Local colorectal cancer recurrence: pelvic MRI evaluation

Beyond Total Mesorectal Excision (TME)-Results of MRI-Guided Multivisceral Resections in T4 Rectal Carcinoma and Local Recurrence

Rectal cancer invading adjacent organs (T4) and locally recurrent rectal cancer (LRRC) pose a special challenge for surgical resection. We investigate the diagnostic performance of MRI and the results that can be achieved with MRI-guided surgery. All consecutive patients who underwent MRI-based multivisceral resection for T4 rectal adenocarcinoma or LRRC between 2005 and 2019 were included. Pelvic MRI findings were reviewed according to a seven-compartment staging system and correlated with histopathology. Outcomes were investigated by comparing T4 tumors and LRRC with respect to cause-specific survival in uni- and multivariate analysis. We identified 48 patients with T4 tumors and 28 patients with LRRC. Overall, 529 compartments were assessed with an accuracy of 81.7%, a sensitivity of 88.6%, and a specificity of 79.2%. Understaging was as low as 3.0%, whereas overstaging was 15.3%. The median number of resected compartments was 3 (interquartile range 3-4) for T4 tumors and 4 (interquartile range 3-5) for LRRC (p = 0.017). In 93.8% of patients with T4 tumors, a histopathologically complete (R0(local)-) resection could be achieved compared to 57.1% in LRRC (p < 0.001). Five-year overall survival for patients with T4 tumors was 53.3% vs. 32.1% for LRRC (p = 0.085). R0-resection and M0-category emerged as independent prognostic factors, whereas the number of resected compartments was not associated with prognosis in multivariate analysis. MRI predicts compartment involvement with high accuracy and especially avoids understaging. Surgery based on MRI yields excellent loco-regional results for T4 tumors and good results for LRRC. The number of resected compartments is not independently associated with prognosis, but R0-resection remains the crucial surgical factor.

The role of rectal endoscopic ultrasonography plus fine needle aspirartion and fine needle biopsy in pelvic masses

BACKGROUND AND AIM

The diagnostic role of endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) and fine needle biopsy (FNB) of pelvic masses has not been well established. We aimed to evaluate the diagnostic accuracy of EUS plus FNA/FNB in suspected local recurrence of pelvic masses.

MATERIALS AND METHODS

All consecutive patients with a history of lower gastrointestinal and pelvic mass undergone EUS-FNA/FNB were included in the study.

RESULTS

In total 34 patients who underwent EUS-guided FNA or FNB of a perirectal mass were enrolled. The sampled lesion was a mass in 22 patients (64.7%) and a lymph node in 10 patients (29.4%). The univariate logistic regression analysis for diagnostic accuracy showed lesion size as a significant predictor of diagnostic accuracy [odds ratio (OR), 1.61; 1.08-2.27; P  = 0.02]. Diagnostic sensitivity was 100% (71.5-100%) with EUS-FNB and 75% (34.9-96.8%) with EUS-FNA ( P  = 0.12); specificity was 100% in both groups ( P  = 1.0). Sample adequacy was 94.1% in the whole cohort, with 20/20 adequacy rate (100%) in the EUS-FNB group and 12/14 (85.7%) in the EUS-FNA group ( P  = 0.28).

CONCLUSION

This is the first study demonstrating the diagnostic yield of EUS plus FNA/FNB in patients with pelvic masses comparing the two needles. Our results highlight the relevance of this technique, especially in undefined masses during oncological follow-up.

Diagnostic performance of [18F]-FDG PET/MR in evaluating colorectal cancer: a systematic review and meta-analysis

PURPOSE

To calculate the diagnostic performance of [¹⁸F]-FDG PET/MR in colorectal cancer (CRC).

METHODS

This study was designed following the PRISMA-DTA guidelines. To be included, published original articles (until December 31, 2021) that met the following criteria were considered eligible: (1) evaluated [¹⁸F]-FDG PET/MR as the diagnostic method to detect CRC; (2) compared [¹⁸F]-FDG PET/MR with histopathology as the reference standard, or clinical/imaging composite follow-up when pathology was not available; (3) provided adequate crude data for meta-analysis. The diagnostic pooled measurements were calculated at patient and lesion levels. Regarding sub-group analysis, diagnostic measurements were calculated in "TNM staging," "T staging," "N staging," "M staging," and "liver metastasis" sub-groups. Additionally, we calculated the pooled performances in "rectal cancer: patient-level" and "rectal cancer: lesion-level" sub-groups. A hierarchical method was used to pool the performances. The bivariate model was conducted to find the summary points. Analyses were performed using STATA 16.

RESULTS

A total of 1534 patients from 18 studies were entered. The pooled sensitivities in CRC lesion detection (tumor, lymph nodes, and metastases) were 0.94 (95%CI: 0.89-0.97) and 0.93 (95%CI: 0.82-0.98) at patient-level and lesion-level, respectively. The pooled specificities were 0.89 (95%CI: 0.84-0.93) and 0.95 (95%CI: 0.90-0.98) at patient-level and lesion-level, respectively. In sub-groups, the highest sensitivity (0.97, 95%CI: 0.86-0.99) and specificity (0.99, 95%CI: 0.84-1.00) were calculated for "M staging" and "rectal cancer: lesion-level," respectively. The lowest sensitivity (0.81, 95%CI: 0.65-0.91) and specificity (0.79, 95%CI: 0.52-0.93) were calculated for "N staging" and "T staging," respectively.

CONCLUSION

This meta-analysis showed an overall high diagnostic performance for [¹⁸F]-FDG PET/MR in detecting CRC lesions/metastases. Thus, this modality can play a significant role in several clinical scenarios in CRC staging and restaging. Specifically, one of the main strengths of this modality is ruling out the existence of CRC lesions/metastases. Finally, the overall diagnostic performance was not found to be affected in the post-treatment setting.

Role of MRI and added value of diffusion-weighted and gadolinium-enhanced MRI for the diagnosis of local recurrence from rectal cancer

PURPOSE

To evaluate whether the addition of gadolinium-enhanced MRI and diffusion-weighted imaging (DWI) improves T2 sequence performance for the diagnosis of local recurrence (LR) from rectal cancer and to assess which approach is better at formulating this diagnosis among readers with different experience.

METHODS

Forty-three patients with suspected LR underwent pelvic MRI with T2 weighted (T2) sequences, gadolinium fat-suppressed T1 weighted sequences (post-contrast T1), and DWI sequences. Three readers (expert: G, intermediate: E, resident: V) scored the likelihood of LR on T2, T2 + post-contrast T1, T2 + DWI, and T2 + post-contrast T1 + DWI.

RESULTS

In total, 18/43 patients had LR; on T2 images, the expert reader achieved an area under the ROC curve (AUC) of 0.916, sensitivity of 88.9%, and specificity of 76%; the intermediate reader achieved values of 0.890, 88.9%, and 48%, respectively, and the resident achieved values of 0.852, 88.9%, and 48%, respectively. DWI significantly improved the AUC value for the expert radiologist by up to 0.999 (p = 0.04), while post-contrast T1 significantly improved the AUC for the resident by up to 0.950 (p = 0.04). For the intermediate reader, both the T2 + DWI AUC and T2 + post-contrast T1 AUC were better than the T2 AUC (0.976 and 0.980, respectively), but with no statistically significant difference. No statistically significant difference was achieved by any of the three readers by comparing either the T2 + DWI AUCs to the T2 + post-contrast T1 AUCs or the AUCs of the two pairs of sequences to those of the combined three sequences. Furthermore, using the T2 sequences alone, all of the readers achieved a fair number of "equivocal" cases: they decreased with the addition of either DWI or post-contrast T1 sequences and, for the two less experienced readers, they decreased even more with the three combined sequences.

CONCLUSIONS

Both DWI and T1 post-contrast MRI increased diagnostic performance for LR diagnosis compared to T2; however, no significant difference was observed by comparing the two different pairs of sequences with the three combined sequences.

Comparison of the diagnostic efficiency for local recurrence of rectal cancer using CT, MRI, PET and PET-CT: A systematic review protocol

BACKGROUND

The risk of local recurrence (LR) continues to threat patients with rectal cancer after surgery or chemoradiotherapy. The main reason is that there is frequently extensive scarring and reactive changes after radiotherapy and resection. Thus, the diagnosis of LR can be challenging. There are different imaging modalities that have been used in the follow-up of rectal cancer, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and positron emission tomography-computed tomography (PET-CT) in clinical practice.

METHODS

We will systematically search PubMed, EMBASE, the Cochrane Library, and Chinese Biomedical Literature Database for diagnostic trials using CT, MRI, PET, and PET-CT to detect LR of rectal cancer in April, 2018. Two review authors will independently screen titles and abstracts for relevance, assess full texts for inclusion, and carry out data extraction and methodological quality assessment using the QUADAS-2 tool. We will use bivariate meta-analysis to estimate summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of CT, MRI, PET, and PET-CT, as well as different sequences of MRI. For each index test, estimates of sensitivity and specificity from each study will be plotted in summary receive operating curve space and forest plots will be constructed for visual examination of variation in test accuracy. We will perform meta-analyses using the hierarchical summary receiver-operating characteristic model to produce summary estimates of sensitivity and specificity. Then, head-to-head and indirect comparison meta-analyses will be carried out.

DISCUSSION

This review will help determine the diagnostic accuracy of CT, MRI, PET, and PET-CT for the diagnosis of patients with LR of rectal cancer.

ETHICS AND DISSEMINATION

Ethics approval and patient consent are not required, as this study is a systematic review.

PROSPERO REGISTRATION NUMBER

CRD42018104918.

Optimal Imaging Strategies for Rectal Cancer Staging and Ongoing Management

Imaging determines the optimal treatment for rectal cancer patients. High-resolution magnetic resonance imaging (MRI) overcomes many of the known limitations of previous methods. When performed in accordance with the recommended standards, MRI enables accurate staging of both early and advanced rectal cancer, accurate response assessment, the delineation of recurrent disease and planning surgical treatment in a safe and effective manner. Tumour-related high-risk features with known adverse outcomes can be preoperatively identified and treated with neoadjuvant chemoradiotherapy. Further, MRI post-treatment tumour response assessment using TRG grading system also predicts the likely survival outcomes and in the future will be used to modify treatment further by stratification into good and poor responders. There is a paucity of literature with validated outcome data concerning use of diffusion-weighted imaging and positron emission tomography (PET)/computed tomography (CT), and in the absence of any validated methods and outcome data, their use in the initial assessment and restaging after treatment is limited to research protocols. Combination MRI and CT is essential for distant spread assessment and recurrent disease, and currently PET-CT is sometimes used in the workup of patients with recurrent and metastatic disease.

Evaluation of the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer, according to the American College of Radiology criteria

Objective

To evaluate the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer.

Materials and Methods

This was a retrospective, single-center study, conducted by reviewing medical records and imaging reports. We included 1060 female patients who underwent magnetic resonance imaging of the pelvis at a cancer center between January 2013 and June 2014. The indications for performing the examination were classified according to the American College of Radiology (ACR) criteria.

Results

The mean age of the patients was 52.6 ± 14.8 years, and 49.8% were perimenopausal or postmenopausal. The majority (63.9%) had a history of cancer, which was gynecologic in 29.5% and nongynecologic in 34.4%. Of the patients evaluated, 44.0% had clinical complaints, the most common being pelvic pain (in 11.5%) and bleeding (in 9.8%), and 34.7% of patients had previously had abnormal findings on ultrasound. Most (76.7%) of the patients met the criteria for undergoing magnetic resonance imaging, according to the ACR guidelines. The main indications were evaluation of tumor recurrence after surgical resection (in 25.9%); detection and staging of gynecologic neoplasms (in 23.3%); and evaluation of pelvic pain or of a mass (in 17.1%).

Conclusion

In the majority of the cases evaluated, magnetic resonance imaging was clearly indicated according to the ACR criteria. The main indication was local recurrence after surgical treatment of pelvic malignancies, which is consistent with the routine protocols at cancer centers.

Diffusion-weighted magnetic resonance imaging in colorectal cancer

Magnetic resonance imaging (MRI) plays now a major role in patients with colorectal cancer regarding tumor staging, surgical planning, therapeutic decision, assessment of tumor response to chemoradiotherapy and surveillance of rectal cancer, and detection and characterization of liver or peritoneal metastasis of colorectal cancers. Diffusion-weighted MRI (DW-MRI) is a functional imaging tool that is now part of the standard MRI protocol for the investigation of patients with colorectal cancer. DW-MRI reflects micro-displacements of water molecules in tissues and conveys high degrees of accuracy to discriminate between benign and malignant colorectal conditions. Thus, in addition to morphological imaging, DW-MRI has an important role to accurately detect colorectal neoplasms and peritoneal implants, to differentiate benign focal liver lesions from metastases and to detect tumor relapse within fibrotic changes. This review provides a comprehensive overview of basic principles, clinical applications and future trends of DW-MRI in colorectal cancers.

Diffusion-weighted imaging for the detection of mesenteric small bowel tumours with Magnetic Resonance--enterography

PURPOSE

To retrospectively investigate the added value of diffusion-weighted MR imaging (DWI) for detecting mesenteric small bowel tumours (MSBTs) via MR-enterography.

MATERIALS AND METHODS

MR-enterographies of 98 patients with suspected MSBTs were blindly analyzed by two independent readers for the presence of MSBTs. Four imaging sets including "standard" (Haste and TrueFisp), "standard + DWI," "standard + gadolinium-enhanced" and "standard + DWI + gadolinium-enhanced" were reviewed. Diagnostic performance of different readings were compared with McNemar's test.

RESULTS

Twenty-nine MSBTs were pathologically confirmed. For R1 (junior radiologist) sensitivity, specificity, PPV, NPV and accuracy for the detection of MSBTs via standard MRI were 52 % [95 % CI: 34 %-70 %] (15/29), 94 % [95 % CI: 89 %-100 %] (65/69), 79 % [95 % CI: 61 %-97 %] (15/19), 82 % [95 % CI: 74 %-91 %] (65/79) and 82 % [95 % CI: 74 %-89 %] (80/98), respectively. For R2 (senior radiologist) they were 76 % [95 % CI: 60 %-91 %] (22/29), 96 % [95 % CI: 91-100 %] (66/69), 88 % [95 % CI: 75 %-100 %] (22/25), 90 % [95 % CI: 84 %-97 %] (66/73) and 90 % [95 % CI: 84 %-96 %] (88/98), respectively. Adding DWI they were 72 % [95 % CI: 56 %-89 %] (21/29), 91 % [95 % CI: 85 %-98 %] (63/69), 78 % [95 % CI: 62 %-94 %] (21/27), 89 % [95 % CI: 81 %-96 %] (63/71) and 87 % [95 % CI: 80 %-94 %] (85/98) for R1 and 79 % [95 % CI: 65 %-94 %] (23/29), 97 % [95 % CI: 93 %-100 %] (67/69), 92 % [95 % CI: 81 %-100 %] (23/25), 92 % [95 % CI: 86 %-98 %] (67/73) and 92 % [95 % CI: 86 %-97 %] (90/98) for R2. Sensitivities for tumour detection were higher after adding DWI to standard MRI, although only for R1 was this significant (P = 0.03). Adding DWI to standard + gadolinium-enhanced MRI did not significantly increase MR performance.

CONCLUSION

DWI improves MSBT detection via MR-enterography compared to standard unenhanced MR-enterography, especially for unexperienced readers.

KEY POINTS

• MR-enterography is accurate for the detection of mesenteric small-bowel tumours. • Diffusion-weighted sequencing helps inexperienced readers detect small-bowel tumours with MR-enterography. • Diffusion-weighted sequencing adds value to standard MR-enterography when gadolinium is contraindicated.

Diffusion-weighted MR imaging of the rectum: clinical applications

Dramatic advances in image quality over the past few years have made diffusion-weighted magnetic resonance imaging (DW-MRI) a promising tool for rectal lesion evaluation. DW-MRI derives its image contrast from differences in the motion of water molecules between tissues. Such imaging can be performed quickly without the need for the administration of exogenous contrast medium. The technique yields qualitative and quantitative information that reflects changes at a cellular level and provides information about tumor cellularity and the integrity of cell membranes. The sensitivity to diffusion is obtained by applying two bipolar diffusion-sensitizing gradients to a standard T2-weighted spin echo sequence. The diffusion-sensitivity can be varied by adjusting the "b-factor", which represents the gradient duration, gradient amplitude and the time interval between the two gradients. The higher the b-value, the greater the signal attenuation from moving water protons. In this review, technical considerations relatively to image acquisition and to quantification methods applied to rectal DW-MRI are discussed. The current clinical applications of DW-MRI, either in the field of inflammatory or neoplastic rectal disease are reviewed. Also, limitations, mainly in terms of persistent lack of standardization or evaluation of tumoral response, and future directions of rectal DW-MRI are discussed. The potential utility of DW-MRI for the evaluation of rectal tumor response is on its way to being admitted but future well-designed and multicenter studies, as well as standardization of DW-MRI, are still required before a consensus can be reached upon how and when to use DW-MRI.

Diffusion-weighted MR imaging for the diagnosis of abscess complicating fistula-in-ano: preliminary experience

OBJECTIVE

To investigate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of abscess-complicating fistula-in-ano.

METHODS

This retrospective study was approved by our Institutional Review Board and informed consent was waived. MRI examinations, including fat-suppressed T2-weighted turbo spin-echo (T2-TSE) MRI and DWMRI, of 24 patients with a fistula-in-ano, were reviewed by two independent readers for the presence and number of visible fistulas, conspicuity and apparent diffusion coefficient (ADC) measurement of suspected fistula tracks and pelvic collections. The reference standard was surgical with follow-up findings.

RESULTS

Sensitivity was 91.2 % [95 % CI: 76 %-98 %] for T2-weighted TSE MRI and 100 % [95 % CI: 90 %-100 %] for DWMRI detecting fistulas. ADC values were lower in abscesses than in inflammatory masses (P = 0.714.10(-6)). The area under the ROC curve was 0.971 and the optimal cut-off ADC value was 1.186 × 10(-3) mm(2)/s, yielding a sensitivity of 100 % [95 % CI: 77 %-100 %], a specificity of 90 % [95 % CI: 66 %-100 %], a positive predictive value of 93 % [95 % CI: 82.8 %-100 %] and a negative predictive value of 90 % [95 % CI: 78 %-100 %] for an abscess diagnosis. Fistula conspicuity was greater with DWMRI than with T2-TSE MRI for the two observers (P = 0.0034 and P = 0.0007).

CONCLUSION

DWMRI shows high sensitivity and specificity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass. Conspicuity of fistulas-in-ano is greater with DWMRI than with T2-weighted TSE MRI.

KEY POINTS

• DWMRI can differentiate between pelvic abscess and inflammatory mass. • DWMRI helps avoid gadolinium-chelate administration in patients with a suspected fistula-in-ano. • DWMRI provides high degrees of conspicuity for fistula-in-ano. • Conspicuity of fistulas is better with DWMRI imaging than with T2-TSE-weighted MRI.

Value of diffusion-weighted and gadolinium-enhanced MRI for the diagnosis of pelvic recurrence from colorectal cancer

PURPOSE

To prospectively assess the added value of gadolinium-enhanced and diffusion-weighted (DWI) MRI for the diagnosis of pelvic recurrence from colorectal cancer (CRC).

MATERIALS AND METHODS

Fifty-two patients with suspected pelvic recurrence from CRC underwent pelvic MRI with T2-weighted ("T2"), gadolinium-enhanced fat-suppressed T1-weighted ("gadolinium") and DWI MR sequences. Three readers (senior radiologist: R1, two residents: R2, R3) scored the likelihood of recurrence on "T2," "T2 + DWI," and "T2 + Gadolinium."

RESULTS

Twenty-seven patients had 42 sites of pelvic recurrence. On "T2," R1 achieved AUC of .95, sensitivity 88.4%, specificity 95.2%. For R2, these figures were .89, 81.4%, 90.5%, for R3 .90, 83.7%, 76%. Both Gadolinium injection and DWI significantly improved AUCs for residents but not for the senior radiologist: up to .988 (R2, P = 0.006) and to .98 (R3, P = 0.01) with DWI and to .96 (R2, P = 0.04), .98 (R3, P = 0.01) after gadolinium. All readers achieved slightly better AUCs with "T2 + DWI" than with "T2+Gadolinium" but not significantly (P = 0.68, P = 0.11, P = 0.3; respectively).

CONCLUSION

For diagnosis of pelvic recurrence from CRC, both DWI and gadolinium-enhanced MRI significantly increase diagnostic performances compared with "T2" MRI for residents. DWI may be helpful in patients with contra-indications to intravenous administration of gadolinium.

Rectal cancer staging: focus on the prognostic significance of the findings described by high-resolution magnetic resonance imaging

High-resolution (HR) magnetic resonance imaging (MRI) has become an indispensable tool for multidisciplinary teams (MDTs) addressing rectal cancer. It provides anatomic information for surgical planning and allows patients to be stratified into different groups according to the risk of local and distant recurrence. One of the objectives of the MDT is the preoperative identification of high-risk patients who will benefit from neoadjuvant treatment. For this reason, the correct evaluation of the circumferential resection margin (CRM), the depth of tumor spread beyond the muscularis propria, extramural vascular invasion and nodal status is of the utmost importance. Low rectal tumors represent a special challenge for the MDT, because decisions seek a balance between oncologic safety, in the pursuit of free resection margins, and the patient's quality of life, in order to preserve sphincter function. At present, the exchange of information between the different specialties involved in dealing with patients with rectal cancer can rank the contribution of colleagues, auditing their work and incorporating knowledge that will lead to a better understanding of the pathology. Thus, beyond the anatomic description of the images, the radiologist's role in the MDT makes it necessary to know the prognostic value of the findings that we describe, in terms of recurrence and survival, because these findings affect decision making and, therefore, the patients' life. In this review, the usefulness of HR MRI in the initial staging of rectal cancer and in the evaluation of neoadjuvant treatment, with a focus on the prognostic value of the findings, is described as well as the contribution of HR MRI in assessing patients with suspected or confirmed recurrence of rectal cancer.