An International Expert-Based Consensus on the Definition of a Clinical Near-Complete Response After Neoadjuvant (Chemo)radiotherapy for Rectal Cancer.

BACKGROUND: A variety of definitions for a clinical near-complete response after neoadjuvant (chemo) radiotherapy for rectal cancer are currently used. This variety leads to inconsistency in clinical practice, long-term outcome, and trial enrollment. OBJECTIVE: The aim of this study was to reach expert-based consensus on the definition of a clinical near-complete response after (chemo) radiotherapy. DESIGN: A modified Delphi process, including a systematic review, 3 surveys, and 2 meetings, was performed with an international expert panel consisting of 7 surgeons and 4 radiologists. The surveys consisted of individual features, statements, and feature combinations (endoscopy, T2-weighted MRI, and diffusion-weighted MRI). SETTING: The modified Delphi process was performed in an online setting; all 3 surveys were completed online by the expert panel, and both meetings were hosted online. MAIN OUTCOME MEASURES: The main outcome was to reach consensus (80% or more agreement). RESULTS: The expert panel reached consensus on a 3-tier categorization of the near-complete response category based on the likelihood of the response to evolve into a clinical complete response after a longer waiting interval. The panelists agreed that a near-complete response is a temporary entity only to be used in the first 6 months after (chemo)radiotherapy. Furthermore, consensus was reached that the lymph node status should be considered when deciding on a near-complete response and that biopsies are not always needed when a near-complete response is found. No consensus was reached on whether primary staging characteristics have to be taken into account when deciding on a near-complete response. LIMITATIONS: This 3-tier subcategorization is expert-based; therefore, there is no supporting evidence for this subcategorization. Also, it is unclear whether this subcategorization can be generalized into clinical practice. CONCLUSIONS: Consensus was reached on the use of a 3-tier categorization of a near-complete response, which can be helpful in daily practice as guidance for treatment and to inform patients with a near-complete response on the likelihood of successful organ preservation. See Video Abstract. UN CONSENSO INTERNACIONAL BASADO EN EXPERTOS ACERCA DE LA DEFINICIN DE UNA RESPUESTA CLNICA CASI COMPLETA DESPUS DE QUIMIORADIOTERAPIA NEOADYUVANTE CONTRA EL CNCER DE RECTO: ANTECEDENTES:Actualmente, se utilizan una variedad de definiciones para una respuesta clínica casi completa después de quimioradioterapia neoadyuvante contra el cáncer de recto. Esta variedad resulta en inconsistencia en la práctica clínica, los resultados a largo plazo y la inscripción en ensayos.OBJETIVO:El objetivo de este estudio fue llegar a un consenso de expertos sobre la definición de una respuesta clínica casi completa después de quimioradioterapia.DISEÑO:Se realizó un proceso Delphi modificado que incluyó una revisión sistemática, 3 encuestas y 2 reuniones con un panel internacional de expertos compuesto por siete cirujanos y 4 radiólogos. Las encuestas consistieron en características individuales, declaraciones y combinaciones de características (endoscopía, T2W-MRI y DWI).AJUSTE:El proceso Delphi modificado se realizó en un entorno en línea; el panel de expertos completó las tres encuestas en línea y ambas reuniones se realizaron en línea.PRINCIPALES MEDIDAS DE RESULTADO:El resultado principal fue llegar a un consenso (≥80% de acuerdo).RESULTADOS:El panel de expertos llegó a un consenso sobre una categorización de tres niveles de la categoría de respuesta casi completa basada en la probabilidad de que la respuesta evolucione hacia una respuesta clínica completa después de un intervalo de espera más largo. Los panelistas coincidieron en que una respuesta casi completa es una entidad temporal que sólo debe utilizarse en los primeros 6 meses después de la quimioradioterapia. Además, se llegó a un consenso en que se debe considerar el estado de los nódulos linfáticos al decidir sobre una respuesta casi completa y que no siempre se necesitan biopsias cuando se encuentra una respuesta casi completa. No se llegó a un consenso sobre si se deben tener en cuenta las características primarias de estadificación al decidir una respuesta casi completa.LIMITACIONES:Esta subcategorización de 3 niveles está basada en expertos; por lo tanto, no hay evidencia que respalde esta subcategorización. Además, no está claro si esta subcategorización puede generalizarse a la práctica clínica.CONCLUSIONES:Se alcanzó consenso sobre el uso de una categorización de 3 niveles de una respuesta casi completa que puede ser útil en la práctica diaria como guía para el tratamiento y para informar a los pacientes con una respuesta casi completa sobre la probabilidad de una preservación exitosa del órgano. (Traducción - Dr. Aurian Garcia Gonzalez).

A multi-centre randomized controlled trial investigating Consolidation Chemotherapy with and without oxaliplatin in distal rectal cancer and Watch & Wait.

BACKGROUND: Neoadjuvant chemoradiation(nCRT) has been considered the preferred initial treatment strategy for distal rectal cancer. Advantages of this approach include improved local control after radical surgery but also the opportunity for organ preserving strategies (Watch and Wait-WW). Consolidation chemotherapy(cCT) regimens using fluoropyrimidine-based with or without oxalipatin following nCRT have demonstrated to increase complete response and organ preservation rates among these patients. However, the benefit of adding oxaliplatin to cCT compared to fluoropirimidine alone regimens in terms of primary tumor response remains unclear. Since oxalipatin-treatment may be associated with considerable toxicity, it becomes imperative to understand the benefit of its incorporation into standard cCT regimens in terms of primary tumor response. The aim of the present trial is to compare the outcomes of 2 different cCT regimens following nCRT (fluoropyrimidine-alone versus fluoropyrimidine + oxaliplatin) for patients with distal rectal cancer. METHODS: In this multi-centre study, patients with magnetic resonance-defined distal rectal tumors will be randomized on a 1:1 ratio to receive long-course chemoradiation (54 Gy) followed by cCT with fluoropyrimidine alone versus fluoropyrimidine + oxaliplatin. Magnetic resonance(MR) will be analyzed centrally prior to patient inclusion and randomization. mrT2-3N0-1 tumor located no more than 1 cm above the anorectal ring determined by sagittal views on MR will be eligible for the study. Tumor response will be assessed after 12 weeks from radiotherapy(RT) completion. Patients with clinical complete response (clinical, endoscopic and radiological) may be enrolled in an organ-preservation program(WW). The primary endpoint of this trial is decision to organ-preservation surveillance (WW) at 18 weeks from RT completion. Secondary endpoints are 3-year surgery-free survival, TME-free survival, distant metastases-free survival, local regrowth-free survival and colostomy-free survival. DISCUSSION: Long-course nCRT with cCT is associated with improved complete response rates and may be a very attractive alternative to increase the chances for organ-preservation strategies. Fluoropyrimidine-based cCT with or without oxaliplatin has never been investigated in the setting of a randomized trial to compare clinical response rates and the possibility of organ-preservation. The outcomes of this study may significantly impact clinical practice of patients with distal rectal cancer interested in organ-preservation. TRIAL REGISTRATION: www. CLINICALTRIALS: gov NCT05000697; registered on August 11th, 2021.

Liver Surgery: Important Considerations for Pre- and Postoperative Imaging.

Liver surgery may be a curative treatment option not only for primary liver neoplasms but also for liver metastases in selected patients. The number of liver surgeries performed worldwide has increased, but surgical morbidity associated with these surgeries remains significant. Therefore, radiologists need to understand the terminology, surgical techniques, resectability and unresectability criteria, and possible postoperative complications as these are part of the decision-making process. Because vascular and biliary variations are common, an adequate preoperative anatomic evaluation determines the best surgical technique, helps identify patients in whom additional surgical steps will be required, and reduces the risk of inadvertent injury. The surgeon must ensure that the future liver remnant is sufficient to maintain adequate function, aided by the radiologist who can provide valuable information such as the presence of steatosis, biliary dilatation, signs of cirrhosis, and portal hypertension, in addition to the volume of the future liver remnant. Postoperative complications must also be understood and evaluated. The most common postoperative complications are vascular (bleeding, thrombosis, and ischemia), biliary (fistulas, bilomas, and strictures), infectious (incisional or deep), those related to liver failure, and even tumor recurrence. An invited commentary by Winslow is available online. Online supplemental material is available for this article. ©RSNA, 2022.

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

PURPOSE: To analyze the associations between positron emission tomography (PET)/magnetic resonance imaging (MRI) features for primary rectal tumors and metastases. PROCEDURES: Between November 2016 and April 2018, 101 patients with rectal adenocarcinoma were included in this prospective study (NCT02537340) for whole-body PET/MRI for baseline staging. Two readers analyzed the PET/MRI; they assessed the semiquantitative PET features of the primary tumor and the N- and M-stages. Another reader analyzed the MRI features for locoregional staging. The reference standard for confirming metastatic disease was biopsy or imaging follow-up. Non-parametric tests were used to compare the PET/MRI features of the participants with or without metastatic disease. Binary logistic regression was used to evaluate the associations between the primary tumor PET/MRI features and metastatic disease. RESULTS: A total of 101 consecutive participants (median age 62 years; range: 33-87 years) were included. Metastases were detected in 35.6% (36 of 101) of the participants. Among the PET/MRI features, higher tumor lesion glycolysis (352.95 vs 242.70; P = .46) and metabolic tumor volume (36.15 vs 26.20; P = .03) were more frequent in patients with than in those without metastases. Additionally, patients with metastases had a higher incidence of PET-positive (64% vs 32%; P = .009) and MRI-positive (56% vs 32%; P = .03) mesorectal lymph nodes, extramural vascular invasion (86% vs 49%; P > .001), and involvement of mesorectal fascia (64% vs 42%; P = .04); there were also differences between the mrT stages of these two groups (P = .008). No differences in the maximum standardized uptake values for the primary tumors in patients with and without metastases were observed (18.9 vs 19.1; P = .56). Multivariable logistic regression showed that extramural vascular invasion on MRI was the only significant predictor (adjusted odds ratio, 3.8 [95% CI: 1.1, 13.9]; P = .001). CONCLUSION: PET/MRI facilitated the identification of participants with a high risk of metastatic disease, though these findings were based mainly on MRI features.

Diagnostic accuracy of FDG-PET/MRI versus pelvic MRI and thoracic and abdominal CT for detecting synchronous distant metastases in rectal cancer patients.

PURPOSE: We compared the diagnostic accuracy of detecting distant metastases for baseline rectal cancer staging between PET/MRI and conventional staging (CS). MATERIALS AND METHODS: This prospective study from November 2016 to April 2018 included 101 rectal adenocarcinoma patients for primary staging. These patients underwent whole-body PET/MRI in addition to CS (pelvic MRI and thoracic and abdominal contrast-enhanced CT). Different readers analyzed CS and PET/MRI findings for primary tumor, nodal, and metastatic staging. The presence, number, and location of metastases were recorded according to the organ involved (non-regional lymph nodes (LNs), liver, lungs, or others). Lesions were defined as positive, negative, or indeterminate. The number of lesions per organ was limited to 10. The McNemar test was used to compare the accuracies. RESULTS: PET/MRI exhibited a higher accuracy in detecting metastatic disease than CS in all patients (88.4% vs. 82.6%, p = 0.003) and in patients with extramural vascular invasion (EMVI) (88.9% vs. 85.5%, p = 0.013). The detection rate of PET/MRI was superior to that of CS for all lesions [84.1% vs. 68.9%, p = 0.001], as well as those in the liver (89.2% vs. 84.2%), non-regional LNs (90.0% vs. 36.7%), and lungs (76.4% vs. 66.9%). PET/MRI correctly classified 19/33 (57.5%) patients with indeterminate lesions on CS. CONCLUSION: PET/MRI yields higher accuracy than CS for detecting distant synchronous metastases in the baseline staging of patients with rectal cancer and EMVI. PET/MRI exhibited a higher detection rate than CS for identifying non-regional LNs, hepatic lesions, and pulmonary lesions as well as correctly classifying patients with indeterminate lesions. TRIAL REGISTRATION: NCT02537340.

Role of magnetic resonance imaging in organ-preserving strategies for the management of patients with rectal cancer.

Total mesorectal excision has been the most effective treatment strategy adopted to reduce local recurrence rates among patients with rectal cancer. The morbidity associated with this radical surgical procedure led surgeons to challenge the standard therapy particularly when dealing with superficial lesions or good responders after neoadjuvant radiotherapy, to which radical surgery may be considered overtreatment. In this subset of patients, less invasive procedures in an organ-preserving strategy may result in good oncological and functional outcomes. In order to tailor the most appropriate treatment option, accurate baseline staging and reassessment of tumor response are relevant. MRI is the most robust tool for the precise selection of patients that are candidates for organ preservation; therefore, radiologists must be familiar with the criteria used to guide the management of these patients. The purpose of this article is to review the relevant features that radiologists should know in order to provide valuable information during the multidisciplinary discussion and ultimate management decision.

CT Staging to Triage Selection of Patients With Poor-Prognosis Rectal Cancer for Neoadjuvant Treatment.

OBJECTIVE. The purpose of this study was to evaluate CT as a screening tool for determining high risk of local recurrence of rectal tumors in a scenario of limited MRI availability. MATERIALS AND METHODS. Data were retrospectively analyzed for 180 consecutively registered patients with rectal adenocarcinoma and no previous treatment who underwent baseline CT and MRI staging within 30 days of each other. Two radiologists independently reviewed CT and MR images. CT scans were interpreted in multiplanar reformation. High risk of local recurrence was based on the MRI reference standard: T3cd (more than 5 mm of mesorectal fat infiltration) or T4 disease, N2 nodal status, mesorectal fascia involvement, extramural venous invasion, or positive pelvic sidewall nodes. The performance of CT for determination of high risk of local tumor recurrence was evaluated. RESULTS. Among the 180 patients 128 (71%) met MRI criteria for high risk of local recurrence. CT sensitivity was 84.4% (108/128) and specificity was 78.8% (41/52). The positive predictive value (PPV) of any high-risk CT feature was 90.7% (108/119). When T status was considered, the sensitivity of CT was 75.2% (79/105), specificity was 90.7% (68/75), and PPV was 91.9% (79/86). When tumors within 5.0 cm of the anal verge were excluded, sensitivity was 89.5% (51/57), specificity was 85.7% (24/28), and PPV was 92.7% (51/55). Using CT for disease staging could reduce MRI use by 66%. CONCLUSION. Tumors at high risk of local recurrence can be identified with CT without baseline MRI. Use of CT rather than MRI could markedly reduce costs of baseline staging and shorten time to initiation of neoadjuvant treatment.

Organ Preservation Among Patients With Clinically Node-Positive Rectal Cancer: Is It Really More Dangerous?

BACKGROUND: Select patients with complete clinical response to chemoradiation have been managed without radical surgery. The presence of radiologic evidence of nodal metastases at baseline could be a risk factor for local tumor regrowth, more advanced stage at the time of recurrence, and worse distant metastases-free survival. OBJECTIVE: The purpose of this study was to compare the outcomes of patients with baseline node-positive and node-negative cancer after neoadjuvant chemoradiation and complete clinical response managed nonoperatively. DESIGN: This was a retrospective review of consecutive patients with nonmetastatic distal rectal cancer undergoing neoadjuvant chemoradiation. PATIENTS: Consecutive patients with clinical and radiologic evidence of complete clinical response at 8 to 10 weeks were managed nonoperatively and enrolled in a strict follow-up program (watch and wait). Patients with incomplete clinical response or tumor regrowth after initial complete clinical response were referred to surgery. MAIN OUTCOMES MEASURES: Surgery-free and distant metastases-free survival were compared between patients according to nodal status at baseline. RESULTS: A total of 117 patients with node-positive and 218 with node-negative cancer at baseline were reviewed. Overall, 62 (53.0%; node positive) and 135 (61.9%; node negative) achieved a complete clinical response and were managed nonoperatively (p = 0.13). Patients with baseline node-positive cancer had similar rates of pathologic nodal metastases at the time of recurrence. Five-year surgery-free (39.7% vs 46.8%; p = 0.2) and distant metastases-free survival (77.5% vs 80.5%; p = 0.49) were similar between baseline node-positive and node-negative patients. LIMITATIONS: This was a retrospective study with a small sample size and possible inaccurate nodal staging. CONCLUSIONS: Patients with rectal cancer with node-positive cancer at baseline who develop a complete clinical response after neoadjuvant chemoradiation are not at increased risk for local tumor regrowth or development of more advanced disease at the time of recurrence. These patients seem to be safe candidates for organ-preserving strategies after achieving complete clinical response. See Video Abstract at http://links.lww.com/DCR/A902.

How Reliable Is CT Scan in Staging Right Colon Cancer?

BACKGROUND: The observation of inferior oncologic outcomes after surgery for proximal colon cancers has led to the investigation of alternative treatment strategies, including surgical procedures and neoadjuvant systemic chemotherapy in selected patients. OBJECTIVE: The purpose of this study was to determine the accuracy of CT staging in proximal colon cancer in detecting unfavorable pathologic features that may aid in the selection of ideal candidates alternative treatment strategies, including extended lymph node dissection and/or neoadjuvant chemotherapy. DESIGN: This was a retrospective consecutive series. SETTINGS: Trained abdominal radiologists from 2 centers performed a blinded review of CT scans obtained to locally stage proximal colon cancer according to previously defined prognostic groups, including T1/2, T3/4, N+, and extramural venous invasion. CT findings were compared with histopathologic results as a reference standard. Unfavorable pathologic findings included pT3/4, pN+, or extramural venous invasion. PATIENTS: Consecutive patients undergoing right colectomy in 2 institutions between 2011 and 2016 were retrospectively reviewed from a prospectively collected database. MAIN OUTCOME MEASURES: T status, nodal status, and extramural venous invasion status comparing CT with final histologic findings were measured. RESULTS: Of 150 CT scans reviewed, CT failed to identify primary cancer in 18%. Overall accuracy of CT to identify unfavorable pathologic features was 63% with sensitivity, specificity, positive predictive value, and negative predictive value of 63% (95% CI, 54%-71%), 63% (95% CI, 46%-81%), 87% (95% CI, 80%-94%) and 30% (95% CI, 18%-41%). Only cT3/4 (55% vs 45%; p = 0.001) and cN+ (42% vs 58%; p = 0.02) were significantly associated with correct identification of unfavorable features at final pathology. CT scans overstaged and understaged cT in 23.7% and 48.3% and cN in 28.7% and 53.0% of cases. LIMITATIONS: The study was limited by its retrospective design, relatively small sample size, and heterogeneity of CT images performed in different institutions with variable equipment and technical details. CONCLUSIONS: Accuracy of CT scan for identification of pT3/4, pN+, or extramural venous invasion was insufficient to allow for proper identification of patients at high risk for local recurrence and/or in whom to consider alternative treatment strategies. Locoregional overstaging and understaging resulted in inappropriate treatment strategies in <48%. See Video Abstract at http://links.lww.com/DCR/A935.

The Estimate of the Impact of Coccyx Resection in Surgical Field Exposure During Abdominal Perineal Resection Using Preoperative High-Resolution Magnetic Resonance.

OBJECTIVE: To estimate the improvement in surgical exposure by removal of the coccyx, during abdomino-perineal resection (APR), in rectal cancer patients. METHODS: Retrospective study of 29 consecutive patients with rectal cancer was carried out. Using MR T2 sagittal series, the solid angle was estimated using the angle determined by the anterior resection margin and the tip of coccyx (no coccyx resection) or the tip of last sacral vertebra (coccyx resection). The solid angle provides an estimate of the tridimensional surface area provided by an original angle resulting in the best estimate of the surgeon's view/exposure to the critical dissecting point of choice (anterior rectal wall). The difference ("Gain") in surgical field exposure by removal of the coccyx was compared by the solid angle variation between the two estimates (with and without the coccyx). RESULTS: Routine removal of the coccyx determines an average 42% (95% CI 27-57%) gain in surgical field exposure area facing the anterior rectal wall at the level of the prostate/vagina by the surgeon. Fifteen (51%) patients had ≥30% (median) estimated gain in surgical field exposure by coccygectomy. There was no association between BMI, age or gender and estimated gain in surgical field exposure area. CONCLUSIONS: Routine removal of the coccyx during APR may result in an average increase in 42% in surgical field exposure during APR's perineal dissection. Precise estimation of surgical field exposure gain by removal of the coccyx may be predicted by MR sagittal series for each individual patient.

Multidetector CT evaluation of the postoperative pancreas.

Several pancreatic diseases may require surgical treatment, with most of these procedures classified as resection or drainage. Resection procedures, which are usually performed to remove pancreatic tumors, include pancreatoduodenectomy, central pancreatectomy, distal pancreatectomy, and total pancreatectomy. Drainage procedures are usually performed to treat chronic pancreatitis after the failure of medical therapy and include the Puestow and Frey procedures. The type of surgery depends not only on the patient's symptoms and the location of the disease, but also on the expertise of the surgeon. Radiologists should become familiar with these surgical procedures to better understand postoperative changes in anatomic findings. Multidetector computed tomography is the modality of choice for identifying normal findings after surgery, postoperative complications, and tumor recurrence in patients who have undergone pancreatic surgery.

Helminthic diseases in the abdomen: an epidemiologic and radiologic overview.

Helminthic diseases have a worldwide distribution. They affect billions of people in endemic areas and can result in serious clinical complications. Some parasites have a human gastrointestinal life cycle with resultant abdominal manifestations. However, the symptoms of helminthic diseases are usually nonspecific. Radiologic imaging, along with the identification of risk factors, may help narrow the differential diagnosis. To avoid diagnostic delays, radiologists should be familiar with the geographic distribution, transmission cycle, and characteristic and atypical manifestations of common helminthic diseases at abdominal imaging with radiography, computed tomography, magnetic resonance imaging, and ultrasonography. Awareness of the clinical, epidemiologic, and pathogenic characteristics of these diseases also may be helpful for narrowing the diagnosis when imaging features are nonspecific.

MR imaging findings of iron overload.

Hemochromatosis can be classified as (a) primary, when it originates from a genetic disturbance that promotes the increase of iron absorption, or (b) secondary, when it relates to chronic diseases or to multiple transfusions. The distribution of iron accumulation differs between these two forms; therefore, they can be distinguished by using imaging methods in the majority of cases. Magnetic resonance (MR) imaging is the most sensitive and specific imaging modality in the diagnosis of hemochromatosis. The susceptibility effect caused by the accumulation of iron leads to signal loss in the affected tissues, particularly with the T2*-weighted sequences, which makes the diagnosis of iron overload possible. By using MR imaging techniques, it is possible to estimate the hepatic iron concentration in a noninvasive way, thereby avoiding repeated biopsies. Hemochromatosis can lead to complications, such as a higher frequency of neoplasia, particularly the development of hepatocellular carcinoma. Other neoplasms, such as colorectal tumors, are also associated. Complications related to the treatment of chronic anemia include the appearance of peliosis hepatis and tumors, which can regress after the suspension of treatment with drugs. Knowledge of the disease and of the patterns of iron deposition in patients with iron overload enables not only diagnosis, but also treatment, follow-up, and the detection of possible complications by using imaging methods.