One millimetre is the safe cut-off for magnetic resonance imaging prediction of surgical margin status in rectal cancer

Incidental Findings and Their Significance in Rectal MRI: UK Experience

ABSTRACT

Rectal MRI studies used to stage and guide surgical or nonsurgical management of rectal cancer may harbor incidental findings (IFs) of varying significance. St George's Hospital uses a four-sequence MRI protocol which does not employ diffusion-weighted imaging (DW-MRI).

OBJECTIVES

To determine the frequency and significance of incidental findings identified when using a rectal MRI protocol which does not employ DW-MRI.

METHODS

Retrospective analysis of rectal MRI study reports for IFs and stratifying their significance. Medical records were reviewed to clarify IFs of interest.

RESULTS

One hundred thirty-four studies met the inclusion criteria for the study (75 men, mean age 65). 51/134 (38%) of studies had IFs. Fifteen percent (n = 7/46) of baseline studies for a new cancer had significant IFs. The commonest IF was diverticular disease (n = 10); however, a bladder malignancy was also identified.

CONCLUSION

Clinically significant IFs exist in 12% of patients undergoing rectal MRI, and any type of IFs exist in 38% of patients undergoing rectal MRI studies. The rate of significant IFs is comparable with other authors both in rectal and prostate MRI but with fewer overall IFs, possibly due to the lack of DW-MRI sequences in our local protocol. Our study is the first to assess IFs using a rectal MRI protocol which does not employ DW-MRI, and the results should be considered by centers when planning their rectal MRI protocol.

Peritoneal reflection involvement as a prognostic factor in rectal cancer. Long-term oncological outcomes from a prospective study

PURPOSE

To assess the relevance of peritoneal reflection involvement in long-term oncological outcomes in patients with rectal cancer.

METHODS

Prospective observational study from a specialized colorectal unit that included a consecutive series of patients undergoing mesorectal excision for rectal cancer. Peritoneal reflection (PR) involvement was evaluated on pathological examination using Shepherd's classification. Overall survival (OS), disease-free survival (DFS), and local recurrence (LR) were assessed.

RESULTS

One hundred sixty patients were included in the present analysis. Peritoneal involvement was present in 28.2% of the 85 tumors above or at the level of PR. There were no differences in OS, DFS, or LR according to tumor's height location. The 5-year OS, DFS, and LR for tumors involving PR were 58.3%, 61.7%, and 30.3%, respectively. Patients with peritoneal involvement had a higher LR rate (p = 0.02) and shorter OS (p = 0.04). Shepherd's grade 4 peritoneal involvement was an independent risk factor for OS (HR 2.9; 95% CI 1.1-9.5, p = 0.04) and LR (HR 4.2; 95% CI 1.2-16.9, p = 0.04).

CONCLUSION

After rectal cancer resection, peritoneal involvement is an independent risk factor for local recurrence and poor survival.

Diagnostic Certainty in Characterizing Liver Lesions in Rectal Cancer: Abbreviated Liver MRI versus CT

BACKGROUND

Early diagnosis of metastases is crucial but routine staging with contrast-enhanced multidetector computed tomography (ceMDCT) is suboptimal. A total of 20% will have indeterminate or too small to characterize (TSTC) liver lesions on CT, requiring formal characterization by magnetic resonance imaging (MRI). This UK cross-sectional study reports our experience undertaking routine abbreviated liver MRI (MRI).

PATIENTS AND METHODS

A total of 99 patients with rectal cancer had ceMDCT, abbreviated liver MRI, and rectal MRI at diagnosis. Liver imaging was scored for liver metastases, benign or indeterminate/TSTC lesions on a per patient basis. Primary rectal cancer was risk scored on MRI.

RESULTS

A total of 42/99 (42%) had liver lesion(s) on ceMDCT versus 55/99 (56%) by MRI, and 46/99 (46%) had high-risk rectal cancer. ceMDCT showed 5 patients with liver metastases, 14 with benign lesions, and 23 with indeterminate/TSTC lesions. MRI showed 6 with liver metastases, 45 with benign lesions, and 4 with indeterminate/TSTC lesions. All liver metastases were in high-risk rectal cancer, OR 17.18 (p = 0.06), with 12.5% conversion rate of TSTC lesions to metastases in high-risk rectal cancer and 0% in low-risk rectal cancer. Diagnostic certainty of the liver findings was achieved in 93% of patients by MRI compared with 45% by ceMDCT (p < 0.0001).

DISCUSSION

Abbreviated liver MRI diagnosed fewer indeterminate/TSTC lesions and provided greater diagnostic certainty than ceMDCT, p < 0.0001. High-risk rectal cancer is associated with a higher conversation rate of TSTC lesions to metastases than low-risk rectal cancers. Risk stratified; routine abbreviated liver MRI sequences should be investigated as part of the patient pathway for high-risk rectal cancer.

MRI navigation surgery for T4b rectal cancer using multiple minimally invasive surgical approaches

BACKGROUND

These days, various surgical techniques such as trans-anal, trans-perineal total mesorectal excision, and transvaginal natural orifice transluminal endoscopic surgery have been utilized with flexibility, which was not possible before the laparoscopic era.

METHODS

From January 2014 to January 2023, 40 cases of c(yc)T4b rectal cancer underwent local curative surgery laparoscopically at Kansai Medical University Hospital. In 25 consecutive cases, we adopted multiple approaches (trans-anal total mesorectal excision, transvaginal natural orifice transluminal endoscopic surgery, trans-perineal total mesorectal excision, or prone position first abdominoperineal excision) to remove the deepest part of the tumor indicated by MRI last as the specimen-oriented surgery. The remaining 15 patients underwent top-to-bottom surgery based on standard surgery. The primary endpoint was the local recurrence rate of the specimen-oriented surgery group compared to that of the standard surgery group.

RESULTS

The specimen-oriented surgery group had a median follow-up of 3.9 (0.4-7.4) years with no local recurrence, while the standard surgery group had a median follow-up of 1.5 (0.7-3.7) years with 5 of 15 patients (33%) experiencing more local recurrence than specimen-oriented surgery group (p = 0.005). Comparison of the local recurrence ( +) and ( -) groups showed significant differences in pCRM positive rate, neoadjuvant therapy, tumor size, and approach (specimen-oriented surgery vs. standard surgery) in univariate analysis (p < 0.05). Still, no significant differences were found in the multivariate analysis.

CONCLUSIONS

In the laparoscopic setting, local cure of c(yc)T4b rectal cancer requires a different strategy than open surgery, and specimen-oriented surgery may be a promising procedure.

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

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

Multidisciplinary Team Meeting Significantly Enhances Disease-Free Survival in Stage II-III Rectal Cancer

BACKGROUND

Multidisciplinary team (MDT) meetings have been increasingly recognized for enhancing cancer treatment outcomes; however, their specific impact on stage II-III rectal cancer remains to be fully elucidated.

MATERIALS AND METHODS

This retrospective cohort study investigated the influence of MDT meeting on disease-free survival (DFS) and overall survival (OS) in patients with stage II-III rectal cancer. Propensity score matching (PSM) was used to minimize selection bias. Kaplan-Meier survival analysis and Cox proportional hazards models were used to compare DFS and OS between groups.

RESULTS

A total of 502 patients were included, with 176 whose cases were discussed in MDT meetings and 326 who did not undergo MDT discussions. After PSM, 173 patients were matched in each group. The MDT group exhibited a significantly improved DFS compared to the non-MDT group, both before PSM (HR = 0.618, P = .037) and after PSM (HR = 0.545, P = .012). Subgroup analysis indicated notable benefits of MDT discussions for patients with T3 to 4 tumors, low to mid tumor locations, and node-positive tumors. While there was a trend towards improved OS in the MDT group, this did not reach statistical significance. More MDT group patients received MRI staging and neoadjuvant therapy compared to non-MDT group.

CONCLUSIONS

Discussion in MDT meetings is associated with improved DFS in stage II-III rectal cancer, particularly among patients with locally advanced, low to mid rectal cancer. These findings underscore the importance of incorporating MDT discussions into routine clinical practice to optimize outcomes for rectal cancer patients.

Pelvic exenteration for locally advanced rectal cancer and associated outcomes in England between 1995 and 2016: Analysis of a national database

AIM

The clinical burden of pelvic exenteration (PE) for locally advanced rectal cancer (LARC) is nationally under-reported. The widespread use of pelvic MRI since 2005 has increased the accuracy of local staging and awareness of the need for 'beyond TME (total mesorectal excision)' surgery. The aim of this study was to assess the volume of patients undergoing PE within England, which factors affected survival outcomes and whether the use of MRI has influenced these outcomes.

METHOD

The volume of patients undergoing PE and associated survival outcomes across England between 1995 and 2016 was evaluated from Public Health England Hospital Episode Statistics data.

RESULTS

A total of 2996 patients were recorded as undergoing PE. The 5-year overall survival rate improved after 2005 compared with prior to 2005 (61.7% vs. 37%, p < 0.001), with no significant difference between cancer registries throughout England. After 2005, the volume of patients undergoing PE and undergoing preoperative MRI increased, as did the number of non-T4 cancers operated on. After 2005, age, preoperative MRI and preoperative radiotherapy were the significant factors influencing 5-year overall survival on multivariate analysis.

CONCLUSION

This review of national data confirms that PE outcomes are under-reported. MRI staging aids with the identification of patients suitable for perioperative treatment, surgery or palliation and facilitates treatment planning. Since 2005, MRI, likely in combination with advances in surgery and perioperative treatment, has improved survival outcomes. It is imperative that detailed information from patients with LARC undergoing PE is captured and reported in order to optimize care and future service provision.

Assessing neoadjuvant therapy recommendations in 19 national and international guidelines for rectal cancer

BACKGROUND

 Treatment guidelines belong to the most authoritative sources of evidence-based medicine and are widely implemented by health-care providers. Rectal cancer with an annual incidence of over 730,000 new cases and nearly 340,000 deaths worldwide, remains a significant therapeutic challenge. The total mesorectal excision (TME) leads to a dramatic improvement of local control. The addition of neoadjuvant treatment has been proposed to offer further advancement. However, this addition results in significant functional impairment and a decline in the quality of life.

METHODS

This review critically assesses whether the recommendation for neoadjuvant treatment in current international guidelines is substantiated. A comprehensive search was conducted in July 2022 in PubMed resulting in 988 papers published in English between 2012 and 2022. After exclusions and proofs 19 documents remained for further analysis.

RESULTS

Of the 19 guidelines considered in this review, 11 do not recommend upfront surgery, and 12 do not address the issue of functional impairment following multimodal treatment. The recommendation for neoadjuvant therapy relies on outdated references, lacking differentiated strategies based on current utilisation of MRI staging; numerous guidelines recommend neoadjuvant treatment also to subgroups of patients, who may not need this therapy. Also statements regarding conflicts of interest are often not presented.

CONCLUSIONS

An immediate and imperative step is warranted to align the recommendations with the latest available evidence, thereby affording rectal cancer patients a commensurate standard of care. A meticulous assessment of the guideline formulation process has the potential to avert heterogeneity in the future.

Anatomic Basis of Rectal Cancer Staging: Clarifying Controversies and Misconceptions

Rectal MRI provides a detailed depiction of pelvic anatomy; specifically, the relationship of the tumor to key anatomic structures, including the mesorectal fascia, anterior peritoneal reflection, and sphincter complex. However, anatomic inconsistencies, pitfalls, and confusion exist, which can have a strong impact on interpretation and treatment. These areas of confusion include the definition of the rectum itself, specifically differentiation of the rectum from the anal canal and the sigmoid colon, and delineation of the high versus low rectum. Other areas of confusion include the relative locations of the mesorectal fascia and peritoneum and their significance in staging and treatment, the difference between the mesorectal fascia and circumferential resection margin, involvement of the sphincter complex, and evaluation of lateral pelvic lymph nodes. The impact of these anatomic inconsistencies and sources of confusion is significant, given the importance of MRI in depicting the anatomic relationship of the tumor to critical pelvic structures, to triage surgical resection and neoadjuvant chemoradiotherapy with the goal of minimizing local recurrence. Evolving treatment paradigms also place MRI central in management of rectal cancer. ©RSNA, 2024.

Primary staging of rectal cancer on MRI: an updated pictorial review with focus on common pitfalls and current controversies

Magnetic resonance imaging (MRI) plays a pivotal role in primary staging of rectal cancer, enabling the determination of appropriate management strategies and prediction of patient outcomes. However, inconsistencies and pitfalls exist in various aspects, including rectal anatomy, MRI protocols and strategies for artifact resolution, as well as in T- and N-staging, all of which limit the diagnostic value of MRI. This narrative and pictorial review offers a comprehensive overview of factors influencing primary staging of rectal cancer and the role of MRI in assessing them. It highlights the significance of the circumferential resection margin and its relationship with the mesorectal fascia, as well as the prognostic role of extramural venous invasion and tumor deposits. Special attention is given to tumors of the lower rectum due to their complex anatomy and the challenges they pose in MRI staging. The review also addresses current controversies in rectal cancer staging and the need for personalized risk stratification. In summary, this review provides valuable insights into the role of MRI in the primary staging of rectal cancer, emphasizing key aspects for accurate assessment to enhance patient outcomes.

Optimization of treatment strategies based on preoperative imaging features and local recurrence areas for locally advanced lower rectal cancer after lateral pelvic lymph node dissection

Purpose

Local recurrence (LR) is the main cause of treatment failure in locally advanced lower rectal cancer (LALRC). This study evaluated the preoperative risk factors for LR in patients with LALRC to improve the therapeutic strategies.

Patients and Methods

LALRC patients who underwent total mesorectal excision (TME) with lateral pelvic lymph node (LPN) dissection (LPND) from January 2012 to December 2019 were reviewed. The log-rank test was used to assess local recurrence-free survival (LRFS), and multivariate Cox regression was used to identify the prognostic risk factors for LRFS. Follow-up imaging data were used to classify LR according to the location.

Results

Overall, 376 patients were enrolled, and 8.8% (n=33) of these patients developed LR after surgery. Multivariate analysis identified positive clinical circumferential resection margin (cCRM) as an independent prognostic factor for LRFS (HR: 4.94; 95% CI, 1.75-13.94; P=0.003). The most common sites for LR were the pelvic plexus and internal iliac area (PIA) (54.5%), followed by the central pelvic area (CPA) (39.4%) and obturator area (OA) (6.1%). Following a subgroup analysis, LR in the OA was not associated with positive cCRM. Patients treated with upfront surgery (n=35, 14.1%) had a lower cCRM positive rate when compared with patients treated with neoadjuvant chemoradiotherapy (nCRT) (n=12, 23.5%). However, the LR rate in the nCRT group was still lower (n=28, 36.4%) than that in the upfront surgery group (n=35, 14.%). Among patients with positive cCRM, the LR rate in patients with nCRT remained low (n=3, 10.7%).

Conclusion

Positive cCRM is an independent risk factor for LR after TME plus LPND in LALRC patients. LPND is effective and adequate for local control within the OA regardless of cCRM status. However, for LALRC patients with positive cCRM, nCRT should be considered before LPND to further reduce LR in the PIA and CPA.

The value of multimodality MR in T staging evaluation after neoadjuvant therapy for rectal cancer

BACKGROUND

Surgery is the preferred treatment for rectal cancer, but surgical treatment alone sometimes does not achieve satisfactory results.

OBJECTIVE

To explore the value of multimodal Magnetic Resonance (MR) images in evaluating T staging of rectal cancer after neoadjuvant therapy and to compare and analyze with pathological results.

METHODS

This study retrospectively analyzed 232 patients with stage T3, T4 rectal cancer between January 1, 2017 and October 31, 2022. MR examination was performed within 3 days before surgery. Different MR sequences were used for mrT staging of rectal cancer after neoadjuvant therapy and compared with pathological pT staging. The accuracy of different MR sequences in evaluating T staging of rectal cancer was calculated, and the consistency between the two was analyzed by kappa test. The sensitivity, specificity, negative predictive value and positive predictive value of different MR sequences in evaluating rectal cancer invading mesorectal fascia after neoadjuvant therapy were calculated.

RESULTS

A total of 232 patients with rectal cancer were included in the study. The accuracy of high-resolution T2 WI in evaluating T staging of rectal cancer after neoadjuvant therapy was 49.57%, and the Kappa value was 0.261. The accuracy of high-resolution T2WI combined with diffusion weighted imaging (DWI) in evaluating T staging of rectal cancer after neoadjuvant therapy was 61.64%, and the Kappa value was 0.411. The accuracy of high-resolution combined with DCE-MR images in evaluating T staging of rectal cancer after neoadjuvant therapy was 80.60%, and the Kappa value was 0.706. The sensitivity and specificity of high-resolution t2-weighted imaging (HR-T2WI) combined with dynamic contrast-enhancement magnetic resonance (DCE-MR) in evaluating the invasion of mesorectal fascia were 83.46% and 95.33%, respectively.

CONCLUSION

Compared with HR-T2WI combined with DWI images for mrT staging of rectal cancer after neoadjuvant chemoradiotherapy (N-CRT), HR-T2WI combined with DCE-M has the highest accuracy in evaluating mrT staging of rectal cancer after neoadjuvant therapy (80.60%), and has a high consistency with pathological pT staging. It is the best sequence for T staging of rectal cancer after neoadjuvant therapy. At the same time, the sequence has high sensitivity and specificity in evaluating mesorectal fascia invasion, which can provide accurate perioperative information for the formulation of surgical plan.

Identification of patient subgroups with low risk of postoperative local recurrence for whom total mesorectal excision surgery alone is sufficient: a multicenter retrospective analysis

PURPOSE

For rectal cancer, a multimodality approach is mandatory including neoadjuvant chemoradiotherapy, neoadjuvant chemotherapy, and lateral pelvic lymph node (LPLN) dissection, in addition to the total mesorectal excision (TME). However, these treatments are associated with adverse events. It is important to select patients who do or do not need these treatments.

METHODS

We retrospectively analyzed patients with cStage II and III rectal cancer who underwent curative resection at three hospitals. Recurrence patterns were classified into three types; pelvic cavity, LPLN, and distant recurrences, and the risk factors for each pattern of recurrence were compared. We then analyzed the risk of recurrence in the patients who underwent TME alone.

RESULTS

In total, 506 patients were enrolled in this study. Pelvic cavity recurrence was significantly associated with clinical assumption of circumferential resection margin involvement (cCRM) (p < 0.001), distant recurrence was associated with cN positivity (p < 0.001), and LPLN recurrence was associated with pretreatment LPLN swelling ≥ 5 mm (p < 0.001), lower tumor location (p = 0.016), and serum CEA level > 5 ng/mL (p = 0.008). In patients without cCRM and swollen LPLN, the local recurrence rate was extremely low even if they underwent TME alone; the 5-year recurrence rates of pelvic cavity and LPLN were 2.2% and 1.9%, respectively.

CONCLUSION

Additional treatments to TME for rectal cancer need to be performed based on the risk factors for each recurrence pattern.

Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study

INTRODUCTION

To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement.

METHODS

Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy.

RESULTS

Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR.

CONCLUSIONS

Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface.

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.

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.

Postoperative MRI Findings Following Conventional and Extralevator Abdominoperineal Excision in Low Rectal Cancer

Aim: The disparity in outcomes for low rectal cancer may reflect differences in operative approach and quality. The extralevator abdominoperineal excision (ELAPE) was developed to reduce margin involvement in low rectal cancers by widening the excision of the conventional abdominoperineal excision (c-APE) to include the posterior pelvic diaphragm. This study aimed to determine the prevalence and localization of inadvertent residual pelvic diaphragm on postoperative MRI after intended ELAPE and c-APE. Methods: A total of 147 patients treated with c-APE or ELAPE for rectal cancer were included. Postoperative MRI was performed on 51% of the cohort (n = 75) and evaluated with regard to the residual pelvic diaphragm by a radiologist trained in pelvic MRI. Patient records, histopathological reports, and standardized photographs were assessed. Pathology and MRI findings were evaluated independently in a blinded fashion. Additionally, preoperative MRIs were evaluated for possible risk factors for margin involvement. Results: Magnetic resonance imaging-detected residual pelvic diaphragm was identified in 45 (75.4%) of 61 patients who underwent ELAPE and in 14 (100%) of 14 patients who underwent c-APE. An increased risk of margin involvement was observed in anteriorly oriented tumors with 16 (22%) of 73 anteriorly oriented tumors presenting with margin involvement vs. 7 (9%) of 74 non-anteriorly oriented tumors (p = 0.038). Conclusion: Residual pelvic diaphragm following abdominoperineal excision can be depicted by postoperative MRI. Inadvertent residual pelvic diaphragm (RPD) was commonly found in the series of patients treated with the ELAPE technique. Anterior tumor orientation was a risk factor for circumferential resection margin (CRM) involvement regardless of surgical approach.

Development and Validation of an MRI-Based Nomogram Model for Predicting Disease-Free Survival in Locally Advanced Rectal Cancer Treated With Neoadjuvant Radiotherapy

Objectives

To develop a prognostic prediction MRI-based nomogram model for locally advanced rectal cancer (LARC) treated with neoadjuvant therapy.

Methods

This was a retrospective analysis of 233 LARC (MRI-T stage 3-4 (mrT) and/or MRI-N stage 1-2 (mrN), M0) patients who had undergone neoadjuvant radiotherapy and total mesorectal excision (TME) surgery with baseline MRI and operative pathology assessments at our institution from March 2015 to March 2018. The patients were sequentially allocated to training and validation cohorts at a ratio of 4:3 based on the image examination date. A nomogram model was developed based on the univariate logistic regression analysis and multivariable Cox regression analysis results of the training cohort for disease-free survival (DFS). To evaluate the clinical usefulness of the nomogram, Harrell’s concordance index (C-index), calibration plot, receiver operating characteristic (ROC) curve analysis, and decision curve analysis (DCA) were conducted in both cohorts.

Results

The median follow-up times were 43.2 months (13.3–61.3 months) and 32.0 months (12.3–39.5 months) in the training and validation cohorts. Multivariate Cox regression analysis identified MRI-detected extramural vascular invasion (mrEMVI), pathological T stage (ypT) and perineural invasion (PNI) as independent predictors. Lymphovascular invasion (LVI) (which almost reached statistical significance in multivariate regression analysis) and three other independent predictors were included in the nomogram model. The nomogram showed the best predictive ability for DFS (C-index: 0.769 (training cohort) and 0.776 (validation cohort)). It had a good 3-year DFS predictive capacity [area under the curve, AUC=0.843 (training cohort) and 0.771 (validation cohort)]. DCA revealed that the use of the nomogram model was associated with benefits for the prediction of 3-year DFS in both cohorts.

Conclusion

We developed and validated a novel nomogram model based on MRI factors and pathological factors for predicting DFS in LARC treated with neoadjuvant therapy. This model has good predictive value for prognosis, which could improve the risk stratification and individual treatment of LARC patients.

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.

Imaging and Diagnosis for Planning the Surgical Procedure

The preoperative imaging diagnosis of rectal cancer lies at the heart of oncological staging and has a crucial influence on patient management and therapy planning. Rectal cancer is common, and accurate preoperative staging of tumors using high-resolution magnetic resonance imaging (MRI) is a crucial part of modern multidisciplinary team management (MDT). Indeed, rectal MRI has the ability to accurately evaluate a number of important findings that maBay impact patient management, including distance of the tumor to the mesorectal fascia, presence of lymph nodes, presence of extramural vascular invasion (EMVI), and involvement of the anterior peritoneal reflection/peritoneum and the sphincter complex. Many of these findings are difficult to assess in non-expert hands. In this chapter, we present currently used staging modalities with focus on MRI, including optimization of imaging techniques, tumor staging, interpretation help as well as essentials for reporting.

Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study

INTRODUCTION

To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement.

METHODS

Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy.

RESULTS

Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR.

CONCLUSIONS

Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface.

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.

Prognostic importance of circumferential resection margin in the era of evolving surgical and multidisciplinary treatment of rectal cancer: A systematic review and meta-analysis

BACKGROUND

Circumferential resection margin is considered an important prognostic parameter after rectal cancer surgery, but its impact might have changed because of improved surgical quality and tailored multimodality treatment. The aim of this systematic review was to determine the prognostic importance of circumferential resection margin involvement based on the most recent literature.

METHODS

A systematic literature search of MEDLINE, Embase, and the Cochrane Library was performed for studies published between January 2006 and May 2019. Studies were included if 3- or 5-year oncological outcomes were reported depending on circumferential resection margin status. Outcome parameters were local recurrence, overall survival, disease-free survival, and distant metastasis rate. The Newcastle Ottawa Scale and Jadad score were used for quality assessment of the studies. Meta-analysis was performed using a random effects model and reported as a pooled odds ratio or hazard ratio with 95% confidence interval.

RESULTS

Seventy-five studies were included, comprising a total of 85,048 rectal cancer patients. Significant associations between circumferential resection margin involvement and all long-term outcome parameters were uniformly found, with varying odds ratios and hazard ratios depending on circumferential resection margin definition (<1 mm, ≤1 mm, otherwise), neoadjuvant treatment, study period, and geographical origin of the studies.

CONCLUSION

Circumferential resection margin involvement has remained an independent, poor prognostic factor for local recurrence and survival in most recent literature, indicating that circumferential resection margin status can still be used as a short-term surrogate endpoint.

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.

Rectal cancer staging using MRI: adherence in reporting to evidence-based practice

Background

Magnetic resonance imaging (MRI) is the first-line imaging modality for local staging of rectal cancer. The radiology report should deliver all relevant available imaging information to guide treatment.

Purpose

To explore and describe if there was a gap between the contents in MRI reports for primary staging of rectal cancer in Sweden in 2010 compared to evidence-based practice.

Material and Methods

A total of 243 primary MRI staging reports from 2010, collected from 10 hospitals in four healthcare regions in Sweden, were analyzed using content analysis with a deductive thematic coding scheme based on evidence-based practice. Focus was on: (i) most frequently reported findings; (ii) correlation to key prognostic findings; and (iii) identifying if any findings being reported were beyond the information defined in evidence-based practice.

Results

Most frequently reported findings were spread through the bowel wall or not, local lymph node description, tumor length, and distance of tumor from anal verge. These items accounted for 35% of the reporting content. Of all reported content, 86% correlated with the evidence-based practice. However, these included more information than was generally found in the reports. When adjusting for omitted information, 48% of the reported content were accounted for. Of the reported content, 20% correlated to key pathological prognostic findings. Six types of findings were reported beyond the evidence-based practice, representing 14% of the total reporting content.

Conclusion

There was a gap between everyday practice and evidence-based practice in 2010. This indicates a need for national harmonization and implementation of standardized structured reporting templates.

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.

MRI for Rectal Cancer Primary Staging and Restaging After Neoadjuvant Chemoradiation Therapy: How to Do It During Daily Clinical Practice

PURPOSE

To provide a practical overview regarding the state-of-the-art of the magnetic resonance imaging (MRI) protocol for rectal cancer imaging and interpretation during primary staging and restaging after neoadjuvant chemoradiation therapy (CRT), pointing out technical skills and findings that radiologists should consider for their reports during everyday clinical activity.

METHOD

Both 1.5T and 3.0T scanners can be used for rectal cancer evaluation, using pelvic phased array external coils. The standard MR protocol includes T2-weighted imaging of the pelvis, high-resolution T2-weighted sequences focused on the tumor and diffusion-weighted imaging (DWI). The mnemonic DISTANCE is helpful for the interpretation of MR images: DIS, for distance from the inferior part of the tumor to the anorectal-junction; T, for T staging; A, for anal sphincter complex status; N, for nodal staging; C, for circumferential resection margin status; and E, for extramural venous invasion.

RESULTS

Primary staging with MRI is a cornerstone in the preoperative workup of patients with rectal cancer, because it provides clue information for decisions on the administration of CRT and surgical treatment. Restaging after CRT is crucial for treatment planning, and findings on post-CRT MRI correlate with the patient's prognosis and survival. It may be useful to remember the mnemonic word "DISTANCE" to check and describe all the relevant MRI findings necessary for an accurate radiological definition of tumor stage and response to CRT.

CONCLUSIONS

"DISTANCE" assessment for rectal cancer staging and treatment response estimation after CRT may be helpful as a checklist for a structured reporting.

Improving Rectal Cancer Outcomes with the National Accreditation Program for Rectal Cancer

Background  The treatment of rectal cancer has undergone dramatic changes over the past 50 years. It has evolved from a rather morbid disease usually requiring a permanent stoma, almost exclusively managed by surgeons, to one that involves experts across numerous disciplines to provide the best care for the patient. With significant improvements in surgical techniques, the use of chemotherapy and radiotherapy, advanced imaging, and standardization of pathological assessment, the perioperative morbidity and permanent colostomy rates have significantly decreased. We have seen improvements in the quality of the specimen and rates of recurrence as well as disease-free survival. Rectal cancer, as demonstrated in European trials, has now been recognized as a disease best managed by a multidisciplinary team. Objective  The aim of this article is to evaluate the main body of literature leading to the advances made possible by the new American College of Surgeons Commission on Cancer National Accreditation Program for Rectal Cancer. Results  Following the launch of the American College of Surgeons Commission on Cancer National Accreditation Program for Rectal Cancer, we expect dramatic increases in membership and accreditation, with associated improvement in center performance and, ultimately, in patient outcomes. Limitations  The National Accreditation Program for Rectal Cancer began in 2017. To date, the only data that have been analyzed are from the preintervention phase. Conclusions  Based on the results of studies within the United States and on the successes demonstrated in Europe, it remains our hope and expectation that the management of rectal cancer in the United States will rapidly improve.

The multidisciplinary management of rectal cancer

Rectal cancer treatment has evolved during the past 40 years with the use of a standardized surgical technique for tumour resection: total mesorectal excision. A dramatic reduction in local recurrence rates and improved survival outcomes have been achieved as consequences of a better understanding of the surgical oncology of rectal cancer, and the advent of adjuvant and neoadjuvant treatments to compliment surgery have paved the way for a multidisciplinary approach to disease management. Further improvements in imaging techniques and the ability to identify prognostic factors such as tumour regression, extramural venous invasion and threatened margins have introduced the concept of decision-making based on preoperative staging information. Modern treatment strategies are underpinned by accurate high-resolution imaging guiding both neoadjuvant therapy and precision surgery, followed by meticulous pathological scrutiny identifying the important prognostic factors for adjuvant chemotherapy. Included in these strategies are organ-sparing approaches and watch-and-wait strategies in selected patients. These pathways rely on the close working of interlinked disciplines within a multidisciplinary team. Such multidisciplinary forums are becoming standard in the treatment of rectal cancer across the UK, Europe and, more recently, the USA. This Review examines the essential components of modern-day management of rectal cancer through a multidisciplinary team approach, providing information that is essential for any practising colorectal surgeon to guide the best patient care.

Transperineal minimally invasive APE: preliminary outcomes in a multicenter cohort

Background

Abdominoperineal excision (APE) for rectal cancer is associated with a relatively high risk of positive margins and postoperative morbidity, particularly related to perineal wound healing problems. It is unknown whether the use of a minimally invasive approach for the perineal part of these procedures can improve postoperative outcomes without oncological compromise. The aim of this study was to evaluate the feasibility of minimally invasive transperineal abdominoperineal excision (TpAPE)

Methods

This multicenter retrospective cohort study included all patients having TpAPE for primary low rectal cancer. The primary endpoint was the intraoperative complication rate. Secondary endpoints included major morbidity (Clavien–Dindo ≥ 3), histopathology results, and perineal wound healing.

Results

A total of 32 TpAPE procedures were performed in five centers. A bilateral extralevator APE (ELAPE) was performed in 17 patients (53%), a unilateral ELAPE in 7 (22%), and an APE in 8 (25%). Intraoperative complications occurred in five cases (16%) and severe postoperative morbidity in three cases (9%). There were no perioperative deaths. A positive margin (R1) was observed in four patients (13%) and specimen perforation occurred in two (6%). The unilateral extralevator TpAPE group had worse specimen quality and a higher proportion of R1 resections than the bilateral ELAPE or standard APE groups. The rate of uncomplicated perineal wound healing was 53% (n = 17) and three patients (9%) required surgical reintervention.

Conclusions

TpAPE seems to be feasible with acceptable perioperative morbidity and a relatively low rate of perineal wound dehiscence, while histopathological outcomes remain suboptimal. Additional evaluation of the viability of this technique is needed in the form of a prospective trial with standardization of the procedure, indication, audit of outcomes and performed by surgeons with vast experience in transanal total mesorectal excision.

Prediction of surgical difficulty in minimally invasive surgery for rectal cancer by use of MRI pelvimetry

Background

Technical difficulties in rectal surgery are often related to dissection in a limited surgical field. This study investigated the clinical value of MRI pelvimetry in the prediction of surgical difficulty associated with minimally invasive rectal surgery.

Methods

Patients with rectal cancer who underwent laparoscopic or robotic total mesorectal excision between 2005 and 2017 were reviewed retrospectively and categorized according to surgical difficulty on the basis of duration of surgery, conversion to an open procedure, use of the transanal approach, postoperative hospital stay, blood loss and postoperative complications. Preoperative clinical and MRI‐related parameters were examined to develop a prediction model to estimate the extent of surgical difficulty, and to compare anastomotic leakage rates in the low‐ and high‐grade surgical difficulty groups. Prognosis was investigated by calculating overall and relapse‐free survival, and cumulative local and distant recurrence rates.

Results

Of 121 patients analysed, 104 (86·0 per cent) were categorized into the low‐grade group and 17 (14·0 per cent) into the high‐grade group. Multivariable analysis indicated that high‐grade surgical difficulty was associated with a BMI above 25 kg/m² (odds ratio (OR) 4·45, P = 0·033), tumour size 45 mm or more (OR 5·42, P = 0·042), anorectal angle 123° or more (OR 5·98, P = 0·028) and pelvic outlet less than 82·7 mm (OR 6·62, P = 0·048). All of these features were used to devise a four‐variable scoring model to predict surgical difficulty. In patients categorized as high grade for surgical difficulty, the anastomotic leakage rate was 53 per cent (9 of 17 patients), compared with 9·6 per cent (10 of 104) in the low‐grade group (P < 0·001). The high‐grade group had a significantly higher local recurrence rate than the low‐grade group (P = 0·002).

Conclusion

This study highlights the impact of clinical variables and MRI pelvimetry in the prediction of surgical difficulty in minimally invasive rectal surgery.

Needlescopic surgery for very low rectal cancer with no abdominal skin incision

INTRODUCTION

Needlescopic surgery (NS) is a minimally invasive operation beyond traditional laparoscopic surgery. This study aimed to describe NS for intersphincteric resection (ISR) and abdominoperineal resection (APR) for low rectal cancer without a small abdominal skin incision for extracting the specimen and to evaluate the safety and feasibility of the operation.

METHODS

From January 2011 to April 2016, 36 patients underwent NS for either ISR or APR. By definition, NS for ISR or APR at our institution uses three 3-mm ports and two 5-mm ports at the umbilicus and in the right lower quadrant. The specimen was extracted through the anus or the perineal wound. The feasibility of this operation was determined based on short-term outcomes and pathological findings.

RESULTS

No patients required conversion to open surgery. The mean operation time was 299 minutes, and the mean estimated blood loss was 30 mL. Postoperative complications higher than Clavien-Dindo grade III occurred in 2.8% of patients (n = 1). The median number of harvested lymph nodes was 16 (range, 0-30), and in no case was there a positive circumferential resection margin.

CONCLUSIONS

Needlescopic surgery for ISR or APR is technically safe and feasible for low rectal cancer based on the short-term outcomes and the oncological quality, particularly when compared to conventional laparoscopic surgery as described in previous reports.

Rectal Cancer: Staging

The imaging of rectal cancer has evolved noticeably over the past 2 decades, paralleling the advances in therapy. The methods for imaging rectal cancer are increasingly used in clinical practice with the purpose of helping to detect, characterize and stage rectal cancer. In this setting, MR imaging emerged as the most useful imaging method for primary staging of rectal cancer; the present review focuses on the role of MR imaging in this regard.

Current concepts in imaging for local staging of advanced rectal cancer

Imaging of rectal cancer has an increasingly pivotal role in the diagnosis, staging, and treatment stratification of patients with the disease. This is particularly true for advanced rectal cancers where magnetic resonance imaging (MRI) findings provide essential information that can change treatment. In this review we describe the rationale for the current imaging standards in advanced rectal cancer for both morphological and functional imaging on the baseline staging and reassessment studies. In addition the clinical implications and future methods by which radiologists may improve these are outlined relative to TNM8.

Contemporary view to the principles of rectal cancer diagnostics and treatment according to MRI (literature review)

In this article are reviewed the most recent diagnostic methods for patients with probable and verified rectal cancer, in different stages of treatment. The importance of high quality visualization of rectal cancer, opportunities of magnetic resonance imaging in primary diagnosis and restaging of the disease after neoadjuvant chemotherapy, optimal examination methods and interpretation of images in routine are discussed.

Exercise prehabilitation may lead to augmented tumor regression following neoadjuvant chemoradiotherapy in locally advanced rectal cancer

  Purpose: We evaluate the effect of an exercised prehabilitation programme on tumour response in rectal cancer patients following neoadjuvant chemoradiotherapy (NACRT). Patients and Methods: Rectal cancer patients with (MRI-defined) threatened resection margins who completed standardized NACRT were prospectively studied in a post hoc, explorative analysis of two previously reported clinical trials. MRI was performed at Weeks 9 and 14 post-NACRT, with surgery at Week 15. Patients undertook a 6-week preoperative exercise-training programme. Oxygen uptake (VO2) at anaerobic threshold (AT) wasmeasured at baseline (pre-NACRT), after completion of NACRT and at week 6 (post-NACRT). Tumour related outcome variables: MRI tumour regression grading (ymrTRG) at Week 9 and 14; histopathological T-stage (ypT); and tumour regression grading (ypTRG)) were compared. Results: 35 patients (26 males) were recruited. 26 patients undertook tailored exercise-training with 9 unmatched controls. NACRT resulted in a fall in VO2 at AT -2.0 ml/kg^-1/min^-1(-1.3,-2.6), p < 0.001. Exercise was shown to reverse this effect. VO2 at AT increased between groups, (post-NACRT vs. week 6) by +1.9 ml/kg^-1/min^-1(0.6, 3.2), p = 0.007. A significantly greater ypTRG in the exercise group at the time of surgery was found (p = 0.02). Conclusion: Following completion of NACRT, exercise resulted in significant improvements in fitness and augmented pathological tumour regression.

MRI of Rectal Cancer: Tumor Staging, Imaging Techniques, and Management

Rectal cancer is prone to local recurrence and systemic metastasis. However, owing to improvements in TNM staging and treatment, including a more widespread use of rectal MRI and increased radiologist awareness of the key rectal cancer TNM staging features, the mortality rate of rectal cancer has been declining over the past few decades in adults over 50 years of age. Currently, rectal MRI plays a key role in the pre- and posttreatment evaluation of rectal cancer, assisting the multidisciplinary team in tailoring the most appropriate treatment option. The benefits achieved with rectal MRI are strictly dependent on obtaining good-quality images, which is important for the characterization of the main anatomic structures and their relationship with the tumor. In primary staging, rectal MRI helps the radiologist (a) describe the tumor location and morphology, (b) provide its T and N categories, (c) detect the presence of extramural vascular invasion, and (d) identify its relationship with surrounding structures, including the sphincter complex and involvement of the mesorectal fascia. These features help diagnose locally advanced rectal tumors (categories T3c-d, T4, N1, and N2), for which neoadjuvant chemoradiotherapy (CRT) is indicated. In restaging after neoadjuvant CRT, in addition to reassessing the features noted during primary staging, rectal MRI can help in the assessment of treatment response, especially with the emergence of nonsurgical approaches such as "watch and wait." ^©RSNA, 2019.

Optimal treatment strategy for rectal cancer based on the risk factors for recurrence patterns

BACKGROUND

For rectal cancer, multimodality therapeutic approach is necessary to prevent local recurrence and distant metastasis. However, the efficacy of additional treatments, such as neoadjuvant chemoradiotherapy (nCRT), neoadjuvant chemotherapy (NAC), and lateral pelvic lymph node dissection (LPLND), has not been scrutinized.

METHODS

Recurrence patterns were categorized into local recurrence and distant metastasis. Local recurrence was classified into two types: (1) pelvic cavity recurrence and (2) LPLN recurrence. First, we analyzed the risk factors for each recurrence pattern. Second, based on the status of clinically suspected involvement of circumferential resection margin (cCRM), the efficacy of additional treatments was investigated.

RESULTS

A total of 240 patients was enrolled. nCRT was performed for 25 (10%), NAC was for 46 (19%), and LPLND was for 35 patients (15%). As the recurrence patterns, pelvic cavity recurrence occurred in 15 (6%), LPLN recurrence in 8 (3%), and distant metastasis in 42 patients (18%). Five-year overall survival and relapse-free survival were 87% and 70%, respectively. Multivariate analysis indicated that pelvic cavity recurrence was associated with cCRM status and tumor histology, that LPLN recurrence was with serum carcinoembryonic antigen level and LPLN swelling, and that distant metastasis was with clinical N category. In the cCRM-positive subgroup (n = 66), cumulative rate of pelvic cavity recurrence was lower in the nCRT group than in the NAC or non-NAC/nCRT group (P = 0.02 and 0.09, respectively).

CONCLUSION

cCRM status was associated with pelvic cavity recurrence, and LPLN swelling was with LPLN recurrence. nCRT could reduce pelvic cavity recurrence in cCRM-positive subgroup.

Improved detection of a tumorous involvement of the mesorectal fascia and locoregional lymph nodes in locally advanced rectal cancer using DCE-MRI

PURPOSE

The prediction of an infiltration of the mesorectal fascia (MRF) and malignant lymph nodes is essential for treatment planning and prognosis of patients with rectal cancer. The aim of this study was to assess the additional diagnostic value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the detection of a malignant involvement of the MRF and of mesorectal lymph nodes in patients with locally advanced rectal cancer.

METHODS

In this prospective study, 22 patients with locally advanced rectal cancer were examined with 1.5-T MRI between September 2012 and April 2015. Histopathological assessment of tumor size, tumor infiltration to the MRF, and malignant involvement of locoregional lymph nodes served as standard of reference. Sensitivity and specificity of detecting MRF infiltration and malignant nodes (nodal cut-off size [NCO] ≥ 5 and ≥ 10 mm, respectively) was determined by conventional MRI (cMRI; precontrast and postcontrast T1-weighted, T2-weighted, and diffusion-weighted images) and by additional semi-quantitative DCE-MRI maps (cMRI+DCE-MRI).

RESULTS

Compared to cMRI, additional semi-quantitative DCE-MRI maps significantly increased sensitivity (86 vs. 71% [NCO ≥ 5 mm]/29% [NCO ≥ 10 mm]) and specificity (90 vs. 70% [NCO ≥ 5 mm]) of detecting malignant lymph nodes (p < 0.05). Moreover, DCE-MRI significantly augmented specificity (91 vs. 82%) of discovering a MRF infiltration (p < 0.05), while there was no change in sensitivity (83%; p > 0.05).

CONCLUSION

DCE-MRI considerably increases both sensitivity and specificity for the detection of small mesorectal lymph node metastases (≥ 5 mm but < 10 mm) and sufficiently improves specificity of a suspected MRF infiltration in patients with locally advanced rectal cancer.

Session 3: Beyond TME and radiotherapy MRI evaluation of rectal cancer treatment response

Magnetic resonance imaging plays an increasingly important role in evaluating the effect of cancer treatment. Imaging alone cannot predict pathological complete response and imaging interpretation should be combined with clinical information and endoscopy findings to predict complete response. Professor Blomqvist reviews current and future imaging techniques and whether the quantitative can add significant or important prognostic information over the current qualitative techniques.

Imaging of colorectal cancer - the clue to individualized treatment

Colorectal cancer (CRC) is the most common gastrointestinal neoplasm and the second most common cause for cancer-related death in Europe. Imaging plays an important role both in the primary diagnosis, treatment evaluation, follow-up, and, to some extent, also in prevention. Like in the clinical setting, colon and rectal cancer have to be distinguished as two quite separate entities with different goals of imaging and, consequently, also different technical requirements. Over the past decade, there have been improvements in both more robust imaging techniques and new data and guidelines that help to use the optimal imaging modality for each scenario. For colon cancer, the continued research on computed tomography (CT) colonography (CTC) has led to high-level evidence that puts this technique on eye height to optical colonoscopy in terms of detection of cancer and polyps ≥10 mm. However, also for smaller polyps and thus for screening purposes, CTC seems to be an optimal tool. In rectal cancer, the technical requirements to perform state-of-the art imaging have recently been defined. Evaluation of T-stage, mesorectal fascia infiltration and extramural vascular invasion are the most important prognostic factors that can be identified on MRI. With this information, risk stratification both for local and distal failure is possible, enabling the clinician to tailor the optimal therapeutic approach in non-metastatic rectal cancer. Imaging of metastatic CRC is also covered, although the complex ramifications of treatment options in the metastatic setting are beyond the scope of this article. In this review, the most important recent developments in the imaging of colon and rectal cancer will be highlighted. If used in an interdisciplinary setting, this can lead to an individualized treatment concept for each patient.

Area of residual tumor is a robust prognostic marker for patients with rectal cancer undergoing preoperative therapy

The aim of this study was to elucidate differences in the histological features of rectal cancer between patients treated with preoperative chemoradiotherapy and those treated with preoperative chemotherapy. Area of residual tumor (ART) was also evaluated for its utility as a potential prognostic marker between them. Sixty‐eight patients with rectal cancer who underwent sphincter‐saving surgery were enrolled in this study. Of these, 39 patients received preoperative chemoradiotherapy (CRT group) and 29 patients received preoperative (neoadjuvant) chemotherapy (NAC group). Area of residual tumor was determined by using morphometric software. Tumors in the two groups were compared for differences in their histological features and clinical outcomes. Tumors in the CRT and NAC groups varied greatly with regard to their histological features after preoperative therapy. Tumors in the CRT group showed more marked fibrosis than those in the NAC group. The total ART were significantly smaller in tumors in the CRT group than those in the NAC group. However, in circumferential resection margin‐negative pathologic stage 0‐III cases, clinical outcomes were not statistically different between the CRT and NAC groups. Both ART and pathologic TNM classification were associated with clinical outcome in preoperative CRT and NAC groups, but Dworak regression grade and fibrotic change were not. Tumors in those undergoing preoperative CRT and NAC were shown to differ significantly in their histological features. Area of residual tumor‐based assessment may provide useful prognostic information, regardless of preoperative therapy.

How Should Imaging Direct/Orient Management of Rectal Cancer?

Modern rectal cancer management is dependent on preoperative staging, and radiological assessment is a crucial part of this process. Imaging must provide sufficient information to guide preoperative decision-making that is reliable and reproducible. Different methods have been used for local staging; however, magnetic resonance imaging (MRI) has shown to be the most reliable tool for this purpose. MRI offers prognostic information about the patients and guides the decision between neoadjuvant treatment and total mesorectal excision alone. Also, not only the initial staging but also restaging by MRI can provide significant information regarding tumor response that is essential when considering alternative approaches.

Intersphincteric Resection Pushing the Envelope for Sphincter Preservation

During the last 15 years, a significant evolution has emerged in the surgical treatment of rectal cancer and restoration of bowel continuity has been one of the main goals. For many years the treatment of distal rectal cancer would necessarily require an abdominoperineal resection and end colostomy. The surgical procedure of intersphincteric resection has been proposed to offer sphincter preservation in patients with low rectal cancer and has been legitimized if executed according to adequate oncologic criteria. This article will discuss the best indications, technical aspects, functional, and oncological outcomes of intersphicteric resection in the management of rectal cancer.