Shifting concepts in rectal cancer management: a review of contemporary primary rectal cancer treatment strategies

Development of orthotopic mouse models for mid-low rectal cancer

Mid-low rectal cancer is one of the most common types of rectal cancer and has a poor prognosis. Surgery and chemoradiotherapy are the main treatments for early and advanced rectal cancer with an overall 5-year relative survival rate of only 56.9%. Development of novel antitumor agents is needed. Animal models of disease are indispensable for drug development. The most commonly used animal models of rectal cancer are established by inducing tumors by the subcutaneous transplantation, cecum or peritoneal injection, but not injection in the rectum. Their tumor microenvironment differs from that of rectal tumors in situ, which is hard to precisely simulate the occurrence and development process and drug response of human rectal cancer. In this study, we established orthotopic mouse models of mid-low rectal cancer with primary tumors originating from the rectum, including two models that could simulate the early and advanced stages of the disease, respectively. In the first model, the local primary tumor was restricted to the rectal area of the anal verge by rectal submucosal injection, its growth could be monitored with IVIS live imaging and magnetic resonance imaging. Histological analysis confirmed that the tumor originated from the submucosal layer and then invaded the muscular layer without metastatic tumors. This model may be useful for evaluating drugs for early mid-low rectal cancer in the future. The second model featuring a rectal primary tumor accompanied with abdominal metastases was established via rectal serosal injection. In this model, a large tumor formed at the rectal injection site and then metastasized to the abdominal cavity, reproducing the process from occurrence to metastasis of mid-low rectal cancer, and may be a good tool for the evaluation of drugs for advanced-stage disease. The injection methods used in these models do not require the aid of special colonoscopes, are simple and easy to operate, and have high tumor tumorigenicity and reproducibility. These results suggest that our staged modeling can provide targeted choices for preclinical drug research of mid-low rectal cancer at different stages.

Short-term surgical outcomes of rectal adenocarcinoma surgical treatment in Latin America: a multicenter, retrospective assessment in 49 centers from 12 countries

INTRODUCTION

Rectal cancer is a prevalent disease that requires multidisciplinary management. Results of treatment of patients suffering from this malignancy in Latin America have been scarcely reported before.

METHODS

A retrospective, multicenter study was conducted to report preoperative and operative characteristics of patients intervened for rectal cancer in centers from Latin America during 2015-2022, and the short-term results of treatment were analyzed. The study was open to any center receiving rectal cancer patients, irrespective of volume. The main study outcome was 30-day postoperative complications including any deviation from the normal postoperative course (Clavien Dindo I to V).

RESULTS

A total of 2044 patients from 49 centers in 12 Latin American countries were included, with a mean age of 63 years. Twenty-five percent of patients were operated in low-volume centers. Twenty-nine percent of patients had a tumor located in the low rectum, and only 53% of patients had preoperative MRI for local staging. A total of 1052 patients (52%) received neoadjuvant therapy before surgery. Eighty-six percent of patients were operated by a specialized colorectal surgeon, and 31% of patients were intervened using a conventional approach. A total of 29.9% of patients presented a postoperative complication. The anastomotic leak rate was 8.9%. Fifty-eight percent of pathology reports had less than 12 lymph nodes harvested, and 22.9% of reports did not include mesorectal quality. In the multivariate analysis, neoadjuvant therapy (OR: 1.44, p-value: 0.023), urgent procedures (OR: 3.73, p-value: 0.049), intraoperative complications (OR: 2.21, p-value: 0.046), advanced tumors (OR: 1.39, p-value: 0.036), and prolonged surgery (OR: 1.74, p-value: 0.004) were found to be independently related to suffering postoperative complications.

CONCLUSIONS

This study includes information about the approach and results of rectal cancer management in Latin America at a large scale. In the future, this information can be used as a bridge to identify areas of improvement among rectal cancer patients' treatment in the region.

Comparative analysis of the safety and effectiveness of robotic natural orifice specimen extraction versus laparoscopic surgery for colorectal tumors through systematic review and meta-analysis

The purpose of this study and meta-analysis was to evaluate the perioperative and oncologic results of robotic NOSE versus laparoscopic surgery for colorectal tumors. We plan to perform an extensive electronic search on PubMed, CNKI, Embase, and the Cochrane Library to find research articles published from the beginning of the databases until July 2024 that examine the comparison between robotic natural orifice specimen extraction and laparoscopic surgery in patients with colorectal cancer. Both English and Chinese literature will be included. Literature screening will strictly follow predetermined criteria for inclusion and exclusion, specifically targeting randomized controlled trials and cohort studies. The evaluation of quality will be conducted with the Newcastle-Ottawa Scale (NOS). Review Manager 5.4.1 will be utilized to perform a meta-analysis of data gathered from the studies that are included. The ultimate evaluation included seven past cohort studies with a total of 1117 participants (545 who had robotic NOSE and 572 who had laparoscopic surgery). Patients who had robotic NOSE experienced notable enhancements in LOHS, time to first flatus, time to start the liquid diet, EBL, and postoperative ileus when compared to patients undergoing laparoscopic colorectal surgery. There were no notable discrepancies noted in terms of surgical duration, total complications, lymph node collection, and anastomotic leakage between the two methods. In conclusion, the use of robotic technology for extracting specimens through natural body openings in colorectal surgery is considered to be safe and achievable. It offers notable advantages over laparoscopic surgery, including reduced hospital stay, earlier time to first flatus and liquid intake, decreased EBL, and lower incidence of postoperative ileus.

Comparative analysis of safety and effectiveness between natural orifice specimen extraction and conventional transabdominal specimen extraction in robot-assisted colorectal cancer resection through systematic review and meta-analysis

The goal of this systematic review and meta-analysis is to evaluate the perioperative and oncologic results of natural orifice specimen extraction (NOSE) compared to conventional transabdominal specimen extraction (TASE) in robotic-assisted surgery for colorectal cancer. A comprehensive electronic search will be performed on PubMed, Embase, and the Cochrane Library to find research articles published from the beginning of the databases to July 2024 that focus on patients who have undergone robotic-assisted surgery for colorectal cancer. Specifically, this review will compare NOSE with conventional TASE. Only studies published in English will be considered. Literature screening will adhere closely to predetermined criteria for inclusion and exclusion, specifically targeting randomized controlled trials and cohort studies. The evaluation of quality will involve the use of the Newcastle-Ottawa Scale (NOS). Meta-analysis of the included studies' data will be performed using Review Manager 5.4.1. In the final analysis, 9 retrospective cohort studies comprising 1571 patients were included. Out of these, 732 patients opted for NOSE, while 839 patients chose conventional TASE in robotic colorectal surgery. Patients who received TASE experienced enhancements in hospital stay duration, time until first gas passage, wound infection rates, and time until the first intake of a liquid diet. Nevertheless, there were no notable distinctions noted between the two methods regarding surgery duration, projected blood loss, intestinal blockage, or frequency of anastomotic leakage. In patients undergoing robotic-assisted colorectal surgery, the safety and feasibility of NOSE are demonstrated. Compared to traditional TASE, it provides clear benefits including shorter hospital stays, earlier first flatus, quicker initiation of a liquid diet, and lower risk of wound infection.

Development of Polymethine Dyes for NIR-II Fluorescence Imaging and Therapy

Fluorescence imaging in the second near-infrared window (NIR-II) is burgeoning because of its higher imaging fidelity in monitoring physiological and pathological processes than clinical visible/the second near-infrared window fluorescence imaging. Notably, the imaging fidelity is heavily dependent on fluorescence agents. So far, indocyanine green, one of the polymethine dyes, with good biocompatibility and renal clearance is the only dye approved by the Food and Drug Administration, but it shows relatively low NIR-II brightness. Importantly, tremendous efforts are devoted to synthesizing polymethine dyes for imaging preclinically and clinically. They have shown feasibility in the customization of structure and properties to fulfill various needs in imaging and therapy. Herein, a timely update on NIR-II polymethine dyes, with a special focus on molecular design strategies for fluorescent, photoacoustic, and multimodal imaging, is offered. Furthermore, the progress of polymethine dyes in sensing pathological biomarkers and even reporting drug release is illustrated. Moreover, the NIR-II fluorescence imaging-guided therapies with polymethine dyes are summarized regarding chemo-, photothermal, photodynamic, and multimodal approaches. In addition, artificial intelligence is pointed out for its potential to expedite dye development. This comprehensive review will inspire interest among a wide audience and offer a handbook for people with an interest in NIR-II polymethine dyes.

"WATCH AND WAIT" STRATEGY IN RECTAL CANCER PATIENTS WITH A COMPLETE CLINICAL RESPONSE AFTER NEOADJUVANT CHEMORADIATION THERAPY: A SINGLE-CENTER EXPERIENCE

BACKGROUND

The non-operative management of rectal adenocarcinoma (RA) after neoadjuvant chemoradiation therapy (nCRT) has gained increasing attention. The "Watch and Wait" ("W&W") strategy allows one to avoid surgery-related reduction in the quality of life due to permanent pelvic organ dysfunction or irreversible stoma. Still, the oncological safety of this strategy is under evaluation.

AIM

To share a single-center experience of the "W&W" strategy.

MATERIALS AND METHODS

The retrospective analysis of 125 patients who received nCRT in 2016-2021 was performed. Patients who met the European Society for Medical Oncology (ESMO, 2017) criteria of clinical complete response (cCR) and received non-operative management were analyzed.

RESULTS

Ten patients (8%) were re-staged after nCRT as cCR and followed the "W&W" strategy. Patients' characteristics: 7 female, 3 male; mean age 67.3 years. Tumor characteristics: pre-treatment N+ was present in 7 cases; G1 adenocarcinoma in a majority of cases; mean tumor distance from the anal verge - 5.85 cm; mean tumor circumference - 71%; mean tumor length - 3.87 cm. The mean follow-up time was 30 months. Local regrowth or/and distant metastases developed in 3 cases. The 2-year disease-free survival was 70%.

CONCLUSIONS

Most of the patients following the "W&W" strategy have benefited. However, to reduce the number of relapses, it is necessary to perform a more careful selection of patients.

Comparison of the safety and efficacy of robotic natural orifice specimen extraction surgery and conventional robotic colorectal cancer resection: a propensity score matching study

Robotic resection is widely used to treat colorectal cancer. Although the novel natural orifice specimen extraction surgery (NOSES) results in less trauma, its safety and effectiveness are relatively unknown. In the present study, we used propensity score matching to compare the effectiveness and safety of NOSES and robotic resection for treating colorectal cancer. Present retrospective cohort study included patients who underwent robotic colon and rectal cancer surgery between January 2016 and December 2019 at the Department of Gastrointestinal Surgery, the Second Xiangya Hospital of Central South University. The intraoperative time, intraoperative bleeding, postoperative recovery, postoperative complications, and survival status of the conventional robotic colorectal cancer resection (CRR) (78 patients) and NOSES (89 patients) groups were compared. These results showed that no significant differences were observed between the two groups in terms of early postoperative complications, operation time, and the number of lymph nodes dissected. Compared with the CRR group, NOSES group had shorter postoperative exhaust time [3.06 (0.76) vs. 3.53 (0.92)], earlier eating time [4.12 (1.08) vs. 4.86 (1.73)], lesser intraoperative bleeding [51.23 (26.74) vs. 67.82 (43.44)], lesser degree of pain [80.8% vs. 55.1%], and shorter length of hospital stay [8.73 (2.02) vs. 9.50 (3.45)]. All these parameters were statistically significant (P < 0.05). However, no significant differences were observed in the 3-year overall survival rate and disease-free survival rate between both groups (P > 0.05). Collectively, robotic NOSES is a safe and effective approach for treating rectal and sigmoid colon cancers, could decrease intraoperative bleeding and postoperative complications, and accelerate the speed of intestinal function recovery.

Development and validation of a competitive risk model in patients with rectal cancer: based on SEER database

BACKGROUND

Rectal cancer is one of the most common malignancies. To predict the specific mortality risk of rectal cancer patients, we constructed a predictive nomogram based on a competing risk model.

METHODS

The information on rectal cancer patients was extracted from the SEER database. Traditional survival analysis and specific death analysis were performed separately on the data.

RESULTS

The present study included 23,680 patients, with 16,580 in the training set and 7100 in the validation set. The specific mortality rate calculated by the competing risk model was lower than that of the traditional survival analysis. Age, Marriage, Race, Sex, ICD-O-3Hist/Behav, Grade, AJCC stage, T stage, N stage, Surgery, Examined LN, RX SUMM-SURG OTH, Chemotherapy, CEA, Deposits, Regional nodes positive, Brain, Bone, Liver, Lung, Tumor size, and Malignant were independent influencing factors of specific death. The overall C statistic of the model in the training set was 0.821 (Se = 0.001), and the areas under the ROC curve for cancer-specific survival (CSS) at 1, 3, and 5 years were 0.842, 0.830, and 0.812, respectively. The overall C statistic of the model in the validation set was 0.829 (Se = 0.002), and the areas under the ROC curve for CSS at 1, 3, and 5 years were 0.851, 0.836, and 0.813, respectively.

CONCLUSIONS

The predictive nomogram based on a competing risk model for time-specific mortality in patients with rectal cancer has very desirable accuracy. Thus, the application of the predictive nomogram in clinical practice can help physicians make clinical decisions and follow-up strategies.

A multi-centre randomized controlled trial investigating Consolidation Chemotherapy with and without oxaliplatin in distal rectal cancer and Watch & Wait

BACKGROUND

Neoadjuvant chemoradiation(nCRT) has been considered the preferred initial treatment strategy for distal rectal cancer. Advantages of this approach include improved local control after radical surgery but also the opportunity for organ preserving strategies (Watch and Wait-WW). Consolidation chemotherapy(cCT) regimens using fluoropyrimidine-based with or without oxalipatin following nCRT have demonstrated to increase complete response and organ preservation rates among these patients. However, the benefit of adding oxaliplatin to cCT compared to fluoropirimidine alone regimens in terms of primary tumor response remains unclear. Since oxalipatin-treatment may be associated with considerable toxicity, it becomes imperative to understand the benefit of its incorporation into standard cCT regimens in terms of primary tumor response. The aim of the present trial is to compare the outcomes of 2 different cCT regimens following nCRT (fluoropyrimidine-alone versus fluoropyrimidine + oxaliplatin) for patients with distal rectal cancer.

METHODS

In this multi-centre study, patients with magnetic resonance-defined distal rectal tumors will be randomized on a 1:1 ratio to receive long-course chemoradiation (54 Gy) followed by cCT with fluoropyrimidine alone versus fluoropyrimidine + oxaliplatin. Magnetic resonance(MR) will be analyzed centrally prior to patient inclusion and randomization. mrT2-3N0-1 tumor located no more than 1 cm above the anorectal ring determined by sagittal views on MR will be eligible for the study. Tumor response will be assessed after 12 weeks from radiotherapy(RT) completion. Patients with clinical complete response (clinical, endoscopic and radiological) may be enrolled in an organ-preservation program(WW). The primary endpoint of this trial is decision to organ-preservation surveillance (WW) at 18 weeks from RT completion. Secondary endpoints are 3-year surgery-free survival, TME-free survival, distant metastases-free survival, local regrowth-free survival and colostomy-free survival.

DISCUSSION

Long-course nCRT with cCT is associated with improved complete response rates and may be a very attractive alternative to increase the chances for organ-preservation strategies. Fluoropyrimidine-based cCT with or without oxaliplatin has never been investigated in the setting of a randomized trial to compare clinical response rates and the possibility of organ-preservation. The outcomes of this study may significantly impact clinical practice of patients with distal rectal cancer interested in organ-preservation.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov NCT05000697; registered on August 11^th, 2021.

Current Surgical Methods in Local Rectal Excision

Background

The treatment of rectal cancer has evolved with the advancement of surgical techniques. Less invasive approaches are becoming more accepted as the primary treatment method.

Summary

Such methods as transanal excision, transanal endoscopic microsurgery, and transanal minimally invasive surgery can reduce morbidity and mortality rates. However, not all patients are suitable candidates for these procedures, and proper diagnostics are necessary to establish indications. Compared to total mesorectal excision, transanal excision techniques have been shown to have fewer complications and comorbidities while still being able to remove cancerous tissue entirely. Transanal excision is the simplest method, where the operator removes visible rectal lesions. The basic principle of transanal endoscopic microsurgery is to dilate the rectum mechanically and by air insufflation and then use special surgical instruments to remove suspicious lesions under the vision of a telescope. Transanal minimally invasive surgery combines transanal endoscopic microsurgery and single-incision laparoscopic surgery, making the hard-to-reach proximal rectum accessible to classic laparoscopic instruments.

Key Message

Local excision techniques, when used as a monotherapy for treating patients with rectal cancer, have established themselves as a curative and less radical treatment for strictly selected patients with early rectal carcinoma, leading to improved quality of life. When combined with other modalities such as neoadjuvant chemoradiotherapy, total neoadjuvant therapy, and immunotherapy, transanal surgery can be offered to patients with locally advanced rectal cancer as part of the organ preservation strategy. This review will discuss the patient selection and technical aspects of transanal surgery, showcasing its current role in treating rectal carcinoma.

Evaluation and Predictive Factors of Complete Response in Rectal Cancer after Neoadjuvant Chemoradiation Therapy

The response to neoadjuvant chemoradiation therapy is an important prognostic factor for locally advanced rectal cancer. Although the majority of the patients after neoadjuvant therapy are referred to following surgery, the clinical data show that complete clinical or pathological response is found in a significant proportion of the patients. Diagnostic accuracy of confirming the complete response has a crucial role in further management of a rectal cancer patient. As the rate of clinical complete response, unfortunately, is not always consistent with pathological complete response, accurate diagnostic parameters and predictive markers of tumor response may help to guide more personalized treatment strategies and identify potential candidates for nonoperative management more safely. The management of complete response demands interdisciplinary collaboration including oncologists, radiotherapists, radiologists, pathologists, endoscopists and surgeons, because the absence of a multidisciplinary approach may compromise the oncological outcome. Prediction and improvement of rectal cancer response to neoadjuvant therapy is still an active and challenging field of further research. This literature review is summarizing the main, currently known clinical information about the complete response that could be useful in case if encountering such condition in rectal cancer patients after neoadjuvant chemoradiation therapy, using as a source PubMed publications from 2010–2021 matching the search terms “rectal cancer”, “neoadjuvant therapy” and “response”.

Clinical outcomes and prognostic factors of robotic assisted rectal cancer resection alone versus robotic rectal cancer resection with natural orifice extraction: a matched analysis

Robotic rectal cancer resection with natural orifice extraction is a recently developed minimally invasive surgery used in the treatment of patients with rectal cancer. However, its safety and feasibility remain undiscussed and controversial. This study reported the clinical outcomes and prognostic factors pertaining to traditional robotic assisted rectal cancer resection alone against that of robotic rectal cancer resection with natural orifice extraction to provide a discussion on this issue. 49 patients who underwent robotic rectal cancer resection with natural orifice extraction and 49 matched patients who underwent conventional robotic assisted rectal cancer resection were systematically analyzed in this study. Regarding the baseline characteristics, after matching, no significant differences were observed between the natural orifice specimen extraction (NOSE) group and the robotic assisted rectal cancer resection (RARC) group. Patients in the NOSE group had a reduced visual analog scale (p < 0.001), passed flatus more quickly (p = 0.002) and suffered less surgical stress than those in the RARC group. Moreover, 4 complications were observed in the NOSE group and 7 complications in the RARC group with no significant difference (p = 0.337) in terms of complications. The two groups had a similar survival outcomes, where the 3-year overall survival (p = 0.738) and 3-year progression-free survival (p = 0.986) were all comparable between the two groups. Histological differentiation and T stage could be regarded as independent prognostic factors for 3-year overall survival and 3-year progression-free survival. Robotic rectal cancer resection with natural orifice extraction is a safe and feasible minimally invasive surgery for patients suffering from rectal cancer as it encompasses considerable several advantages. Histological differentiation and T stage may serve as independent prognostic factors for 3-year overall survival and 3-year progression-free survival.

Colonic transit in patients after anterior resection: prospective, comparative study using single-photon emission CT/CT scintigraphy

BACKGROUND

Bowel dysfunction after anterior resection is well documented, but its pathophysiology remains poorly understood. No study has assessed whether postoperative variation in colonic transit contributes to symptoms. This study measured colonic transit using planar scintigraphy and single-photon emission CT (SPECT)/CT in patients after anterior resection, stratified according to postoperative bowel function.

METHODS

Symptoms were assessed using the low anterior resection syndrome (LARS) score. Following gallium-67 ingestion, scintigraphy was performed at predefined time points. Nine regions of interest were defined, and geometric centre (GC), percentage isotope retained, GC velocity index and colonic half-clearance time (T_½ ) determined. Transit parameters were compared between subgroups based on LARS score using receiver operating characteristic (ROC) curve analyses.

RESULTS

Fifty patients (37 men; median age 72·6 (range 44·4-87·7) years) underwent planar and SPECT scintigraphy. Overall, 17 patients had major and nine had minor LARS; 24 did not have LARS. There were significant differences in transit profiles between patients with major LARs and those without LARS: GCs were greater (median 5·94 (range 2·35-7·72) versus 4·30 (2·12-6·47) at 32 h; P = 0·015); the percentage retained isotope was lower (median 53·8 (range 6·5-100) versus 89·9 (38·4-100) per cent at 32 h; P = 0·002); GC velocity indices were greater (median 1·70 (range 1·18-1·92) versus 1·45 (0·98-1·80); P = 0·013); and T_½ was shorter (median 38·3 (17·0-65·0) versus 57·0 (32·1-160·0) h; P = 0·003). Percentage tracer retained at 32 h best discriminated major LARS from no LARS (area under curve (AUC) 0·828).

CONCLUSION

Patients with major LARS had accelerated colonic transit compared with those without LARS, which may help explain postoperative bowel dysfunction in this group. The percentage tracer retained at 32 h had the greatest AUC value in discriminating such patients.

Controversies in Rectal Cancer Treatment and Management

Incorporation of new treatment modalities has significantly increased the complexity of the treatment and management of rectal cancer, including perioperative therapy for local advanced disease and organ preservation for those with response to the preoperative treatment. This review may help practitioners better understand the rationale and selection.

Accuracy of magnetic resonance imaging in predicting dentate line invasion in low rectal cancer

PURPOSE

To retrospectively assess the accuracy of magnetic resonance imaging (MRI) in predicting dentate line invasion in low rectal cancer.

MATERIALS AND METHODS

Eighty-one patients with primary rectal cancer were assessed by dynamic contrast-enhanced MRI. The location of the dentate line was assessed on MRI in 27 patients with upper-mid rectal cancer. Two observers independently evaluated the distance between the distal tumor edge and the MRI-defined dentate line in 54 patients with low rectal cancer, and the imaging and histological findings were compared.

RESULTS

The MRI-defined dentate line was 24.0 ± 3.8 mm above the anal verge in patients with upper-mid rectal cancer. The dentate line invasion status agreed with the histological findings in 49/54 (91%) patients (κ = 0.72 [95% CI 0.50-0.95]) for observer 1, and in 51/54 (94%) patients (κ = 0.83 [0.65-1.00]) for observer 2 in patients with low rectal cancer. Interobserver agreement was good (κ = 0.83 [0.65-1.00]). The MRI-derived distance between the distal tumor edge and the dentate line had significant correlation with the histological distance (r = 0.86 for reader 1 and 0.75 for observer 2).

CONCLUSION

MRI demonstrates high accuracy in predicting dentate line invasion in low rectal cancer.

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.

The Effects of Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer-The Impact in Intratumoral Heterogeneity

Purpose: Intratumoral genetic heterogeneity (ITGH) is a common feature of solid tumors. However, little is known about the effect of neoadjuvant chemoradiation (nCRT) in ITGH of rectal tumors that exhibit poor response to nCRT. Here, we examined the impact of nCRT in the mutational profile and ITGH of rectal tumors and its adjacent irradiated normal mucosa in the setting of incomplete response to nCRT.

Methods and Materials: To evaluate ITGH in rectal tumors, we analyzed whole-exome sequencing (WES) data from 79 tumors obtained from The Cancer Genome Atlas (TCGA). We also compared matched peripheral blood cells, irradiated normal rectal mucosa and pre and post-treatment tumor samples (PRE-T and POS-T) from one individual to examine the iatrogenic effects of nCRT. Finally, we performed WES of 7 PRE-T/POST-T matched samples to examine how nCRT affects ITGH. ITGH was assessed by quantifying subclonal mutations within individual tumors using the Mutant-Allele Tumor Heterogeneity score (MATH score).

Results: Rectal tumors exhibit remarkable ITGH that is ultimately associated with disease stage (MATH score stage I/II 35.54 vs. stage III/IV 44.39, p = 0.047) and lymph node metastasis (MATH score N0 35.87 vs. N+ 45.79, p = 0.026). We also showed that nCRT does not seem to introduce detectable somatic mutations in the irradiated mucosa. Comparison of PRE-T and POST-T matched samples revealed a significant increase in ITGH in 5 out 7 patients and MATH scores were significantly higher after nCRT (median 41.7 vs. 28.8, p = 0.04). Finally, we were able to identify a subset of “enriched mutations” with significant changes in MAFs between PRE-T and POST-T samples. These “enriched mutations” were significantly more frequent in POST-T compared to PRE-T samples (92.9% vs. 7.1% p < 0.00001) and include mutations in genes associated with genetic instability and drug resistance in colorectal cancer, indicating the expansion of tumor cell subpopulations more prone to resist to nCRT.

Conclusions: nCRT increases ITGH and may result in the expansion of resistant tumor cell populations in residual tumors. The risk of introducing relevant somatic mutations in the adjacent mucosa is minimal but non-responsive tumors may have potentially worse biological behavior when compared to their untreated counterparts. This was an exploratory study, and due to the limited number of samples analyzed, our results need to be validated in larger cohorts.

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.

A Systematic Review and Bayesian Network Meta-Analysis: Short-Term and Long-Term Outcomes of Three Surgery Procedures Following Neoadjuvant Chemoradiotherapy for Rectal Cancer

Aim: Our aim was to perform a Bayesian network meta-analysis of short-term and long-term outcomes of open surgery (OS), laparoscopic surgery (LS), and robotic surgery (RS) after neoadjuvant chemoradiotherapy (nCRT) for rectal cancer. Methods: We searched randomized controlled trials (RCTs) and non-RCTs published up to October 2018 from PubMed, Embase, Cochrane Library, and Web of Science. We selected studies referencing the comparison between at least two of OS, LS, and RS. Short-term and long-term outcomes of different surgery procedures were evaluated. Mean differences or odds ratios and their 95% credible interval were pooled with Bayesian modeling. Results: In the network meta-analysis, 15 studies were identified through database searching and other sources that included three RCTs and nine non-RCTs enrolling 2360 patients. As for long-term outcomes, we did not find any significant difference among these surgery procedures after nCRT for rectal cancer in this network meta-analysis. As for short-term outcomes, no significant outcomes were obtained except for operative time, blood loss, length of incision, and time to pass first flatus. Our meta-analysis illustrated that RS had the longest operative time. However, LS had a significantly shorter operative time than RS, shorter incision than OS, shorter time to pass first flatus than OS, and less blood loss than OS. Conclusions: RS was regarded as the inferior surgery procedure after nCRT for rectal cancer. Meanwhile, LS might possibly be the most safe and feasible surgery procedure after nCRT for rectal cancer.

Treatment of Rectal Cancer in Older Adults

PURPOSE OF REVIEW

Rectal cancer is predominantly a disease of older adults but current guidelines do not incorporate the associated specific challenges leading to wide variation in the delivery of cancer care to this subset of population. Here, we will review the current data available regarding the management of rectal cancer in older adults.

RECENT FINDINGS

The greatest challenge arises in the management of stage II/III disease as it involves tri-modality treatment that can be harder to tolerate by frail older patients. Response to neoadjuvant treatment is being used as a new marker to tailor further therapy and possibly avoid surgery. Oxaliplatin can be omitted from the adjuvant treatment without compromising outcomes. Physicians should perform geriatric assessment utilizing many validated tools available to help predict treatment tolerability and outcomes in older adults that can help personalize subsequent management. Most older adults can undergo standard therapy for stages I, II, or III rectal cancer with curative intent. Increasing evidence suggests that patients with a clinical complete response to neoadjuvant treatment may be observed closely with the possibility of avoiding surgery. Studies are evaluating alternate systemic treatments for advanced metastatic disease with the hope of maintaining quality of life without compromising cancer outcomes.

Late assessment of quality of life in patients with rectal carcinoma: comparison between sphincter preservation and definitive colostomy

PURPOSE

Patients with cancer of the lower and middle rectum who are candidates for curative surgery often have negative opinions on definitive colostomy. The purpose of this study is to compare the quality of life (QoL) of patients who undergo standard treatment for rectal cancer with sphincter preservation or definitive colostomy.

METHODS

A total of 125 patients with adenocarcinoma of the lower or middle rectum who underwent radical surgery with curative intent with a follow-up ≥ 1 year were recruited: 83 patients (group 1) were subjected to low anterior resection and low colorectal or coloanal anastomosis-thus preserving their sphincter-and 42 (group 2) were treated with abdominoperineal resection, followed by terminal definitive colostomy. QoL was assessed with the EORTC QLQ-C30 and QLQ-CR29 questionnaires.

RESULTS

Health and global quality of life were similar between groups; however, patients who underwent definitive colostomy had higher scores on the emotional (p value = 0.016) and cognitive function scales (p value = 0.017). Patients with sphincter preservation presented with more symptoms that were related to stool frequency (p value < 0.001), intestinal constipation (p value = 0.005), fecal incontinence (p value = 0.001), buttock pain (p value = 0.023), and nausea and vomiting (p value = 0.036), whereas patients with permanent colostomy had higher scores for dysuria (p value = 0.033).

CONCLUSION

Although global QoL scores did not differ between groups, patients who underwent definitive colostomy had significantly better functional and symptom scale scores, reflecting greater function with fewer symptoms.

Image-guided high-dose-rate interstitial brachytherapy technique for locally recurrent rectal cancer in perineum

Purpose

The aim of the report was the evaluation of application with image-guided high-dose-rate (HDR) interstitial brachytherapy in patients undergoing conventional chemo-radiotherapy for perineal locally recurrent rectal cancer (LRRC).

Material and methods

75-year-old female patient presented with LRRC three years after total mesorectal excision (TME) surgery for rectal cancer with tubular adenocarcinoma (stage IIIB). Despite conventional chemotherapy and external beam radiotherapy, the re-recurrent lesion expanded as 4.5 × 5.5 cm² located in perineum with skin invasion. The loco-regional recurrent tumor was treated with HDR interstitial brachytherapy under ultrasound guidance and magnetic resonance imaging-based treatment planning. The brachytherapy dose was 50 Gy in 10 fractions of 5 Gy each for 5 weeks.

Results

Removal of the perineal LRRC was securely achieved by image-guided HDR interstitial brachytherapy technique. The refractory tumor healed uneventfully after interstitial brachytherapy without recurrence during 26 months of follow-up. The patient had good quality of life without serious complications of treatment.

Conclusions

Image-guided HDR interstitial brachytherapy in selected patient with LRRC in perineum is a proven, effective, and safe treatment method with relatively long-term outcome.

Perioperative pain after robot-assisted versus laparoscopic rectal resection

BACKGROUND

In order to improve the surgical treatment of rectal cancer, robot-assisted laparoscopy has been introduced. The robot has gained widespread use; however, the scientific basis for treatment of rectal cancer is still unclear. The aim of this study was to investigate whether robot-assisted laparoscopic rectal resection cause less perioperative pain than standard laparoscopic resection measured by the numerical rating scale (NRS score) as well as morphine consumption.

METHODS

Fifty-one patients were randomized to either laparoscopic or robot-assisted rectal resection at the Department of Surgery at Aarhus University Hospital in Denmark. The intra-operative analgetic consumption was recorded prospectively and registered in patient records. Likewise all postoperative medicine administration including analgesia was recorded prospectively at the hospital medical charts. All morphine analogues were converted into equivalent oral morphine by a converter. Postoperative pain where measured by numeric rating scale (NRS) every hour at the postoperative care unit and three times a day at the ward.

RESULTS

Opioid consumption during operation was significantly lower during robotic-assisted surgery than during laparoscopic surgery (p=0.0001). However, there were no differences in opioid consumption or NRS in the period of recovery. We found no differences in length of surgery between the two groups; however, ten patients from the laparoscopic group underwent conversion to open surgery compared to one from the robotic group (p=0.005). No significant difference between groups with respect to complications where found.

CONCLUSIONS

In the present study, we found that patients who underwent rectal cancer resection by robotic technique needed less analgetics during surgery than patients operated laparoscopically. We did, however, not find any difference in postoperative pain score or morphine consumption postoperatively between the robotic and laparoscopic group.

GOLPH3 overexpression correlates with poor response to neoadjuvant therapy and prognosis in locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) combined with surgery is a standard therapy for locally advanced rectal cancer (LARC). The aim of this study was to assess the expression of GOLPH3 (Golgi phosphoprotein 3), a newly found oncogene, in LARC as well as its relationship with nCRT sensitivity and prognosis. We retrospectively analyzed 148 LARC cases receiving nCRT and total mesorectal excision (TME). Immunohistochemistry was used to assess GOLPH3 and mTOR (mammalian target of rapamycin) in tumor tissues. Then, the associations of GOLPH3 with pathological characteristics and prognosis of rectal cancer were assessed. The 148 cases included 77 with high GOLPH3 expression (52.03%), which was associated with tumor invasive depth and lymphatic metastasis. Cases with high GOLPH3 expression had 2.58 and 2.71 fold higher local relapse and distant metastasis rates compared with the low expression group. Correlation analyses showed that GOLPH3 was an independent indicator for judging tumor down-staging and postoperative TRG (tumor regression grade), indicating it could predict nCRT sensitivity. In addition, GOLPH3 expression was associated with mTOR levels. Multiple-factor analysis indicated that GOLPH3 was an independent prognosis indicator for 5 year-DFS (disease free survival) and OS (overall survival) in LARC. These results reveal that GOLPH3 is an independent predictive factor for nCRT sensitivity and prognosis in LARC, with a mechanism related to mTOR.

Pilot Study of Intense Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer: Retrospective Review of a Phase II Study

Aims and Background

Locally advanced rectal adenocarcinoma is typically treated with neoadjuvant chemoradiotherapy and surgery. We assessed the effect of an additional cycle of capecitabine/oxaliplatin chemotherapy before surgery in 57 patients with T3/4, N+/- or T1/2, N+ rectal cancer.

Materials and Study Design

Radiotherapy (total dose, 50.4 Gy) was combined with three cycles of chemotherapy (two cycles concomitant with radiotherapy), and each cycle consisted of oxaliplatin (130 mg/m2 on day 1) and capecitabine (825 mg/m2, twice per day from day 1 to day 14) for 21 days. In addition to assessing the safety of this treatment, the primary endpoint was pathological complete response (pCR). The secondary endpoint was the change in primary tumor and node stage from pre-treatment to post-surgery.

Results

Eleven patients (19%) experienced complete tumor regression and 23 patients (40%) experienced tumor regression grade 3. Tumor down-staging occurred in 31 patients (54.4%) and down-staging of nodes occurred in 25 patients (43.9%). There was a significant difference in tumor stage between pre-treatment and post-surgery (P <0.001). Patients with less advanced N stages had significantly better recurrence-free survival but similar metastasis-free survival and overall survival. Tumor regression grade was not associated with overall survival, recurrence-free survival or metastasis-free survival. The most common adverse events were pulmonary infection (n = 6, 10.5%) and intestinal obstruction (n = 6, 10.5%).

Conclusions

An additional cycle of chemotherapy given after chemoradiotherapy and before surgery provided good efficacy and had a satisfactory safety profile in patients with locally advanced rectal cancer.

Sexual and urinary dysfunction following laparoscopic total mesorectal excision in male patients: A prospective study

Aims:

Even with the use of nerve-sparing techniques, there is a risk of bladder and sexual dysfunction after total mesorectal excision (TME). Laparoscopic TME is believed to improve this autonomic nerve dysfunction, but this is not demonstrated conclusively in the literature. In Indian patients generally, the stage at which the patients present is late and presumably the risk of autonomic nerve injury is more; however, there is no published data in this respect.

Materials and Methods:

This prospective study in male patients who underwent laparoscopic TME evaluated the bladder and sexual dysfunction using objective standardised scores, measuring residual urine and post-voided volume. The International Prostatic Symptom Score (IPSS) and International Index of Erectile Function score were used respectively to assess the bladder and sexual dysfunction preoperatively at 1, 3, 6 months and at 1 year.

Results:

Mean age of the study group was 58 years. After laparoscopic TME in male patients, the moderate to severe bladder dysfunction (IPSS <8) is observed in 20.4% of patients at 3 months, and at mean follow-up of 9.2 months, it was seen only in 2.9%. There is more bladder and sexual dysfunction in low rectal tumours compared to mid-rectal tumours. At 3 months, 75% had sexual dysfunction, 55% at median follow-up of the group at 9.2 months.

Conclusion:

After laparoscopic TME, bladder dysfunction is seen in one-fifth of the patients, which recovers in the next 6 months to 1 year. Sexual dysfunction is observed in 75% of patients immediately after TME which improves to 55% over 9.2 months.

Management of the Complete Clinical Response

Organ preservation is considered in the management of selected patients with rectal cancer. Complete clinical response observed after neoadjuvant chemoradiation for rectal cancer is one of these cases. Patients who present complete clinical response are candidates to the watch-and-wait approach, when radical surgery is not immediately performed and is offered only to patients in the event of a local relapse. These patients are included in a strict follow-up, and up of 70% of them will never be operated during the follow-up. This strategy is associated with similar oncological outcomes as patients operated on, and the advantage of avoiding the morbidity associated to the radical operation. In this article we will discuss in detail the best candidates for this approach, the protocol itself, and the long-term outcomes.

Predictors of Bowel Function in Long-term Rectal Cancer Survivors with Anastomosis

BACKGROUND

Bowel function in long-term rectal cancer survivors with anastomosis has not been characterized adequately. We hypothesized that bowel function is associated with patient, disease, and treatment characteristics.

METHODS

The cohort study included Kaiser Permanente members who were long-term (≥5 years) rectal cancer survivors with anastomosis. Bowel function was scored using the self-administered, 14-item Memorial Sloan-Kettering Cancer Center Bowel Function Index. Patient, cancer, and treatment variables were collected from the electronic medical chart. We used multiple regression to assess the relationship of patient- and treatment-related variables with the bowel function score.

RESULTS

The study included 381 anastomosis patients surveyed an average 12 years after their rectal cancer surgeries. The total bowel function score averaged 53 (standard deviation, 9; range, 31-70, higher scores represent better function). Independent factors associated with worse total bowel function score included receipt of radiation therapy (yes vs. no: 5.3-unit decrement, p < 0.0001), tumor distance from the anal verge (≤6 cm vs. >6 cm: 3.2-unit decrement, p < 0.01), and history of a temporary ostomy (yes vs. no: 4.0-unit decrement, p < 0.01). One factor measured at time of survey was also associated with worse total bowel function score: ever smoking (2.3-unit decrement, p < 0.05). The regression model explained 20% of the variation in the total bowel function score.

CONCLUSIONS

Low tumor location, radiation therapy, temporary ostomy during initial treatment, and history of smoking were linked with decreased long-term bowel function following an anastomosis. These results should improve decision-making about surgical options.

New Strategies in Rectal Cancer

In recent years, our understanding of rectal cancer has improved, including how locally advanced disease responds to chemotherapy and radiation. This has led to new innovations and advances in the treatment of rectal cancer, which includes organ-preserving strategies for responsive disease, and minimally invasive approaces for the performance of total mesorectal excision/protectomyh for persistently advanced disease. This article discusses new strategies for rectal cancer therapy, including Watch and Wait, local excision, minimally invasive proctectomy, and transanal total mesorectal excision particularly in the setting of preoperative multimodality treatment.

Is neoadjuvant chemoradiotherapy always necessary for mid/high local advanced rectal cancer: A comparative analysis after propensity score matching

AIM

This study was aimed to compare perioperative and oncological outcomes of mid/high locally advanced midrectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (NCRT) vs. surgery alone, and to identify risk factors for local recurrence in mid/high LARC.

METHOD

A total of 471 mid/high LARC patients treated with surgery alone or NCRT (50.4 Gy in 28 fractions) with concurrent FOLFOX/XELOX followed by TME in 6-8 weeks from 2008 to 2014 were matched 1:1 by using propensity score analysis. Perioperative and survival outcome was compared between groups. Multivariate analyze was performed to identify risk factors for local recurrence.

RESULTS

Two hundred and two patients were matched for the analysis. Postoperative morbidity was similar between groups. With a mean follow-up of 57 months, the 5-year overall survival (NCRT vs. surgery alone: 80.4% vs. 81.4%; p = 0.978), 5-year local recurrence rates (3.1% vs. 5%; p = 0.467), and 5-year distant metastasis rates (29.5% vs. 23.7%; p = 0.140) were similar between two groups. Cox regression analysis showed that the circumferential resection margin (CRM) involvement (OR = 5.205, p = 0.005) was the only risk factor for local recurrence in mid/high LARC patients.

CONCLUSION

In matched cohorts of mid/high LARC patients, surgery alone provided comparable oncological outcome, when compared with NCRT. CRM involvement was the only risk factor for local recurrence in mid/high rectal cancer. NCRT may not be always needed in mid/high LARC. A threatened CRM could be diagnosed up front and prevented by selecting CRT for these patients.

Definitive high-dose radiotherapy with concurrent chemotherapy for locally advanced rectal cancer: A case report and literature review

BACKGROUND

Standard management for locally advanced rectal cancer (LARC) involves preoperative chemoradiotherapy (CRT) and radical surgery. However, this level of treatment may be unnecessary for a subgroup of LARC patients. Previous reports have shown that approximately 20% of LARC patients experience a complete tumor response to preoperative CRT. Post-CRT nonoperative management of these patients may prevent morbidities associated with radical surgery. To our knowledge, this case report firstly presents the favorable long-term outcomes of a LARC patient who underwent definitive aim CRT.

METHODS

The patient was 73 years' old, and staging workups revealed T3N2bM0 rectal adenocarcinoma. He agreed to receive CRT, but refused surgery. A radiotherapy (RT) dose of 64.8 Gy was prescribed, which was higher than conventional (50.4 Gy) preoperative aim RT. The regimen of concurrent chemotherapy was the same as that used in preoperative aim CRT: 2 cycles of 5-fluorouracil and leucovorin.

RESULTS

Three months after CRT completion, a complete tumor response was identified clinically. Colonoscopic biopsy after 1 year showed no tumor cells. This patient is alive after 4 years with no evidence of recurrence or severe toxicity.

CONCLUSION

The long-term outcomes of this case indicate the feasibility of definitive high-dose RT with concurrent chemotherapy for LARC.

Preoperative chemoradiotherapy followed by transanal local excision for T3 distal rectal cancer: A case report

Local excision (LE) for rectal cancer is currently indicated for selected T1 stage tumors. However, preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer not only improves local disease control, but also leads to a decrease in the stage and size of the primary mural tumor, along with a decrease in the risk of regional lymphadenopathy. The present study reports the outcome of a patient with T3N0M0 rectal cancer who was treated with LE following preoperative CRT. The distal pole of the tumor was located 2 cm from the anal verge. Preoperative pelvic radiotherapy of 50.4 Gy was administered in 28 fractions. Chemotherapy using 5-fluorouracil and leucovorin was administered during the first and last weeks of radiotherapy. The tumor response to CRT, was found to be marked at 7 weeks after CRT completion, and a complete response was presumed clinically. Transanal full-thickness LE was performed, and pathological examination revealed the absence of residual cancer cells. After 30 months of close follow-up, the patient was alive with no evidence of disease, and treatment-associated severe toxicities were not observed. Although a longer follow-up period is required, this case report suggests that LE may also be a feasible alternative treatment for T3 rectal cancer, which exhibits a marked response to preoperative CRT, particularly in elderly and comorbid patients contraindicated for radical surgery, or patients who are reluctant to undergo sphincter-ablation surgery.

Impact of neoadjuvant therapy in downstaging of lower rectal adenocarcinoma and the role of pelvic magnetic resonance in staging

ABSTRACT Objective: to evaluate the effect of neoadjuvant therapy on the stage (TNM) of patients with rectal adenocarcinoma and validate the use of MRI as a method of determining locoregional stage. Methods: we conducted a retrospective study of 157 patients with lower rectum adenocarcinoma, whom we divided into two groups: Group 1, 81 patients (52%) who had undergone surgical treatment initially, with the purpose to analyze the accuracy of locoregional staging by pelvic magnetic resonance imaging throug the comparison of radiological findings with pathological ones; Group 2, 76 patients (48%), who had been submitted to neoadjuvant therapy (chemotherapy and radiation) prior to definitive surgical treatment, so as to evaluate its effects on the stage by comparing clinical and radiological findings with pathology. Results: In group 1, the accuracy of determining tumor depth (T) and lymph node involvement (N) was 91.4% and 82.7%, respectively. In group 2, neoadjuvant therapy decreased the T stage, N stage and TNM stage in 51.3%, 21% and 48.4% of cases, respectively. Conclusion: neoadjuvant therapy in patients with rectal adenocarcinoma is effective in decreasing disease stage, and pelvic magnetic resonance imaging is effective for locoregional staging.

Celecoxib induces apoptosis but up-regulates VEGF via endoplasmic reticulum stress in human colorectal cancer in vitro and in vivo

PURPOSE

In our previous study, we found that celecoxib, a kind of COX-2 inhibitor, led to cell apoptosis while up-regulating the expression of vascular endothelial growth factor (VEGF) in colorectal cancer HCT116 cells (COX-2 deficient), and endoplasmic reticulum (ER) stress was involved in the mechanism. Thus, we would like to explore whether these results are universal for other colorectal cancer cells, especially for COX-2-expressing ones, and whether the results in vitro and in vivo are matched.

METHODS

HT29 cells (COX-2 expressing) were treated with celecoxib under different conditions to evaluate cell apoptosis, VEGF expression and the activation of ER stress. HT29 and HCT116 xenograft tumor models were established to evaluate anti-tumor effects and verify the experiment results we obtained in vitro.

RESULTS

Celecoxib (≥60 µM) up-regulated the expression of ER stress markers (GRP78 and CHOP) and induced cell apoptosis accompanying with a correlated increased expression of VEGF in HT29 cells. Celecoxib-induced gene expression and cell apoptosis were inhibited by an ER stress inhibitor, PBA. In xenograft models, celecoxib treatment inhibited tumor growth with increased GRP78 and VEGF, which was consistent with the results in vitro.

CONCLUSIONS

Celecoxib, both in vitro and in vivo, induced apoptosis of colorectal cancer cells but increased the VEGF levels at the same time in a COX-2-independent manner, namely by activating ER stress. The increased VEGF would impair the effect of celecoxib and bring drug resistant; hence, the optimal schedule of the combination of celecoxib with anti-VEGF drugs needs to be explored.

Intravoxel Incoherent Motion-derived Histogram Metrics for Assessment of Response after Combined Chemotherapy and Radiation Therapy in Rectal Cancer: Initial Experience and Comparison between Single-Section and Volumetric Analyses

Purpose To determine the diagnostic performance of intravoxel incoherent motion (IVIM) parameters and apparent diffusion coefficient (ADC) to assess response to combined chemotherapy and radiation therapy (CRT) in patients with rectal cancer by using histogram analysis derived from whole-tumor volumes and single-section regions of interest (ROIs). Materials and Methods The institutional review board approved this retrospective study of 31 patients with rectal cancer who underwent magnetic resonance (MR) imaging before and after CRT, including diffusion-weighted imaging with 34 b values prior to surgery. Patient consent was not required. ADC, perfusion-related diffusion fraction (f), slow diffusion coefficient (D), and fast diffusion coefficient (D*) were calculated on MR images acquired before and after CRT by using biexponential fitting. ADC and IVIM histogram metrics and median values were obtained by using whole-tumor volume and single-section ROI analyses. All ADC and IVIM parameters obtained before and after CRT were compared with histopathologic findings by using t tests with Holm-Sidak correction. Receiver operating characteristic curves were generated to evaluate the diagnostic performance of IVIM parameters derived from whole-tumor volume and single-section ROIs for prediction of histopathologic response. Results Extreme values aside, results of histogram analysis of ADC and IVIM were equivalent to median values for tumor response assessment (P > .06). Prior to CRT, none of the median ADC and IVIM diffusion metrics correlated with subsequent tumor response (P > .36). Median D and ADC values derived from either whole-volume or single-section analysis increased significantly after CRT (P ≤ .01) and were significantly higher in good versus poor responders (P ≤ .02). Median IVIM f and D* values did not significantly change after CRT and were not associated with tumor response to CRT (P > .36). Interobserver agreement was excellent for whole-tumor volume analysis (range, 0.91-0.95) but was only moderate for single-section ROI analysis (range, 0.50-0.63). Conclusion Median D and ADC values obtained after CRT were useful for discrimination between good and poor responders. Histogram metrics did not add to the median values for assessment of tumor response. Volumetric analysis demonstrated better interobserver reproducibility when compared with single-section ROI analysis. (©) RSNA, 2016 Online supplemental material is available for this article.

Metabolic and molecular relative percentage coreduction in patients with locally advanced rectal cancer treated with neoadjuvant therapy

PURPOSE

Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR) and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumour progression and are important targets for cancer therapeutics. (18)F-FDG maximum standardized uptake value (SUVmax) on PET/CT is a marker of tumour metabolic activity. The purpose of this study was to measure percentage reductions in SUVmax (∆SUVmax%), VEGFR-2 (∆VEGFR-2%), EGFR (∆EGFR%) and COX-2 (∆COX-2%) in patients with locally advanced rectal cancer (LARC) after preoperative treatment, and to correlate the changes in these markers of response with pathological response in terms of tumour regression grade (TRG) using Rödel's scale and long-term clinical outcome.

METHODS

VEGFR-2, EGFR and COX-2 were measured using a quantitative and qualitative compound immunohistochemistry analysis (immunoreactive score) of the pretreatment endoscopic biopsy and definitive surgical specimens. Composite indexes using ∆SUVmax% and the three molecules were developed to differentiate patients with metabolic and molecular responses from nonresponders. Cox proportional hazards model was used to explore associations between the tumour markers, disease-free survival (DFS) and overall survival (OS).

RESULTS

The analysis included 38 patients with a median follow-up of 86 months (range 5 - 113 months). The ∆VEGFR-2%/∆SUVmax% index correctly identified 13 of 19 pathological responders (TRG 3 and 4) and 17 of 19 nonresponders (TRG 0 - 2) (sensitivity 68 %, specificity 89 %, accuracy 79 %, positive predictive value 87 %, negative predictive value 74 %). In multivariate analysis, only the ∆VEGFR-2%/∆SUVmax% index was associated with DFS (HR 0.11, p = 0.001) and OS (HR 0.15, p = 0.02).

CONCLUSION

In patients with LARC the ∆VEGFR-2%/∆SUVmax% response index is associated with outcome. Determination of the optimal diagnostic cut-off level for this novel biomarker association should be explored. Evaluation in a clinical trial is required to determine whether selected patients could benefit from treatment with a VEGFR-targeted therapeutic agent.

Watch and wait approach to rectal cancer: A review

In 2014, there were an estimated 136800 new cases of colorectal cancer, making it the most common gastrointestinal malignancy. It is the second leading cause of cancer death in both men and women in the United States and over one-third of newly diagnosed patients have stage III (node-positive) disease. For stage II and III colorectal cancer patients, the mainstay of curative therapy is neoadjuvant therapy, followed by radical surgical resection of the rectum. However, the consequences of a proctectomy, either by low anterior resection or abdominoperineal resection, can lead to very extensive comorbidities, such as the need for a permanent colostomy, fecal incontinence, sexual and urinary dysfunction, and even mortality. Recently, trends of complete regression of the rectal cancer after neoadjuvant chemoradiation therapy have been confirmed by clinical and radiographic evaluation-this is known as complete clinical response (cCR). The “watch and wait” approach was first proposed by Dr. Angelita Habr-Gama in Brazil in 2009. Those patients with cCR are followed with close surveillance physical examinations, endoscopy, and imaging. Here, we review management of rectal cancer, the development of the “watch and wait” approach and its outcomes.

Next-Generation Sequencing of Matched Primary and Metastatic Rectal Adenocarcinomas Demonstrates Minimal Mutation Gain and Concordance to Colonic Adenocarcinomas

CONTEXT

-Colorectal carcinoma is the third most common cause of cancer death in males and females in the United States. Rectal adenocarcinoma can have distinct therapeutic and surgical management from colonic adenocarcinoma owing to its location and anatomic considerations.

OBJECTIVE

-To determine the oncologic driver mutations and better understand the molecular pathogenesis of rectal adenocarcinoma in relation to colon adenocarcinoma.

DESIGN

-Next-generation sequencing was performed on 20 cases of primary rectal adenocarcinoma with a paired lymph node or solid organ metastasis by using an amplicon-based assay of more than 2800 Catalogue of Somatic Mutations in Cancer (COSMIC)-identified somatic mutations.

RESULTS

-Next-generation sequencing data were obtained on both the primary tumor and metastasis from 16 patients. Most rectal adenocarcinoma cases demonstrated identical mutations in the primary tumor and metastasis (13 of 16, 81%). The mutations identified, listed in order of frequency, included TP53, KRAS, APC, FBXW7, GNAS, FGFR3, BRAF, NRAS, PIK3CA, and SMAD4.

CONCLUSIONS

-The somatic mutations identified in our rectal adenocarcinoma cohort showed a strong correlation to those previously characterized in colonic adenocarcinoma. In addition, most rectal adenocarcinomas harbored identical somatic mutations in both the primary tumor and metastasis. These findings demonstrate evidence that rectal adenocarcinoma follows a similar molecular pathogenesis as colonic adenocarcinoma and that sampling either the primary or metastatic lesion is valid for initial evaluation of somatic mutations and selection of possible targeted therapy.

The effect of multidisciplinary teams for rectal cancer on delivery of care and patient outcome: has the use of multidisciplinary teams for rectal cancer affected the utilization of available resources, proportion of patients meeting the standard of care, and does this translate into changes in patient outcome?

BACKGROUND

We hypothesized that mandatory multidisciplinary team (MDT) participation improves process evaluation, outcomes, and technical aspects of surgery for rectal cancer in a stable practice of colorectal surgery.

METHODS

A retrospective review of MDT data was conducted of all patients with colorectal cancer since 2010. Demographic, clinical stage, process evaluation, quality of surgery, and outcome data were collected. Total mesorectal excision and MDT required participation started 2013.

RESULTS

One hundred thirty patients were included in this study: 47 patients in 2014; 41 patients in 2013; and 42 patients pre-MDT. Improvements were seen in 12 of the 14 preoperative process variables, 6 significantly. Improvement in the completeness of total mesorectal excision (0% to 76%) was significant. Local recurrence occurred in 10% of the pre-MDT group, and follow-up is ongoing in the MDT groups.

CONCLUSIONS

MDT participation improves care of patients with rectal cancer. Preoperative clinical staging, multimodality treatment, pathologic staging, and technical aspects of surgery have improved.

The expression and prognostic significance of bcl-2-associated transcription factor 1 in rectal cancer following neoadjuvant therapy

AIMS

bcl-2-associated transcription factor 1 (BCLAF1) is a nuclear protein that binds to bcl-related proteins and can induce apoptosis and autophagy. The aim of this study was to investigate the expression of BCLAF1 in a series of rectal cancers following neoadjuvant therapy.

METHODS AND RESULTS

Immunohistochemistry was performed on a post-neoadjuvant therapy rectal cancer tissue microarray. It contained rectal cancers (n = 248), lymph node metastases (n = 76), and non-neoplastic rectal mucosal samples (n = 73). A monoclonal antibody against BCLAF1 that we have developed was used. Non-neoplastic rectal epithelium showed nuclear localization of BCLAF1 in both crypt and surface epithelial cells, whereas rectal cancers showed both nuclear and cytoplasmic BCLAF1 expression. Most rectal cancers showed moderate or strong nuclear immunoreactivity, but showed weak cytoplasmic immunoreactivity. Cytoplasmic BCLAF1 expression was increased in primary rectal cancers as compared with non-neoplastic rectal mucosa (P = 0.008). Negative and weak nuclear BCLAF1 expression was associated with a poor prognosis [hazard ratio (HR) 0.502, 95% confidence interval (CI) 0.269-0.939, χ(2) = 4.876, P = 0.027]. Nuclear BCLAF1 expression was independently prognostic in a multivariate model (HR 0.431, 95% CI 0.221-0.840, P = 0.013).

CONCLUSIONS

This study has shown that both cytoplasmic BCLAF1 expression and nuclear BCLAF1 expression are increased in post-neoadjuvant therapy rectal cancer, and that negative and weak nuclear BCLAF1 expression are independently associated with a poor prognosis.

URINARY DYSFUNCTION AFTER SURGICAL TREATMENT FOR RECTAL CANCER

BackgroundThe impact on quality of life attributed to treatment for rectal cancer remains high. Deterioration of the urinary function is a relevant complication within that context.ObjectiveTo detect the presence of urinary dysfunction and its risk factors among individuals underwent surgical treatment for rectal cancer.MethodsThe present prospective study analyzed 42 patients from both genders underwent surgical treatment for rectal adenocarcinoma with curative intent. The version of the International Prostatic Symptom Score (IPSS) questionnaire validated for the Portuguese language was applied at two time-points: immediately before and 6 months after surgery. Risk factors for urinary dysfunction were analysed by means of logistic regression and Student’s t-test.ResultsEight (19%) participants exhibited moderate-to-severe urinary dysfunction 6 months after surgery; the average IPSS increased from 1.43 at baseline to 4.62 six months after surgery (P<0.001). None of the variables assessed as potential risk factors exhibited statistical significance, i.e., age, gender, distance from tumour to anal margin, neoadjuvant therapy, adjuvant therapy, type of surgery, surgical approach (laparoscopy or laparotomy), and duration of surgery.ConclusionThis study identified an incidence of 19% of moderate to severe urinary dysfuction after 6 months surveillance. No risk factor for urinary dysfunction was identified in this population.

MRI of Rectal Cancer: An Overview and Update on Recent Advances

OBJECTIVE

MRI is the modality of choice for rectal cancer staging. The high soft-tissue contrast of MRI accurately assesses the extramural tumor spread and relation to mesorectal fascia and the sphincter complex. This article reviews the role of MRI in the staging and treatment of rectal cancer. The relevant anatomy, MRI techniques, preoperative staging, post-chemoradiation therapy (CRT) imaging, and tumor recurrence are discussed with special attention to recent advances in knowledge.

CONCLUSION

MRI is the modality of choice for staging rectal cancer to assist surgeons in obtaining negative surgical margins. MRI facilitates the accurate assessment of mesorectal fascia and the sphincter complex for surgical planning. Multiparametric MRI may also help in the prediction and estimation of response to treatment and in the detection of recurrent disease.

Comparative Outcomes of Neoadjuvant Treatment Prior to Total Mesorectal Excision and Total Mesorectal Excision Alone in Selected Stage II/III Low and Mid Rectal Cancer

BACKGROUND

Current guidelines advocate that all rectal cancer patients with American Joint Committee on Cancer (AJCC) stages II and III disease should be subjected to neoadjuvant therapy. However, improvements in surgical technique have resulted in single-digit local recurrence rates with surgery only.

METHODS

Operative, postoperative, and oncological outcomes of patients with and without neoadjuvant therapy were compared between January 2002 and December 2013. For this purpose, all patients resected with low anterior rectal resection (LAR) and total mesorectal excision (TME) who had or had not been irradiated were identified from the authors' prospectively maintained database. Patients who were excluded were those with high rectal cancer or AJCC stage IV disease; in the surgery-only group, patients with AJCC stage I disease or with pT4Nx rectal cancer; and in the irradiated patients, patients with ypT4Nx or cT4Nx rectal cancer.

RESULTS

Overall, 454 consecutive patients were included. A total of 342 (75 %) patients were irradiated and 112 (25 %) were not irradiated. Median follow-up for all patients was 48 months. Among patients with and without irradiation, pathological circumferential resection margin positivity rates (2.9 vs. 1.8 %, p = 0.5) were not different. At 5 years, in irradiated patients compared with surgery-only patients, the incidence of local recurrence was decreased (4.5 vs. 3.8 %, p = 0.5); however, systemic recurrences occurred more frequently (10 vs. 17.8 %, p = 0.2). Irradiation did not affect overall or disease-free survival (neoadjuvant treatment vs. surgery-only: 84.9 vs. 88.2 %, p = 0.9; 76 vs. 79.1 %, p = 0.8).

CONCLUSIONS

The current study adds to the growing evidence that suggests a selective rather than generalized indication for neoadjuvant treatment in stages II and III rectal cancer.

Nonoperative management of rectal cancer: identifying the ideal patients

Neoadjuvant chemoradiation (CRT) is considered one of the preferred treatment strategies for patients with locally advanced rectal cancer. This strategy may lead to significant tumor regression, ultimately leading to a complete pathologic response in up to 42% of patients. Assessment of tumor response following CRT and before radical surgery may identify patients with a complete clinical response who could possibly be managed nonoperatively with strict follow-up (watch-and-wait strategy). The present article deals with critical issues regarding appropriate selection of patients for this approach.

Current imaging of rectal cancer

Recent advances in rectal cancer surgery and treatment as well as new developments in magnetic resonance imaging (MRI) technique have led to extensive research in the field of preoperative imaging of rectal cancer and to an abundant literature. Pelvic MRI has indeed become an important part of the decision-making process for patients with rectal cancer. The aim of this article is to give current guidelines in terms of which imaging method to perform and also to review the role of imaging, with emphasis on MRI, not only for tumor primary staging but also for reevaluation of the tumor after neoadjuvant therapy, highlighting the role of new so-called "functional MR techniques". Future trends are also discussed.

Elective resection versus observation after nonoperative management of complicated diverticulitis with abscess: a systematic review and meta-analysis

BACKGROUND

Initial management of diverticulitis with abscess formation has progressed from a surgical emergency to nonoperative management with antibiotics and percutaneous drainage followed by delayed resection. Controversy has arisen regarding the necessity of elective surgery, when nonoperative management has successfully resolved the index attack.

OBJECTIVE

The aim of this systematic review was to analyze the literature to determine the recurrence rate in those patients who were successfully managed nonoperatively and determine the role of elective surgical resection.

DATA SOURCES

An electronic literature search of PubMed, MEDLINE, EMBASE, and the Cochrane Database of Collected Reviews performed from 1986 to 2014. The search terms used were as follows: "diverticulitis," "abscess," "diverticular abscess," "percutaneous drainage," and "surgery."

STUDY SELECTION

Studies included for review evaluated the management of diverticular abscesses and the subsequent role of delayed elective resection.

INTERVENTIONS

All of the studies were systematically reviewed and underwent a meta-analysis.

MAIN OUTCOME MEASURES

End points were the need for surgery and recurrent attacks without surgery.

RESULTS

Twenty-two studies reporting a total of 1051 patients with acute diverticulitis with abscess formation (modified Hinchey grades IB and II) were included in the review. Percutaneous drainage was successful in 49% patients (diameter, >3 cm) and antibiotic therapy in 14% patients. Urgent surgery during the index hospitalization was performed in 30% of patients, elective resection in 36%, and no surgery in 35%. Recurrence rates were high, with 39% in patients awaiting elective resection and 18% in the nonsurgery group, with an overall recurrence rate of 28%. Of the whole cohort, only 28% had no surgery and no recurrence during follow-up.

LIMITATIONS

Sample size, heterogeneity, selection and treatment bias, and limited follow-up of included studies were limitations to this study.

CONCLUSIONS

The evidence from the literature is weak but still suggests that complicated diverticulitis with abscess formation is associated with a high probability of resective surgery, whereas conservative management may result in chronic or recurrent diverticular symptoms.

Prognostic and predictive values of the immunoscore in patients with rectal cancer

PURPOSE

To determine whether the tumor immune infiltrate, as recently evaluated with the Immunoscore methodology, could be a useful prognostic marker in patients with rectal cancers.

EXPERIMENTAL DESIGN

The influence of the immune infiltrate on patient's outcome was investigated in patients with or without preoperative chemoradiation therapy (pCRT). The density of total (CD3(+)) and cytotoxic (CD8(+)) T lymphocytes was evaluated by immunohistochemistry and quantified by a dedicated image analysis software in surgical specimens of patients with rectal cancer (n = 111) who did not receive pCRT and in tumor biopsies performed before pCRT from additional 55 patients. The results were correlated with tumor recurrence, patient's survival, and response to pCRT.

RESULTS

The densities of CD3(+) and CD8(+) lymphocytes and the associated Immunoscore (from I0 to I4) were significantly correlated with differences in disease-free and overall survival (HR, 1.81 and 1.72, respectively; all P < 0.005). Cox multivariate analysis supports the advantage of the Immunoscore compared with the tumor-node-metastasis (TNM) staging in predicting recurrence and survival (all P < 0.001). Lymph node ratio added information in a prognostic model (all P < 0.05). In addition, high infiltration of CD3(+) and CD8(+) lymphocytes in tumor biopsies was associated with downstaging of the tumor after pCRT (CD3(+) cells; Fisher exact test P = 0.01).

CONCLUSIONS

The Immunoscore could be a useful prognostic marker in patients with rectal cancer treated by primary surgery. The determination of the immune infiltrate in biopsies before treatment could be a valuable information for the prediction of response to pCRT.