resection margin that tends to involve the sphincters and surrounding organs, pelvic lymph node metastasis, and anastomotic complications. In this regard, colorectal surgeons should be aware of issues beyond the performance of total mesorectal excision (TME). For decades, abdominoperineal resection had been the standard of care for low-lying RC; however, its association with high rates of tumor recurrence, tumor perforation, and poorer survival has stimulated the development of novel surgical techniques and modifications, such as extralevator abdominoperineal excision. Similarly, difficult dissections and poor visualization, especially in obese patients with low-lying tumors, have led to the development of transanal TME or the "bottom-to-up" approach. Additionally, while neoadjuvant chemoradiotherapy has allowed for the execution of more sphincter-saving procedures without oncologic compromise, functional outcomes remain an issue. Nevertheless, neoadjuvant treatment can lead to significant tumor regression and complete pathological response, permitting the utilization of organ-preserving strategies. At present, an East and West dualism pervades the management of lateral lymph node metastasis, thereby calling for a more global and united approach. Moreover, with the increasing importance of quality of life, a tailored, individualized treatment approach is of utmost importance when taking into account oncologic and anticipated functional outcomes.

Neoadjuvant therapy and subsequent treatment in rectal cancer: balance between oncological and functional outcomes

Current practice of neoadjuvant therapy and total mesorectal excision (TME) in rectal cancer bears the weakness in systemic disease control and long-term functional outcomes. With increasing concerns of the balance between cure and quality of life, new strategies are developed to better oncological outcomes at least cost of function damage. Attractive options to adjust neoadjuvant modality include escalation of radiotherapy, intensification of chemotherapy, and chemoradiotherapy with consolidation or full-course chemotherapy. Subsequently, organ-preserving strategies have gained the popularity. Surgical or nonsurgical approaches that spare the rectum are used as possible alternatives for radical surgery, though high-quality TME remains the last resort to offer reliable local disease control. This review discusses new strategies of neoadjuvant therapy and subsequent management, with a specific focus on the balance between oncological and functional outcomes.