The accuracy of MRI, endorectal ultrasonography, and computed tomography in predicting the response of locally advanced rectal cancer after preoperative therapy: A metaanalysis. Surgery. 2016;159:688-699. [PMID: 26619929 DOI: 10.1016/j.surg.2015.10.019]

Evaluating the predictive value of endoscopic findings for residual colorectal cancer following neoadjuvant combination immunotherapy

BACKGROUND

Endoscopy allows for the direct observation of primary tumor characteristics and responses after neoadjuvant treatment. However, reports on endoscopic evaluation following neoadjuvant immunotherapy remain limited.

AIM

To examine the predictive value of endoscopic findings of primary tumors for responses to neoadjuvant immunotherapy.

METHODS

This retrospective study, conducted at a tertiary center in China, evaluated 74 patients with colorectal cancer, including 17 with deficient mismatch repair (dMMR) and 15 with proficient mismatch repair (pMMR) tumors. Patients underwent neoadjuvant immunotherapy followed by surgery. Endoscopic findings before and after neoadjuvant immunotherapy were reviewed and compared with the pathology of the resected specimens.

RESULTS

In the pMMR group (n = 57 evaluable patients), endoscopy identified 11/17 patients who achieved a complete response (CR), while misidentifying 1/40 patients with residual disease as CR (64.7% vs 2.5%, P < 0.01). Conversely, 22/40 patients with residual disease were accurately identified as achieving a partial response (PR), with 1/17 patients who achieved CR misclassified as PR (55.0% vs 5.9%, P < 0.01). The sensitivity, specificity, and accuracy of endoscopic diagnosis for pathological CR were 64.7%, 97.5%, and 87.7%, respectively. In the dMMR cohort, endoscopy classified 9/17 patients as CR and 2 of the remaining patients with residual tumors as PR (64.3% vs 66.7%, P = 0.73). The method demonstrated 100% sensitivity and 82.4% accuracy in diagnosing pathological CR.

CONCLUSION

Endoscopic evidence of CR or PR was well correlated with postoperative pathological outcomes in the pMMR cohort. Despite endoscopic indications of tumor residue, a complete pathological response post-surgery was possible in the dMMR cohort.

Local resection in rectal cancer: When, who and how?

Local resection (LR) in rectal cancer is indicated in stage T1N0M0 without unfavorable pathological factors, achieving oncologically satisfactory outcomes through transanal endoscopic surgery techniques. However, the initial step involves accurate staging and selection of these tumors through specific tests conducted in specialized colorectal units. For T2N0M0 tumors and T1 tumors with poor prognostic factors, the standard treatment is total mesorectal excision (TME), a procedure associated with high postoperative morbidity and mortality, functional impairments, and reduced quality of life. Therefore, new organ-preservation strategies are being explored as alternatives to TME. These include neoadjuvant therapy combined with LR, which has shown promising results, and neoadjuvant therapy followed by a "Watch and Wait" approach -where patients with complete clinical response are selected for strict surveillance- as an ideal future treatment, although there are still current challenges to be addressed.

Radiomics in rectal cancer: current status of use and advances in research

Rectal cancer is a leading cause of morbidity and mortality among patients with malignant tumors in China. In light of the advances made in therapeutic approaches such as neoadjuvant therapy and total mesorectal excision, precise preoperative assessment has become crucial for developing a personalized treatment plan. As an emerging technology, radiomics has gained widespread application in the diagnosis, assessment of treatment response, and analysis of prognosis for rectal cancer by extracting high-throughput quantitative features from medical images. Radiomics thus demonstrates considerable potential for optimizing clinical decision-making. In this paper, we reviewed recent research focusing on advances in the use of radiomics for managing rectal cancer. The review covers TNM staging of tumors, assessment of neoadjuvant therapy outcomes, and survival prediction. We also discuss the challenges and prospects for future developments in translational medicine, particularly the need for data standardization, consistent feature extraction methodologies, and rigorous model validation.

Great Debates: Surgery or Watch and Wait After Total Neoadjuvant Therapy for Rectal Cancer

Locally advanced rectal cancer has traditionally been treated with multimodal therapy including neoadjuvant chemoradiotherapy followed by surgical resection. More recent data suggests that in appropriate patients, total neoadjuvant treatment (TNT) makes it possible to adopt a "watch and wait" approach. Advocates for watch and wait argue that patients with a complete or near-complete clinical response to TNT have comparable overall and disease-free survival to their counterparts who undergo surgical resection, and also have a better quality of life, fewer complications, and potentially avoid a stoma. The dogma of surgery as regional curative intent therapy has been challenged by similar recurrence rates among those treated with total mesorectal excision (TME) and those treated with watch and wait. Furthermore, those who develop local recurrence in the watch and wait groups are equally salvageable, either by surgery, brachytherapy, or chemotherapy. While watch and wait is not appropriate in all patients, this manuscript highlights the benefits and drawbacks of both therapeutic modalities.

Outcomes of rectal cancer treatment in rural Australia and New Zealand: analysis of the bowel cancer outcomes registry

BACKGROUND

The demographics and geography of Australia and New Zealand (ANZ), with few metropolitan centres and vast, sparsely populated rural areas, represent a challenge to providing equal care to all patients. This study aimed to compare rectal cancer care at rural and urban hospitals in ANZ.

METHODS

From the Bowel Cancer Outcomes Registry (BCOR, formerly known as the Bi-National Colorectal Cancer Audit; BCCA), rectal cancer patients treated between 2007 and 2020 were compared based on hospital location (urban versus rural). Propensity-score matching was performed to correct for differences in baseline characteristics between groups.

RESULTS

A total of 9385 rectal cancer patients were identified from the BCOR: 1329 (14.2%) were treated at rural hospitals and 8056 (85.8%) at urban hospitals. Propensity-score matching resulted in 889 patients in each group, matched for age, ASA score, hospital type (public/private), tumour height from the anal verge, and pre-treatment cT- and cAJCC-stage. Rural patients had fewer pre-treatment MRIs (67.9% versus 74.7%; P = 0.002), and underwent less neoadjuvant therapy (44.7% versus 50.9%; P = 0.01). Rural patients underwent fewer ULARs (39.4% versus 45.6%; P = 0.03), and fewer anastomoses were formed (67.9% versus 74.4%; P = 0.05). CRM rates and postoperative AJCC stages (P = 0.19) were similar between groups (P = 0.87). Fewer rural patients received adjuvant chemotherapy (37.8% versus 43.3%; P = 0.02).

CONCLUSION

There are significant differences in pre-treatment MRI rates, (neo)adjuvant treatment rates and surgical procedures performed between rectal cancer patients treated at rural and urban hospitals in ANZ, while CRM rates and postoperative AJCC stages are similar.

A Review of Neoadjuvant Therapy and the Watch-and-Wait Protocol in Rectal Cancer: Current Evidence and Future Directions

The treatment of rectal cancer underwent a significant change with the introduction of total mesorectal excision (TME), which substantially improved recurrence rates. However, TME is associated with complications such as fecal incontinence and poor bladder control, especially in tumors located near the anal verge. The watch-and-wait (WW) protocol has emerged as an alternative for patients achieving a clinical complete response (cCR) following neoadjuvant radiochemotherapy. This narrative review, developed according to the Scale for the Assessment of Narrative Review Articles guidelines, evaluates neoadjuvant treatments and the WW protocol for rectal cancer. Literature was sourced from the PubMed database using specific search terms related to neoadjuvant therapy and the WW protocol, resulting in 63 articles selected for discussion. Neoadjuvant treatment, including chemoradiation and short-course radiotherapy, is indicated for T3 and T4 rectal adenocarcinomas. Studies like the German Rectal Cancer Study Group and the PRODIGE 23 trial have shown the benefits of preoperative treatment, including improved disease-free survival and reduced local recurrence rates. However, challenges in adopting the WW protocol include the risk of local regrowth and distant metastasis. Immune checkpoint inhibitors have shown promise in mismatch repair-deficient patients, yet the data are insufficient to fully endorse WW for these cases. The WW protocol is viable for selected rectal cancer patients, with ongoing debates regarding criteria for inclusion. Key challenges include accurately identifying cCR and managing patients with near-complete responses. MRI and endoscopic evaluation are crucial for assessing treatment response, although achieving a pathological complete response remains uncertain. The WW strategy offers a potential organ-preserving approach in rectal cancer management but requires careful patient selection and comprehensive risk-benefit discussions. Further research is needed to refine criteria for inclusion and optimize treatment protocols, enhancing outcomes while minimizing invasive interventions.

Nonoperative management and local excision after neoadjuvant chemoradiation therapy for rectal cancer

Locally advanced extraperitoneal rectal cancer represents a significant clinical challenge, and currently, the standard treatment is based on neoadjuvant chemoradiation therapy (CRT) followed by radical surgical resection with total mesorectal excision (TME). In the last 30 years, its management has undergone significant changes due to the improvement of complementary radio- and chemotherapy treatments, the improvement of minimally invasive surgical approaches and the diffusion of organ-sparing approaches, such as nonoperative management, commonly called "watch and wait" (NOM) and local excision (LE), in highly selected patients who achieve a major or complete response to neoadjuvant CRT. This review aimed to critically examine the efficacy and oncological safety of NOM and LE compared to those of standard TME in rectal cancer patients after neoadjuvant CRT. Both the pros and cons of these approaches were strictly analyzed, providing a comprehensive and critical overview of these novel management strategies for rectal cancer.

Evaluation of transrectal ultrasound-guided tru-cut biopsy as a complementary method for predicting pathological complete response in rectal cancer after neoadjuvant treatment: a phase II prospective and diagnostic trial

IMPORTANCE

Patients with pathological complete response (pCR) of rectal cancer following neoadjuvant treatment had better oncological outcomes. However, reliable methods for accurately predicting pCR remain limited.

OBJECTIVE

To evaluate whether transrectal ultrasound-guided tru-cut biopsy (TRUS-TCB) adds diagnostic value to conventional modalities for predicting pathological complete response in patients with rectal cancer after neoadjuvant treatment.

DESIGN, SETTING, AND PARTICIPANTS

This study evaluated data of patients with rectal cancer who were treated with neoadjuvant treatment and reassessed using TRUS-TCB and conventional modalities before surgery. This study is registered with ClinicalTrials.gov.

MAIN OUTCOMES AND MEASURES

The primary outcome was accuracy, along with secondary outcomes including sensitivity, specificity, negative predictive value, and positive predictive value in predicting tumour residues. Final surgical pathology was used as reference standard.

RESULTS

Between June 2021 and June 2022, a total of 74 patients were enroled, with 63 patients ultimately evaluated. Among them, 17 patients (28%) exhibited a complete pathological response. TRUS-TCB demonstrated an accuracy of 0.71 (95% CI, 0.58-0.82) in predicting tumour residues. The combined use of TRUS-TCB and conventional modalities significantly improved diagnostic accuracy compared to conventional modalities alone (0.75 vs. 0.59, P =0.02). Furthermore, TRUS-TCB correctly reclassified 52% of patients erroneously classified as having a complete clinical response by conventional methods. The occurrence of only one mild adverse event was observed.

CONCLUSIONS AND RELEVANCE

TRUS-TCB proves to be a safe and accessible tool for reevaluation with minimal complications. The incorporation of TRUS-TCB alongside conventional methods leads to enhanced diagnostic performance.

Retrospective Evaluation of the Efficacy of Total Neoadjuvant Therapy and Chemoradiotherapy Neoadjuvant Treatment in Relation to Surgery in Patients with Rectal Cancer

Background and Objective: In the therapeutic strategy of rectal cancer, radiotherapy has consolidated its important position and frequent use in current practice due to its indications as neoadjuvant, adjuvant, definitive, or palliative treatment. In recent years, total neoadjuvant therapy (TNT) has been established as the preferred regimen compared to concurrent neoadjuvant chemoradiotherapy (CRT). In relation to better outcomes, the percentage of patients who achieved pathological complete response (pCR) after neoadjuvant treatment is higher in the case of TNT. This study aimed to analyze the response to TNT compared to neoadjuvant CRT regarding pCR rate and the change in staging after surgical intervention. Materials and Methods: We performed a retrospective study on 323 patients with rectal cancer and finally analyzed the data of 201 patients with neoadjuvant treatment, selected based on the inclusion and exclusion criteria. Patients received CRT neoadjuvant therapy or TNT neoadjuvant therapy with FOLFOX or CAPEOX. Results: Out of 157 patients who underwent TNT treatment, 19.74% had pathological complete response, whereas in the group with CRT (n = 44), those with pCR were 13.64%. After neoadjuvant treatment, the most frequent TNM classifications were ypT2 (40.30%) and ypN0 (79.10%). The statistical analysis of the postoperative disease stage, after neoadjuvant therapy, showed that the most frequent changes were downstaging (71.14%) and complete response (18.41%). Only four patients (1.99%) had an upstaging change. The majority of patients (88.56%) initially presented clinical evidence of nodal involvement whereas only 20.9% of the patients still presented regional disease at the time of surgical intervention. Conclusions: By using TNT, a higher rate of stage reduction is obtained compared to the neoadjuvant CRT treatment. The post-neoadjuvant-treatment imagistic evaluation fails to accurately evaluate the response. A better response to TNT was observed in young patients.

Can rectal MRI and endorectal ultrasound accurately predict the complete response to neoadjuvant immunotherapy for rectal cancer?

Background

Standardized assessments of clinical complete response (cCR) to neoadjuvant chemoradiotherapy (nCRT) for rectal cancer have been established, but their utility and accuracy remain unclear. This study aimed to evaluate the clinical diagnostic value of rectal magnetic resonance imaging (MRI) and endorectal ultrasonography (ERUS) for the determination of cCRs after neoadjuvant immunotherapy and to investigate the concordance between cCR and pathological complete response (pCR).

Methods

Ninety-four patients with rectal cancer treated with neoadjuvant radiotherapy with or without immunotherapy were included. The sensitivity, specificity, and accuracy of each evaluation method were calculated.

Results

Combined MRI and ERUS assessments found cCR in seven of the 94 patients in our cohort. In the non-immunotherapy group, the sensitivity, specificity, and accuracy of MRI for diagnosing cCR were 50.0%, 85.2%, and 77.1%, respectively, whereas those of ERUS were 50.0%, 92.6%, and 82.9%, respectively; those of combined MRI and ERUS were 25.0%, 96.3%, and 87.5%, respectively. In the immunotherapy group, the sensitivity, specificity, and accuracy with which MRI identified CR were 51.7%, 76.7%, and 64.4%, respectively; those of ERUS were 13.8%, 90.0%, and 52.5%, respectively, and those of combined MRI and ERUS were 10.3%, 96.7%, and 54.2%, respectively. We also found that 32 of 37 patients with pCR did not meet the cCR evaluation criteria. Of these pCR patients, 78.4% (29/37) received immunotherapy. In the entire cohort, there were five pCRs among the seven cCRs. Of the four cCRs that occurred in the immunotherapy group, three were pCRs.

Conclusions

Rectal MRI and/or ERUS did not provide sufficiently accurate assessments of cCR in patients with rectal cancer receiving neoadjuvant therapy, especially immunotherapy, and cCR did not predict pCR.

Sense and non-sense of imaging in the era of organ preservation for rectal cancer

This review summarizes the current applications and benefits of imaging modalities for organ preservation in the treatment of rectal cancer. The concept of organ preservation in the treatment of rectal cancer has revolutionized the way rectal cancer is managed. Initially, organ preservation was limited to patients with locally advanced rectal cancer who needed neoadjuvant therapy to reduce tumor size before surgery and achieved complete response. However, neoadjuvant therapy is now increasingly utilized for smaller and less aggressive tumors to achieve primary organ preservation. Additionally, more intensive neoadjuvant strategies are employed to improve complete response rates and increase the chances of successful organ preservation. The selection of patients for organ preservation is a critical component of treatment, and imaging techniques such as digital rectal exam, endoscopy, and MRI are commonly used for this purpose. In this review, we provide an overview of what imaging modalities should be chosen and how they can aid in the selection and follow-up of patients undergoing organ-preserving strategies.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study

OBJECTIVES

A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them.

METHODS

Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2 years.

RESULTS

We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated.

CONCLUSIONS

MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients' response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients.

KEY POINTS

• The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients' scans were interpreted with high accuracy and low variability, suggesting that these patients' pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.

Total neoadjuvant therapy for locally advanced rectal cancer: a narrative review

Locally advanced rectal cancer has traditionally been treated with chemoradiotherapy (CRT) followed by surgery and adjuvant chemotherapy. However, a new strategy, total neoadjuvant therapy, involves the administration of CRT and neoadjuvant chemotherapy with the aim of eradicating micrometastases earlier and achieving greater control of the disease. The use of total neoadjuvant therapy has shown higher rates of pathological complete response and resectability compared with CRT, including improved survival. Nevertheless, distant relapse is the main cause of morbidity and mortality in locally advanced rectal cancer. To address this, new biomarkers are being developed to predict disease response.

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

A prospective cohort study on active surveillance after neoadjuvant chemoradiotherapy for esophageal cancer: protocol of Surgery As Needed for Oesophageal cancer-2

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRT) followed by esophagectomy is a standard treatment for potentially curable esophageal cancer. Active surveillance in patients with a clinically complete response (cCR) 12 weeks after nCRT is regarded as possible alternative to standard surgery. The aim of this study is to monitor the safety, adherence and effectiveness of active surveillance in patients outside a randomized trial.

METHODS

This nationwide prospective cohort study aims to accrue operable patients with non-metastatic histologically proven adenocarcinoma or squamous cell carcinoma of the esophagus or esophagogastric junction. Patients receive nCRT and response evaluation consists of upper endoscopy with bite-on-bite biopsies, endoscopic ultrasonography plus fine-needle aspiration of suspicious lymph nodes and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography scan. When residue or regrowth of tumor in the absence of distant metastases is detected, surgical resection is advised. Patients with cCR after nCRT are suitable to undergo active surveillance. Patients can consult an independent physician or psychologist to support decision-making. Primary endpoint is the number and severity of adverse events in patients with cCR undergoing active surveillance, defined as complications from response evaluations, delayed surgery and the development of distant metastases. Secondary endpoints include timing and quality of diagnostic modalities, overall survival, progression-free survival, fear of cancer recurrence and decisional regret.

DISCUSSION

Active surveillance after nCRT may be an alternative to standard surgery in patients with esophageal cancer. Similar to organ-sparing approaches applied in other cancer types, the safety and efficacy of active surveillance needs monitoring before data from randomized trials are available.

TRIAL REGISTRATION

The SANO-2 study has been registered at ClinicalTrials.gov as NCT04886635 (May 14, 2021) - Retrospectively registered.

Patient-derived tumor organoids predict responses to irinotecan-based neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

Adding irinotecan to neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) increases the pathologic complete response (pCR) rate but brings more toxicities. Robust biomarkers to predict response to irinotecan-based nCRT are extremely necessary for selecting the right patients. Our previous study suggests that patient-derived tumor organoids (PDTOs) sensitivity to chemoradiotherapy matches patient responses. In this study, we investigated whether PDTOs sensitivity to irinotecan can predict complete response (CR) and survival. Eligible patients receiving irinotecan-based nCRT between April 5, 2017 and December 11, 2020 were enrolled in the training cohort (n = 91) for response prediction and survival analysis. Patients receiving nCRT between February 21, 2021 and September 17, 2021 were included in the validation cohort (n = 27). Predictive performances of irinotecan organoid size ratio (OSR) for CR or pCR were evaluated. The irinotecan-sensitive groups had higher response rates compared with the insensitive groups (training cohort: 71.8% vs 24.4%, P < .0001; validation cohort, 81.8% vs 18.8%, P = .002). Moreover, the irinotecan-sensitive group had higher rates of 3-year disease-free survival (DFS: 71.6% vs 55.5%, P = .034) and distant metastasis-free survival (DMFS, 77.9% vs 57.2%, P = .015) than the irinotecan-insensitive group. 5-FU and irradiation sensitivities failed to predict 3-year DFS (5-FU: 65.4% vs 61.9%, P = .643; irradiation: 84.8% vs 57.8%; P = .072). Performances of irinotecan OSR to predict CR or pCR were good in the training cohort (CR: AUC = 0.828; 95% CI = 0.723-0.932; pCR: AUC = 0.864; 95% CI = 0.759-0.961). The validation showed robust predictive ability (CR: AUC = 0.796, 95% CI = 0.5974-0.9952; pCR: AUC = 0.917, 95% CI = 0.7921-1.0000). Irinotecan sensitivity in PDTOs was a predictive and prognostic factor in LARC.

Prevalent Pseudoprogression and Pseudoresidue in Patients With Rectal Cancer Treated With Neoadjuvant Immune Checkpoint Inhibitors

BACKGROUND

Immune checkpoint inhibitor (ICI) treatment in patients with microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) tumors holds promise in reshaping organ preservation in rectal cancer. However, the benefits are accompanied by distinctive patterns of response, introducing a dilemma in the response evaluation for clinical decision-making.

PATIENTS AND METHODS

Patients with locally advanced rectal cancer with MSI-H/dMMR tumors receiving neoadjuvant ICI (nICI) treatment (n=13) and matched patients receiving neoadjuvant chemoradiotherapy (nCRT; n=13) were included to compare clinical response and histopathologic features.

RESULTS

Among the 13 patients receiving nICI treatment, in the final radiologic evaluation prior to surgery (at a median of 103 days after initiation of therapy), progressive disease (n=3), stable disease (n=1), partial response (n=7), and complete response (n=2) were observed. However, these patients were later confirmed as having pathologic complete response, resulting in pseudoprogression and pseudoresidue with incidences of 23.1% (n=3) and 76.9% (n=10), respectively, whereas no pseudoprogression was found in the 13 patients receiving nCRT. We further revealed the histopathologic basis underlying the pseudoprogression and pseudoresidue by discovering the distinctive immune-related regression features after nICI treatment, including fibrogenesis, dense lymphocytes, and plasma cell infiltration.

CONCLUSIONS

Pseudoprogression and pseudoresidue were unique and prevalent response patterns in MSI-H/dMMR rectal cancer after nICI treatment. Our findings highlight the importance of developing specific strategies for response evaluation in neoadjuvant immunotherapy to identify patients with a good response in whom sphincter/organ-preserving or watch-and-wait strategies may be considered.

MRI VS. FDG-PET for diagnosis of response to neoadjuvant therapy in patients with locally advanced rectal cancer

Aim

In this study, we aimed to compare the diagnostic values of MRI and FDG-PET for the prediction of the response to neoadjuvant chemoradiotherapy (NACT) of patients with locally advanced Rectal cancer (RC).

Methods

Electronic databases, including PubMed, Embase, and the Cochrane library, were systematically searched through December 2021 for studies that investigated the diagnostic value of MRI and FDG-PET in the prediction of the response of patients with locally advanced RC to NACT. The quality of the included studies was assessed using QUADAS. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR), and the area under the ROC (AUC) of MRI and FDG-PET were calculated using a bivariate generalized linear mixed model, random-effects model, and hierarchical regression.

Results

A total number of 74 studies with recruited 4,105 locally advanced RC patients were included in this analysis. The pooled sensitivity, specificity, PLR, NLR, and AUC for MRI were 0.83 (95% CI: 0.77-0.88), 0.85 (95% CI: 0.79-0.89), 5.50 (95% CI: 4.11-7.35), 0.20 (95% CI: 0.14-0.27), and 0.91 (95% CI: 0.88-0.93), respectively. The summary sensitivity, specificity, PLR, NLR and AUC for FDG-PET were 0.81 (95% CI: 0.77-0.85), 0.75 (95% CI: 0.70-0.80), 3.29 (95% CI: 2.64-4.10), 0.25 (95% CI: 0.20-0.31), and 0.85 (95% CI: 0.82-0.88), respectively. Moreover, there were no significant differences between MRI and FDG-PET in sensitivity (P = 0.565), and NLR (P = 0.268), while the specificity (P = 0.006), PLR (P = 0.006), and AUC (P = 0.003) of MRI was higher than FDG-PET.

Conclusions

MRI might superior than FGD-PET for the prediction of the response of patients with locally advanced RC to NACT.

microRNAs combined to radiomic features as a predictor of complete clinical response after neoadjuvant radio-chemotherapy for locally advanced rectal cancer: a preliminary study

OBJECTIVE

To define a predictive Artificial Intelligence (AI) algorithm based on the integration of a set of biopsy-based microRNAs expression data and radiomic features to understand their potential impact in predicting clinical response (CR) to neoadjuvant radio-chemotherapy (nRCT). The identification of patients who would truly benefit from nRCT for Locally Advanced Rectal Cancer (LARC) could be crucial for an improvement in a tailored therapy.

METHODS

Forty patients with LARC were retrospectively analyzed. An MRI of the pelvis before and after nRCT was performed. In the diagnostic biopsy, the expression levels of 7 miRNAs were measured and correlated with the tumor response rate (TRG), assessed on the surgical sample. The accuracy of complete CR (cCR) prediction was compared for i) clinical predictors; ii) radiomic features; iii) miRNAs levels; and iv) combination of radiomics and miRNAs.

RESULTS

Clinical predictors showed the lowest accuracy. The best performing model was based on the integration of radiomic features with miR-145 expression level (AUC-ROC = 0.90). AI algorithm, based on radiomics features and the overexpression of miR-145, showed an association with the TRG class and demonstrated a significant impact on the outcome.

CONCLUSION

The pre-treatment identification of responders/NON-responders to nRCT could address patients to a personalized strategy, such as total neoadjuvant therapy (TNT) for responders and upfront surgery for non-responders. The combination of radiomic features and miRNAs expression data from images and biopsy obtained through standard of care has the potential to accelerate the discovery of a noninvasive multimodal approach to predict the cCR after nRCT for LARC.

Radiomics Approaches for the Prediction of Pathological Complete Response after Neoadjuvant Treatment in Locally Advanced Rectal Cancer: Ready for Prime Time?

In recent years, neoadjuvant therapy of locally advanced rectal cancer has seen tremendous modifications. Adding neoadjuvant chemotherapy before or after chemoradiotherapy significantly increases loco-regional disease-free survival, negative surgical margin rates, and complete response rates. The higher complete rate is particularly clinically meaningful given the possibility of organ preservation in this specific sub-population, without compromising overall survival. However, all locally advanced rectal cancer most likely does not benefit from total neoadjuvant therapy (TNT), but experiences higher toxicity rates. Diagnosis of complete response after neoadjuvant therapy is a real challenge, with a risk of false negatives and possible under-treatment. These new therapeutic approaches thus raise the need for better selection tools, enabling a personalized therapeutic approach for each patient. These tools mostly focus on the prediction of the pathological complete response given the clinical impact. In this article, we review the place of different biomarkers (clinical, biological, genomics, transcriptomics, proteomics, and radiomics) as well as their clinical implementation and discuss the most recent trends for future steps in prediction modeling in patients with locally advanced rectal cancer.

Impact of Prediagnosis Risk of Major Depressive Disorder and Health-Related Quality of Life on Treatment Choice for Stage II-III Rectal Cancer

PURPOSE

We hypothesized that depressive symptoms and health-related quality of life (HRQOL) reported by patients before their cancer diagnoses would be associated with treatment choice for stage II and III rectal cancer, specifically whether patients underwent surgery.

METHODS

The Surveillance, Epidemiology, and End Results and Medicare Health Outcomes Survey linked data set was used to identify patients with stage II-III rectal adenocarcinoma diagnosed between 2004 and 2013 who had completed the health outcomes survey within 36 months before their cancer diagnoses. Risk for major depressive disorder (MDD) was determined on the basis of responses to screening questions for depressive disorders. HRQOL was assessed using the Mental Component Summary and Physical Component Summary of the 36-Item Short Form Survey and Veterans RAND 12-Item Health Survey. Using univariable and multivariable analyses, we assessed for associations between health survey responses and ultimate treatment modality.

RESULTS

We identified 142 evaluable patients, of whom 109 (76.8%) underwent surgery. Thirty patients (21.1%) met criteria for being at risk for MDD before their cancer diagnoses. Patients at risk for MDD underwent surgery less often than those not at risk (P = .0499), and this association strengthened after adjusting for patient characteristics (odds ratio, 0.17; 95% CI, 0.04 to 0.82; P = .027). There was a nonsignificant trend between higher Mental Component Summary scores (indicating higher self-reported mental HRQOL) and increased frequency of undergoing surgery (P = .081). There were no significant associations between the Physical Component Summary and treatment modality.

CONCLUSION

In Medicare beneficiaries with stage II-III rectal cancer, those at risk for MDD underwent standard-of-care treatment with surgery less frequently. Further studies are warranted to assess the effect of mental health on clinical decision making in this patient population.

Short-term outcomes of chemoradiotherapy and local excision versus total mesorectal excision in T2-T3ab,N0,M0 rectal cancer: a multicentre randomised, controlled, phase III trial (the TAU-TEM study)

BACKGROUND

The standard treatment of T2-T3ab,N0,M0 rectal cancers is total mesorectal excision (TME) due to the high recurrence rates recorded with local excision. Initial reports of the combination of pre-operative chemoradiotherapy (CRT) and transanal endoscopic microsurgery (TEM) have shown reductions in local recurrence. The TAU-TEM study aims to demonstrate the non-inferiority of local recurrence and the improvement in morbidity achieved with CRT-TEM compared with TME. Here we describe morbidity rates and pathological outcomes.

PATIENTS AND METHODS

This was a prospective, multicentre, randomised controlled non-inferiority trial including patients with rectal adenocarcinoma staged as T2-T3ab,N0,M0. Patients were randomised to the CRT-TEM or the TME group. Patients included, tolerance of CRT and its adverse effects, surgical complications (Clavien-Dindo and Comprehensive Complication Index classifications) and pathological results (complete response in the CRT-TEM group) were recorded in both groups. Patients attended follow-up controls for local and systemic relapse.

TRIAL REGISTRATION

NCT01308190.

RESULTS

From July 2010 to October 2021, 173 patients from 17 Spanish hospitals were included (CRT-TEM: 86, TME: 87). Eleven were excluded after randomisation (CRT-TEM: 5, TME: 6). Modified intention-to-treat analysis thus included 81 patients in each group. There was no mortality after CRT. In the CRT-TEM group, one patient abandoned CRT, 1/81 (1.2%). The CRT-related morbidity rate was 29.6% (24/81). Post-operative morbidity was 17/82 (20.7%) in the CRT-TEM group and 41/81 (50.6%) in the TME group (P < 0.001, 95% confidence interval 42.9% to 16.7%). One patient died in each group (1.2%). Of the 81 patients in the CRT-TEM group who received the allocated treatment, 67 (82.7%) underwent organ preservation. Pathological complete response in the CRT-TEM group was 44.3% (35/79). In the TME group, pN1 were found in 17/81 (21%).

CONCLUSION

CRT-TEM treatment obtains high pathological complete response rates (44.3%) and a high CRT compliance rate (98.8%). Post-operative complications and hospitalisation rates were significantly lower than those in the TME group. We await the results of the follow-up regarding cancer outcomes and quality of life.

Correlation of Tumor Response Between Flexible Sigmoidoscopy and Magnetic Resonance Imaging in Patients Undergoing Neoadjuvant Therapy for Locally Advanced Rectal Cancer: A Retrospective Review

BACKGROUND

The National Accreditation Program for Rectal Cancer recommends a pelvic MRI to assess the response to neoadjuvant therapy for advanced rectal cancers. However, there is no single restaging modality that can identify all patients with complete tumor response. At our institution, we perform both a pelvic MRI and a flexible sigmoidoscopy (FS) after neoadjuvant therapy prior to surgical resection.

OBJECTIVE

The objective is to elucidate the correlation of tumor response between FS and MRI in patients undergoing neoadjuvant therapy for locally advanced rectal cancer.

DESIGN

Single institution from 2010 to 2019. Retrospective cohort study comparing local tumor response on FS to MRI utilizing final pathology as the gold standard for comparison.

PATIENTS

Patients with confirmed locally advanced rectal adenocarcinoma (stage II or III) who underwent neoadjuvant therapy prior to surgical intervention and underwent flexible endoscopy and a standardized rectal cancer protocol MRI to evaluate tumor response.

RESULTS

A total of 48 patients were evaluated. Seven (14%) patients had a complete pathological response. MRI adequately reported 1 (14%), while FS found 4 (57.14%) out of the 7 complete responders. Nevertheless, this did not reach statistical significance (P = .06). On logistic regression analysis, flexible sigmoidoscopy had a 5.5 higher likelihood to report an accurate complete response (OR 5.5, 95% CI: 1.02-29.64; P = .047).

CONCLUSIONS

Flexible sigmoidoscopy should be used in conjunction with MRI in the work up of patients who have received neoadjuvant therapy for advanced rectal cancer prior to surgical resection.

The Promise of Magnetic Resonance Imaging in Radiation Oncology Practice in the Management of Brain, Prostate, and GI Malignancies

Magnetic resonance imaging (MRI) has a key role to play at multiple steps of the radiotherapy (RT) treatment planning and delivery process. Development of high-precision RT techniques such as intensity-modulated RT, stereotactic ablative RT, and particle beam therapy has enabled oncologists to escalate RT dose to the target while restricting doses to organs at risk (OAR). MRI plays a critical role in target volume delineation in various disease sites, thus ensuring that these high-precision techniques can be safely implemented. Accurate identification of gross disease has also enabled selective dose escalation as a means to widen the therapeutic index. Morphological and functional MRI sequences have also facilitated an understanding of temporal changes in target volumes and OAR during a course of RT, allowing for midtreatment volumetric and biological adaptation. The latest advancement in linear accelerator technology has led to the incorporation of an MRI scanner in the treatment unit. MRI-guided RT provides the opportunity for MRI-only workflow along with online adaptation for either target or OAR or both. MRI plays a key role in post-treatment response evaluation and is an important tool for guiding decision making. In this review, we briefly discuss the RT-related applications of MRI in the management of brain, prostate, and GI malignancies.

The Multimodal Management of Locally Advanced Rectal Cancer: Making Sense of the New Data

In the past 40 years, the treatment of locally advanced rectal cancer has evolved with the addition of radiotherapy or chemoradiotherapy and providing (neo)adjuvant systemic chemotherapy to major surgery. However, recent trends have focused on improving our ability to risk-stratify patients and tailoring treatment to achieve the best oncologic outcome while limiting the impact on long-term quality of life. Therefore, there has been increasing interest in pursuing a watch-and-wait approach to achieve organ preservation. Several retro- and prospective studies suggest safety of the watch-and-wait approach, though it is still considered controversial due to limited clinical evidence, concerns about tumor regrowth, and subsequent distant progression. To further reduce treatment, MRI risk stratification, together with patient characteristics and patient preferences, can guide personalized treatment and reserve radiation and chemotherapy for a select patient population. Ultimately, improved options for reassessment during neoadjuvant treatment may allow for more adaptive therapy options based on treatment response. This article provides an overview of some major developments in the multimodal treatment of locally advanced rectal cancer. It reviews some relevant, controversial issues of the watch-and-wait approach and opportunities to personally tailor and reduce treatment. It also reviews the overall neoadjuvant treatment, including total neoadjuvant therapy trials, and how to best optimize for a potential complete response. Finally, it provides an algorithm as an example of how such a personalized, tailored, adaptive, and reduced treatment could look like in the future.

C-Reactive Protein as Predictive Biomarker for Response to Chemoradiotherapy in Patients with Locally Advanced Rectal Cancer: A Retrospective Study

The standard of care for the treatment of locally advanced rectal cancer is neoadjuvant chemoradiotherapy (nCRT) followed by surgery, but complete response rates are reduced. To find predictive biomarkers of response to therapy, we conducted a retrospective study evaluating blood biomarkers before nCRT. Hemoglobin (Hg), C-reactive protein (CRP), platelets, carcinoembryonic antigen, carbohydrate antigen 19.9 levels, and neutrophil/lymphocyte ratio were obtained from 171 rectal cancer patients before nCRT. Patients were classified as responders (Ryan 0-1; ycT0N0), 59.6% (n = 102), or nonresponders (Ryan 2-3), 40.3% (n = 69), in accordance with the Ryan classification. A logistic regression using prognostic pretreatment factors identified CRP ≤ 3.5 (OR = 0.05; 95%CI: 0.01-0.21) as a strong independent predictor of response to treatment. Multivariate analysis showed that CRP was an independent predictor of disease-free survival (DFS) (HR = 5.48; 95%CI: 1.54-19.48) and overall survival (HR = 6.10; 95%CI 1.27-29.33) in patients treated with nCRT. Platelets were an independent predictor of DFS (HR = 3.068; 95%CI: 1.29-7.30) and OS (HR= 4.65; 95%CI: 1.66-13.05) and Hg was revealed to be an independent predictor of DFS (HR = 0.37; 95%CI: 0.15-0.90) in rectal cancer patients treated with nCRT. The lower expression of CRP is independently associated with an improved response to nCRT, DFS, and OS.

[Complete response after neoadjuvant therapy: how certain is radiology?]

The concept of total neoadjuvant therapy (TNT) means a paradigm shift in the treatment of patients with rectal cancer. In cases in which the TNT induced a complete clinical response (cCR), an organ preserving watch and wait therapy concept can now be provided more often; however, this increases the demand for imaging for the determination of cCR and in the subsequent follow-up. In this article, the performance of radiology in these scenarios will be evaluated and discussed. Magnetic resonance imaging (MRI) is the current standard for local assessment of the rectum with a high sensitivity for diagnosis and staging of rectal cancer, residual tumor and tumor recurrence. However, the certain exclusion of residual malignant tissue is still difficult, in particular the differentiation of residual scar tissue from vital residual tumor is only possible with low specificity and a moderate negative predictive value (NPV). The currently discussed criteria for the assessment of imaging have not yet been validated in large cohorts and are frequently subjective. An improvement of the diagnostic accuracy for identification of cCR in patients after TNT and for monitoring patients in watch and wait treatment concepts can certainly be achieved by the integration of MRI, endoscopy and endosonography as well as clinical parameters. This should enable for identification of patients with an incomplete response or local recurrence, in time for extended treatment to be initiated without relevant impact on the patient outcome.

Preoperative radiotherapy 5 × 5 Gy and short versus long interval between surgery for resectable rectal cancer: 10-Year follow-up of the randomised controlled trial

BACKGROUND

Studies on short-course preoperative radiotherapy in combination with total mesorectal excision for rectal cancer reported improved local control without clear survival benefits. The optimal fractionation and interval between radiotherapy and surgery are still under debate. We, therefore, aimed to report 10-year results of a randomized clinical trial (RCT, NCT01444495) comparing different time intervals between irradiation and surgery for rectal cancer.

MATERIAL AND METHODS

Data from the RCT conducted at a single academic centre were reviewed based on regular control visits with the median follow-up of 12 years. Patients with rectal cancer were randomly assigned to short-course preoperative radiotherapy (5 × 5 Gy) followed by surgery 7-10 days (short interval) or 4-5 weeks (long interval) after the end of irradiation. The primary endpoint was the local recurrence rate at 5 years. The secondary endpoints included overall survival, disease-free survival, systemic recurrence rate, and downstaging.

RESULTS

A total of 154 patients were randomly assigned to short (n = 77) or long interval (n = 77) surgery. The cumulative incidence of local recurrence at 10 years was 1.3% and 11.7% in the short and long-interval groups, respectively (p = 0.031). Accordingly, the incidence of systemic relapse was 14.3% versus 9.1% (p = 0.0319). There were no differences in the overall 10-year survival between patients subject to short and long-interval surgery (58% vs 61%, p = 0.754). However, patients with downstaging after radiotherapy had significantly better 10-year survival rates than non-responders.

CONCLUSIONS

Short-course preoperative radiotherapy with delayed surgery demonstrated an increased risk of local relapse over a 10-year follow-up.

Tumor Volume as Predictor of Pathologic Complete Response Following Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

PURPOSE

Neoadjuvant chemoradiation followed by surgery is the current standard of care in the treatment of locally advanced rectal cancer. Those who achieved pathologic complete response, following this standard of care, complete pathologic response (pCR) had better outcome. Until now there are no reliable clinical parameters to predict this response. The purpose of the study was to evaluate whether tumor volume may serve as a predictive factor in patients treated with neoadjuvant chemoradiotherapy.

MATERIALS AND METHODS

Between September 2015 and September 2019, patients diagnosed with stage IIA to IIIC rectal adenocarcinoma, who were treated with neoadjuvant chemoradiation, were enrolled to this study. All patients underwent rectal ultrasound, pelvic magnetic resonance imaging, fluorodeoxyglucose-positron emission tomography-computed tomography and the diagnosis was confirmed by pathology report. Radiation therapy was consisted of 50 Gy delivered to the tumor site, 2 Gy a day, 5 times a week and to the pelvic lymph nodes for a total of 45 Gy in 1.8 Gy a day, 5 times a week. The gross tumor volume (GTV) was contoured by radiation oncology expert, reviewed by radiology and nuclear medicine expert and approved by radiation therapy tumor board. Chemotherapy was consisted of either capecitabine 875 mg/m2 twice a day or continuous. IV infusion of 5 fluorouracil 375 mg/m2 for 4 consecutive days in a 3 weeks apart. Operation, either low anterior or abdominoperineal resection was carried out 6 to 8 weeks following completion of treatment. Patients were assigned to either complete pathologic response (pCR) or non-pCR groups. GTV, among other clinical and treatment parameters, were evaluated for prediction of pCR. Statistical methods included independent t test, logistic regression, area under the curve-receiver operating characteristic, Bayesian independent statistics and multilayer perceptron model.

RESULTS

One hundred ninety-three patients were enrolled to this study, 6 were excluded due to metastatic disease detected at the time of operation. Seventy had stage II and 117 had stage III. Forty-four of 187 (23.5%) patients achieved pCR and 143 patients had either partial or no response/progressive disease. Among the 44 pCR group, 21 had stage II and 23 had stage III disease. Treatment interruption, defined as either a delay of up to 1 week in radiation, and a dose reduction to 75%, was occurred in 42 patients. Sex, ethnicity, distance from anal verge to tumor, height, weight, age, delivered radiation dose, radiotherapy techniques, clinical T and N stage and GTV were evaluated for prediction of pCR. GTV at the volume of <39.5 cm3 was the only significant predictive factor to detect pCR by logistic regression model (P<0.01) and by Bayesian independent test (P=0.026). Area under the receiver operating characteristic curve of GTV <39.5 cm3 showed area under the curve of 0.715 (P=0.009) for stage II and area under the curve of 0.62 (P>0.05) for stage III.

CONCLUSION

GTV may serve as a predictive factor for achieving pCR in locally advanced rectal cancer after neoadjuvant chemoradiotherapy.

Multidisciplinary management of elderly patients with rectal cancer: recommendations from the SICG (Italian Society of Geriatric Surgery), SIFIPAC (Italian Society of Surgical Pathophysiology), SICE (Italian Society of Endoscopic Surgery and new technologies), and the WSES (World Society of Emergency Surgery) International Consensus Project

BACKGROUND AND AIMS

Although rectal cancer is predominantly a disease of older patients, current guidelines do not incorporate optimal treatment recommendations for the elderly and address only partially the associated specific challenges encountered in this population. This results in a wide variation and disparity in delivering a standard of care to this subset of patients. As the burden of rectal cancer in the elderly population continues to increase, it is crucial to assess whether current recommendations on treatment strategies for the general population can be adopted for the older adults, with the same beneficial oncological and functional outcomes. This multidisciplinary experts' consensus aims to refine current rectal cancer-specific guidelines for the elderly population in order to help to maximize rectal cancer therapeutic strategies while minimizing adverse impacts on functional outcomes and quality of life for these patients.

METHODS

The discussion among the steering group of clinical experts and methodologists from the societies' expert panel involved clinicians practicing in general surgery, colorectal surgery, surgical oncology, geriatric oncology, geriatrics, gastroenterologists, radiologists, oncologists, radiation oncologists, and endoscopists. Research topics and questions were formulated, revised, and unanimously approved by all experts in two subsequent modified Delphi rounds in December 2020-January 2021. The steering committee was divided into nine teams following the main research field of members. Each conducted their literature search and drafted statements and recommendations on their research question. Literature search has been updated up to 2020 and statements and recommendations have been developed according to the GRADE methodology. A modified Delphi methodology was implemented to reach agreement among the experts on all statements and recommendations.

CONCLUSIONS

The 2021 SICG-SIFIPAC-SICE-WSES consensus for the multidisciplinary management of elderly patients with rectal cancer aims to provide updated evidence-based statements and recommendations on each of the following topics: epidemiology, pre-intervention strategies, diagnosis and staging, neoadjuvant chemoradiation, surgery, watch and wait strategy, adjuvant chemotherapy, synchronous liver metastases, and emergency presentation of rectal cancer.

Computertomography-Based Prediction of Complete Response Following Neoadjuvant Chemoradiotherapy of Locally Advanced Rectal Cancer

Therapeutic strategies for patients with locally advanced rectal cancer (LARC) who are achieving a pathological complete response (pCR) after neoadjuvant radio-chemotherapy (neoCRT) are being increasingly investigated. Recent trials challenge the current standard therapy of total mesorectal excision (TME). For some patients, the treatment strategy of “watch-and-wait” seems a preferable procedure. The key factor in determining individual treatment strategies following neoCRT is the precise evaluation of the tumor response. Contrast-enhanced computer tomography (ceCT) has proven its ability to discriminate benign and malign lesions in multiple cancers. In this study, we retrospectively analyzed the ceCT based density of LARC in 30 patients, undergoing neoCRT followed by TME. We compared the tumors´ pre- and post-neoCRT density and correlated the results to the amount of residual vital tumor cells in the resected tissue. Overall, the density decreased after neoCRT, with the highest decrease in patients achieving pCR. Densitometry demonstrated a specificity of 88% and sensitivity of 68% in predicting pCR. Thus, we claim that ceCT based densitometry is a useful tool in identifying patients with LARC who may benefit from a “watch-and-wait” strategy and suggest further prospective studies.

Accuracy of High Resolution Multidetector Computed Tomography in the Local Staging of Rectal Cancer

Background Magnetic resonance imaging (MRI) is the gold standard for local staging of rectal cancer. Advanced computed tomography (CT) machines are now capable of high-resolution images of rectal cancer and utilized for CT perfusion. The possibility of local staging of rectal cancer by CT needs to be explored.

Purpose The aim of the study is to evaluate accuracy of high-resolution CT for local rectal cancer staging.

Methods A high-resolution CT was performed for local staging of rectal cancer in our study group of 93 patients, where 64 underwent primary surgery and 29 underwent surgery post neoadjuvant chemoradiotherapy (NACRT).

Results In differentiating stages T2-and-less than T2 from T3–T4 rectal cancer, accuracy, sensitivity, specificity, and kappa score in overall patients were 91%, 87%, 94%, and 0.8; in primary surgery group were 89%, 76%, 94%, and 0.7; in NACRT group were 97%, 100%, 94%, and 0.9; in low rectal group were 94%, 89%, 97%, and 0.82, respectively.

Conclusion High resolution CT is an accurate tool for local staging of rectal cancer.

"Rectal cancer survival: A retrospective analysis of MRI features and their association with prognosis"

PURPOSE

To assess rectal cancer aggressiveness using magnetic resonance (MR) imaging features and to investigate their relationship with patient prognosis.

MATERIALS AND METHODS

Clinical information and Pelvic MR scans of 106 consecutive patients with primary rectal cancer (RC) were analyzed. Clinical symptoms, age, sex, tumor location, and patient´s survival were recorded. The variables investigated by MR were: depth or mural/extramural tumor involvement, distance to mesorectal margin, lymph node involvement, vascular, peritoneal or sphincter complex infiltration. The association between imaging features and disease-free survival (DFS) was also assessed using a Kaplan-Meier model. Differences between survival curves were tested for significance using the Mantel-Cox LogRank test.

RESULTS

The final study population was 106 patients (65 males, 41 females). The median age was 69.5 years (range, 39-92 years). No significant differences were found between death risk and sex, age or tumor location (p>0,05). However, the relative risk (RR) of tumor mortality increased significantly with the presence of the variables: vascular infiltration (×5), T4 tumors (× 4.57), N2 lymph node involvement (more than 3 affected nodes × 4.11) and mesorectal fascia involvement (× 3,77).

CONCLUSION

Tumor extension, number of pathological lymph nodes, mesorectal fascia involvement and vascular infiltration values obtained on initial MR imaging staging showed a significant difference for disease-free survival in RC at six years of control.

Is It Time to Introduce PET/CT in Rectal Cancer Guidelines?

At the moment, international guidelines for rectal cancer suggest to consider F-FDG PET/CT scan in a few conditions: (1) at disease presentation in case of suspected or proven metastatic synchronous adenocarcinoma with potentially curable M1 disease; (2) in the recurrence workup for serial carcinoembryonic antigen level elevation; (3) in the recurrence workup with metachronous metastases documented by CT, MRI, or biopsy; (4) in case of strong contraindication to IV contrast agent administration; and (5) to evaluate an equivocal finding on a contrast-enhanced CT or MRI. PET/CT is not indicated in the follow-up or surveillance of rectal cancer. On the other hand, an attentive evaluation of the literature shows that PET/CT may also be used in some circumstances with significant levels of diagnostic accuracy. This review article aims to emphasize differences between current international guidelines and scientific literature in the role of PET/CT in rectal cancer.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Limited Role for Routine Restaging After Neoadjuvant Therapy in Locally Advanced Rectal Cancer

BACKGROUND

Although many patients with locally advanced rectal cancer undergo restaging imaging after neoadjuvant chemoradiotherapy and before surgery, the benefit of this practice is unclear. The purpose of this study was to examine the impact of reimaging on outcomes.

MATERIALS AND METHODS

We performed a retrospective analysis of consecutive patients with stage 2 and 3 rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy between May 2005 and April 2018. Patient and disease characteristics, imaging, treatment, and oncologic outcomes were compared between those who underwent restaging and those who went directly to surgery. Predictors of outcomes and cost effectiveness of restaging were determined.

RESULTS

Of 224 patients, 146 underwent restaging. Six restaged patients had findings leading to a change in management. There was no difference in freedom from recurrence (P = 0.807) and overall survival (P = 0.684) based on restaging. Pretreatment carcinoembryonic antigen level >3 ng/mL (P = 0.010), clinical T stage 4 (P = 0.016), and pathologic T4 (P = 0.047) and N2 (P = 0.002) disease increased the risk of death, whereas adjuvant chemotherapy decreased the risk of death (P < 0.001) on multivariate analysis. Disease recurrence was lower with pelvic exenteration (P = 0.005) and in females (P = 0.039) and higher with pathologic N2 (P = 0.003) and N3 (P = 0.002) disease. The average cost of reimaging is $40,309 per change in management; however, $45 is saved per patient when downstream surgical costs are considered.

CONCLUSIONS

Imaging restaging after neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer rarely changes treatment and does not improve survival. In a subset of patients at higher risk for worse outcome, reimaging may be beneficial.

Non-operative management of rectal cancer

Despite advances in technique, surgical resection of rectal cancer remains a morbid procedure that can lead a profound decrease in a patient's quality of life. A novel method of management, termed "Non-operative management" (NOM), mirrors the management of anal carcinoma. Patients undergo definitive treatment with only chemotherapy and radiation, with resection reserved only for salvage. Current data is encouraging- both in reduction in morbidity and similar, if not superior oncologic results. However, there are a number of barriers to the wide adoption of this practice. This manuscript seeks to describe the rationale and execution of NOM as well as present the current data and pitfalls of the approach.

Locally Advanced Rectal Cancer Evaluation by Magnetic Resonance Imaging after Neoadjuvant Therapy on Decision Making: Cancer Center Experience and Literature Review

PURPOSE

An accurate clinical and radiological staging is the pyramid of treatment decisions in locally advanced rectal cancer (LARC). Guidelines recommended neoadjuvant chemoradiation therapy (CRT) followed by surgical resection for fit patients with LARC. Determining the aggressiveness of intervention while avoiding needless morbidity according to patient risk remains an unmet pre-operative decision-making need. With newer magnetic resonance imaging (MRI) techniques and image acquisition available at our Cancer Center, we seek to retrospectively review the correlation between pre- and post-CRT MRI response to the surgical pathological stage in order to aide multidisciplinary team decision making.

METHODS

Our Cancer Center Rectal Cancer Registry between 2011 and 2015 included 57 patients with LARC, 20 completed standard CRT with surgery, and of those 10 had repeated MRI after CRT.

RESULTS

Our retrospective case series revealed that 90% of the patients had a downstage tumor response on surgical specimen compared to radiological evaluation after CRT, and furthermore, all patients who were re-staged with MRI prior to surgery correlated with the gold standard pathological stage (p = 0.02).

CONCLUSIONS

Post-CRT MRI could potentially aide decision making to further avoid 20% of patients with a complete pathological response from a morbid surgery, whereas 10% of patients with an upstaged disease state may require a more aggressive neoadjuvant or planned surgical intervention. We concluded that future multidisciplinary oncology care treatment decision making would benefit from a repeat MRI after neoadjuvant CRT of LARC.

The value of four imaging modalities in diagnosing lymph node involvement in rectal cancer: an overview and adjusted indirect comparison

Several systematic reviews have investigated the accuracy of imaging modalities for lymph node involvement of rectal cancer, but there are considerable differences in conclusions. This overview aimed to assess the methodological and reporting quality of systematic reviews that evaluated the diagnostic value of imaging modalities for lymph node involvement in patients with rectal cancer and to compare the diagnostic value of different modalities for lymph node involvement. The PubMed, EMBASE, Cochrane Library and Chinese Biomedicine Literature were searched to identify relevant systematic reviews. The methodological quality was assessed using the AMSTAR checklist, and the reporting quality was assessed using PRISMA-DTA checklist. The indirect comparison was conducted to compare the accuracy of different imaging modalities. Seven systematic reviews involving 353 primary studies were included. The median (Range) AMSTAR scores were 6.0 (4.0-9.0); the median (Range) PRISMA-DTA scores were 18.0 (11.0-23.0). Sensitivity of MRI [0.69 (95% CI 0.63, 0.77)] was significantly higher than that of ERUS [0.57 (95% CI 0.53, 0.62)]. Specificity of ERUS [0.80 (95% CI 0.77, 0.83)] was significantly higher than that of CT [0.72 (95% CI 0.67, 0.78)]. Positive likelihood ratio of EUS [3.04 (95% CI 2.75, 3.36)] was significantly higher than that of CT [2.21 (95% CI 1.69, 2.90)]. EUS had better diagnostic value than CT and ERUS in the diagnosis of lymph node involvement. Compared with CT and ERUS, MRI was more sensitive. EUS and MRI had comparable diagnostic accuracy, but no modality was proved to be particularly accurate.

The value of magnetic resonance imaging to diagnose pathological complete response of rectal cancer after therapy: A protocol for meta-analysis

BACKGROUND

Although the trends of colorectal incidence rate and mortality have decreased during the past 20 years, however, they are still high. Neoadjuvant chemoradiotherapy is recommended as the standard treatment strategy of local advanced rectal cancer followed by surgery and adjuvant therapy. Predicting pathological complete response (pCR) accurately is relative to the next treatment strategy to avoid extensive therapy. And there are more and more physicians who would like to choose pelvic MRI imaging to evaluate the state of rectal cancer. Therefore, our analysis will aim to assess the value of MRI to predict pCR of rectal cancer after therapy and distinguish which sequence and magnetic strength is the best one to diagnose pCR.

METHODS

Comprehensive computer-based search will be performed using the PubMed, EMBASE, Cochrane Library, and CBM database (last updated in April 2018), 2 reviewers will extract the related information respectively. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under the hierarchical summary receiver-operating characteristic curves will be calculated to estimate the diagnostic accuracy of different sequences and intensities of magnetic resonance imaging. Methodological quality will be assessed using the Quality Assessment of Diagnostic Accuracy Studies tool.

RESULTS

The results of this analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

The ability of different MRI sequences and magnetic intensities to identify pCR will be evaluated and the best one to diagnose pCR of rectal cancer after therapy will be recommended.

ETHICS AND DISSEMINATION

Ethics approval and patient consent are not required, as this study is a meta-analysis based on published studies.

PROSPERO REGISTRATION NUMBER

CRD42018105672.

Diagnostic accuracy of endoscopic ultrasound, computed tomography, magnetic resonance imaging, and endorectal ultrasonography for detecting lymph node involvement in patients with rectal cancer: A protocol for an overview of systematic reviews

BACKGROUND

Rectal cancer is one of the most common tumors and is the leading cause of cancer-related deaths in developed countries. Lymph node involvement remains the strongest prognostic factor associated with a worse prognosis in patients with rectal cancer. Several systematic reviews have investigated the accuracy of endoscopic ultrasound, computed tomography, magnetic resonance imaging, and endorectal ultrasonography for lymph node involvement of rectal cancer and compared the diagnostic accuracy of different imaging techniques, but there are considerable differences in conclusions. This study aims to assess the methodological quality and reporting quality of systematic reviews and to determine which diagnostic imaging techniques is the optimal modality for the diagnosis of lymph node involvement in patients with rectal cancer.

METHODS

We will search PubMed, EMBASE, Cochrane Library, and Chinese Biomedicine Literature to identify relevant studies from inception to June 2018. We will include systematic reviews that evaluated the accuracy of diagnostic imaging techniques for lymph node involvement. The methodological quality will be assessed using AMASAR checklist, and the reporting quality will be assessed using PRISMA-DTA checklist. The pairwise meta-analysis and indirect comparisons will be performed using STATA V.12.0.

RESULTS

The results of this overview will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This overview will provide comprehensive evidence of different diagnostic imaging techniques for detecting lymph node involvement in patients with rectal cancer.

ETHICS AND DISSEMINATION

Ethics approval and patient consent are not required as this study is an overview based on published systematic reviews.

PROSPERO REGISTRATION NUMBER

CRD42018104906.

MRI-Based Apparent Diffusion Coefficient for Predicting Pathologic Response of Rectal Cancer After Neoadjuvant Therapy: Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to assess the use of apparent diffusion coefficient (ADC) during DWI for predicting complete pathologic response of rectal cancer after neoadjuvant therapy.

MATERIALS AND METHODS

A systematic review of available literature was conducted to retrieve studies focused on the identification of complete pathologic response of locally advanced rectal cancer after neoadjuvant chemoradiation, through the assessment of ADC evaluated before, after, or both before and after treatment, as well as in terms of the difference between pretreatment and posttreatment ADC. Pooled mean pretreatment ADC, posttreatment ADC, and Δ-ADC (calculated as posttreatment ADC minus pretreatment ADC divided by pretreatment ADC and multiplied by 100) in complete responders versus incomplete responders were calculated. For each parameter, we also pooled sensitivity and specificity and calculated the area under the summary ROC curve.

RESULTS

We found 10 prospective and eight retrospective studies. Overall, pathologic complete response was observed in 22.2% of patients. Pooled mean pretreatment ADC in complete responders was 0.84 × 10^-3 mm²/s versus 0.89 × 10^-3 mm²/s in incomplete responders (p = 0.33). Posttreatment ADC values were 1.51 × 10^-3 mm²/s and 1.29 × 10^-3 mm²/s, in complete and incomplete responders, respectively (p = 0.00001). The Δ-ADC percentages were also significantly higher in complete responders than in incomplete responders (59.7% vs 29.7%, respectively, p = 0.016). Pooled sensitivity, specificity, and AUC were 0.743, 0.755, and 0.841 for pretreatment ADC; 0.800, 0.737, and 0.782 for posttreatment ADC; and 0.832, 0.806, and 0.895 for Δ-ADC.

CONCLUSION

Use of ADC during DWI is a promising technique for assessment of results of neoadjuvant treatment of rectal cancer.

Report from the 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference; Winnipeg, Manitoba; 29-30 September 2017

The 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference (wcgccc) was held in Winnipeg, Manitoba, 29-30 September 2017. The wcgccc is an interactive multidisciplinary conference attended by health care professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer.

Prognostic value of pathological node status after neoadjuvant radiotherapy for rectal cancer

Background

The prognostic value of pathological lymph node status following neoadjuvant radiotherapy (ypN) remains unclear. This study was designed to determine whether ypN status predicted overall survival.

Methods

Patients with locally advanced rectal adenocarcinoma who underwent neoadjuvant long-course radiation between 2005 and 2014 were identified from the National Cancer Data Base, and divided into ypN0, ypN1 and ypN2 groups. The primary outcome was overall survival. Univariable and multivariable analyses were used to determine factors associated with overall survival.

Results

Of 12 271 patients, 3713 (30·3 per cent) were found to have residual nodal positivity. A majority of patients with ypN1 (1663 of 2562) and ypN2 (878 of 1151) disease had suspected lymph node-positive disease before neoadjuvant therapy, compared with 3959 of 8558 with ypN0 tumours (P &lt; 0·001). Moreover, ypN1 and ypN2 were significantly associated with ypT3–4 disease (65·7 and 83·0 per cent respectively versus 39·4 per cent for ypN0; P &lt; 0·001). In unadjusted analyses, survival differed significantly between ypN groups (P &lt; 0·001). Five-year survival rates were 81·6, 71·3 and 55·0 per cent for patients with ypN0, ypN1 and ypN2 disease respectively. After adjustment for confounding variables, ypN1 and ypN2 remained independently associated with overall survival: hazard ratio (HR) 1·61 (95 per cent c.i. 1·46 to 1·77) and 2·63 (2·34 to 2·95) respectively (P &lt; 0·001). Overall survival was significantly longer in patients with ypN1–2 combined with ypT0–2 status than among those with ypT3–4 tumours even with ypN0 status (P = 0·031). Clinical nodal status before neoadjuvant therapy was not significantly associated with overall survival (HR 1·05, 0·97 to 1·13; P = 0·259).

Conclusion

Both ypT and ypN status is of prognostic significance following neoadjuvant therapy for rectal cancer.

Intravoxel Incoherent Motion MRI of Rectal Cancer: Correlation of Diffusion and Perfusion Characteristics With Prognostic Tumor Markers

OBJECTIVE

The objective of our study was to evaluate the intravoxel incoherent motion (IVIM)-DWI derived parameters and their relationships with tumor prognostic markers using 3-T MRI in patients with rectal cancer.

SUBJECTS AND METHODS

Fifty-two patients with histopathologically proven rectal cancer who underwent preoperative pelvic MRI were prospectively enrolled in this study. Diffusion and perfusion parameters including the apparent diffusion coefficient (ADC), pure diffusion coefficient, perfusion fraction, and pseudodiffusion coefficient derived from IVIMDWI were independently measured by two radiologists. Comparisons of IVIM-DWI-derived parameters in patients with different tumor prognostic markers were made using the independent-samples t test, ANOVA, and Mann-Whitney U test. The correlations between IVIM-DWI-derived parameters and tumor grade and tumor stage were further evaluated using Spearman correlation analysis. Interobserver agreement was evaluated using the intraclass correlation coefficient (ICC).

RESULTS

Excellent interobserver reproducibility was obtained for the IVIM-DWI-derived parameters (range of ICCs with 95% limits of agreement = 0.9309-0.9948, which is narrow). ADC, pseudodiffusion coefficient, and perfusion fraction tended to rise with greater tumor differentiation (r = 0.520, p < 0.001; r = 0.447, p = 0.001; r = 0.354, p = 0.010, respectively). The pure diffusion coefficient and pseudodiffusion coefficient showed a trend of decreasing with increasing tumor stages (r = 0.479, p < 0.001; r = 0.517, p < 0.001). The group of patients with extramural vascular invasion (EMVI) showed lower pseudodiffusion coefficient values than the group of patients with no EMVI (p < 0.05).

CONCLUSION

IVIM-DWI-derived parameters in patients with rectal cancer, especially the pseudodiffusion coefficient, are associated with tumor grade and tumor stage and show statistically significant differences between subjects with EMVI and those without EMVI. IVIM-DWI-derived parameters would be helpful in predicting tumor aggressiveness and prognosis.

Optimal Interval for 18F-FDG-PET After Chemoradiotherapy for Rectal Cancer

INTRODUCTION

Although ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) has been increasingly used to evaluate the response to preoperative chemoradiotherapy (CRT) in patients with rectal cancer, the optimal intervals between completion of CRT, PET, and surgery have not been fully investigated.

PATIENTS AND METHODS

A total of 148 consecutive patients with rectal adenocarcinoma who received CRT followed by FDG-PET and radical surgery were retrospectively analyzed. The association between the FDG-PET maximum standardized uptake value (SUVmax) and pathological response was assessed using a logistic regression model, with a primary focus on the intervals between CRT and PET as well as between PET and surgery.

RESULTS

The baseline SUVmax showed no association with pathological response (P = .201; area under the curve [AUC] = 0.528), whereas the SUVmax after CRT completion showed a strong association (P < .001; AUC = 0.707). Logistic regression analysis revealed that the ability of the SUVmax to accurately predict pathological good responders was significantly associated with a long CRT-PET interval (≥ 7 weeks; P = .027), but was not affected by the length of PET-surgery interval. In patients with a short CRT-PET interval (< 7 weeks), the ability of the SUVmax to predict good responders was poor (P = .201; AUC = 0.669); however, in patients with long intervals (≥ 7 weeks), the predictive ability markedly improved (P < .001; AUC = 0.879).

CONCLUSION

A minimum wait time of 7 weeks is recommended before performing FDG-PET after neoadjuvant CRT for rectal cancer to obtain maximal predictive accuracy for pathological response.