Rectal cancer: local staging and assessment of lymph node involvement with endoluminal US, CT, and MR imaging--a meta-analysis

Diagnostic performance of node-RADS classification for primary lymph node assessment in rectal cancer: a modality benchmarking study

PURPOSE

To evaluate how well the Node Reporting and Data System (Node-RADS) diagnoses lymph node involvement (LNI) in the initial stages of rectal cancer, utilizing contrast-enhanced CT (CE-CT), T2-weighted MRI (T2WI) and contrast-enhanced T1-weighted MRI (T1CE).

METHODS

This retrospective study included 113 rectal cancer patients who underwent radical surgery without neoadjuvant therapy. Two radiologists independently assessed regional lymph nodes using the highest NODE-RADS classification and histopathology as reference criteria. Diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Statistical analysis was performed using the McNemar test with Bonferroni correction for multiple comparisons.

RESULTS

Node-RADS showed improved diagnostic performance over short-axis diameter (SAD) in all modalities (AUC: 0.838 vs. 0.744 for CE-CT, 0.845 vs. 0.747 for T2WI, 0.853 vs. 0.786 for T1CE; all P < 0.05). The sensitivity and specificity of Node-RADS across three modalities ranged from 76.19 - 78.57% and 91.55 - 92.96%, respectively. Pairwise comparisons of sensitivity and specificity among the three modalities showed no significant differences after Bonferroni correction (all McNemar test P = 1.0). There was no significant difference in Node-RADS performance among the three modalities (all P > 0.05). The weighted kappa values were 0.742-0.798.

CONCLUSION

Node-RADS demonstrated superior diagnostic performance over SAD measurements and similar diagnostic effectiveness in assessing LNI for primary rectal cancer stages across CE-CT, T2WI, and T1CE.

Mesenteric benign lymph node enlargement in colorectal cancer: Friend or foe?

INTRODUCTION

Benign lymph node enlargement (BLNE) is common in colorectal cancer; however, few studies have investigated its influence on prognosis, clinicopathological features, and pathogenesis.

METHODS

A cohort study was conducted to analyze the clinicopathologic features and prognosis of colorectal cancer patients, categorized based on the presence or absence of BLNE. Given the correlation between lymph nodes and immune response, immunohistochemistry, transcriptome analysis, and exon sequencing were employed to further investigate the differences in the immune microenvironment of primary tumors.

RESULTS

Overall, 630 AJCC stage I/II patients were included in the study, with 131 in the BLNE group and 499 in the Non-BLNE (NBLNE) group. Patients in the BLNE group were found to have a significantly better disease-free survival (DFS) (hazard ratio [HR] 0.44, P = 0.016) and overall survival (OS) (HR 0.46, P = 0.011) than those in the NBLNE group. Pathologically, compared with the NBLNE group, the BLNE group had more mature tertiary lymphoid structures (66.7 % vs. 36.5 %, P = 0.002) and higher immunoscores (18.8 % vs. 2.1 %, P = 0.004) in primary tumor tissue. Also, transcriptome analysis showed that, compared with NBLNE, the genes upregulated in BLNE were enriched in immune-related pathways, such as adaptive immune response and immuno-regulatory interactions. Whole-exon sequencing analysis revealed a higher tumor mutation burden (TMB) in the BLNE group [6.03 (5.59, 7.59) vs. 5.33 (4.62, 6.34), P = 0.025].

CONCLUSION

BLNE is positively associated with the prognosis of colorectal cancer, possibly because patients with BLNE have a stronger anti-tumor immune response.

Quantitative Dynamic Contrast-Enhanced Magnetic Resonance Imaging and Positron Emission Tomography (PET) for Distinguishing Metastatic Lymph Nodes from Nonmetastatic Among Patients with Rectal Cancer: A Systematic Review and Meta-Analysis

Objective  The objective of this research was to assess the proficiency of quantitative dynamic contrast-enhanced magnetic resonance imaging (QDCE-MRI) and positron emission tomography (PET) imaging in distinguishing between metastatic and nonmetastatic lymph nodes in cases of rectal carcinoma. Method  This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards. Two independent reviewers systematically searched databases including PubMed, Embase, Web of Science, and the Cochrane Library. The research took place in July 2022, with no restriction on the initial date of publication. For the analysis, we utilized Stata software (version 16.0), Review Manager (version 5.3), and the Open Meta-Analyst computational tool. Results  A total of 19 studies consisting of 1,451 patients were included in the current meta-analysis. The differences between metastatic and nonmetastatic lymph node parameters were significant by using short axis and Ktrans (6.9 ± 4 vs. 5.4 ± 0.5, 0.22 ± 0.1 vs. 0.14 ± 0.1, respectively). Contrast-enhanced MRI (CE-MRI) showed 73% sensitivity, 71% specificity, and 79% accuracy in detecting metastatic lymph nodes among rectal cancer patients based on six included studies ( n  = 530). The overall sensitivity, specificity, and accuracy of QDCE-MRI using Ktrans was calculated to be 80, 79, and 80%, respectively. Furthermore, PET-computed tomography (CT) showed a sensitivity of 80%, specificity of 91%, and accuracy of 86% in distinguishing metastatic lymph nodes. Quality utility analysis showed that using CE-MRI, QDCE-MRI, and PET-CT would increase the posttest probability to 69, 73, and 85%, respectively. Conclusion  QDCE-MRI demonstrates a commendable sensitivity and specificity, but slightly overshadowed by the higher specificity of PET-CT at 91%, despite comparable sensitivities. However, the heterogeneity in PET-CT sensitivity across studies and its high specificity indicate variability that can influence clinical decision-making. Thus, combining these imaging techniques and perhaps newer methods like PET/MRI could enhance diagnostic accuracy, reduce variability, and improve patient management strategies in rectal cancer.

Application of dielectric properties for identification of normal and malignant gastrointestinal tumors and lymph nodes ex vivo

A need exists for a quick, simple method to accurately assess resection margins and lymph node metastases in gastrointestinal cancer surgeries. We aimed to develop a real-time, non-destructive technique to differentiate between normal and cancerous tissues using dielectric properties. Dielectric properties of tissues from 50 gastric and 120 colorectal cancer patients were measured during surgery using an open-ended coaxial probe, spanning frequencies from 10 MHz to 4 GHz. Lymph nodes were classified based on pathology into metastatic and non-metastatic, and tissues were divided into cancerous and normal, the latter being 3 cm from the cancer edge. Statistically significant differences in dielectric properties were found between metastatic and non-metastatic lymph nodes (P < 0.05), and between normal and malignant tissues. Metastatic lymph nodes showed higher dielectric permittivity and conductivity across the frequency range, with no significant difference between gastric and colorectal cancers. The coaxial probe method distinguishes between metastatic and non-metastatic lymph nodes by their dielectric properties within 10-4000 MHz, offering a potential tool for real-time identification of malignant tissues during surgery, despite not identifying the cancer type.

DNA methylation biomarkers for predicting lymph node metastasis in colorectal cancer

Colorectal cancer is one of the most common cancers worldwide. Lymph node metastasis is an important marker of colorectal cancer progression and plays a key role in the evaluation of patient prognosis. Accurate preoperative assessment of lymph node metastasis is crucial for devising appropriate treatment plans. However, current clinical imaging methods have limitations in many aspects. Therefore, the discovery of a method for accurately predicting lymph node metastasis is crucial clinical decision-making. DNA methylation is a common epigenetic modification that can regulate gene expression, which also has an important impact on the development of colorectal cancer. It is considered to be a promising biomarker with good specificity and stability and has promising application in predicting lymph node metastasis in patients with colorectal cancer. This article reviews the characteristics and limitations of currently available methods for predicting lymph node metastasis in patients with colorectal cancer and discusses the role of DNA methylation as a biomarker.

Evaluation of MRI characterisation of histopathologically matched lymph nodes and other mesorectal nodal structures in rectal cancer

PURPOSE

To evaluate current MRI-based criteria for malignancy in mesorectal nodal structures in rectal cancer.

METHOD

Mesorectal nodal structures identified on baseline MRI as lymph nodes were anatomically compared to their corresponding structures histopathologically, reported as lymph nodes, tumour deposits or extramural venous invasion. All anatomically matched nodal structures from patients with primary surgery and all malignant nodal structures from patients with neoadjuvant treatment were included. Mixed-effects logistic regression models were used to evaluate the morphological criteria irregular margin, round shape, heterogeneous signal and nodal size, as well as the combined 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus criteria, with histopathological nodal status as the gold standard.

RESULTS

In total, 458 matched nodal structures were included from 46 patients (mean age, 67.7 years ± 1.5 [SD], 27 men), of which 19 received neoadjuvant treatment. The strongest associations in the univariable model were found for short-axis diameter ≥ 5 mm (OR 21.43; 95% CI: 4.13-111.29, p < 0.001) and heterogeneous signal (OR 9.02; 95% CI: 1.33-61.08, p = 0.024). Only size remained significant in multivariable analysis (OR 12.32; 95% CI: 2.03-74.57, p = 0.006). When applying the ESGAR consensus criteria to create a binary classification of nodal status, the OR of malignant outcome for nodes with positive ESGAR was 8.23 (95% CI: 2.15-31.50, p = 0.002), with corresponding sensitivity and specificity of 54% and 85%, respectively.

CONCLUSION

The results confirm the role of morphological and size criteria in predicting lymph node metastases. However, the current criteria might not be accurate enough for nodal staging.

KEY POINTS

Question Pretreatment lymph node staging in rectal cancer is challenging, and the ESGAR consensus criteria are not fully validated. Findings Although the ESGAR criteria correlated with malignant outcomes, diagnostic performance in terms of particular sensitivity, but also specificity, was not high. Clinical relevance Accurate nodal staging in rectal cancer is crucial for individual treatment planning. However, this validation of the current ESGAR consensus criteria suggests that these should be used with caution.

Simultaneous integrated boost to lateral pelvic lymph nodes during chemoradiotherapy in high-risk rectal cancer

BACKGROUND

Preoperative chemoradiotherapy combined with total mesorectal excision (TME) is a standard treatment for locally advanced rectal cancer (LARC). However, lateral pelvic lymph nodes (LPLNs) are often inadequately treated with standard regimens. This study examines the treatment and postoperative outcomes in LARC patients receiving a simultaneous integrated boost (SIB) for LPLNs during long-course chemoradiotherapy.

METHODS

This retrospective study included high-risk LARC patients (UICC, "Union Internationale Contre le Cancer", stage III) treated with preoperative chemoradiotherapy and SIB to LPLNs. Radiotherapy was delivered to the primary tumor and elective volumes with 50.4 Gy in 28 fractions, and an SIB with a median dose of 60.2 Gy was administered to clinically positive LPLNs. TME quality and postoperative complications were assessed using MERCURY and Clavien-Dindo, respectively. Time-to-event data were analyzed according to Kaplan-Meier.

RESULTS

Between 2019 and 2023, 27 patients with high-risk LARC and LPLN metastases were treated with chemoradiotherapy. After a median follow-up of 19 months, 2‑year overall survival was 80%, disease-free survival 80%, and local control of dose-escalated lymph nodes 100%. Three patients were managed nonoperatively after a clinical complete response on endoscopy and imaging. Of the 22 patients who had surgery, only one had complications higher than Clavien-Dindo grade I; TME was graded as MERCURY I in 73%.

DISCUSSION AND CONCLUSION

The SIB approach for LPLNs in LARC is feasible, does not increase postoperative morbidity, and achieves excellent local control. This study supports the consideration of dose-escalated radiotherapy for LPLNs to address high local recurrence risks.

MRI of the Rectum: A Decade into DISTANCE, Moving to DISTANCED

Over the past decade, advancements in rectal cancer research have reshaped treatment paradigms. Historically, treatment for locally advanced rectal cancer has focused on neoadjuvant long-course chemoradiotherapy, followed by total mesorectal excision. Interest in organ preservation strategies has been strengthened by the introduction of total neoadjuvant therapy with improved rates of complete clinical response. The administration of systemic induction chemotherapy and consolidation chemoradiotherapy in the neoadjuvant setting has introduced a new dimension to the treatment landscape and patients now face a more intricate decision-making process, given the expanded therapeutic options. This complexity underlines the importance of shared decision-making and brings to light the crucial role of radiologists. MRI, especially high-spatial-resolution T2-weighted imaging, is heralded as the reference standard for rectal cancer management because of its exceptional ability to provide staging and prognostic insights. A key evolution in MRI interpretation for rectal cancer is the transition from the DISTANCE mnemonic to the more encompassing DISTANCED-DIS, distal tumor boundary; T, T stage; A, anal sphincter complex; N, nodal status; C, circumferential resection margin; E, extramural venous invasion; D, tumor deposits. This nuanced shift in the mnemonic captures a wider range of diagnostic indicators. It also emphasizes the escalating role of radiologists in steering well-informed decisions in the realm of rectal cancer care.

Diagnosis of Anal Cancer: Symptoms, Imaging, and Endoscopy

Anal cancer is an uncommon disease in a sensitive region of the body that benefits from early and systematic workup and treatment. Main modalities for workup include history, physical examination, and MRI. PET scan and computed tomography scan are helpful in assessing spread of disease. High-resolution anoscopy may be useful in identifying precancerous lesions but come with a high-learning curve.

Contact X-ray Brachytherapy as a Boost Therapy After Neoadjuvant (Chemo)Radiation in High-Risk Locally Advanced Rectal Cancer

PURPOSE

Radical surgery following neoadjuvant therapy is the standard of care for locally advanced rectal cancer. A contact x-ray brachytherapy (CXB) boost can alternatively be used to treat residual disease postneoadjuvant (chemo)radiation, especially in patients who are not suitable for or do not wish to have surgery. Its role has mostly been studied to date in low- to intermediate-risk patients. We have now evaluated the utility of CXB boost in high-risk rectal cancers after their tumors have been significantly downstaged by neoadjuvant (chemo)radiation.

MATERIALS AND METHODS

Oncological outcomes and treatment tolerability were evaluated in 328 patients based on rectal cancer treatment risk stratification: low-/intermediate-risk (cT1-3ab, N0-1, M0, no extramural venous invasion, mesorectal fascia involvement >1 mm) and high-risk (cT3cd-4/N2, M0, mesorectal fascia ≤1 mm, and/or extramural venous invasion positive).

RESULTS

With a median follow-up of 33 (IQR, 15-54) months and a median age of 73 (IQR, 62-80) years, no significant differences were found between low/intermediate and high-risk groups in clinical complete response (78% vs. 73%, P = .32), local regrowth (16.6% vs. 22.4%, P = .41), nodal (1.8% vs. 5.8%, P = .051) or regional (1.3% vs. 2.9%, P = .33) relapse, or postradiation toxicities (P = .16). However, the high-risk group had a higher distant relapse rate (21.2% vs. 10.7%, P = .01), with no significant differences in 3-year organ preservation (80% vs. 87%, P = .25), 5-year disease-free survival (62% vs. 64%, P = .46), or overall survival (67% vs. 64%, P = .88). Longer treatment time, treatment gap >24 weeks between therapies, and administration of a higher than standard CXB dose were newly identified factors that negatively impacted outcomes.

CONCLUSIONS

High-risk patients with rectal cancer treated with CXB boost had more distant relapses, but comparable locoregional tumor control, organ preservation, disease-free survival, and overall survival to lower risk patients, with acceptable toxicities. CXB boost is, therefore, a viable option for selected high-risk patients with rectal cancer. Timely reassessment, prompt referral, and CXB dose optimization are crucial for improving outcomes.

Localized Rectal Cancer: Indian Consensus and Guidelines

The rising incidence of colorectal cancer (CRC) in India, particularly the prevalence of rectal cancer over colon cancer (0.7:1), has been a growing concern in recent decades; especially notable is the trend of increasing cases among young CRC patients. Given the diverse treatment approaches for rectal cancer globally and the varying economic capacities of patients in low to middle-income countries (LMICs) like India, it is essential to establish consensus guidelines that are specifically tailored to meet the needs of these patients. To achieve this, a panel comprising 30 eminent rectal cancer experts convened to conduct a comprehensive and impartial evaluation of existing practices and recent advancements in the field. Through meticulous scrutiny of published literature and a consensus-building process that involved voting on pertinent questions, the panel formulated management strategies. These recommendations are the result of a rigorous, evidence-based process and encapsulate the collective wisdom and judgment of leading authorities in the field.

Lymphovascular invasion is a dominant risk factor for lymph node metastasis in T2 rectal cancer

Background and study aims Surgical resection is standard treatment of T2 rectal cancer due to risk of concomitant lymph node metastases (LNM). Local resection could potentially be an alternative to surgical treatment in a subgroup of patients with low risk of LNM. The aim of this study was to identify clinical and histopathological risk factors of LNM in T2 rectal cancer. Patients and methods This was a retrospective registry-based population study on prospectively collected data on all patients with T2 rectal cancer undergoing surgical resection in Sweden between 2009 and 2021. Potential risk factors of LNM, including age, gender, resection margin, lymphovascular invasion (LVI), histologic grade, mucinous cancer, and perineural invasion (PNI) were analyzed using univariate and multivariate logistic regression. Results Of 1607 patients, 343 (21%) with T2 rectal cancer had LNM. LVI (odds ratio [OR] = 4.21, P < 0.001) and age < 60 years (OR = 1.80, P < 0.001) were significant and independent risk factors. However, PNI (OR = 1.50, P = 0.15), mucinous cancer (OR = 1.14, P = 0.60), histologic grade (OR = 1.47, P = 0.07) and non-radical resection margin (OR = 1.64, P = 0.38) were not significant risk factors for LNM in multivariate analyses. The incidence of LNM was 15% in the absence of any risk factor. Conclusions This was a large study on LNM in T2 rectal cancer which showed that LVI is the dominant risk factor. Moreover, low age constituted an independent risk factor, whereas gender, resection margin, PNI, histologic grade, and mucinous cancer were not independent risk factors of LNM. Thus, these findings may provide a useful basis for management of patients after local resection of early rectal cancer.

Utility of abbreviated MRI in the post-treatment evaluation of rectal cancer

BACKGROUND

Post-treatment evaluation of patients with rectal cancer (RC) using magnetic resonance imaging (MRI) burdens medical resources, necessitating an exploration of abbreviated protocols.

PURPOSE

To evaluate the diagnostic performance of abbreviated MRI (A-MRI) for the post-treatment evaluation of RC patients.

MATERIAL AND METHODS

This retrospective study included RC patients who underwent non-contrast rectal MRI and standard liver MRI, as well as abdominal contrast-enhanced computed tomography (CECT) for post-treatment evaluation. A-MRI comprised diffusion-weighted imaging (DWI) and T2-weighted imaging of the upper abdomen and the pelvic cavity. Three radiologists independently reviewed A-MRI, CECT, and standard liver MRI in the detection of viable disease. The diagnostic performances were compared using a reference standard considering all available information, including pathology, FDG-PET, endoscopic results, and clinical follow-up.

RESULTS

We included 78 patients (50 men, 28 women; mean age=60.9 ± 10.2 years) and observed viable disease in 34 (43.6%). On a per-patient-basis analysis, A-MRI showed significantly higher sensitivity (95% vs. 81%, P = 0.04) and higher accuracy (93% vs. 82%, P < 0.01), compared to those of CECT, while A-MRI showed comparable sensitivity (91% vs. 91%, P = 0.42) and accuracy (97% vs. 98%, P = 0.06) to that of standard liver MRI. On a per-lesion-based analysis, A-MRI exhibited significantly superior lesion detectability than that of CECT (figure of merit 0.91 vs. 0.77, P < 0.01) and comparable to that of standard liver MRI (figure of merit 0.91 vs. 0.92, P = 0.75).

CONCLUSION

A-MRI exhibited higher sensitivity and diagnostic accuracy than those of CECT in the post-treatment evaluation of RC, while it showed comparable performances with standard liver MRI. A-MRI provides diagnostic added value in the follow-up of RC patients.

Diagnostic role of F-18 FDG PET/CT in determining preoperative Lymph node status of patients with rectal cancer: a meta-analysis

PURPOSE

To obtain performance values of PET/CT for determining the nodal status of rectal cancer.

MATERIALS

A comprehensive literature search was performed on PubMed and Embase for original diagnostic accuracy studies on the diagnostic performance of PET-CT for detection of LN metastasis in rectal cancer. The QUADAS-2 was used to evaluate the methodological quality of each study. Pooled sensitivity, specificity, and AUC were calculated to estimate the diagnostic role of PET/CT using a random-effects model. A subgroup analysis was performed to investigate the influence of different parameters on diagnostic performance.

RESULTS

A total of 15 studies and 1209 patients were included. A publication bias was observed. The pooled sensitivity, specificity, and AUC for PET/CT was 0.62 (95% CI 0.49, 0.74), 0.94 (95% CI 0.87, 0.97), and 0.87 (95% CI 0.83-0.89), respectively. Per-node basis yields higher accuracy than per-patient basis, with pooled sensitivities of 0.65 (95% CI 0.50-0.79) vs. 0.56 (95% CI 0.36-0.77) and specificities of 0.96 (95% CI 0.92-1.00) vs. 0.88 (95% CI 0.76-1.00), but there were no significant differences in diagnostic accuracy.

CONCLUSION

PET/CT has high specificity but moderate sensitivity for the detection of LN metastasis in rectal cancer. The current data suggests that the diagnostic capabilities of this method is limited due to its moderate sensitivity.

Evolution of clinical nature, treatment and survival of locally recurrent rectal cancer: Comparative analysis of two national cross-sectional cohorts

BACKGROUND

In the Netherlands, use of neoadjuvant radiotherapy for rectal cancer declined after guideline revision in 2014. This decline is thought to affect the clinical nature and treatability of locally recurrent rectal cancer (LRRC). Therefore, this study compared two national cross-sectional cohorts before and after the guideline revision with the aim to determine the changes in treatment and survival of LRRC patients over time.

METHODS

Patients who underwent resection of primary rectal cancer in 2011 (n = 2094) and 2016 (n = 2855) from two nationwide cohorts with a 4-year follow up were included. Main outcomes included time to LRRC, synchronous metastases at time of LRRC diagnosis, intention of treatment and 2-year overall survival after LRRC.

RESULTS

Use of neoadjuvant (chemo)radiotherapy for the primary tumour decreased from 88.5% to 60.0% from 2011 to 2016. The 3-year LRRC rate was not significantly different with 5.1% in 2011 (n = 114, median time to LRRC 16 months) and 6.3% in 2016 (n = 202, median time to LRRC 16 months). Synchronous metastasis rate did not significantly differ (27.2% vs 33.7%, p = 0.257). Treatment intent of the LRRC shifted towards more curative treatment (30.4% vs. 47.0%, p = 0.009). In the curatively treated group, two-year overall survival after LRRC diagnoses increased from 47.5% to 78.7% (p = 0.013).

CONCLUSION

Primary rectal cancer patients in 2016 were treated less often with neoadjuvant (chemo)radiotherapy, while LRRC rates remained similar. Those who developed LRRC were more often candidate for curative intent treatment compared to the 2011 cohort, and survival after curative intent treatment also improved substantially.

2-[18F]FDG PET-based quantification of lymph node metabolic heterogeneity for predicting lymph node metastasis in patients with colorectal cancer

BACKGROUND AND PURPOSE

The pre-surgical estimation of lymph node (LN) metastasis in colorectal cancer (CRC) poses a significant diagnostic predicament. The associations between LN morphology, density, and metabolic heterogeneity and LN metastasis status in CRCs have been seldomly examined through the lens of radiomics. This research aimed to assess 2-[18F]FDG PET-based quantification of intratumoral metabolic heterogeneity for predicting lymph node metastasis in patients with colorectal cancer.

MATERIALS AND METHODS

The construction of the model utilized data from 264 CRC patients, all of whom underwent preoperative 2-[18F]FDG PET/CT. Radiomic features were extracted from PET and CT images of LNs. Least absolute shrinkage and selection operator (LASSO) regression was implemented for selecting pertinent imaging features with a tenfold cross-validation. The predictive accuracy for LN metastasis status was juxtaposed against traditional methodologies (comprising CT-reported LN status and PET/CT-reported LN status) by deploying the receiver operating characteristic (ROC) curve analysis. The radiomics signature was evaluated based on discrimination, calibration, and clinical utility parameters. The model was further subjected to validation using an independent cohort of 132 patients from the period of January 2012 to June 2020.

RESULTS

The radiomics model was composed of eight significant radiomic features (five from PET and three from CT), encapsulating metabolic and density heterogeneity. The radiomics signature (area under the curve (AUC), 0.908) showcased a significantly superior performance compared to CT-reported LN status (AUC, 0.563, P < 0.001) and PET/CT-reported LN status (AUC, 0.64, P < 0.001) for predicting LN-positive or LN-negative status. The radiomics signature (AUC, 0.885) also showcased a significantly superior performance compared to CT-reported LN status (AUC, 0.587, P < 0.001) and PET/CT-reported LN status (AUC, 0.621, P < 0.001) to identify N1 and N2. This signature maintained its independence from clinical risk factors and exhibited robustness in the validation test set. Decision curve analysis attested to the clinical utility of the radiomics signature.

CONCLUSIONS

The radiomics signature based on 2-[18F]FDG PET/CT, which derived image features directly from LNs irrespective of clinical risk factors, displayed enhanced diagnostic performance compared to conventional CT or PET/CT-reported LN status. This allows for the identification of pre-surgical LN metastasis status and facilitates a patient-specific prediction of LN metastasis status in CRC patients.

Contemporary management of rectal cancer

The management of rectal cancer has undergone significant changes over the past 50 years, and this has been associated with major improvements in overall outcomes and quality of life. From standardization of total mesorectal excision to refinements in radiation delivery and shifting of chemoradiotherapy treatment to favor a neoadjuvant approach, as well as the development of targeted chemotherapeutics, these management strategies have continually aimed to achieve locoregional and systemic control while limiting adverse effects and enhance overall survival. This article highlights evolving aspects of rectal cancer therapy including improved staging modalities, total neoadjuvant therapy, the role of short-course and more selective radiotherapy strategies, as well as organ preservation. We also discuss the evolving role of minimally invasive surgery and comment on lateral pelvic lymph node dissection.

Key message

Rectal cancer management is constantly evolving through refinements in radiation timing and delivery, modification of chemoradiotherapy treatment schedules, and increasing utilization of minimally invasive surgical techniques and organ preservation strategies. This manuscript aims to provide a synopsis of recent changes in the management of rectal cancer, highlighting contemporary modifications in neoadjuvant approaches and surgical management to enhance the knowledge of surgeons who care for this challenging population.

Effect of laparoscopic versus open surgery on postoperative wound complications in patients with low rectal cancer: A meta-analysis

This meta-analysis was conducted to evaluate the effect of microinvasive and open operations on postoperative wound complications in low rectal carcinoma patients. Research on limited English has been conducted systematically in PubMed, Embase, Cochrane Library and Web of Science. The date up to the search was in August 2023. Following review of the classification and exclusion criteria for this research and the evaluation of its quality in the literature, there were a total of 266 related papers, which were reviewed for inclusion in the period from 2004 to 2017. A total of 1774 cases of low rectal cancer were enrolled. Of these 913 cases, the laparoscopic operation was performed on 913 cases, while 861 cases were operated on low rectal carcinoma. The overall sample was between 10 and 482. Five trials described the efficacy of laparoscopy have lower risk than open on postoperative wound infection in patients with low rectal cancer (OR, 0.72;95 % CI, 0.48,1.09 p = 0.12). Three studies results showed that the anastomotic leak was not significantly different between open and laparoscopy (OR, 0.86; 95% CI, 0.58,1.26 p = 0.44). Six surgical trials in low rectal cancer patients reported haemorrhage, and five cases of surgical time were reported, with laparoscopy having fewer bleeding compared with open surgery (MD, -188.89; 95% CI, -341.27, -36.51 p = 0.02). Compared with laparoscopy, the operation time was shorter for the open operation (MD, 33.06; 95% CI, 30.56, 35.57 p < 0.0001). Overall, there is no significant difference between laparoscopy and open surgery in terms of incidence of infection and anastomosis leak. However, the rate of haemorrhage in laparoscopy is lower，and operation time in open surgery is lower.

Abandonment of Routine Radiotherapy for Nonlocally Advanced Rectal Cancer and Oncological Outcomes

Importance

Neoadjuvant short-course radiotherapy was routinely applied for nonlocally advanced rectal cancer (cT1-3N0-1M0 with >1 mm distance to the mesorectal fascia) in the Netherlands following the Dutch total mesorectal excision trial. This policy has shifted toward selective application after guideline revision in 2014.

Objective

To determine the association of decreased use of neoadjuvant radiotherapy with cancer-related outcomes and overall survival at a national level.

Design, Setting, and Participants

This multicenter, population-based, nationwide cross-sectional cohort study analyzed Dutch patients with rectal cancer who were treated in 2011 with a 4-year follow-up. A similar study was performed in 2021, analyzing all patients that were surgically treated in 2016. From these cohorts, all patients with cT1-3N0-1M0 rectal cancer and radiologically unthreatened mesorectal fascia were included in the current study. The data of the 2011 cohort were collected between May and October 2015, and the data of the 2016 cohort were collected between October 2020 and November 2021. The data were analyzed between May and October 2022.

Main Outcomes and Measures

The main outcomes were 4-year local recurrence and overall survival rates.

Results

Among the 2011 and 2016 cohorts, 1199 (mean [SD] age, 68 [11] years; 430 women [36%]) of 2095 patients (57.2%) and 1576 (mean [SD] age, 68 [10] years; 547 women [35%]) of 3057 patients (51.6%) had cT1-3N0-1M0 rectal cancer and were included, with proportions of neoadjuvant radiotherapy of 87% (2011) and 37% (2016). Four-year local recurrence rates were 5.8% and 5.5%, respectively (P = .99). Compared with the 2011 cohort, 4-year overall survival was significantly higher in the 2016 cohort (79.6% vs 86.4%; P < .001), with lower non-cancer-related mortality (13.8% vs 6.3%; P < .001).

Conclusions and Relevance

The results of this cross-sectional study suggest that an absolute 50% reduction in radiotherapy use for nonlocally advanced rectal cancer did not compromise cancer-related outcomes at a national level. Optimizing clinical staging and surgery following the Dutch total mesorectal excision trial has potentially enabled safe deintensification of treatment.

Lateral Lymph Node Dissection for Locally Advanced Rectal Carcinoma: A Step-by-Step Description of Surgical Anatomical Planes During Cadaveric Dissection and Minimally Invasive Surgery

PURPOSE

Total mesorectal excision (TME) is accepted as gold standard method in rectal cancer globally. But there is no standard for lateral lymph nodes. Combination of neoadjuvant treatment plus lateral lymph node dissection (LLND) in select patients might be a promising method. Our purpose is to describe the anatomic landmarks of LLND on cadavers and minimally invasive surgery.

MATERIALS AND METHODS

Local advanced rectal cancer and lateral lymph node (LLN) metastasis are accepted as an indication of neoadjuvant treatment. LLND was performed according to preoperative imaging after radiochemotherapy.

RESULTS

Twenty-eight (10.5%) of 267 patients with rectal cancer who had suspected lateral lymph node metastasis (LLNM) with magnetic resonance imaging (MRI) underwent LLND in addition to TME after neoadjuvant chemoradiotherapy. Eight of them had LLNM. Three patients had bilateral LLND and only 1 had LLNM. The median number of harvested lymph nodes was 6. The rates of LLNM increased with the presence of poor prognosis markers. One regional and 1 distant recurrence were detected in patients who had no LLN metastasis compared with2 regional and 4 distant recurrences in the LLN-positive group.

CONCLUSIONS

Local advanced rectal cancer cases may benefit from LLND, but it does not appear to have an effect on overall survival. There is no consensus whether size and/or morphologic criteria in MRI are the ideal guide for LLND.

Adjuvant chemotherapy in patients with clinically node-negative but pathologically node-positive rectal cancer in the Netherlands: A retrospective analysis

INTRODUCTION

Accurate clinical staging of rectal cancer is hampered by suboptimal sensitivity of MRI in the detection of regional lymph node metastases. Consequently, some patients may be understaged and have been withheld neoadjuvant (chemo)radiotherapy in retrospect. Although Dutch guidelines do not advocate adjuvant chemotherapy (ACT) in rectal cancer, some of these clinically understaged patients receive ACT according to local policy. We aim to assess the benefit of ACT in these patients.

METHODS

Population-based data from patients with clinically node-negative (cN0) but pathologically node-positive (pN+) rectal cancer that underwent total mesorectal excision (TME) without neoadjuvant treatment between 2008 and 2018 were obtained from the Netherlands Cancer Registry. Missing data were handled by multiple imputation. Stabilised inverse probability treatment weighting (sIPTW) was used to balance clinical characteristics. Overall survival (OS) was compared in ACT and non-ACT patients.

RESULTS

Of 34,724 patients, 13,861 had cN0 disease of whom 3016 were pN+ (21.8%). 1466 (48.6%) of these patients underwent upfront TME and were included. Median follow-up was 84 months (95% confidence interval [CI] 76-97) versus 79 months (95% CI 77-81) in patients that did (n = 290, 19.8%) and did not (n = 1176, 80.2%) receive ACT, respectively. After sIPTW adjustment, ACT was associated with improved OS (hazard ratio 0.70; 95% CI 0.49-0.99; p = 0.04). The estimated 5-year OS rate was 74.2% versus 65.3%, respectively.

CONCLUSION

In this population-based cohort of patients with cN0 but pN+ rectal cancer who underwent upfront TME, ACT was associated with a significant OS benefit. These data support to discuss ACT in this population.

A radiomics model based on T2WI and clinical indexes for prediction of lateral lymph node metastasis in rectal cancer

OBJECTIVE

The aim of this study was to explore the clinical value of a radiomics prediction model based on T2-weighted imaging (T2WI) and clinical indexes in predicting lateral lymph node (LLN) metastasis in rectal cancer patients.

METHODS

This was a retrospective analysis of 106 rectal cancer patients who had undergone LLN dissection. The clinical risk factors for LLN metastasis were selected by multivariable logistic regression analysis of the clinical indicators of the patients. The LLN radiomics features were extracted from the pelvic T2WI of the patients. The least absolute shrinkage and selection operator algorithm and backward stepwise regression method were adopted for feature selection. Three LLN metastasis prediction models were established through logistic regression analysis based on the clinical risk factors and radiomics features. Model performance was assessed in terms of discriminability and decision curve analysis in the training, verification and test sets.

RESULTS

The model based on the combined T2WI radiomics features and clinical risk factors demonstrated the highest accuracy, surpassing the models based solely on either T2WI radiomics features or clinical risk factors. Specifically, the model achieved an AUC value of 0.836 in the test set. Decision curve analysis revealed that this model had the greatest clinical utility for the vast majority of the threshold probability range from 0.4 to 1.0.

CONCLUSION

Combining T2WI radiomics features with clinical risk factors holds promise for the noninvasive assessment of the biological characteristics of the LLNs in rectal cancer, potentially aiding in therapeutic decision-making and optimizing patient outcomes.

Development of a Diagnostic Artificial Intelligence Tool for Lateral Lymph Node Metastasis in Advanced Rectal Cancer

BACKGROUND

Metastatic lateral lymph node dissection can improve survival in patients with rectal adenocarcinoma, with or without chemoradiotherapy. However, the optimal imaging diagnostic criteria for lateral lymph node metastases remain undetermined.

OBJECTIVE

To develop a lateral lymph node metastasis diagnostic artificial intelligence tool using deep learning, for patients with rectal adenocarcinoma who underwent radical surgery and lateral lymph node dissection.

DESIGN

Retrospective study.

SETTINGS

Multicenter study.

PATIENTS

A total of 209 patients with rectal adenocarcinoma, who underwent radical surgery and lateral lymph node dissection at 15 participating hospitals, were enrolled in the study and allocated to training (n = 139), test (n = 17), or validation (n = 53) cohorts.

MAIN OUTCOME MEASURES

In the neoadjuvant treatment group, images taken before pretreatment were classified as baseline images and those taken after pretreatment as presurgery images. In the upfront surgery group, presurgery images were classified as both baseline and presurgery images. We constructed 2 types of artificial intelligence, using baseline and presurgery images, by inputting the patches from these images into ResNet-18, and we assessed their diagnostic accuracy.

RESULTS

Overall, 124 patients underwent surgery alone, 52 received neoadjuvant chemotherapy, and 33 received chemoradiotherapy. The number of resected lateral lymph nodes in the training, test, and validation cohorts was 2418, 279, and 850, respectively. The metastatic rates were 2.8%, 0.7%, and 3.7%, respectively. In the validation cohort, the precision-recall area under the curve was 0.870 and 0.963 for the baseline and presurgery images, respectively. Although both baseline and presurgery images provided good accuracy for diagnosing lateral lymph node metastases, the accuracy of presurgery images was better than that of baseline images.

LIMITATIONS

The number of cases is small.

CONCLUSIONS

An artificial intelligence tool is a promising tool for diagnosing lateral lymph node metastasis with high accuracy.

DESARROLLO DE UNA HERRAMIENTA DE INTELIGENCIA ARTIFICIAL PARA EL DIAGNSTICO DE METSTASIS EN GANGLIOS LINFTICOS LATERALES EN CNCER DE RECTO AVANZADO

ANTECEDENTES:Disección de nódulos linfáticos laterales metastásicos puede mejorar la supervivencia en pacientes con adenocarcinoma del recto, con o sin quimiorradioterapia. Sin embargo, aún no se han determinado los criterios óptimos de diagnóstico por imágenes de los nódulos linfáticos laterales metastásicos.OBJETIVO:Nuestro objetivo fue desarrollar una herramienta de inteligencia artificial para el diagnóstico de metástasis en nódulos linfáticos laterales mediante el aprendizaje profundo, para pacientes con adenocarcinoma del recto que se sometieron a cirugía radical y disección de nódulos linfáticos laterales.DISEÑO:Estudio retrospectivo.AJUSTES:Estudio multicéntrico.PACIENTES:Un total de 209 pacientes con adenocarcinoma del recto, que se sometieron a cirugía radical y disección de nódulos linfáticos laterales en 15 hospitales participantes, se inscribieron en el estudio y se asignaron a cohortes de entrenamiento (n = 139), prueba (n = 17) o validación (n = 53).PRINCIPALES MEDIDAS DE RESULTADO:En el grupo de tratamiento neoadyuvante, las imágenes tomadas antes del tratamiento se clasificaron como imágenes de referencia y las posteriores al tratamiento, como imágenes previas a la cirugía. En el grupo de cirugía inicial, las imágenes previas a la cirugía se clasificaron como imágenes de referencia y previas a la cirugía. Construimos dos tipos de inteligencia artificial, utilizando imágenes de referencia y previas a la cirugía, ingresando los parches de estas imágenes en ResNet-18. Evaluamos la precisión diagnóstica de los dos tipos de inteligencia artificial.RESULTADOS:En general, 124 pacientes se sometieron a cirugía solamente, 52 recibieron quimioterapia neoadyuvante y 33 recibieron quimiorradioterapia. El número de nódulos linfáticos laterales removidos en los cohortes de entrenamiento, prueba y validación fue de 2,418; 279 y 850, respectivamente. Las tasas metastásicas fueron 2.8%, 0.7%, y 3.7%, respectivamente. En el cohorte de validación, el área de recuperación de precisión bajo la curva fue de 0.870 y 0.963 para las imágenes de referencia y antes de la cirugía, respectivamente. Aunque tanto las imágenes previas a la cirugía como las iniciales proporcionaron una buena precisión para diagnosticar metástasis en los nódulos linfáticos laterales, la precisión de las imágenes previas a la cirugía fue mejor que la de las imágenes iniciales.LIMITACIONES:El número de casos es pequeño.CONCLUSIÓN:La inteligencia artificial es una herramienta prometedora para diagnosticar metástasis en los nódulos linfáticos laterales con alta precisión. (Traducción-Dr. Aurian Garcia Gonzalez ).

A Longitudinal MRI-Based Artificial Intelligence System to Predict Pathological Complete Response After Neoadjuvant Therapy in Rectal Cancer: A Multicenter Validation Study

BACKGROUND

Accurate prediction of response to neoadjuvant chemoradiotherapy is critical for subsequent treatment decisions for patients with locally advanced rectal cancer.

OBJECTIVE

To develop and validate a deep learning model based on the comparison of paired MRI before and after neoadjuvant chemoradiotherapy to predict pathological complete response.

DESIGN

By capturing the changes from MRI before and after neoadjuvant chemoradiotherapy in 638 patients, we trained a multitask deep learning model for response prediction (DeepRP-RC) that also allowed simultaneous segmentation. Its performance was independently tested in an internal and 3 external validation sets, and its prognostic value was also evaluated.

SETTINGS

Multicenter study.

PATIENTS

We retrospectively enrolled 1201 patients diagnosed with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy before total mesorectal excision. Patients had been treated at 1 of 4 hospitals in China between January 2013 and December 2020.

MAIN OUTCOME MEASURES

The main outcome was the accuracy of predicting pathological complete response, measured as the area under receiver operating curve for the training and validation data sets.

RESULTS

DeepRP-RC achieved high performance in predicting pathological complete response after neoadjuvant chemoradiotherapy, with area under the curve values of 0.969 (0.942-0.996), 0.946 (0.915-0.977), 0.943 (0.888-0.998), and 0.919 (0.840-0.997) for the internal and 3 external validation sets, respectively. DeepRP-RC performed similarly well in the subgroups defined by receipt of radiotherapy, tumor location, T/N stages before and after neoadjuvant chemoradiotherapy, and age. Compared with experienced radiologists, the model showed substantially higher performance in pathological complete response prediction. The model was also highly accurate in identifying the patients with poor response. Furthermore, the model was significantly associated with disease-free survival independent of clinicopathological variables.

LIMITATIONS

This study was limited by its retrospective design and absence of multiethnic data.

CONCLUSIONS

DeepRP-RC could be an accurate preoperative tool for pathological complete response prediction in rectal cancer after neoadjuvant chemoradiotherapy.

UN SISTEMA DE IA BASADO EN RESONANCIA MAGNTICA LONGITUDINAL PARA PREDECIR LA RESPUESTA PATOLGICA COMPLETA DESPUS DE LA TERAPIA NEOADYUVANTE EN EL CNCER DE RECTO UN ESTUDIO DE VALIDACIN MULTICNTRICO

ANTECEDENTES:La predicción precisa de la respuesta a la quimiorradioterapia neoadyuvante es fundamental para las decisiones de tratamiento posteriores para los pacientes con cáncer de recto localmente avanzado.OBJETIVO:Desarrollar y validar un modelo de aprendizaje profundo basado en la comparación de resonancias magnéticas pareadas antes y después de la quimiorradioterapia neoadyuvante para predecir la respuesta patológica completa.DISEÑO:Al capturar los cambios de las imágenes de resonancia magnética antes y después de la quimiorradioterapia neoadyuvante en 638 pacientes, entrenamos un modelo de aprendizaje profundo multitarea para la predicción de respuesta (DeepRP-RC) que también permitió la segmentación simultánea. Su rendimiento se probó de forma independiente en un conjunto de validación interna y tres externas, y también se evaluó su valor pronóstico.ESCENARIO:Estudio multicéntrico.PACIENTES:Volvimos a incluir retrospectivamente a 1201 pacientes diagnosticados con cáncer de recto localmente avanzado y sometidos a quimiorradioterapia neoadyuvante antes de la escisión total del mesorrecto. Eran de cuatro hospitales en China en el período entre enero de 2013 y diciembre de 2020.PRINCIPALES MEDIDAS DE RESULTADO:Los principales resultados fueron la precisión de la predicción de la respuesta patológica completa, medida como el área bajo la curva operativa del receptor para los conjuntos de datos de entrenamiento y validación.RESULTADOS:DeepRP-RC logró un alto rendimiento en la predicción de la respuesta patológica completa después de la quimiorradioterapia neoadyuvante, con valores de área bajo la curva de 0,969 (0,942-0,996), 0,946 (0,915-0,977), 0,943 (0,888-0,998), y 0,919 (0,840-0,997) para los conjuntos de validación interna y las tres externas, respectivamente. DeepRP-RC se desempeñó de manera similar en los subgrupos definidos por la recepción de radioterapia, la ubicación del tumor, los estadios T/N antes y después de la quimiorradioterapia neoadyuvante y la edad. En comparación con los radiólogos experimentados, el modelo mostró un rendimiento sustancialmente mayor en la predicción de la respuesta patológica completa. El modelo también fue muy preciso en la identificación de los pacientes con mala respuesta. Además, el modelo se asoció significativamente con la supervivencia libre de enfermedad independientemente de las variables clinicopatológicas.LIMITACIONES:Este estudio estuvo limitado por el diseño retrospectivo y la ausencia de datos multiétnicos.CONCLUSIONES:DeepRP-RC podría servir como una herramienta preoperatoria precisa para la predicción de la respuesta patológica completa en el cáncer de recto después de la quimiorradioterapia neoadyuvante. (Traducción-Dr. Felipe Bellolio ).

Concordance and Clinical Significance of Genomic Alterations in Progressive Tumor Tissue and Matched Circulating Tumor DNA in Aggressive-variant Prostate Cancer

Sequencing of circulating tumor DNA (ctDNA) is a minimally invasive approach to reveal the genomic alterations of cancer; however, its comparison with sequencing of tumor tissue has not been well documented in real-world patients with aggressive-variant prostate cancer (AVPC). Concordance of genomic alterations was assessed between progressive tumor tissue and matched ctDNA by next-generation sequencing for 63 patients with AVPC. Associations of genomic alterations with progression-free survival (PFS) and overall survival (OS) were investigated using Kaplan-Meier and Cox regression analyses. A total of 161 somatic mutations (SMs) and 84 copy-number variants (CNVs) were detected in tumors, of which 97 were also found in ctDNA, giving concordance of 39.6% (97/245) across all SMs and CNVs, 49.7% for SMs only and 20.2% for CNVs only. Across all patients with AVPC, chemotherapy was associated with significantly longer median PFS (6 vs. 0.75 months, P = 0.001) and OS (11 vs. 8 months, P < 0.001) than next-generation hormonal therapy (NHT). Among types of chemotherapy, additional platinum-based chemotherapy was associated with significantly longer median PFS and OS than docetaxel only in patients with TP53, RB1, or PTEN alterations, and in those with ctDNA% ≥ 13.5%. The concordance analysis first provides evidence for combining the sequencing of ctDNA and tumor tissue in real-world patients with AVPC. Chemotherapy is associated with significantly better survival than NHT, and the benefit of additional platinum-based chemotherapy may depend on the presence of alterations in TP53, RB1, or PTEN and on a sufficiently high proportion of ctDNA in patients with AVPC.

SIGNIFICANCE

AVPC is a highly malignant and heterogeneous disease. Sequencing of ctDNA is a minimally invasive approach to reveal genomic alterations. On the basis of the current real-world study, we found ctDNA does not fully recapitulate the landscape of genomic alterations from progressive tumor tissue in AVPC. We also revealed AVPC can benefit from chemotherapy, especially platinum-based regimens. TP53/RB1/PTEN alterations in ctDNA or tumor tissue could be biomarkers for platinum-based chemotherapy in this setting.

Diagnostic Performance of Rectal CT for Staging Rectal Cancer: Comparison with Rectal MRI and Histopathology

Purpose

To compare the diagnostic performance of rectal CT with that of high-resolution rectal MRI and histopathology in assessing rectal cancer.

Materials and Methods

Sixty-seven patients with rectal cancer who underwent rectal CT with rectal distension using sonographic gel and high-resolution MRI were enrolled in this study. The distance from the anal verge/anorectal junction, distance to the mesorectal fascia (MRF), extramural depth (EMD), extramesorectal lymph node (LN) involvement, extramural venous invasion (EMVI), and T/N stages in rectal CT/MRI were analyzed by two gastrointestinal radiologists. The CT findings of 20 patients who underwent radical surgery without concurrent chemoradiotherapy were compared using histopathology. Interclass correlations and kappa statistics were used.

Results

The distance from the anal verge/anorectal junction showed an excellent intraclass correlation between CT and MRI for both reviewers. For EMD, the distance to the MRF, presence of LNs, extramesorectal LN metastasis, EMVI, T stage, and intermodality kappa or weighted kappa values between CT and MRI showed excellent agreement. Among the 20 patients who underwent radical surgery, T staging, circumferential resection margin involvement, EMVI, and LN metastasis on rectal CT showed acceptable concordance rates with histopathology.

Conclusion

Dedicated rectal CT may be on par with rectal MRI in providing critical information to patients with rectal cancer.

Magnifying chromoendoscopy is a reliable method in the selection of rectal neoplasms for local excision

PURPOSE

Adequate staging of early rectal neoplasms is essential for organ-preserving treatments, but magnetic resonance imaging (MRI) frequently overestimates the stage of those lesions. We aimed to compare the ability of magnifying chromoendoscopy and MRI to select patients with early rectal neoplasms for local excision.

METHODS

This retrospective study in a tertiary Western cancer center included consecutive patients evaluated by magnifying chromoendoscopy and MRI who underwent en bloc resection of nonpedunculated sessile polyps larger than 20 mm, laterally spreading tumors (LSTs) [Formula: see text] 20 mm, or depressed-type lesions of any size (Paris 0-IIc). Sensitivity, specificity, accuracy, and positive and negative predictive values of magnifying chromoendoscopy and MRI to determine which lesions were amenable to local excision (i.e., [Formula: see text] T1sm1) were calculated.

RESULTS

Specificity of magnifying chromoendoscopy was 97.3% (95% CI 92.2-99.4), and accuracy was 92.7% (95% CI 86.7-96.6) for predicting invasion deeper than T1sm1 (not amenable to local excision). MRI had lower specificity (60.5%, 95% CI 43.4-76.0) and lower accuracy (58.3%, 95% CI 43.2-72.4). Magnifying chromoendoscopy incorrectly predicted invasion depth in 10.7% of the cases in which the MRI was correct, while magnifying chromoendoscopy provided a correct diagnosis in 90% of the cases in which the MRI was incorrect (p = 0.001). Overstaging occurred in 33.3% of the cases in which magnifying chromoendoscopy was incorrect and 75% of the cases in which MRI was incorrect.

CONCLUSION

Magnifying chromoendoscopy is reliable for predicting invasion depth in early rectal neoplasms and selecting patients for local excision.

Oncologic outcomes of watch-and-wait strategy or surgery for low to intermediate rectal cancer in clinical complete remission after adjuvant chemotherapy: a systematic review and meta-analysis

BACKGROUND

A watch-and-wait (WW) strategy or surgery for low to intermediate rectal cancer that has reached clinical complete remission (cCR) after neoadjuvant chemotherapy (nCRT) or total neoadjuvant therapy (TNT) has been widely used in the clinic, but both treatment strategies are controversial.

OBJECTIVE

The aim of this study was to compare the oncologic outcomes of a watch-and-wait strategy or a surgical approach to treat rectal cancer in complete remission and to report the evidence-based clinical advantages of the two treatment strategies.

METHODS

Seven national and international databases were searched for clinical trials comparing the watch-and-wait strategy with surgical treatment for oncological outcomes in patients with rectal cancer in clinical complete remission.

RESULTS

In terms of oncological outcomes, there was no significant difference between the watch-and-wait strategy and surgical treatment in terms of overall survival (OS) (HR = 0.92, 95% CI (0.52, 1.64), P = 0.777), and subgroup analysis showed no significant difference in 5-year disease-free survival (5-year DFS) between WW and both local excision (LE) and radical surgery (RS) (HR = 1.76, 95% CI (0.97, 3.19), P = 0.279; HR = 1.98, 95% CI (0.95, 4.13), P = 0.164), in distant metastasis rate (RR = 1.12, 95% CI (0.73, 1.72), P = 0.593), mortality rate (RR = 1.62, 95% CI (0.93, 2.84), P = 0.09), and organ preservation rate (RR = 1.05, 95% CI (0.94, 1.17), P = 0.394) which were not statistically significant and on the outcome indicators of local recurrence rate (RR = 2.09, 95% CI (1.44, 3.03), P < 0.001) and stoma rate (RR = 0.35, 95% CI (0.20, 0.61), P < 0.001). There were significant differences between the WW group and the surgical treatment group.

CONCLUSION

There were no differences in OS, 5-year DFS, distant metastasis, and mortality between the WW strategy group and the surgical treatment group. The WW strategy did not increase the risk of local recurrence compared with local resection but may be at greater risk of local recurrence compared with radical surgery, and the WW group was significantly better than the surgical group in terms of stoma rate; the WW strategy was evidently superior in preserving organ integrity compared to radical excision. Consequently, for patients who exhibit a profound inclination towards organ preservation and the evasion of stoma formation in the scenario of clinically complete remission of rectal cancer, the WW strategy can be contemplated as a pragmatic alternative to surgical interventions. It is, however, paramount to emphasize that the deployment of such a strategy should be meticulously undertaken within the ambit of a multidisciplinary team's management and within specialized centers dedicated to rectal cancer management.

Magnetic resonance imaging accuracy in staging early and locally advanced rectal cancer

INTRODUCTION

Magnetic Resonance Imaging (MRI) is the standard pretreatment staging in patients with rectal cancer. Accurate tumor staging is paramount to determining the appropriate treatment course for patients diagnosed with rectal cancer. The current study aims to re-evaluate the accuracy of pre-operative MRI in staging of both early and locally advanced rectal cancer following completion of neoadjuvant therapy (NAT) compared to the pathologic stage.

METHODS

A retrospective review of patients treated for rectal cancer between 2015 and 2020 at a single academic institution. All patients underwent rectal cancer protocol MRIs before surgical resection. Analysis was carried out in two groups: early rectal cancer: T1/2 N0 tumors with upfront surgical resection (N = 40); and locally advanced disease: T3 or greater or N+ disease receiving NAT, with restaging MRI following NAT (n = 63).

RESULTS

103 patients were included in analysis. MRI accuracy in early tumors was 35% ICC = 0.52 (95% CI 0.25-0.71) T stage and 66% ICC = 0 (95% CI -0.24, 0.29) for 29 patients with nodal data for N stage. There was 28% understaging of T2 tumors and 34% understaging of N0 stage by MRI. Post NAT MRI had 44% accuracy ICC = 0.57 (95% CI -0.15-0.20) T stage and 60% accuracy ICC = 0.32 (95% CI 0.08-0.52) N stage. Tumor invasion was overstaged on MRI: 40% T2, 29% T3, 90% T4. Nodal inaccuracy was due to overstaging, 61% N1, 90% N2.

CONCLUSIONS

In locally advanced rectal cancer MRI overstaged tumors, this could be due to the continued effect of NAT from MRI to resection. This overstaging is of little clinical significance as it doesn't alter the treatment plan, except in cases of complete clinical response. In early rectal cancer, MRI had limited accuracy compared to pathology, understaging a quarter of patients who would benefit from NAT before surgery. Other adjunct imaging modalities should be considered to improve accuracy in staging early rectal cancer and consideration of complete response and enrollment in watch and wait protocols.

Value of biplane transrectal ultrasonography plus micro-flow imaging in preoperative T staging and rectal cancer diagnosis in combination with CEA/CA199 and MRI

BACKGROUND

Rectal cancer is one of the most common malignant tumors and has a high incidence rate and fatality rate. Accurate preoperative T staging of rectal cancer is critical for the selection of appropriate rectal cancer treatment. Various pre-operative imaging methods are available, and the identification of the most accurate method for clinical use is essential for patient care. We investigated the value of biplane transrectal ultrasonography (TRUS) combined with MFI in preoperative staging of rectal cancer and explored the value of combining TRUS plus MFI with CEA/CA199 and MRI.

METHODS

A total of 87 patients from Daping Hospital with rectal cancer who underwent TRUS examination plus MFI were included. Grades of MFI were determined by Alder classification. Among the total patients, 64 underwent MRI and serum CEA/CA199 tests additionally within one week of TRUS. Pathological results were used as the gold standard for cancer staging. Concordance rates between TRUS, MRI, and CEA/CA199 for tumors at different stages were compared.

RESULTS

There were no significant differences between the Alder classification and pathological T staging. The concordance rate of TRUS and MFI for rectal cancer T staging was 72.4% (K = 0.615, p < 0.001). Serum CEA and CA199 levels were significantly different in tumors at different stages and increased progressively by pathological stage (p < 0.001); the accuracy rate was 71.88% (K = 0.599, p < 0.001), while that of MRI was 51.56% (K = 0.303, p < 0.001), indicating that TRUS had higher consistency in the preoperative T staging of rectal cancer. The combination of TRUS, MRI, and CEA/CA199 yielded an accuracy rate of 90.6%, which was higher than that of any method alone.

CONCLUSIONS

Preoperative T staging of rectal cancer from biplane TRUS plus MFI was highly consistent with postoperative pathological T staging. TRUS combined with MRI and serum CEA/CA199 had a greater value in the diagnosis of rectal cancer and a higher diagnostic rate than any examination alone.

Endoscopic Submucosal Dissection, Endoscopic Mucosal Resection, and Transanal Minimally Invasive Surgery for the Management of Rectal and Anorectal Lesions: A Narrative Review

Endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR), and transanal minimally invasive surgery (TAMIS) are modern techniques that now play a crucial role in the treatment of colorectal lesions. ESD is a minimally invasive endoscopic procedure that allows for the resection of lesions of any size in a single piece, with clear advantages regarding oncological outcomes and recurrences. However, it is a complex technique, requiring high endoscopic skills, expertise, and specialized training, with higher rates of adverse events expected compared with EMR. EMR is another endoscopic technique used to remove superficial gastrointestinal tumors, particularly those that are limited to the mucosal layer. It is a faster and more accessible procedure, with fewer adverse events, although it only allows for an en-bloc resection of lesions measuring 15-20 mm. TAMIS is a minimally invasive surgical technique used to remove rectal tumors, involving the insertion of a single-port device through the anus, allowing for a better visualization and removal of the tumor with minimal disruption. This article reviews the current applications and evidence regarding these techniques, in search for the most adequate treatment for the removal of lesions in the rectum and anorectal junction, as these locations possess distinct characteristics that demand a more specific approach.

DIAGNOSTICS OF LYMPHOGENIC METASTASIS IN PATIENTS WITH RECTAL CANCER BY COMBINING MRI WITH BLOOD CEA ASSESSMENT

AIM

To improve the diagnostics of lymphogenic metastasis in patients with rectal cancer (RCa) by combining magnetic resonance imaging (MRI) with the blood carcinoembryonic antigen (CEA) level assessment.

MATERIALS AND METHODS

We have systematized and analyzed the results of the examination and treatment of 77 patients with stage II-III rectal adenocarcinoma (T2-3N0-2M0). Before the start of neoadjuvant treatment as well as 8 weeks after its completion, computed tomography (CT) and MRI were performed. We analyzed such prognostic criteria as the size, shape, and structure of lymph nodes as well as the patterns of contrast accumulation. As a prognostic marker, CEA levels in the blood of patients with RCa before surgical treatment were assessed.

RESULTS

Radiological exams showed a rounded shape and heterogeneous structure to be the most informative for predicting metastatic lymph node damage, increasing the probability by 4.39 and 4.98 times, respectively. After neoadjuvant treatment, the percentage of positive histopathological reports on lymph node involvement decreased significantly to 21.6% (р ˂ 0.001). MRI showed 76% sensitivity and 48% specificity for assessing lymphogenic metastasis. CEA levels differed significantly between stages II and III (N1-2) (р ˂ 0.032) with a threshold value of 3.95 ng/ml.

CONCLUSIONS

In order to increase the effectiveness of the diagnosis of lymphogenic metastasis using radiological examination methods in RCa patients, such prognostic criteria as the round shape and heterogeneous structure of the lymph nodes and the threshold level of CEA should be considered.

Radiological lymph-node size improves the prognostic value of systemic inflammation index in rectal cancer with pathologically negative nodes

BACKGROUND

The relationship between the radiological lymph node (rLN) size and survival outcome in node-negative rectal cancer is still uncertain. In this study, we aimed to explore the role of enlarged rLN in predicting the survival of node-negative rectal cancers.

METHODS

We retrospectively reviewed the records of 722 node-negative rectal cancer who underwent curative resection. Factors associated with DFS (disease-free survival) and CSS (cancer-specific survival) were assessed with univariate and multivariate analysis. Survival analysis was performed according to presence with or without enlarged rLN. Combining rLN with NLR as a new index-inflammation immune score (IIS) for predicting survival. Comparing different models to assess the predictive powers.

RESULTS

A total of 119 patients had tumor recurrence and 73 patients died due to cancer. Patients with enlarged rLN (≥5 mm) was significantly associated with better DFS (HR:0.517, 95%CI:0.339-0.787, p = 0.002) and CSS (HR:0.43, 95%CI:0.242-0.763, p = 0.004). The risk factors of recurrence were rLN, neutrophil-lymphocyte ratio (NLR), CEA level, and distance from the anal verge. The risk of recurrence increased by 1.88- and 2.83-fold for the high score in IIS compared with the low and intermediate score group (All p < 0.001). Similarly, the high score in IIS also increased the risk of cancer-specific death. In the model comparison, the AIC and LR were improved by including the rLN into the NLR model for DFS and CSS prediction (All p < 0.05).

CONCLUSIONS

Node-negative rectal cancer patients with enlarged rLN had a better survival outcome. IIS might be a more comprehensive and complete inflammation immune index for survival prediction.

Stage IV Colorectal Cancer Management and Treatment

(1) Background: Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related mortality worldwide. Up to 50% of patients with CRC develop metastatic CRC (mCRC). Surgical and systemic therapy advances can now offer significant survival advantages. Understanding the evolving treatment options is essential for decreasing mCRC mortality. We aim to summarize current evidence and guidelines regarding the management of mCRC to provide utility when making a treatment plan for the heterogenous spectrum of mCRC. (2) Methods: A comprehensive literature search of PubMed and current guidelines written by major cancer and surgical societies were reviewed. The references of the included studies were screened to identify additional studies that were incorporated as appropriate. (3) Results: The standard of care for mCRC primarily consists of surgical resection and systemic therapy. Complete resection of liver, lung, and peritoneal metastases is associated with better disease control and survival. Systemic therapy now includes chemotherapy, targeted therapy, and immunotherapy options that can be tailored by molecular profiling. Differences between colon and rectal metastasis management exist between major guidelines. (4) Conclusions: With the advances in surgical and systemic therapy, as well as a better understanding of tumor biology and the importance of molecular profiling, more patients can anticipate prolonged survival. We provide a summary of available evidence for the management of mCRC, highlighting the similarities and presenting the difference in available literature. Ultimately, a multidisciplinary evaluation of patients with mCRC is crucial to selecting the appropriate pathway.

Correlation between lymph node size on pathology and metastatic disease in right-sided colon cancer: A retrospective review

BACKGROUND

Identification of positive lymph nodes in colon cancer can significantly impact treatment. Few studies have examined the role of lymph node size in staging and prognosis. This study evaluated the relationship between lymph node size and lymph node metastases in right-sided colon cancer.

METHODS

Retrospective chart review was performed for patients undergoing colectomy for right-sided colon cancer from 2015 to 2020 across a single multi-hospital health system. Patients under age 18 or who did not have invasive adenocarcinoma upon pathological examination were excluded. Primary endpoints assessed lymph node size and lymph node metastases. 572 patients were stratified by lymph node size; lymph nodes ≥5 mm (n = 308) were characterized as enlarged.

RESULTS

All surgical specimens examined had adequate number of lymph nodes for staging. 33.9% of all specimens examined contained lymph node metastases. Patients with enlarged lymph nodes were significantly more likely to have lymph node metastases than those with normal-sized lymph nodes (p < 0.001). Enlarged lymph nodes were associated with advanced nodal staging.

CONCLUSIONS

Patients with enlarged nodes were significantly more likely to have lymph node metastases than those with normal-sized lymph nodes. Further research to analyze these enlarged lymph nodes on radiologic imaging is warranted to determine the role of radiographic assessment of lymph node size during pre-operative staging.

MRI anatomy of the rectum: key concepts important for rectal cancer staging and treatment planning

A good understanding of the MRI anatomy of the rectum and its surroundings is pivotal to ensure high-quality diagnostic evaluation and reporting of rectal cancer. With this pictorial review, we aim to provide an image-based overview of key anatomical concepts essential for treatment planning, response evaluation and post-operative assessment. These concepts include the cross-sectional anatomy of the rectal wall in relation to T-staging; differences in staging and treatment between anal and rectal cancer; landmarks used to define the upper and lower boundaries of the rectum; the anatomy of the pelvic floor and anal canal, the mesorectal fascia, peritoneum and peritoneal reflection; and guides to help discern different pelvic lymph node stations on MRI to properly stage regional and non-regional rectal lymph node metastases. Finally, this review will highlight key aspects of post-treatment anatomy, including the assessment of radiation-induced changes and the evaluation of the post-operative pelvis after different surgical resection and reconstruction techniques.

SAR user guide to the rectal MR synoptic report (primary staging)

Rectal MR is the key diagnostic exam at initial presentation for rectal cancer patients. It is the primary determinant in establishing clinical stage for the patient and greatly impacts the clinical decision-making process. Consequently, structured reporting for MR is critically important to ensure that all required information is provided to the clinical care team. The SAR initial staging reporting template has been constructed to address these important items, including locoregional extent and factors impacting the surgical approach and management of the patient. Potential outputs to each item are defined, requiring the radiologist to commit to a result. This provides essential information to the surgeon or oncologist to make specific treatment deisions for the patient. The SAR Initial Staging MR reporting template has now been officially adopted by the NAPRC (National Accreditation Program for Rectal Cancer) under the American College of Surgery. With the recent revisions to the reporting template, this user guide has been revamped to improve its practicality and support to the radiologist to complete the structured report. Each line item of the report is supplemented with clinical perspectives, images, and illustrations to help the radiologist understand the potential implications for a given finding. Common errors and pitfalls to avoid are highlighted. Ideally, rectal MR interpretation should not occur in a vacuum but in the context of a multi-disciplinary tumor board to ensure that healthcare providers use common terminology and share a solid understanding of the strengths and weaknesses of MR.

Endoluminal ultrasound versus magnetic resonance imaging in assessment of rectal cancer after neoadjuvant therapy

BACKGROUND

Accurate rectal tumor staging guides the choice of treatment options. EUS and MRI are the main modalities for staging.

AIM OF THE WORK

To compare the performance of EUS and MRI for loco-regional staging of anorectal cancer after neo-adjuvant therapy.

METHODS

Seventy-three (37 male, 36 female) patients with rectal cancer after neo-adjuvant chemoradiotherapy were enrolled. Histopathological staging after surgery were used as reference for comparing the yield of loco-regional staging for EUS and MRI. EUS and MRI were done 1 month after completion of neo-adjuvant therapy.

RESULTS

Regarding post-surgical T staging, eight patients had early tumor (T2 = 16 and T1 = 9) and thirty six were locally advanced (T3 = 36), while N staging, forty patients with negative nodes and 33 were positive (N1 = 22 and N2 = 11). Comparing EUS to MRI, it showed a higher sensitivity (95.7% vs. 78.7%), specificity (84.6% vs. 68.0%) and accuracy (91.8% vs. 75.3%) for staging early and locally advanced tumor. Also, it had a higher sensitivity (78.8% vs. 69.7%), specificity (75.0% vs. 65.0%) and accuracy (76.7% vs. 67.1%) for detection of lymph nodes.

CONCLUSION

EUS appears to be more accurate than MRI in loco-regional staging of rectal carcinoma after neo-adjuvant therapy.

Interventional gastroenterology in oncology

Cancer is one of the foremost health problems worldwide and is among the leading causes of death in the United States. Gastrointestinal tract cancers account for almost one third of the cancer-related mortality globally, making it one of the deadliest groups of cancers. Early diagnosis and prompt management are key to preventing cancer-related morbidity and mortality. With advancements in technology and endoscopic techniques, endoscopy has become the core in diagnosis and management of gastrointestinal tract cancers. In this extensive review, the authors discuss the role endoscopy plays in early detection, diagnosis, and management of esophageal, gastric, colorectal, pancreatic, ampullary, biliary tract, and small intestinal cancers.

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

Background

Rectal cancer (RC) is one of the most common malignant tumors. Ferroptosis is an iron-dependent form of cell death, which plays an important role in various cancers. However, the correlation between ferroptosis-related genes (FRGs) and prognosis in RC remains unclear.

Methods

Gene expression data from The Cancer Genome Atlas Rectum adenocarcinoma (TCGA-READ) and GSE87211 were downloaded. Clustering and functional enrichment were evaluated. A FRGs risk score was established based on the univariate Cox analysis and the Least absolute shrinkage and selection operator (LASSO) analysis. K-M analysis and ROC analysis were conducted to determine prognostic values. qRT-PCR was performed to validate levels of mRNA expression. Multivariate Cox analysis was used to build a prognostic prediction model based on the risk score.

Results

Based on FRGs, RC patients were grouped into two clusters. In the functional enrichment of differentially expressed genes between the two clusters, immune-related pathways dominated. A novel FRGs signature with 14 genes related to the overall survival (OS) of RC was established. qRT-PCR of the 14 genes identified TP63, ISCU, PLIN4, MAP3K5, OXSR, FANCD2 and ATM were overexpressed in RC tissue; HSPB1, MAPK1, ABCC1, PANX1, MAPK9 and ATG7 were underexpressed; TUBE1 had no difference. The high-risk group had a significantly lower OS than the low-risk group (P < 0.001), and ROC curve analysis confirmed the signature’s predictive capacity. Multivariate analysis demonstrated that the risk score and age were independent prognostic factors.

Conclusion

A novel FRGs model can be used to predict the prognosis in RC, as well as to guide individual treatment.

Value of texture analysis based on dynamic contrast-enhanced magnetic resonance imaging in preoperative assessment of extramural venous invasion in rectal cancer

Objective

Accurate preoperative assessment of extramural vascular invasion (EMVI) is critical for the treatment and prognosis of rectal cancer. The aim of our research was to develop an assessment model by texture analysis for preoperative prediction of EMVI.

Materials and methods

This study enrolled 44 rectal patients as train cohort, 7 patients as validation cohort and 18 patients as test cohort. A total of 236 texture features from DCE MR imaging quantitative parameters were extracted for each patient (59 features of Ktrans, Kep, Ve and Vp), and key features were selected by least absolute shrinkage and selection operator regression (LASSO). Finally, clinical independent risk factors, conventional MRI assessment, and T-score were incorporated to construct an assessment model using multivariable logistic regression.

Results

The T-score calculated using the 4 selected key features were significantly correlated with EMVI (p < 0.010). The area under the receiver operating characteristic curve (AUC) was 0.797 for discriminating between EMVI-positive and EMVI-negative patients with a sensitivity of 88.2% and specificity of 70.4%. The conventional MRI assessment of EMVI had a sensitivity of 23.53% and a specificity of 96.30%. The assessment model showed a greatly improved performance with an AUC of 0.954 (sensitivity, 88.2%; specificity, 92.6%) in train cohort, 0.833 (sensitivity, 66.7%; specificity, 100%) in validation cohort and 0.877 in test cohort, respectively.

Conclusions

The assessment model showed an excellent performance in preoperative assessment of EMVI. It demonstrates strong potential for improving the accuracy of EMVI assessment and provide a reliable basis for individualized treatment decisions.

Impact of preoperative chemoradiation with higher dose intensity modulated radiotherapy on pathological complete response for locally advanced rectal cancer: a systematic review

INTRODUCTION

Neoadjuvant chemoradiation (CRT) followed by total mesorectal excision is the current standard-of-care for locally advanced UICC II-III stage rectal cancer (LARC). A pathological complete response (pCR) correlates with survival. Improvements of pCR, including dose escalation, should be explored. The aim of this explorative analysis is to assess the impact on pCR of intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB).

AREAS COVERED

A literature search via PICO (Population, Intervention, Comparison, Outcome) in MEDLINE/PubMed and EMBASE and a systematic review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Metanalysis) methodology were performed. Studies that reported pCR rate in patients with LARC in clinical stage T2N+M0 or cT3/4 N0/+M0 treated with preoperative CRT with SIB-IMRT/VMAT (Volumetric Modulated Arc Therapy) were included. Sixty-two studies were identified, but only eight clinical trials with a total of 311 patients were included . Median follow-up was 16-61 months. pCR reached the value of 38%. Good survival outcomes were observed with a mild toxicity profile.

EXPERT OPINION

Radiotherapy dose intensification in LARC showed a slight increase of pCR compared to historical studies. Prospective evaluations are necessary to define which patients would benefit most.

Clinical Robotic Surgery Association (India Chapter) and Indian rectal cancer expert group’s practical consensus statements for surgical management of localized and locally advanced rectal cancer

Introduction

There are standard treatment guidelines for the surgical management of rectal cancer, that are advocated by recognized physician societies. But, owing to disparities in access and affordability of various treatment options, there remains an unmet need for personalizing these international guidelines to Indian settings.

Methods

Clinical Robotic Surgery Association (CRSA) set up the Indian rectal cancer expert group, with a pre-defined selection criterion and comprised of the leading surgical oncologists and gastrointestinal surgeons managing rectal cancer in India. Following the constitution of the expert Group, members identified three areas of focus and 12 clinical questions. A thorough review of the literature was performed, and the evidence was graded as per the levels of evidence by Oxford Centre for Evidence-Based Medicine. The consensus was built using the modified Delphi methodology of consensus development. A consensus statement was accepted only if ≥75% of the experts were in agreement.

Results

Using the results of the review of the literature and experts’ opinions; the expert group members drafted and agreed on the final consensus statements, and these were classified as “strong or weak”, based on the GRADE framework.

Conclusion

The expert group adapted international guidelines for the surgical management of localized and locally advanced rectal cancer to Indian settings. It will be vital to disseminate these to the wider surgical oncologists and gastrointestinal surgeons’ community in India.

COL10A1 allows stratification of invasiveness of colon cancer and associates to extracellular matrix and immune cell enrichment in the tumor parenchyma

Background

Treatment options for metastatic colorectal cancer (CRC) are mostly ineffective. We present new evidence that tumor tissue collagen type X alpha 1 (COL10A1) is a relevant candidate biomarker to improve this dilemma.

Methods

Several public databases had been screened to observe COL10A1 expression in transcriptome levels with cell lines and tissues. Protein interactions and alignment to changes in clinical parameters and immune cell invasion were performed, too. We also used algorithms to build a novel COL10A1-related immunomodulator signature. Various wet-lab experiments were conducted to quantify COL10A1 protein and transcript expression levels in disease and control cell models.

Results

COL10A1 mRNA levels in tumor material is clinical and molecular prognostic, featuring upregulation compared to non-cancer tissue, increase with histomorphological malignancy grading of the tumor, elevation in tumors that invade perineural areas, or lymph node invasion. Transcriptomic alignment noted a strong positive correlation of COL10A1 with transcriptomic signature of cancer-associated fibroblasts (CAFs) and populations of the immune compartment, namely, B cells and macrophages. We verified those findings in functional assays showing that COL10A1 are decreased in CRC cells compared to fibroblasts, with strongest signal in the cell supernatant of the cells.

Conclusion

COL10A1 abundance in CRC tissue predicts metastatic and immunogenic properties of the disease. COL10A1 transcription may mediate tumor cell interaction with its stromal microenvironment.

Development and validation of a high-resolution T2WI-based radiomic signature for the diagnosis of lymph node status within the mesorectum in rectal cancer

Purpose

The aim of this study was to explore the feasibility of a high-resolution T2-weighted imaging (HR-T2WI)-based radiomics prediction model for diagnosing metastatic lymph nodes (LNs) within the mesorectum in rectal cancer.

Method

A total of 604 LNs (306 metastatic and 298 non-metastatic) from 166 patients were obtained. All patients underwent HR-T2WI examination and total mesorectal excision (TME) surgery. Four kinds of segmentation methods were used to select region of interest (ROI), including method 1 along the border of LNs; method 2 along the expanded border of LNs with an additional 2–3 mm; method 3 covering the border of LNs only; and method 4, a circle region only within LNs. A total of 1,409 features were extracted for each method. Variance threshold method, Select K Best, and Lasso algorithm were used to reduce the dimension. All LNs were divided into training and test sets. Fivefold cross-validation was used to build the logistic model, which was evaluated by the receiver operating characteristic (ROC) with four indicators, including area under the curve (AUC), accuracy (ACC), sensitivity (SE), and specificity (SP). Three radiologists with different working experience in diagnosing rectal diseases assessed LN metastasis respectively. The diagnostic efficiencies with each of four segmentation methods and three radiologists were compared to each other.

Results

For the test set, the AUCs of four segmentation methods were 0.820, 0.799, 0.764, and 0.741; the ACCs were 0.725, 0.704, 0.709, and 0.670; the SEs were 0.756, 0.634, 0.700, and 0.589; and the SPs were 0.696, 0.772, 0.717, and 0.750, respectively. There was no statistically significant difference in AUC between the four methods (p > 0.05). Method 1 had the highest values of AUC, ACC, and SE. For three radiologists, the overall diagnostic efficiency was moderate. The corresponding AUCs were 0.604, 0.634, and 0.671; the ACCs were 0.601, 0.632, and 0.667; the SEs were 0.366, 0.552, and 0.392; and the SPs were 0.842, 0.715, and 0.950, respectively.

Conclusions

The proposed HR-T2WI-based radiomic signature exhibited a robust performance on predicting mesorectal LN status and could potentially be used for clinicians in order to determine the status of metastatic LNs in rectal cancer patients.