The prognostic significance of postchemoradiotherapy high-resolution MRI and histopathology detected extramural venous invasion in rectal cancer. Ann Surg. 2015;261:473-479. [PMID: 25243543 DOI: 10.1097/sla.0000000000000848]

Comparative effectiveness of two abbreviated rectal MRI protocols in assessing tumor response to neoadjuvant chemoradiotherapy in patients with rectal cancer

The present study aimed to compare the effectiveness of two abbreviated magnetic resonance imaging (MRI) protocols in assessing the response to neoadjuvant chemoradiotherapy (CRT) in patients with rectal cancer. Data from the examinations of 62 patients with rectal cancer who underwent neoadjuvant CRT and standard contrast-enhanced rectal MRI were retrospectively evaluated. Standard contrast-enhanced T2-weighted imaging (T2-WI), post-contrast T1-weighted imaging (T1-WI) and diffusion-weighted imaging (DWI) MRI, as well as two abbreviated protocols derived from these images, namely protocol AB1 (T2-WI and DWI) and protocol AB2 (post-contrast fat-suppressed (FS) T1-WI and DWI), were assessed. Measurements of lesion length and width, lymph node short-axis length, tumor staging, circumferential resection margin (CRM), presence of extramural venous invasion (EMVI), luminal mucin accumulation (MAIN), mucinous response, mesorectal fascia (MRF) involvement, and MRI-based tumor regression grade (mrTRG) were obtained. The reliability and compatibility of the AB1 and AB2 protocols in the evaluation of tumor response were analyzed. The imaging performed according to the AB1 and AB2 protocols revealed significant decreases in lesion length, width and lymph node size after CRT. These protocols also showed reductions in lymph node positivity, CRM, MRF, EMVI.Furthermore, both protocols were found to be reliable in determining lesion length and width. Additionally, compliance was observed between the protocols in determining lymph node size and positivity, CRM involvement, and EMVI after CRT. In conclusion, the use of abbreviated MRI protocols, specifically T2-WI with DWI sequences or post-contrast FS T1-WI with DWI sequences, is effective for evaluating tumor response in patients with rectal cancer following neoadjuvant CRT. The AB protocols examined in this study yielded similar results in terms of lesion length and width, lymph node positivity, CRM involvement, EMVI, MAIN, and MRF involvement.

Improving the local excision strategy for rectal cancer after chemoradiotherapy: Surgical and oncological results

INTRODUCTION

Local excision (LE) for good responders after chemoradiotherapy (CRT) for rectal cancer is oncologically safe. Although the GRECCAR 2 trial did not demonstrate any advantages in morbidity, it provided useful information for optimising patient selection. This study assessed the impact of these results on our practice by focusing on the evolution of our selection criteria and management modalities for these patients over 10 years.

METHODS

Data were collected using our retrospective database of 110 patients who underwent LE after CRT for low and middle rectal cancer between 2010 and 2022 before (Group 1) and after (Group 2) consideration of the GRECCAR 2 trial results.

RESULTS

The pretherapeutic selection criteria remained stable after the GRECCAR 2 trial, although in Group 2, completion total mesorectal excision (TME) for ypT2 tumours with favourable tumour regression grade was abandoned, improving the organ preservation rate at 1 year from 63.3 % to 91.8 % (p < 0.01). The operative time and length of stay after LE were reduced by half in Group 2 (p < 0.01). The intention-to-treat rate for severe morbidity was also halved, but was not significant (8.2 % vs. 16.3 %, p = 0.24). Among patients with a 3-year follow-up data, disease-free survival was comparable between Group 1 (89.8 %) and Group 2 (85.4 %) (p = 0.51) with one locoregional recurrence in each group (2.0 % vs. 2.1 %, p = 1).

CONCLUSION

LE is a safe and effective strategy when performed in a "high-volume" centre. Improved methods for assessing tumour response and the selection criteria for completion TME enhanced surgical outcomes without compromising oncological outcomes.

Implications of pretreatment extramural venous invasion in rectal cancer patients: A population-based study

AIM

Extramural venous invasion detected by MRI (mrEMVI) has in several expert centre studies been identified as an important prognostic factor in rectal cancer, and in guiding neoadjuvant therapy. However, population-based evidence for mrEMVI as a predictor for recurrent disease is lacking.

METHOD

This was a multicentre retrospective study based on the Swedish Colorectal Cancer Registry. The study period encompassed patients operated with abdominal resection for rectal cancer 2017-2021, with follow-up until January 2023. Patients diagnosed at hospitals with radiological registry data coverage <90% or with metastatic disease were excluded. Pretreatment mrEMVI constituted exposure, while recurrence-free survival was the main outcome. Distant and local recurrence, and overall survival were secondary outcomes, and pretreatment and postoperative scenarios were explored using multivariable Cox regression with multiple imputation. Hazard ratios (HRs) with 95% confidence intervals (CIs) were reported.

RESULTS

A total of 2737 patients from 13 hospitals were eligible for analysis. Pretreatment mrEMVI was reported in 14.5% of patients, while 71.9% had negative findings and 13.6% had missing data. In the pretreatment scenario, mrEMVI was an independent predictor for worse recurrence-free survival with an adjusted HR of 1.64 (95% CI: 1.31-2.06). In the postoperative MDT setting, the influence of mrEMVI on recurrence-free survival decreased with an adjusted HR of 1.27 (95% CI: 1.00-1.61).

CONCLUSION

mrEMVI at diagnosis is an independent predictor of recurrence-free survival in an unselected population of rectal cancer patients undergoing abdominal resection.

Ultra-High-Resolution T2-Weighted PROPELLER MRI of the Rectum With Deep Learning Reconstruction: Assessment of Image Quality and Diagnostic Performance

OBJECTIVE

The aim of this study was to evaluate the impact of ultra-high-resolution acquisition and deep learning reconstruction (DLR) on the image quality and diagnostic performance of T2-weighted periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) imaging of the rectum.

MATERIALS AND METHODS

This prospective study included 34 patients who underwent magnetic resonance imaging (MRI) for initial staging or restaging of rectal tumors. The following 4 types of oblique axial PROPELLER images perpendicular to the tumor were obtained: a standard 3-mm slice thickness with conventional reconstruction (3-CR) and DLR (3-DLR), and 1.2-mm slice thickness with CR (1.2-CR) and DLR (1.2-DLR). Three radiologists independently evaluated the image quality and tumor extent by using a 5-point scoring system. Diagnostic accuracy was evaluated in 22 patients with rectal cancer who underwent surgery after MRI without additional neoadjuvant therapy (median interval between MRI and surgery, 22 days). The signal-to-noise ratio and tissue contrast were measured on the 4 types of PROPELLER imaging.

RESULTS

1.2-DLR imaging showed the best sharpness, overall image quality, and rectal and lesion conspicuity for all readers ( P < 0.01). Of the assigned scores for tumor extent, extramural venous invasion (EMVI) scores showed moderate agreement across the 4 types of PROPELLER sequences in all readers (intraclass correlation coefficient, 0.60-0.71). Compared with 3-CR imaging, the number of cases with MRI-detected extramural tumor spread was significantly higher with 1.2-DLR imaging (19.0 ± 2.9 vs 23.3 ± 0.9, P = 0.03), and the number of cases with MRI-detected EMVI was significantly increased with 1.2-CR, 3-DLR, and 1.2-DLR imaging (8.0 ± 0.0 vs 9.7 ± 0.5, 11.0 ± 2.2, and 12.3 ± 1.7, respectively; P = 0.02). For the diagnosis of histopathologic extramural tumor spread, 3-CR and 1.2-CR had significantly higher specificity than 3-DLR and 1.2-DLR imaging (0.75 and 0.78 vs 0.64 and 0.58, respectively; P = 0.02), and only 1.2-CR had significantly higher accuracy than 3-CR imaging (0.83 vs 0.79, P = 0.01). The accuracy of MRI-detected EMVI with reference to pathological EMVI was significantly lower for 3-CR and 3-DLR compared with 1.2-CR (0.77 and 0.74 vs 0.85, respectively; P < 0.01), and was not significantly different between 1.2-CR and 1.2-DLR (0.85 vs 0.80). Using any pathological venous invasion as the reference standard, the accuracy of MRI-detected EMVI was significantly the highest with 1.2-DLR, followed by 1.2-CR, 3-CR, and 3-DLR (0.71 vs 0.67 vs 0.59 vs 0.56, respectively; P < 0.01). The signal-to-noise ratio was significantly highest with 3-DLR imaging ( P < 0.05). There were no significant differences in tumor-to-muscle contrast between the 4 types of PROPELLER imaging.

CONCLUSIONS

Ultra-high-resolution PROPELLER T2-weighted imaging of the rectum combined with DLR improved image quality, increased the number of cases with MRI-detected extramural tumor spread and EMVI, but did not improve diagnostic accuracy with respect to pathology in rectal cancer, possibly because of false-positive MRI findings or false-negative pathologic findings.

Pretreatment MRI-detected extramural venous invasion as a prognostic and predictive biomarker for neoadjuvant chemoradiotherapy in non-metastatic rectal cancer: a propensity score matched analysis

OBJECTIVES

This study evaluated pretreatment magnetic resonance imaging (MRI)-detected extramural venous invasion (pmrEMVI) as a predictor of survival after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Medical records of 1184 patients with rectal adenocarcinoma who underwent TME between January 2011 and December 2016 were reviewed. MRI data were collected from a computerized radiologic database. Cox proportional hazards analysis was used to assess local, systemic recurrence, and disease-free survival risk based on pretreatment MRI-assessed tumor characteristics. After propensity score matching (PSM) for pretreatment MRI features, nCRT therapeutic outcomes according to pmrEMVI status were evaluated. Cox proportional hazards analysis was used to identify risk factors for early recurrence in patients receiving nCRT.

RESULTS

Median follow-up was 62.8 months. Among all patients, the presence of pmrEMVI was significantly associated with worse disease-free survival (DFS; HR 1.827, 95% CI 1.285-2.597, p = 0.001) and systemic recurrence (HR 2.080, 95% CI 1.400-3.090, p < 0.001) but not local recurrence. Among patients with pmrEMVI, nCRT provided no benefit for oncological outcomes before or after PSM. Furthermore, pmrEMVI( +) was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

CONCLUSIONS

pmrEMVI is a poor prognostic factor for DFS and SR in patients with non-metastatic rectal cancer and also serves as a predictive biomarker of poor DFS and SR following nCRT in LARC. Therefore, for patients who are positive for pmrEMVI, consideration of alternative treatment strategies may be warranted.

CLINICAL RELEVANCE STATEMENT

This study demonstrated the usefulness of pmrEMVI as a predictive biomarker for nCRT, which may assist in initial treatment decision-making in patients with non-metastatic rectal cancer.

KEY POINTS

• Pretreatment MRI-detected extramural venous invasion (pmrEMVI) was significantly associated with worse disease-free survival and systemic recurrence in patients with non-metastatic rectal cancer. • pmrEMVI is a predictive biomarker of poor DFS following nCRT in patients with LARC. • The presence of pmrEMVI was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

Prognostic impact of extramural venous invasion detected by contrast-enhanced CT colonography in colon cancer

BACKGROUND

The impact of computed tomography (CT)-detected extramural venous invasion on the recurrence of colon cancer is not fully understood. The aim of this study was to investigate the clinical significance of extramural venous invasion diagnosed before surgery by contrast-enhanced CT colonography using three-dimensional multiplanar reconstruction images.

METHODS

Patients with colon cancer staged greater than or equal to T2 and/or stage I-III who underwent contrast-enhanced CT colonography between 2013 and 2018 at the National Cancer Center Hospital in Japan were retrospectively investigated for CT-detected extramural venous invasion. Inter-observer agreement for the detection of CT-detected extramural venous invasion was evaluated and Kaplan-Meier survival curves were plotted for recurrence-free survival using CT-TNM staging and CT-detected extramural venous invasion. Preoperative clinical variables were analysed using Cox regression for recurrence-free survival.

RESULTS

Out of 922 eligible patients, 544 cases were analysed (50 (9.2 per cent) were diagnosed as positive for CT-detected extramural venous invasion and 494 (90.8 per cent) were diagnosed as negative for CT-detected extramural venous invasion). The inter-observer agreement for CT-detected extramural venous invasion had a κ coefficient of 0.830. The group positive for CT-detected extramural venous invasion had a median follow-up of 62.1 months, whereas the group negative for CT-detected extramural venous invasion had a median follow-up of 60.7 months. When CT-TNM stage was stratified according to CT-detected extramural venous invasion status, CT-T3 N(-)extramural venous invasion(+) had a poor prognosis compared with CT-T3 N(-)extramural venous invasion(-) and CT-stage I (5-year recurrence-free survival of 50.6 versus 89.3 and 90.1 per cent respectively; P < 0.001). In CT-stage III, the group positive for CT-detected extramural venous invasion also had a poor prognosis compared with the group negative for CT-detected extramural venous invasion (5-year recurrence-free survival of 52.0 versus 78.5 per cent respectively; P = 0.003). Multivariable analysis revealed that recurrence was associated with CT-T4 (HR 3.10, 95 per cent c.i. 1.85 to 5.20; P < 0.001) and CT-detected extramural venous invasion (HR 3.08, 95 per cent c.i. 1.90 to 5.00; P < 0.001).

CONCLUSION

CT-detected extramural venous invasion was found to be an independent predictor of recurrence and could be used in combination with preoperative TNM staging to identify patients at high risk of recurrence.

Survival outcomes of different neoadjuvant treatment regimens in patients with locally advanced rectal cancer and MRI-detected extramural venous invasion

PURPOSE

MRI-detected extramural venous invasion (mrEMVI) is associated with poor survival outcomes in patients with locally advanced rectal cancer (LARC). An mrEMVI-positive status is considered a strong indication for neoadjuvant treatment, but the optimal regimen is unknown.

PATIENTS AND METHODS

We retrospectively compared pathological and survival outcomes of 584 patients diagnosed with mrEMVI-positive rectal cancer between January 2013 and October 2021, and receiving either neoadjuvant chemotherapy (NCT) alone, neoadjuvant chemoradiotherapy (nCRT) alone, or nCRT plus NCT, prior to total mesorectal excision. Propensity score matching (PSM) was used to balance clinical bias between groups, which were compared using chi-square testing and Kaplan-Meier curves.

RESULTS

Median follow-up was 33.9 (range, 10.2-100.4) months. The 3-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS) rates for all patients were 90.4%, 57.5%, 61.1%, and 85.7%, respectively. Of 584 mrEMVI-positive patients at the time of diagnosis, 457 (78.3%) were EMVI-negative on surgical pathology, and they had significantly better 3-year OS, DMFS, DFS, and LRFS rates (all p < 0.001) than patients who remained EMVI-positive. After PSM was applied, patients receiving nCRT alone had significantly better 3-year OS (96.8% vs. 86.5%, p = 0.005) and DMFS (67.1% vs. 53.5%, p = 0.03) rates than those receiving NCT alone. Patients receiving NCT plus nCRT had higher pathological complete response (PCR) (10.8% vs. 2.7%, p = 0.04) and downstaging (33.8% vs. 5.3%, p < 0.001) rates than those receiving nCRT alone, but survival rates did not differ (all p > 0.05).

CONCLUSION

Most EMVI-positive patients with LARC converted to EMVI-negative after neoadjuvant treatment, resulting in improved OS and DFS. Patients receiving nCRT had more favorable survival outcomes than those receiving NCT, suggesting the importance of including neoadjuvant radiotherapy. Patients receiving NCT in addition to nCRT had higher rates of PCR and downstaging, but their survival rates were not better.

MRI Assessment of Extramural Venous Invasion Before and After Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer and Its Association with Disease-Free and Overall Survival

BACKGROUND

Extramural venous invasion (EMVI) on baseline MRI is associated with poor prognosis in patients with locally advanced rectal cancer. This study investigated the association of persistent EMVI after total neoadjuvant therapy (TNT) (chemoradiotherapy and systemic chemotherapy) with survival.

METHODS

Baseline MRI, post-TNT MRI, and surgical pathology data from 175 patients with locally advanced rectal cancer who underwent TNT and total mesorectal excision between 2010 and 2017 were retrospectively analyzed for evidence of EMVI. Two radiologists assessed EMVI status with disagreement adjudicated by a third. Pathologic EMVI status was assessed per departmental standards. Cox regression models evaluated the associations between EMVI and disease-free and overall survival.

RESULTS

EMVI regression on both post-TNT MRI and surgical pathology was associated with disease-free survival (hazard ratio, 0.17; 95% confidence interval (CI), 0.04-0.64) and overall survival (hazard ratio, 0.11; 95% CI, 0.02-0.68). In an exploratory analysis of 35 patients with EMVI on baseline MRI, only six had EMVI on pathology compared with 18 on post-TNT MRI; these findings were not associated (p = 0.2). Longer disease-free survival was seen with regression on both modalities compared with remaining positive. Regression on pathology alone, independent of MRI EMVI status, was associated with similar improvements in survival.

CONCLUSIONS

Baseline EMVI is associated with poor prognosis even after TNT. EMVI regression on surgical pathology is common even with persistent EMVI on post-TNT MRI. EMVI regression on surgical pathology is associated with improved DFS, while the utility of post-TNT MRI EMVI persistence for decision-making and prognosis remains unclear.

Neoadjuvant chemotherapy with modified FOLFOXIRI for locally advanced rectal cancer to transform effectively EMVI and MRF from positive to negative: results of a long-term single center phase 2 clinical trial

PURPOSE

Chemoradiotherapy (CRT) remains the standard treatment for locally advanced rectal cancer (LARC). This phase 2 clinical trial was designed to evaluate the efficacy and safety of neoadjuvant triplet chemotherapy with mFOLFOXIRI (folinic acid, 5-fluorouracil, oxaliplatin, and irinotecan) in LARC.

PATIENTS AND METHODS

The patients with LARC (the lower edge more than 5 cm from the anal verge) received up to 5 cycles of mFOLFOXIRI. MRI was performed to assess the baseline and postchemotherapy TN stage. Radical resection was performed within 4-6 weeks from the last dose of chemotherapy if the tumor shrank or remained stable. Adjuvant chemotherapy with mFOLFOX6 or XELOX was recommended. Postoperative radiation was planned for R1 resection, ypT4b, ypN2 and a positive CRM. The primary endpoint was the pathological complete response (pCR) rate.

RESULTS

From February 2016 to March 2019, 50 patients were enrolled. Forty-eight (96%) were clinically node-positive, 28 (56.5%) with MRF invasion and 39 (78.4%) were EMVI positive. The median cycle of neoadjuvant mFOLFOXIRI chemotherapy was 5 (range,1-5). A total of 46/50 (92%) patients underwent total mesorectal excision (TME) surgery, all with R0 resection. The pCR rate was 4.3% (2/46). Twenty-three of 46 (50%) patients with cN + achieved a pathological node-negative status. The proportions of pathologically positive CRM and EMVI were 2.2% and 34.7%, respectively. Adjuvant radiotherapy was given to 14/46 (30.4%) patients. The most common Grade 3 or > toxicities included neutrocytopenia (50%), leukopenia (14%) and diarrhea (12%) during the neoadjuvant chemotherapy period. Clinically meaningful postoperative complications included pneumonia (n = 1), pelvic infection (n = 1) and anastomotic fistula (n = 1). With a median follow-up time of 51.2 months, local recurrences and distant metastases were confirmed in 3 (6.5%) and 9 (19.6%) of cases, respectively. The 3-year disease free survival (DFS) and overall survival (OS)rates were 75.8% and 86.8%.

CONCLUSION

Neoadjuvant chemotherapy with mFOLFOXIRI yielded a significant down-staging effect and seemed to be effective in eliminating EMVI and transforming the positive MRF to negative in LARC. The survival results are promising. The long-term follow-up showed promising DFS and OS rates accompanied by a favorable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03443661, 23/02/2018.

Watch-and-Wait Approach to Rectal Cancer: The Role of Imaging

The diagnosis and treatment of rectal cancer have evolved dramatically over the past several decades. At the same time, its incidence has increased in younger populations. This review will inform the reader of advances in both diagnosis and treatment. These advances have led to the watch-and-wait approach, otherwise known as nonsurgical management. This review briefly outlines changes in medical and surgical treatment, advances in MRI technology and interpretation, and landmark studies or trials that have led to this exciting juncture. Herein, the authors delve into current state-of-the-art methods to assess response to treatment with MRI and endoscopy. Currently, these methods for avoiding surgery can be used to detect a complete clinical response in as many as 50% of patients with rectal cancer. Finally, the limitations of imaging and endoscopy and future challenges will be discussed.

Extramural vascular invasion nomogram before radical resection of rectal cancer based on magnetic resonance imaging

Purpose

This study verified the value of magnetic resonance imaging (MRI) to construct a nomogram to preoperatively predict extramural vascular invasion (EMVI) in rectal cancer using MRI characteristics.

Materials and methods

There were 55 rectal cancer patients with EMVI and 49 without EMVI in the internal training group. The external validation group consisted of 54 rectal cancer patients with EMVI and 55 without EMVI. High-resolution rectal T2WI, pelvic diffusion-weighted imaging (DWI) sequences, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) were used. We collected the following data: distance between the lower tumor margin and the anal margin, distance between the lower tumor margin and the anorectal ring, tumor proportion of intestinal wall, mrT stage, maximum tumor diameter, circumferential resection margin, superior rectal vein width, apparent diffusion coefficient (ADC), T2WI EMVI score, DWI and DCE-MRI EMVI scores, demographic information, and preoperative serum tumor marker data. Logistic regression analyses were used to identify independent risk factors of EMVI. A nomogram prediction model was constructed. Receiver operating characteristic curve analysis verified the predictive ability of the nomogram. P &lt; 0.05 was considered significant.

Result

Tumor proportion of intestinal wall, superior rectal vein width, T2WI EMVI score, and carbohydrate antigen 19-9 were significant independent predictors of EMVI in rectal cancer and were used to create the model. The areas under the receiver operating characteristic curve, sensitivities, and specificities of the nomogram were 0.746, 65.45%, and 83.67% for the internal training group, respectively, and 0.780, 77.1%, and 71.3% for the external validation group, respectively.

Data conclusion

A nomogram including MRI characteristics can predict EMVI in rectal cancer preoperatively and provides a valuable reference to formulate individualized treatment plans and predict prognosis.

Prognostic Impact of Extramural Lymphatic, Vascular, and Perineural Invasion in Stage II Colon Cancer: A Comparison With Intramural Invasion

BACKGROUND

Lymphatic invasion, vascular invasion, and perineural invasion are prognostic factors for colon cancer. However, the prognostic significance of those factors according to the location of permeation (intramural and extramural invasion) in stage II colon cancer is still unclear.

OBJECTIVE

This study aimed to clarify whether the location of lymphatic invasion, vascular invasion, and perineural invasion could affect the survival of patients with stage II colon cancer.

DESIGN

This was a retrospective cohort study.

SETTINGS

This study took place at a university teaching hospital.

PATIENTS

A total of 1130 patients with stage II colon cancers who underwent radical surgery at the Seoul National University Hospital between July 2003 and December 2015 were included.

MAIN OUTCOME MEASURES

Patients were classified according to the location of lymphatic invasion, vascular invasion, and perineural invasion. Survival outcomes were compared among those without invasion and those with intramural and extramural invasion. Primary end point is overall survival and secondary end point is disease-free survival.

RESULTS

Disease-free survival and overall survival of patients with extramural invasion were worse than those of patients without invasion and those with intramural invasion. Multivariate analysis for survival outcomes confirmed that extramural invasion was a significant independent prognostic factor. However, both disease-free survival and overall survival were not significantly different between patients without invasion and those with intramural invasion.

LIMITATIONS

This study was limited by its retrospective design.

CONCLUSIONS

Extramural invasion was associated with worse prognosis in stage II colon cancer, but intramural invasion was not. Therefore, pathologic reports about the location of lymphatic invasion, vascular invasion, and perineural invasion might be helpful for predicting prognosis and for determining the need of adjuvant chemotherapy in stage II colon cancers. See Video Abstract at http://links.lww.com/DCR/B939 .

IMPACTO PRONSTICO DE LA INVASION EXTRAMURAL LINFTICA, VASCULAR Y PERINEURAL EN EL CNCER DE COLON ESTADO II ESTUDIO COMPARATIVO CON RELACIN A LA INVASIN INTRAMURAL

ANTECEDENTES:La invasión linfática, vascular y perineural son factores pronósticos para el cáncer de colon. Sin embargo, la importancia pronóstica de estos factores de acuerdo con la ubicación de la permeabilidad (invasión intramural y extramural) del cáncer de colon en estadío II aún no está aclarada.OBJETIVO:El presente estudio tiene por objetivo, el de aclarar si la localización de la invasión linfática, vascular y perineural podría afectar la sobrevida en los pacientes con cáncer de colon en estadío II.DISEÑO:Estudio de cohortes de caracter retrospectivo.AJUSTES:Nuestro estudio se llevó a cabo en un hospital docente universitario.PACIENTES:Se incluyeron un total de 1130 pacientes diagnosticados con cáncer de colon en estadío II, los cuales fueron sometidos a cirugía radical en el Hospital Universitario Nacional de Seúl, entre julio de 2003 y diciembre de 2015.PRINCIPALES MEDIDAS DE RESULTADO:Los pacientes fueron clasificados según la localización de la invasión linfática, vascular y perineural. Los resultados de la sobrevida fueron comparados con aquellos sin invasión y los otros con invasión intramural y extramural. El objetivo final primario fué la sobrevida global, el objetivo final secundario fué la sobrevida libre de enfermedad.RESULTADOS:La sobrevida libre de enfermedad y la sobrevida global de los pacientes con invasión extramural fueron mucho peores en relacion a las de los pacientes sin invasión y aquellos con invasión intramural. El análisis multivariado de los resultados de la sobrevida confirmaron que la invasión extramural es un factor pronóstico independiente muy significativo. Sin embargo, tanto la sobrevida libre de enfermedad, como la sobrevida global no fueron significativamente diferentes entre los pacientes sin invasión y aquellos con invasión intramural.LIMITACIONES:Estudio limitado por su diseño con caracter retrospectivo.CONCLUSIONES:La invasión extramural fué asociada con un peor pronóstico en el cáncer de colon en estadío II, pero la invasión intramural no lo fué. Por tanto, los informes anatomopatológicos sobre la ubicación de la invasión linfática, vascular y perineural, podrían ser útiles para predecir el pronóstico y determinar el menester de la quimioterapia adyuvante en los cánceres de colon en estadío II. Consulte Video Resumen en http://links.lww.com/DCR/B939 . (Traducción-Dr. Xavier Delgadillo ).

Japanese multicenter prospective study investigating laparoscopic surgery for locally advanced rectal cancer with evaluation of CRM and TME quality (PRODUCT trial)

Aim

In Japan, we have not been able to validate the results of laparoscopic surgery for locally advanced rectal cancer using the universal index "circumferential resection margin (CRM)." Previously, we established a semi-opened circular specimen processing method and validated its feasibility. In the PRODUCT trial, we aimed to assess CRM in patients with locally advanced rectal cancer who underwent laparoscopic rectal resection.

Methods

This was a multicenter, prospective, observational study. Eligible patients had histologically confirmed rectal adenocarcinoma located at or below 12 cm above the anal verge with clinical stage II or III and were scheduled for laparoscopic or robotic surgery. The primary endpoint was pathological CRM. CRM ≤1 mm was defined as positive.

Results

A total of 303 patients operated on between August 2018 and January 2020 were included in the primary analysis. The number of patients with clinical stage II and III was 139 and 164, respectively. Upfront surgery was performed for 213 patients and neoadjuvant therapy for 90 patients. The median CRM was 4.0 mm (IQR, 2.1-8.0 mm), and CRM was positive in 26 cases (8.6%). Univariate and multivariate analyses demonstrated that a predicted CRM from the mesorectal fascia of ≤1 mm on MRI was the significant factor for positive CRM (P = .0012 and P = .0045, respectively).

Conclusion

This study showed the quality of laparoscopic rectal resection based on the CRM in Japan. Preoperative MRI is recommended for locally advanced rectal cancer to prevent CRM positivity.

The prognostic value of extramural venous invasion in preoperative MRI of rectal cancer patients

AIM

This study aimed to examine the prognostic value of extramural venous invasion observed in preoperative MRI on survival and recurrences.

METHOD

In total, 778 rectal cancer patients were evaluated in multidisciplinary meetings in Helsinki University Hospital during the years 2016-2018. 635 patients met the inclusion criteria of stage I-III disease and were intended for curative treatment at the time of diagnosis. 128 had extramural venous invasion in preoperative MRI.

RESULTS

The median follow-up time was 2.5 years. In a univariate analysis extramural venous invasion was associated with poorer disease-specific survival (hazard ratio [HR] 2.174, 95% CI 1.118-4.224, P = 0.022), whereas circumferential margin ≤1 mm, tumour stage ≥T3c or nodal positivity were not. Disease recurrence occurred in 17.3% of the patients: 13.4% had metastatic recurrence only, 1.7% mere local recurrence and 2.2% both metastatic and local recurrence. In multivariate analysis, extramural venous invasion (HR 1.734, 95% CI 1.127-2.667, P = 0.012) and nodal positivity (HR 1.627, 95% CI 1.071-2.472, P = 0.023) were risk factors for poorer disease-free survival (DFS). Circumferential margin ≤1 mm was a risk factor for local recurrence in multivariate analysis (HR 5.675, 95% CI 1.274-25.286, P = 0.023).

CONCLUSION

In MRI, circumferential margin ≤1 mm is a risk factor for local recurrence, but the risk is quite well controlled with chemoradiotherapy and extended surgery. Extramural venous invasion instead is a significant risk factor for poorer DFS and new tools to reduce the systemic recurrence risk are needed.

Assessment of the 2020 NICE criteria for preoperative radiotherapy in patients with rectal cancer treated by surgery alone in comparison with proven MRI prognostic factors: a retrospective cohort study

BACKGROUND

Selection of patients for preoperative treatment in rectal cancer is controversial. The new 2020 National Institute for Health and Care Excellence (NICE) guidelines, consistent with the National Comprehensive Cancer Network guidelines, recommend preoperative radiotherapy for all patients except for those with radiologically staged T1-T2, N0 tumours. We aimed to assess outcomes in non-irradiated patients with rectal cancer and to stratify results on the basis of NICE criteria, compared with known MRI prognostic factors now omitted by NICE.

METHODS

For this retrospective cohort study, we identified patients undergoing primary resectional surgery for rectal cancer, without preoperative radiotherapy, at Basingstoke Hospital (Basingstoke, UK) between Jan 1, 2011, and Dec 31, 2016, and at St Marks Hospital (London, UK) between Jan 1, 2007, and Dec 31, 2017. Patients with MRI-detected extramural venous invasion, MRI-detected tumour deposits, and MRI-detected circumferential resection margin involvement were categorised as MRI high-risk for recurrence (local or distant), and their outcomes (disease-free survival, overall survival, and recurrence) were compared with patients defined as high-risk according to NICE criteria (MRI-detected T3+ or MRI-detected N+ status). Kaplan-Meier and Cox proportional hazards analyses were used to compare the groups.

FINDINGS

378 patients were evaluated, with a median of 66 months (IQR 44-95) of follow up. 22 (6%) of 378 patients had local recurrence and 68 (18%) of 378 patients had distant recurrence. 248 (66%) of 378 were classified as high-risk according to NICE criteria, compared with 121 (32%) of 378 according to MRI criteria. On Kaplan-Meier analysis, NICE high-risk patients had poorer 5-year disease-free survival compared with NICE low-risk patients (76% [95% CI 70-81] vs 87% [80-92]; hazard ratio [HR] 1·91 [95% CI 1·20-3·03]; p=0·0051) but not 5-year overall survival (80% [74-84] vs 88% [81-92]; 1·55 [0·94-2·53]; p=0·077). MRI criteria separated patients into high-risk versus low-risk groups that predicted 5-year disease-free survival (66% [95% CI 57-74] vs 88% [83-91]; HR 3·01 [95% CI 2·02-4·47]; p<0·0001) and 5-year overall survival (71% [62-78] vs 89% [84-92]; 2·59 [1·62-3·88]; p<0·0001). On multivariable analysis, NICE risk assessment was not associated with either disease-free survival or overall survival, whereas MRI criteria predicted disease-free survival (HR 2·74 [95% CI 1·80-4·17]; p<0·0001) and overall survival (HR 2·44 [95% CI 1·51-3·95]; p=0·00027). 139 NICE high-risk patients who were defined as low-risk based on MRI criteria had similar disease-free survival as 118 NICE low-risk patients; therefore, 37% (139 of 378) of patients in this study cohort would have been overtreated with NICE 2020 guidelines. Of the 130 patients defined as low-risk by NICE guidelines, 12 were defined as high-risk on MRI risk stratification and would have potentially been missed for treatment.

INTERPRETATION

Compared to previous guidelines, implementation of the 2020 NICE guidelines will result in significantly more patients receiving preoperative radiotherapy. High-quality MRI selects patients with good outcomes (particularly low local recurrence) without radiotherapy, with little margin for improvement. Overuse of radiotherapy could occur with this unselective approach. The high-risk group, with the most chance of benefiting from preoperative radiotherapy, is not well selected on the basis of NICE 2020 criteria and is better identified with proven MRI prognostic factors (extramural venous invasion, tumour deposits, and circumferential resection margin).

FUNDING

None.

ACR Appropriateness Criteria® Staging of Colorectal Cancer: 2021 Update

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Prognostic significance of MR identified EMVI, tumour deposits, mesorectal nodes and pelvic side wall disease in locally advanced rectal cancer

AIM

To study the prognostic significance of MRI identified tumour deposits (TD), extramural vascular invasion (EMVI), lymph node metastases (LNM) and pelvic sidewall (PSW) disease in rectal cancer.

METHODS

This IRB approved study was conducted on patients with stage IIA-IIIC rectal adenocarcinoma treated with neoadjuvant long course chemoradiotherapy (LCCRT) and total mesorectal excision (TME) type of surgery between 2012-2018. A radiologist blinded to outcome reviewed staging and restaging magnetic resonance imaging (MRI) for TD, EMVI, LNM and PSW. The agreement between four radiologists was studied and we obtained outcome data from a prospectively maintained database. The prognostic significance of imaging findings was assessed.

RESULTS

A total of 297 (186 males) patients with a mean age of 47.3 (SD14.4) years were included in the study. The majority had T3 (n = 206) or T4 (n = 59) stage disease. The mean duration of follow-up was 49.3 ± 25 months (6.6-101 months). 5-year overall (OS) and disease-free survival (DFS) was 84% and 74%, respectively. Staging and restaging MRI had EMVI in 49.5% and 31.3%; TD in 47.5% and 31.6%; LNM in 61.1% and 38.1% and PSW in 11.4% and 6.1%. OS was adversely affected by EMVI, TD and PSW with the adjusted HR (aHR) of 3.32, 3.31, 3.27 for staging MRI and 2.99, 3.1, 2.81 for restaging MRI, respectively, p < 0.05. DFS was affected by EMVI (aHR = 1.85, 2.33) and TD (aHR = 1.83, 2.19), p < 0.05. Persistence of these findings after LCCRT led to worst outcome. Intra- and interobserver agreement for EMVI, TD and LN was 0.789, 0.734, 0.406 and 0.449, 0.354, 0.376, respectively, p < 0.001.

CONCLUSIONS

MRI identified that TD, EMVI and PSW disease are independent poor prognostic indicators in rectal cancer patients. Interobserver agreement for these findings was moderate to fair.

Correlation and prognostic value of CT-detected extramural venous invasion and pathological lymph-vascular invasion in colon cancer

PURPOSE

To explore the association between CT-detected extramural vascular invasion (ctEMVI) and lymph-vascular invasion (LVI) in colon cancer, and analyze the prognostic value of ctEMVI in different conditions of LVI.

METHODS

This single-center, retrospective study included 448 colon cancer patients from January 2015 to December 2017. Preoperative CT features and clinical and pathological data were collected. Associations between ctEMVI and LVI were tested. Univariate and multivariate logistic regression was performed. Multivariate Cox regression was performed adjusted with propensity score(PS). Kaplan-Meier method was used to compare survival differences between the ctEMVI and LVI groups. A 1:1 patient pairing was conducted using PS matching to assess the prognostic effect of ctEMVI in LVI subgroups.

RESULTS

Among the 448 patients, there were 261 men and 187 women, with an average age of 63 ± 12 years. The coincidence rate of ctEMVI and LVI was 73.9%. The k coefficient for identifying ctEMVI was 0.84. ctEMVI and LVI were both independent risk factors for overall survival (ctEMVI: HR 2.8, 95% CI 1.5-5.5; LVI: HR 2.2, 95% CI 1.2-4.1) and metastasis-free survival (ctEMVI: HR 3.3, 95% CI 1.7-6.4; LVI: HR 2.4, 95% CI 1.3-4.5) adjusted with PS. In the LVI(+) subgroup, the prognosis of ctEMVI(+) was significantly worse than that of ctEMVI(-); in the LVI(-) subgroup, the prognosis of different ctEMVI states was similar.

CONCLUSION

ctEMVI is an independent prognostic risk factor and has different prognostic value in different LVI states. It is recommended to perform the evaluation in routine work, especially for patients with positive LVI.

MRI for Rectal Cancer: Staging, mrCRM, EMVI, Lymph Node Staging and Post-Treatment Response

Rectal cancer is a relatively common malignancy in the United States. Magnetic resonance imaging (MRI) of rectal cancer has evolved tremendously in recent years, and has become a key component of baseline staging and treatment planning. In addition to assessing the primary tumor and locoregional lymph nodes, rectal MRI can be used to help with risk stratification by identifying high-risk features such as extramural vascular invasion and can assess treatment response for patients receiving neoadjuvant therapy. As the practice of rectal MRI continues to expand further into academic centers and private practices, standard MRI protocols, and reporting are critical. In addition, it is imperative that the radiologists reading these cases work closely with surgeons, medical oncologists, radiation oncologists, and pathologists to ensure we are providing the best possible care to patients. This review aims to provide a broad overview of the role of MRI for rectal cancer.

The importance of MRI for rectal cancer evaluation

Magnetic resonance imaging (MRI) has gained increasing importance in the management of rectal cancer over the last two decades. The role of MRI in patients with rectal cancer has expanded beyond the tumor-node-metastasis (TNM) system in both staging and restaging scenarios and has contributed to identifying "high" and "low" risk features that can be used to tailor and personalize patient treatment; for instance, selecting the patients for neoadjuvant chemoradiation (NCRT) before the total mesorectal excision (TME) surgery based on risk of recurrence. Among those features, the status of the circumferential resection margin (CRM), extramural vascular invasion (EMVI), and tumor deposits (TD) have stood out. Moreover, MRI also has played a role in surgical planning, especially when the tumor is located in the low rectum, when the relationship between tumor and the anal canal is important to choose the best surgical approach, and in cases of locally advanced or recurrent tumors invading adjacent pelvic organs that may require more complex surgeries such as pelvic exenteration. As approaches using organ preservation emerge, including transanal local excision and "watch-and-wait", MRI may help in the patient selection for those treatments, follow up, and detection of tumor regrowth. Additionally, potential MRI-based prognostic and predictive biomarkers, such as quantitative and semi-quantitative metrics derived from functional sequences like diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE), and radiomics, are under investigation. This review provides an overview of the current role of MRI in rectal cancer in staging and restaging and highlights the main areas under investigation and future perspectives.

MRI-detected extramural vascular invasion (mrEMVI) as the best predictive factor to identify candidates to total neoadjuvant therapy in locally advanced rectal cancer

BACKGROUND AND OBJECTIVES

Chemotherapy in locally advanced rectal cancer (LARC) is shifting from an adjuvant setting to a total neoadjuvant therapy (TNT) strategy, that relies on distant metastases (DM) risk prediction. This study aims to assess the accuracy of magnetic resonance imaging-detected extramural vascular invasion (mrEMVI) as predictive factor for DM in LARC, compared with other MRI-detected and pathologic factors.

METHODS

This retrospective single-center study analyzed data extracted from a series of consecutive patients curatively resected for rectal cancer at Mauriziano Hospital in Turin (Italy) from January 2013 to December 2018.

RESULTS

Data from 69 patients were analyzed. MrEMVI was detected in 31 (44.9%) cases. Median follow-up was 39.9 months. DM and local recurrence occurred in 19 (27.5%) and 4 (5.8%) patients. One- and 3-year cumulative incidence of DM were 32.3% (95% confidence interval [CI]: 0.17-0.49) and 56.8% (95% CI: 0.35-0.74) in the mrEMVI-positive group and 5.4% (95% CI: 0.01-0.16) and 14.0% (95% CI: 0.05-0.27) in the mrEMVI-negative group (log-rank test, p < 0.001). In the multivariate analysis of MRI factors, mrEMVI was the only independent predictor of DM (HR: 3.59, CI: 1.21-10.69, p = 0.02).

CONCLUSIONS

This study confirmed that mrEMVI is a powerful predictor of DM in LARC. It should be routinely reported and considered during multidisciplinary care strategy planning.

Oncologic Outcomes Associated With MRI-detected Extramural Venous Invasion (mrEMVI) in Rectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND

The role of MRI-detected EMVI (mrEMVI) as a reliable prognostic factor in rectal cancer has been emphasized in recent years but this finding remains underreported by many institutions.

OBJECTIVE

This review aimed to demonstrate the importance of pre- and post-treatment MRI-detected EMVI as independent prognostic factors of adverse oncologic outcomes in patients undergoing neoadjuvant therapy followed by total mesorectal excision.

METHODS

This review was designed using the PRISMA guidelines. The following electronic databases were searched from January 2002 to January 2020: CENTRAL, Ovid MEDLINE, PubMed, and Ovid Embase. Main outcomes included DFS and overall survival (OS). Other outcomes of interest comprised positive resection margin and synchronous metastases.

RESULTS

Seventeen studies involving a total of 3821 patients were included for data synthesis. For preneoadjuvant treatment mrEMVI, pooled hazard ratio (HR) estimate for DFS was 2.30 (95% confidence intervals (CI) 1.54-3.44) for higher recurrence in mrEMVI-positive patients. mrEMVI-positive patients were found to have a lower OS with a pooled HR of 1.68 (95%CI 1.27-2.22). Pooled risk ratio for synchronous metastasis was 4.11 (95%CI 2.80-6.02) for mrEMVI-positivity. For postneoadjuvant treatment EMVI (ymrEMVI), positive status showed a lower DFS with a pooled HR of 2.04 (95%CI 1.55-2.69). Risk ratio of having a positive resection margin status was 2.95 (95%CI 1.75-4.98) for ymrEMVI-positive patients.

CONCLUSIONS

This review showed that oncologic outcomes are significantly worse for both pre- and post-neoadjuvant treatment mrEMVI-positive patients. MRI-detected EMVI should be consistently reported in rectal cancer staging and may provide guidance for the targeted use of additional systemic therapy.

Extramural venous invasion (EMVI) in colorectal cancer is associated with increased cancer recurrence and cancer-related death

INTRODUCTION

Colorectal cancer (CRC) outcomes vary depending on tumour biology, with several features used to predict disease behaviour. Extramural venous invasion (EMVI) is associated with negative outcomes and its presence has been established as an indicator of more aggressive disease in CRC.

METHODS

A prospectively maintained database was examined for patients undergoing curative resection for non-metastatic CRC between 2012 and 2018 in a tertiary institution. Clinicopathological factors were compared to assess their impact on recurrence, all-cause mortality and cancer-related death. Kaplan Meier analysis of the association between EMVI and these endpoints was performed, and univariable and multivariable analysis was carried out to establish the relationship of predictive factors in oncological outcomes.

RESULTS

Eighty-eight (13.5%) of 654 patients developed recurrence. The mean time to recurrence was 19.8 ± 13.5 months. There were 36 (5.5%) cancer-related deaths at a mean duration of follow-up of 46.3 ± 21.6 months. Two hundred and sixty-six patients had extramural venous invasion (40.7%). EMVI was significantly associated with reduced overall recurrence-free survival, systemic recurrence-free survival, and increased cancer-related death on univariate analysis (p < 0.001 for all, Fig. 1), and multivariable analysis (OR 1.8 and 2.1 respectively, p < 0.05 for both).

CONCLUSION

EMVI is associated with a poor prognosis, independent of stage, nodal status and other histopathological features. The presence of EMVI should be strongly considered as an indication for adjuvant therapy.

Combination of extramural venous invasion and lateral lymph node size detected with magnetic resonance imaging is a reliable biomarker for lateral lymph node metastasis in patients with rectal cancer

PURPOSE

Pathological extramural venous invasion (EMVI) is defined as the active invasion of malignant cells into veins beyond the muscularis propria in colorectal cancer. It is associated with poor prognosis and increases the risk of disease recurrence. Specific findings on MRI (termed MRI-EMVI) are reportedly associated with pathological EMVI. In this study, we aimed to identify risk factors for lateral lymph node (LLN) metastasis related to rectal cancer and to evaluate whether MRI-EMVI could be a new and useful imaging biomarker to help LLN metastasis diagnosis besides LLN size.

METHODS

We investigated 67 patients who underwent rectal resection and LLN dissection for rectal cancer. We evaluated MRI-EMVI grading score and examined the relationship between MRI-EMVI and LLN metastasis.

RESULTS

Pathological LLN metastasis was detected in 18 cases (26.9%), and MRI-EMVI was observed in 32 cases (47.8%). Patients were divided into two cohorts, according to LLN metastasis. Multivariate analyses demonstrated that higher risk of LLN metastasis was significantly associated with MRI-EMVI (P = 0.0112) and a short lateral lymph node axis (≥ 5 mm) (P = 0.0002). The positive likelihood ratios of MRI-EMVI alone, LLN size alone, and the combination of both factors were 2.12, 4.84, and 16.33, respectively. Patients negative for both showed better 2-year relapse-free survival compared to other patients (84.4% vs. 62.1%, P = 0.0374).

CONCLUSIONS

MRI-EMVI was a useful imaging biomarker for identifying LLN metastasis in patients with rectal cancer. The combination of MRI-EMVI and LLN size can improve diagnostic accuracy.

The added value of full and reduced field-of-view apparent diffusion coefficient maps for the evaluation of extramural venous invasion in rectal cancer

OBJECTIVE

To investigate the added value of the quantitative analysis of full and reduced field-of-view apparent diffusion coefficient (fADC and rADC) maps for evaluating extramural venous invasion (EMVI) in rectal cancer.

MATERIALS AND METHODS

A total of 94 rectal cancer patients who underwent direct surgical resection were enrolled in this prospective study. The EMVI status of each patient was evaluated on T2-weighted imaging. The mean values of fADC and rADC within the whole tumor were obtained, and histogram parameters were also extracted. Multivariate binary logistic regression analysis was used to analyze independent predictors of EMVI and construct combined models. Receiver operating characteristic (ROC) curves were applied to assess the diagnostic performance.

RESULTS

The energy, skewness, total energy, and kurtosis of fADC map, and the energy and total energy of rADC map were significantly different between the EMVI-positive and EMVI-negative groups (all P < 0.05). Multivariate logistic regression analysis revealed that kurtosis of fADC and circumferential percentage of tumor were independent predictors of EMVI (odds ratio 1.684 and 2.647, P = 0.020 and 0.009). These two parameters combined with subjective evaluation demonstrated the superior diagnostic performance with the area under the ROC curve, sensitivity, specificity, and accuracy of 0.841 (95% CI 0.752-0.909), 0.739, 0.803, and 0.809, respectively.

CONCLUSION

Whole-tumor histogram analysis of ADC map could potentially provide additional information to improve the diagnostic efficiency for assessing EMVI in rectal cancer, which may be beneficial for treatment decision-making.

Radiologic Factors and Areas of Local Recurrence in Locally Advanced Lower Rectal Cancer After Lateral Pelvic Lymph Node Dissection

BACKGROUND

Identifying preoperative risk factors of local recurrence and patterns of treatment failure resulting after rectal cancer management is important for planning treatment strategies and improving the results of multidisciplinary care.

OBJECTIVE

The purpose of this study was to analyze the associations between the preoperative factors and local recurrence and to investigate the local recurrence areas in patients with locally advanced lower rectal cancer who underwent lateral pelvic lymph node dissection.

DESIGN

The study used a retrospective cohort design.

SETTINGS

It was conducted at a single institution.

PATIENTS

Overall 469 patients with locally advanced lower rectal adenocarcinoma located below the peritoneal reflex who received curative resection with lateral pelvic lymph node dissection during 2010 to 2018 were included.

MAIN OUTCOME MEASURES

Independent risk factors for local recurrence were assessed using multivariate Cox regression. Local recurrence was classified into 3 areas using follow-up images.

RESULTS

A total of 286 patients underwent upfront surgery, 132 patients received neoadjuvant chemotherapy followed by surgery, and 51 patients received preoperative chemoradiotherapy followed by surgery. Eighty-six patients (18.3%) were extramural venous invasion positive, and 113 patients (24.1%) were circumferential resection margin positive. The median follow-up period was 46 months. Local recurrence showed significant association with extramural venous invasion positive (HR = 2.596 (95% CI, 1.321-5.102); p = 0.006) or circumferential resection margin positive (HR = 2.298 (95% CI, 1.158-4.560); p = 0.017). The incidence of local recurrence was observed in 51 patients (10.8%), with the pelvic plexus and internal iliac area being the most frequent (6.6%), followed by the central pelvis area (3.8%), and was markedly low in the obturator area (0.4%).

LIMITATIONS

This was a retrospective, single-institution design.

CONCLUSIONS

Extramural venous invasion status and circumferential resection margin status were associated with a high local recurrence rate in patients who underwent lateral pelvic lymph node dissection. In addition, local recurrence in the obturator area was low compared with that in other areas. See Video Abstract at http://links.lww.com/DCR/B683.

FACTORES RADIOLGICOS Y REAS DE RECURRENCIA LOCAL EN EL CNCER DE RECTO INFERIOR LOCALMENTE AVANZADO DESPUS DE LA DISECCIN GANGLIONAR PLVICA LATERAL

ANTECEDENTES:El identificar los factores de riesgo preoperatorios para recurrencia local y los patrones de fracaso del tratamiento que resultan del manejo del cáncer de recto es importante para planificar las estrategias de tratamiento y mejorar los resultados de la atención multidisciplinaria.OBJETIVO:Analizar las asociaciones entre los factores preoperatorios y la recidiva local, e investigar las áreas de recidiva local en pacientes con cáncer de recto inferior localmente avanzado que se sometieron a disección de ganglios linfáticos pélvicos laterales.DISEÑO:Un diseño de cohorte retrospectivo.ENTORNO CLÍNICO:Una sola institución.PACIENTES:Un total de 469 pacientes con adenocarcinoma rectal inferior localmente avanzado ubicado debajo del reflejo peritoneal que recibieron resección curativa con disección de ganglios linfáticos pélvicos laterales durante 2010-2018.PRINCIPALES MEDIDAS DE RESULTADO:Los factores de riesgo independientes de recurrencia local se evaluaron mediante regresión de Cox multivariante. La recurrencia local se clasificó en 3 áreas utilizando imágenes de seguimiento.RESULTADOS:Doscientos ochenta y seis pacientes se sometieron a cirugía inicial, 132 pacientes recibieron quimioterapia neoadyuvante seguida de cirugía y 51 pacientes recibieron quimiorradioterapia preoperatoria seguida de cirugía. Ochenta y seis pacientes (18,3%) fueron positivos para invasión venosa extramural y 113 pacientes (24,1%) fueron positivos para el margen de resección circunferencial. La mediana del período de seguimiento fue de 46 meses. La recidiva local mostró una asociación significativa con la invasión venosa extramural positiva (cociente de riesgo: 2,596; intervalo de confianza del 95%: 1,321-5,102; p = 0,006) o el margen de resección circunferencial positivo (cociente de riesgo: 2,298; intervalo de confianza del 95%: 1,158-4,560; p = 0,017). La incidencia de recidiva local se observó en 51 pacientes (10,8%), siendo el plexo pélvico y el área ilíaca interna los más frecuentes (6,6%), seguidos del área pélvica central (3,8%), y fue marcadamente baja en el área del obtudador (0.4%).LIMITACIONES:Un diseño retrospectivo de una sola institución.CONCLUSIONES:El estado de invasión venosa extramural o el estado del margen de resección circunferencial se asociaron con una alta tasa de recurrencia local en pacientes que se sometieron a disección de ganglios linfáticos pélvicos laterales. Además, la recurrencia local en el área del obturador fue baja en comparación con la de otras áreas. Consulte Video Resumen en http://links.lww.com/DCR/B683.

Preoperative assessment and optimisation for pelvic exenteration in locally advanced and recurrent rectal cancer: A review

The pre-operative phase in planning a pelvic exenteration or extended resections is critical to optimising patient outcomes. This review summarises the key components of preoperative assessment and planning in patients with locally advanced rectal cancer (LARC) and locally recurrent rectal cancer (LLRC) being considered for potential curative resection. The preoperative period can be considered in 5 key phases: 1) Multidisciplinary meeting (MDT) review and recommendation for neoadjuvant therapy and surgery, 2) Anaesthetic preoperative assessment of fitness for surgery and quantification of risk, 3) Shared decision making with the patient and the process of informed consent, 4) Prehabilitation and physiological optimisation 5) Technical aspects of surgical planning. This review will focus on patients who have been recommended for surgery by the MDT and have completed neoadjuvant therapy. Other important considerations beyond the scope of this review are the various neoadjuvant strategies employed which in this patient group include Total Neo-adjuvant Therapy and reirradiation. Critical to improving perioperative outcomes is the dual aim of achieving a negative resection margin in a patient fit enough for extended surgery. Advanced, realistic communication is required pre-operatively and should be maintained throughout recovery. Optimising patient's physiological and psychological reserve with a preoperative prehabilitation programme is important, with physiotherapy, psychological and nutritional input. From a surgical perspective, image based technical preoperative planning is important to identify risk points and ensure correct surgical strategy. Careful attention to the entire patient journey through these 5 preoperative phases can optimise outcomes with the accumulation of marginal gains at multiple timepoints.

Value of Primary Rectal Tumor PET/MRI in the Prediction of Synchronic Metastatic Disease

PURPOSE

To analyze the associations between positron emission tomography (PET)/magnetic resonance imaging (MRI) features for primary rectal tumors and metastases.

PROCEDURES

Between November 2016 and April 2018, 101 patients with rectal adenocarcinoma were included in this prospective study (NCT02537340) for whole-body PET/MRI for baseline staging. Two readers analyzed the PET/MRI; they assessed the semiquantitative PET features of the primary tumor and the N- and M-stages. Another reader analyzed the MRI features for locoregional staging. The reference standard for confirming metastatic disease was biopsy or imaging follow-up. Non-parametric tests were used to compare the PET/MRI features of the participants with or without metastatic disease. Binary logistic regression was used to evaluate the associations between the primary tumor PET/MRI features and metastatic disease.

RESULTS

A total of 101 consecutive participants (median age 62 years; range: 33-87 years) were included. Metastases were detected in 35.6% (36 of 101) of the participants. Among the PET/MRI features, higher tumor lesion glycolysis (352.95 vs 242.70; P = .46) and metabolic tumor volume (36.15 vs 26.20; P = .03) were more frequent in patients with than in those without metastases. Additionally, patients with metastases had a higher incidence of PET-positive (64% vs 32%; P = .009) and MRI-positive (56% vs 32%; P = .03) mesorectal lymph nodes, extramural vascular invasion (86% vs 49%; P > .001), and involvement of mesorectal fascia (64% vs 42%; P = .04); there were also differences between the mrT stages of these two groups (P = .008). No differences in the maximum standardized uptake values for the primary tumors in patients with and without metastases were observed (18.9 vs 19.1; P = .56). Multivariable logistic regression showed that extramural vascular invasion on MRI was the only significant predictor (adjusted odds ratio, 3.8 [95% CI: 1.1, 13.9]; P = .001).

CONCLUSION

PET/MRI facilitated the identification of participants with a high risk of metastatic disease, though these findings were based mainly on MRI features.

Orthotopic Versus Allotopic Implantation: Comparison of Radiological and Pathological Characteristics

Background

In experimental animal models, implantation location might influence the heterogeneity and overall development of the tumor, leading to an interpretation bias.

Purpose

To investigate the effects of implantation location in experimental tumor model using magnetic resonance imaging (MRI) and pathological findings.

Study Type

Prospective.

Subjects

Forty‐five breast cancer‐bearing mice underwent orthotopic (N = 15) and heterotopic (intrahepatic [N = 15] and subcutaneous [N = 15]) implantation.

Field Strength/Sequence

Sequences including: T1‐weighted turbo spin echo sequence, T2‐weighted blade sequence, diffusion‐weighted imaging, pre‐ and post‐contrast T1 mapping, multi‐echo T2 mapping at 3.0 T.

Assessment

MRI was performed at 7, 14, and 21 days after implantation. Native T1, post‐contrast T1, T2, and apparent diffusion coefficient (ADC) of tumors, the tumor volume and necrosis volume within tumor were obtained. Lymphocyte cells from H&E staining, Ki67‐positive, and CD31‐positive cells from immunohistochemistry were determined.

Statistical Tests

One‐way analysis of variance and Spearman's rank correlation were performed. P value <0.05 was considered statistically significant.

Results

The tumor volume (intrahepatic vs. orthotopic vs. subcutaneous: 587.50 ± 77.62 mm³ vs. 814.00 ± 43.85 mm³ vs. 956.13 ± 119.22 mm³), necrosis volume within tumor (89.10 ± 26.60 mm³ vs. 292.41 ± 57.92 mm³ vs. 179.91 ± 31.73 mm³, respectively), ADC at day 21 (543.41 ± 42.28 vs. 542.92 ± 99.67 vs. 369.83 ± 42.90, respectively), and post‐contrast T1 at all timepoints (day 7: 442.00 ± 11.52 vs. 435.00 ± 22.90 vs. 394.33 ± 29.95; day 14: 459.00 ± 26.11 vs. 436.83 ± 26.01 vs. 377.00 ± 27.83; day 21: 463.50 ± 23.49 vs. 458.00 ± 34.28 vs. 375.00 ± 30.55) were significantly different between three groups. Necrosis volumes of subcutaneous and intrahepatic tumors were significantly lower than those of orthotopic tumors. The CD31‐positive rate in the intrahepatic implantation was significantly higher than in orthotopic and subcutaneous groups. Necrosis volume (r = −0.71), ADC (r = −0.85), and post‐contrast T1 (r = −0.75) were strongly correlated with vascular invasion index.

Data Conclusion

Orthotopic and heterotopic tumors have their unique growth kinetics, necrosis volume, and vascular invasion. Non‐invasive MR quantitative parameters, including ADC and post‐contrast T1, may reflect vascular invasion in mice.

Level of Evidence

1

Technical Efficacy

Stage 3

MRI-detected extramural venous invasion of rectal cancer: Multimodality performance and implications at baseline imaging and after neoadjuvant therapy

MRI is routinely used for rectal cancer staging to evaluate tumor extent and to inform decision-making regarding surgical planning and the need for neoadjuvant and adjuvant therapy. Extramural venous invasion (EMVI), which is intravenous tumor extension beyond the rectal wall on histopathology, is a predictor for worse prognosis. T2-weighted images (T2WI) demonstrate EMVI as a nodular-, bead-, or worm-shaped structure of intermediate T2 signal with irregular margins that arises from the primary tumor. Correlative diffusion-weighted images demonstrate intermediate to high signal corresponding to EMVI, and contrast enhanced T1-weighted images demonstrate tumor signal intensity in or around vessels. Diffusion-weighted and post contrast images may increase diagnostic performance but decrease inter-observer agreement. CT may also demonstrate obvious EMVI and is potentially useful in patients with a contraindication for MRI. This article aims to review the spectrum of imaging findings of EMVI of rectal cancer on MRI and CT, to summarize the diagnostic accuracy and inter-observer agreement of imaging modalities for its presence, to review other rectal neoplasms that may cause EMVI, and to discuss the clinical significance and role of MRI-detected EMVI in staging and restaging clinical scenarios.

Prognostic Importance of MRI-Detected Extramural Venous Invasion in Rectal Cancer: A Literature Review and Systematic Meta-Analysis

PURPOSE

Extramural venous invasion (EMVI) is recognized as a poor prognostic factor in rectal cancer. There are well-documented limitations associated with pathology detection of EMVI, including variable reporting and the inability to use it preoperatively to guide neoadjuvant treatment. Magnetic resonance imaging (MRI)-detected EMVI (mrEMVI) has been proposed as an imaging biomarker. This review assesses the prognostic significance of mrEMVI on survival outcomes and whether regression of mrEMVI after neoadjuvant therapy is associated with improvements in survival.

METHODS AND MATERIALS

An electronic search was carried out using MEDLINE and EMBASE databases using the search terms "rectum," "cancer,", "MRI," and "outcomes." A systematic review and meta-analysis were carried out in accordance with Preferred Reporting for Systematic Reviews and Meta-Analyses guidelines using Review Manager software. A qualitative review was performed.

RESULTS

A total of 7399 articles were identified, of which 33 were relevant to the review question. After a qualitative assessment, 20 articles were included in the meta-analysis. Baseline mrEMVI positivity is associated with significantly worsened overall survival (hazard ratio [HR] 1.84; 95% confidence interval [CI], 1.33-2.54; P = .0001) and significantly worsened disease-free survival (HR 2.41; 95% CI, 2.02-2.89; P < .00001). After neoadjuvant treatment, a positive mrEMVI status is associated with a significantly worsened overall and disease-free survival. Only 3 papers specifically looked at mrEMVI regression, but the results show that persistent mrEMVI-positive status after treatment is associated with significantly worsened disease-free survival compared with a change in mrEMVI from positive to negative (HR 1.93; 95% CI, 1.39-2.68; P < .0001). A subgroup analysis of MRI-detected lymph node metastases showed no significant association with survival, with a hazard ratio of 1.33 (95% CI, 0.98-1.80; P = .06).

CONCLUSION

mrEMVI is significantly associated with worsened survival outcomes, both at baseline and after neoadjuvant treatment. Additionally, there is evidence that regression of mrEMVI after neoadjuvant treatment is associated with improved survival compared with mrEMVI persistence. The findings of this review emphasize the need for accurate and consistent reporting of mrEMVI status before and after neoadjuvant treatment and support the inclusion of mrEMVI into staging systems preferentially over lymph node metastases.

The prognostic value of MRI-detected extramural vascular invasion (mrEMVI) for rectal cancer patients treated with neoadjuvant therapy: a meta-analysis

OBJECTIVES

The purpose of this meta-analysis was to evaluate the prognostic value of MRI-detected extramural vascular invasion (mrEMVI) and mrEMVI after neoadjuvant therapy (ymrEMVI) in rectal cancer patients receiving neoadjuvant therapy.

METHODS

A systematic search of the PubMed, Web of Science, Embase, and Cochrane Library databases was carried out up to June 2020. Studies that evaluated mrEMVI, used treatment with neoadjuvant therapy, and reported survival were included. The time-to-event outcomes (OS and DFS rates) are expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). If the HR was not reported in the study, it was calculated from the survival curve using methods according to Parmar's recommendation. The Newcastle-Ottawa scale was used to assess the methodological quality of the studies included in the meta-analysis.

RESULTS

A total of 2237 patients from 11 studies were included, and the pooled analysis of the overall results from eight studies showed that patients who were mrEMVI positive at baseline had significantly worse disease-free survival (DFS) (random-effects model: HR = 2.50 [1.84, 3.14]; Z = 5.83, p < 0.00001). The pooled analysis of the overall results from six studies showed that patients who were ymrEMVI positive following neoadjuvant therapy had significantly worse DFS (random-effects model: HR = 2.24 [1.73, 2.90], Z = 6.12, p < 0.00001). Patients with mrEMVI positivity at baseline were also associated with worse overall survival (OS) (random-effects model: HR = 1.93 [1.36, 2.73]; Z = 3.71, p < 0.00001).

CONCLUSION

mrEMVI and ymrEMVI positivity are poor prognostic factors for rectal cancer patients treated with neoadjuvant therapy. The precise evaluation of EMVI may contribute to designing individualised treatments and improving patient outcomes.

KEY POINTS

• Extramural vascular invasion (EMVI) is a prognostic factor for rectal cancer. • MRI can be used to evaluate EMVI status before (mrEMVI) and after neoadjuvant therapy (ymrEMVI). • The evaluation of mrEMVI and ymrEMVI in neoadjuvant therapy would provide an early assessment of patient prognosis.

MRI Staging in an Evolving Management Paradigm for Rectal Cancer, From the AJR Special Series on Cancer Staging

The treatment of rectal cancer centers around the distinct but related goals of management of distant metastases and management of local disease. Optimal local management requires attention to the primary tumor and its anatomic relationship to surrounding pelvic structures, with the goal of minimizing local recurrence (LR). High-resolution MRI is ideally suited for this purpose; application of MRI-based criteria in conjunction with optimized surgical and pathologic techniques have successfully reduced LR rates. This success has led to a shift away from using the TNM-based National Comprehensive Cancer Network (NCCN) guidelines as the sole determinant of whether a patient receives neoadjuvant chemoradiation. The new model uses a hybrid approach for assigning risk categories that combines elements of the TNM staging system with MRI-based anatomic features. These risk categories incorporate tumor proximity to the circumferential resection margin, T category, distance to the anal verge and presence of extramural venous invasion, to classify rectal tumors as low, intermediate, or high-risk. This approach has been validated by accumulated data from numerous multi-institutional studies. This review illustrates key anatomic concepts, depicts common interpretive errors and pitfalls, and discusses ongoing limitations; these insights should guide radiologists in optimal rectal MRI interpretation.

The development and validation of a predictive model for recurrence in rectal cancer based on radiological and clinicopathological data

OBJECTIVE

To develop a prediction model for recurrence by incorporating radiological and clinicopathological prognostic factors in rectal cancer patients.

METHODS

All radiologic and clinicopathologic data of 489 patients with rectal cancer, retrospectively collected from a single institution between 2009 and 2013, were used to develop a predictive model for recurrence using the Cox regression. The model performance was validated on an independent cohort between 2015 and 2017 (N = 168).

RESULTS

Out of 489 derivative patients, 103 showed recurrence after surgery. The prediction model was constructed with the following four significant predictors: distance from anal verge, MR-based extramural venous invasion, pathologic nodal stage, and perineural invasion (HR: 1.69, 2.09, 2.59, 2.29, respectively). Each factor was assigned a risk score corresponding to HR. The derivation and validation cohort were classified by sum of risk scores into 3 groups: low, intermediate, and high risk. Each of these groups showed significantly different recurrence rates (derivation cohort: 13.4%, 35.3%, 61.5 %; validation cohort: 6.2%, 23.7%, 64.7%). Our new model showed better performance in risk stratification, compared to recurrence rates of tumor node metastasis (TNM) staging in the validation cohort (stage I: 3.6%, II: 12%, III: 30.2%). The area under the receiver operating characteristic curve of the new prediction model was higher than TNM staging at 3-year recurrence in the validation cohort (0.853 vs. 0.731; p = .009).

CONCLUSIONS

The new risk prediction model was strongly correlated with a recurrence rate after rectal cancer surgery and excellent for selection of high-risk group, who needs more active surveillance.

KEY POINTS

• Multivariate analysis revealed four significant risk factors to be MR-based extramural venous invasion, perineural invasion, nodal metastasis, and the short distance from anal verge among the radiologic and clinicopathologic data. • Our new recurrence prediction model including radiologic data as well as clinicopathologic data showed high predictive performance of disease recurrence. • This model can be used as a comprehensive approach to evaluate individual prognosis and helpful for the selection of highly recurrent group who needs more active surveillance.

Development and validation of an MRI-based radiomic nomogram to distinguish between good and poor responders in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy

PURPOSE

In the clinical management of patients with locally advanced rectal cancer (LARC), the early identification of poor and good responders after neoadjuvant chemoradiotherapy (N-CRT) is essential. Therefore, we developed and validated predictive models including MRI findings from the structured report template, clinical and radiomics parameters to differentiate between poor and good responders in patients with locally advanced rectal cancer who underwent neoadjuvant chemoradiotherapy.

METHODS

Preoperative multiparametric MRI from 183 patients with locally advanced rectal cancer (122 in the training cohort, 61 in the validation cohort) was included in this retrospective study. After preprocessing, radiomic features were extracted and two methods of feature selection was applied to reduce the number of radiomics features. Logistic regression (LR) and random forest (RF) machine learning classifiers were trained to identify good responders from poor responders. Multivariable logistic regression analysis was used to incorporate the radiomic signature and clinical risk factors into a nomogram. Classifier performance was evaluated using the area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

For the differentiation of poor and good responders, the radiomics model with an LR classifier achieved AUCs of 0.869 and 0.842 for the training and validation cohorts, respectively. The nomogram showed the highest reproducibility and prognostic ability in the training and validation cohorts, with AUCs of 0.923 (95% confidence interval, 0.872-0.975) and 0.898 (0.819-0.978), respectively. Additionally, the nomogram achieved significant risk stratification of patients in respect to progression free survival (PFS).

CONCLUSIONS

The nomogram accurately differentiated good and poor responders in patients with LARC undergoing N-CRT, and showed significant performance for predicting PFS.

Prediction of false-negative extramural venous invasion in patients with rectal cancer using multiple mathematical models of diffusion-weighted imaging

PURPOSE

To investigate the parameters from mono-exponential, stretched-exponential, and intravoxel incoherent motion diffusion-weighted imaging (DWI) models for evaluating false-negative extramural venous invasion (EMVI) on conventional magnetic resonance imaging (MRI) in rectal cancer patients.

MATERIAL AND METHODS

Seventy-two rectal cancer patients with negative EMVI on conventional MRI who underwent direct surgical resection were enrolled in this prospective study. The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), distributed diffusion coefficient (DDC), and water molecular diffusion heterogeneity index (α) values within the whole tumor were obtained to identify the patients with false-negative EMVI. Receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic performance. Multivariate binary logistic regression analysis was conducted to determine the independent risk factors.

RESULTS

The DDC, D*, f, and α values were significantly different in the EMVI-positive and EMVI-negative groups (P =  0.018, and P <  0.001, respectively). The D*, f, and α values demonstrated good diagnostic performance with area under the ROC curve (AUC) of 0.861, 0.824, and 0.854, respectively. The combined model, including D*, α, and tumor location, proved superior diagnostic performance with the AUC, sensitivity, specificity, and accuracy of 0.971, 0.917, 0.967, and 0.931, respectively. The AUC of the combined model was significantly higher than that of the D*, f, and DDC (P = 0.004, 0.045, and 0.002, respectively).

CONCLUSION

Multi-b-value DWI may be a potential tool for identifying micro-EMVI in rectal cancer. The combination of DWI parameters and tumor location leads to superior diagnostic performance.

MRI-detected extramural vascular invasion potentiates the risk for pathological metastasis to the lateral lymph nodes in rectal cancer

PURPOSE

Multidisciplinary treatment for locally advanced rectal cancer requires an accurate assessment of the risk of metastasis to the lateral lymph nodes (LNs). We herein aimed to stratify the risk of pathological metastasis to lateral LNs based on the preoperatively detected malignant features.

METHODS

All patients with rectal cancer who underwent surgery from January 2016 to July 2020 were identified. We recorded the TNM factors; perirectal and lateral LN sizes; and MRI findings, including mesorectal fascia involvement, extramural vascular invasion (EMVI), tumor site, and tumor distance from the anal verge.

RESULTS

101 patients underwent rectal resection with lateral lymph node dissection, of whom 16 (15.8%) exhibited pathological metastases to the lateral LNs. Univariate analyses demonstrated that lateral LN metastasis was significantly correlated with mrEMVI positivity (p = 0.0023) and a baseline lateral LN short-axis length of ≥ 5 mm (p < 0.0001). These significant associations were confirmed by a multivariate analysis (p = 0.0254 and 0.0027, respectively). The lateral LN metastasis rate was as high as 44% in cases bearing both risk factors, compared to 0% in cases lacking both risk factors.

CONCLUSION

The results elucidated in this study may contribute to risk stratification, which can be used when determining the indications for lateral lymph node dissection.

Persistent extramural vascular invasion positivity on magnetic resonance imaging after neoadjuvant chemoradiotherapy predicts poor outcome in rectal cancer

BACKGROUND

In rectal cancer, extramural vascular invasion (EMVI) is the presence of tumour cells in blood vessels outside the muscular layer, which is associated with poor prognosis. Regression of EMVI on MRI following neoadjuvant chemoradiotherapy or its persistence may have prognostic implications.

METHODS

This retrospective study included 52 patients with rectal cancer who underwent total mesorectal excision following long-course neoadjuvant chemoradiotherapy (CRT). EMVI assessments were done on previous pelvic MRIs obtained before neoadjuvant CRT and eight weeks after the completion of neoadjuvant chemoradiotherapy in initially EMVI positive cases.

RESULTS

Persistently EMVI positive patients had worse overall survival and disease-free survival compared to initially EMVI negative patients and patients who returned to negative (p < 0.001 for both). Multivariate analysis identified persistent EMVI positivity after neoadjuvant treatment (HR, 102.9; p = 0.003) as significant independent predictor of worse overall survival; and persistent EMVI positivity (HR, 17.0; p = 0.002), mesorectal fascia involvement after neoadjuvant treatment (HR, 8.0; p = 0.017), and poor differentiation (HR, 10.3, p = 0.012) as significant independent predictors of worse disease-free survival.

CONCLUSION

Persistent EMVI positivity after neoadjuvant therapy appears to be an independent factor for poor overall survival; and persistent EMVI positivity as well as mesorectal fascia involvement on post neoadjuvant therapy MRI and poor differentiation appears to be important predictors of poor disease-free survival in rectal cancer patients.

Preliminary results of simultaneous integrated boost intensity-modulated radiation therapy based neoadjuvant chemoradiotherapy on locally advanced rectal cancer with clinically suspected positive lateral pelvic lymph nodes

Background

Lateral pelvic lymph node (LPLN) is approximately 11–14% and always associated with poorer prognosis. This study investigated the efficacy and safety of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) based on neoadjuvant chemoradiotherapy (NCRT) on locally advanced rectal cancer (LARC) patients with clinically suspected positive LPLNs.

Methods

We retrospectively screened distal LARC patients with NCRT in our center from May 2016 and June 2019. The diagnostic criteria of positive LPLN were nodes of over 7 mm in short axis and irregular border or mixed-signal intensity. All patients with clinically suspected positive LPLN received 56–60 Gy SIB-IMRT in the LPLN area. Concurrent chemotherapy regimens were capecitabine as monotherapy treatment or in combination with oxaliplatin. The toxicities, local-regional recurrence (LRR), and disease-free survival (DFS) were investigated.

Results

Fifty-two eligible patients with clinically suspected positive LPLN were screened and analyzed. The median distance from the distal tumor to the anal verge was 4 cm (range, 0–8 cm), while magnetic resonance imaging (MRI) analysis revealed the median short diameter of the pelvic LPLN to be 8 mm (range, 7–20 mm). There were 28 (53.8%) mesorectal fascia (MRF) positive and 22 (42.3%) extramural venous invasion (EMVI) positive patients. A radiotherapy dose of 41.8 Gy was administered to the pelvic area, while the LPLN received a median SIB dose of 60.0 Gy (range, 56–60 Gy) across 22 fractions. Synchronous capecitabine with or without oxaliplatin was administered during radiotherapy. In summary, 15 (28.8%) patients displayed grade 2–3 radiation-related toxicity, 8 (15.4%) patients underwent additional LPLN dissection, and positive nodes (26 nodes in total) were not observed. One patient suffered a LLR in the presacral region. The median follow-up duration was 21.2 months (range, 4.7–45.0 months), while the duration of 1- and 2-year DFS were 89.9% and 74.6%, respectively. Patients did not display LPLN recurrence.

Conclusions

The safety and efficacy of SIB-IMRT on clinically suspected positive LPLN of LARC patients were deemed acceptable. Patients did not exhibit in-field LPLN recurrence after NCRT combined with single total mesorectal excision (TME).

Risk of nodal disease in patients with MRI-detected extramural vascular invasion in rectal cancer: a systematic review and meta-analysis

BACKGROUND

The impact of magnetic resonance imaging-detected extramural vascular invasion (mrEMVI) in distant metastasis is well known but its correlation with prevalence of lymph node metastasis is less studied. The aim of this systematic review and meta-analysis was to assess the prevalence of nodal disease in mrEMVI-positive and negative cases in rectal cancer.

METHODS

Following guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic literature search in PubMed, Web of Science, Cochrane Library, and EMBase was carried out to identify relevant studies published up to May 2019.

RESULTS

Our literature search generated 10 studies (863 and 1212 mrEMVI-positive and negative patients, respectively). The two groups (mrEMVI-positive and negative) were significantly different in terms of nodal disease status (odds ratio [OR] 3.15; 95% confidence interval [CI] 2.12-4.67; p < 0.001). The prevalence of nodal disease was 75.90% vs 52.56% in the positive mrEMVI vs negative mrEMVI group, respectively (p < 0.001). The prevalence of positive lymph node in positive mrEMVI patients treated with neoadjuvant/adjuvant chemoradiotherapy (nCRT/CRT) (OR 2.47; 95% CI 1.65-3.69; p < 0.001) was less compared with the patients who underwent surgery alone (OR 6.25; 95% CI 3.74-10.44; p < 0.001).

CONCLUSION

The probability of positive lymph nodes in cases of positive mrEMVI is distinctly greater compared with negative cases in rectal cancer. Positive mrEMVI indicates risk of nodal disease prevalence increased by threefold in rectal cancer.

Can extranodal tumour deposits be diagnosed on MRI? Protocol for a multicentre clinical trial (the COMET trial)

INTRODUCTION

Tumour deposits (TDs) are a poor prognostic marker when seen on pathology, and are worse than lymph node metastases (LNMs). They are now being reported on MRI as discontinuous nodules of extramural venous invasion but this diagnosis has not been validated and it is unclear how it correlates with the diagnosis of TDs on pathology.

METHODS AND ANALYSIS

This is a prospective interventional clinical trial which aims to directly map the location of TDs on MRI and correlate what is seen on MRI with the pathology findings at each location. All patients with rectal cancer undergoing resectional surgery are eligible (including those undergoing preoperative therapy). The primary outcome is the prevalence of TDs seen on pathology. Secondary outcomes are to assess radiological and pathological interobserver agreement, assess the effect of TDs on prognosis and carry out exploratory work looking at differences between TDs and LNMs. The estimated sample size is 100 to detect a twofold increase in the pathological diagnosis of TD when MRI mapping is used.

ETHICS AND DISSEMINATION

Ethical approval has been granted from the South Central-Hampshire B Research and Ethics Committee (IRAS 217627). The study will be carried out under standard operative procedures within the Royal Marsden Hospital.

TRIAL REGISTRATION NUMBER

NCT03303547.

The prognostic importance of MRI detected extramural vascular invasion (mrEMVI) in locally advanced rectal cancer

BACKGROUND

MRI detected extramural vascular invasion (mrEMVI) is a poor prognostic factor in rectal cancer patients. The objectives of this study were to assess survival outcomes in patients with and without mrEMVI and to compare the prognostic value of mrEMVI with other rectal cancer features.

METHODS

In a Dutch high volume rectal cancer center cohort of sixty-seven locally advanced rectal cancer patients, an independent radiologist reviewed all primary staging MRI scans. The presence of mrEMVI was correlated to tumor specific and survival outcomes.

RESULTS

20/67 patients had mrEMVI positive rectal cancer. 55% (11/20) developed metachronous metastases, compared with 23% (11/47) in the mrEMVI negative group (OR 4.0, p = 0.01). Overall survival was also decreased with a Hazard ratio of 3.3 (p = 0.01). A multivariable logistic regression with a backward selection procedure was conducted including cT-stage, c-N-stage, extramural tumor invasion depth, mesorectal fascia involvement, distance to anorectal junction, tumor length, mrEMVI, CEA level, and synchronous metastases. After stepwise removal based on p value, only positive mrEMVI remained as a single significant predictor for metachronous metastases (OR: 4.16 , p < 0.05).

CONCLUSION

Positive mrEMVI is a poor prognostic factor in locally advanced rectal cancer with a 4-fold increased risk of developing metachronous metastases after surgery and a worsened overall survival. mrEMVI also appeared an independent risk factor, with a stronger prediction for metachronous metastases than other MRI-detectable tumor characteristics. mrEMVI should be incorporated in all risk stratification guidelines for rectal cancer.

Magnetic resonance imaging performed before and after preoperative chemoradiotherapy in rectal cancer: predictive factors of recurrence and prognostic significance of MR-detected extramural venous invasion

PURPOSE

To evaluate the role of magnetic resonance imaging (MRI) performed before and after neoadjuvant chemoradiotherapy (nCRT) in predicting risk of recurrence in rectal cancer and to investigate the prognostic significance of MR-detected extramural venous invasion (mr-EMVI) and of its regression after nCRT.

METHODS

During 2005-2016, 87 patients with rectal cancer underwent pre- and post-nCRT MRI before surgery. Two radiologists independently reviewed MR examinations retrospectively, assessing T stage, nodal involvement, circumferential resection margin (CRM) status, and mr-EMVI. All four parameters assessed in pre- and post-nCRT MRI were correlated with the risk of recurrence. Correlation with disease-free survival (DFS) was investigated for significant predictive factors in pre-nCRT MRI and for mr-EMVI and its possible regression in post-nCRT MRI.

RESULTS

15 of 87 patients developed recurrence, with a relapse-rate of 17.2%. Statistical analysis showed a significant correlation between CRM involvement and mr-EMVI assessed in pre-nCRT MRI and the risk of recurrence; 3 years-DFS in patients positive for these two parameters was significantly shorter compared with negatives. In post-nCRT MRI, all four parameters correlated significantly with recurrence: mr-EMVI affected significantly 3 years-DFS and its regression after nCRT correlated with a trend toward improvement of survival outcomes, although not statistically significant.

CONCLUSIONS

CRM involvement and mr-EMVI assessed in pre-nCRT MRI should be considered early predictive factors of recurrence in rectal cancer. MRI performed after nCRT has a significant value in predicting risk of recurrence: mr-EMVI confirmed to be a poor prognosis predictor and its regression or persistence after nCRT could have influences on treatment and follow-up strategies.

Staging of Locally Advanced Rectal Cancer Beyond TME

The management of rectal cancer is complex and continually evolving. With advancements in technology and the use of multidisciplinary teams to guide the treatment decision making, staging, oncologic, and functional outcomes are improving, and the management is moving toward personalized treatment strategies to optimize each individual patient's outcomes. Key in this evolution is imaging. Magnetic resonance imaging (MRI) has emerged as the dominant method of pelvic imaging in rectal cancer, and use of MRI for staging is best practice in multiple international guidelines. MRI allows a noninvasive assessment of the tumor site, relationship to surrounding structures, and provides highly accurate rectal cancer staging, which is necessary for determining the appropriate treatment strategy. However, the applications of MRI extend far beyond pretreatment staging. MRI can be used to predict outcomes in locally advanced rectal cancer and guide the surgical or nonsurgical plan, serving as a predictive and prognostic biomarker. With continued MRI hardware improvement and new sequence development, MRI may offer new perspectives in the assessment of treatment response and new innovations that could provide better insight into the staging, restaging, and outcomes with rectal cancer.

Preoperative predictive risk to cancer quality in robotic rectal cancer surgery

BACKGROUND

Circumferential resection margin (CRM) involvement is widely considered the strongest predictor of local recurrence after TME. This study aimed to determine preoperative factors associated with a higher risk of pathological CRM involvement in robotic rectal cancer surgery.

METHODS

This was a retrospective review of a prospectively maintained database of consecutive adult patients who underwent elective, curative robotic low anterior or abdominoperineal resection with curative intent for primary rectal adenocarcinoma in a tertiary referral cancer center from March 2012 to September 2019. Pretreatment magnetic resonance imaging (MRI) reports were reviewed for all the patients. Risk factors for pathological CRM involvement were investigated using Firth's logistic regression and a predictive model based on preoperative radiological features was formulated.

RESULTS

A total of 305 patients were included, and 14 (4.6%) had CRM involvement. Multivariable logistic regression found both T3 >5 mm (OR 6.12, CI 1.35-36.44) and threatened or involved mesorectal fascia (OR 4.54, CI 1.33-17.55) on baseline MRI to be preoperative predictors of pathologic CRM positivity, while anterior location (OR 3.44, CI 0.72-33.13) was significant only on univariate analysis. The predictive model showed good discrimination (area under the receiver-operating characteristic curve >0.80) and predicted a 32% risk of positive CRM if all risk factors were present.

CONCLUSION

Patients with pre-operatively assessed threatened radiological margin, T3 tumors with greater than 5 mm extension and anterior location are at risk for a positive CRM. The predictive model can preoperatively estimate the CRM positivity risk for each patient, allowing surgeons to tailor management to improve oncological outcomes.