Moderne Bildgebung beim Rektumkarzinom

Colorectal cancer is one of the most common malignant diseases. Accurate preoperative staging is of great importance in order to provide patients with optimal treatment. There are various imaging modalities for staging rectal cancer according to the TNM system. For local staging, endorectal ultrasound (EUS) and magnetic resonance imaging (MRI) are the most suitable imaging tools. With modern high resolution MRI scans infiltration of the mesorectal fascia can be assessed with a high degree of accuracy, an important aid for decision-making with respect to respectability and prognosis of rectal cancer. On the other hand, due to technical limitations it is not possible to perform staging of distant metastases with MRI in the same examination. For this purpose computed tomography (CT) remains the optimal method. Further research is required to define the role of PET and PET/CT in the staging of rectal cancer.     

Target Volume Definition in Rectal Cancer: What Is the Best Imaging Modality?

All patients with rectal cancer should undergo an accurate preoperative staging, including local staging for tumour extension and reliable staging for synchronous distant metastases. Imaging is of utmost importance as a basis for selecting the optimal treatment strategies and as an aid for precise target delineation. Anatomical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) have been the most commonly used pretreatment staging modalities, whereas endorectal ultrasonography may be useful for staging of smaller tumours (T2 or lower). MRI is the most accurate imaging technique for staging of T3 and T4 tumours. The role of fluorodeoxyglucose positron emission tomography (PET)/CT is under investigation, and diffusion-weighted MRI seems promising for prediction of pathological complete response. For target delineation, planning CT, preferably contrast-enhanced, is the most used imaging technique. For locally advanced tumours, coregistration with MRI or PET/CT may prove to be useful. In this article, the literature published on target delineation in rectal cancer radiotherapy is evaluated, with focus on the best imaging modality for volume definition and radiotherapy planning.     

Current Issues in the Staging of Esophageal Cancer

Staging technology and the 1983 international staging system for esophageal cancer have changed. The 1988 system is based on depth of wall penetration and regional lymph node involvement; it abandons the previous criteria of tumor length and degree of obstruction. The clinical reasoning behind this change is reviewed. New staging technology includes chest computed tomography (CT), magnetic resonance imaging (MRI), tranesophageal ultrasound (EUS), and invasive surgical staging. Overall accuracy of CT to predict depth of penetration is 80% to 85%. CT accuracy of regional lymph node status is less than 69%, but it is 90% accurate in the detection of distant metastases. MRI is comparable. EUS is 71% to 98% accurate in predicting depth of tumor invasion. Although highly sensitive (85% to 95%), the accuracy of EUS in predicting the status of lymph nodes is adversely affected by low specificity (50% to 60%), reducing its overall accuracy of node prediction to 70% to 88%. EUS may fail to assess intra-abdominal disease in 21% to 36% of patients secondary to esophageal obstruction. Regional nodes on both sides of the diaphragm can be assessed by laparoscopy combined with thoracoscopy. Thoracoscopy and laparoscopy have a greater than 92% accuracy in staging regional nodes. Such information is indispensable for the design of treatment fields. Combinations of these new technologies may provide improved preresectional staging.     

Role of endoscopy in staging colorectal cancer

The treatment of colorectal cancer depends in large measure on the depth of tumor invasion and the extent of lymph node involvement. Endoscopic ultrasonography (EUS) has added a new dimension to the evaluation of tumor invasion and lymph node involvement in gastrointestinal cancer. The overall EUS accuracy for colorectal cancer T-staging is 78%, specificity is 73%, and sensitivity is 94%. In determining the nodal involvement by tumor, EUS has an accuracy of 75%, specificity of 73%, and sensitivity of 74%. Comparison with computerized tomography (CT), magnetic resonance imaging (MRI), and MRI with endorectal coil (MRIEC) shows that EUS is an effective single modality for assessing tumor penetration of the rectal wall. It does not, however, allow the assessment of distant metastatic disease. For assessing lymph node involvement, MRIEC offers the most comprehensive information.     

Staging beim Magenkarzinom

Background

An early diagnosis by optimal diagnostics and tumor staging are required for correct management of gastric cancer. Modern imaging techniques are used to determine the best therapeutic options within surgical and multimodal concepts and to avoid surgery for inoperable cases.

Objective

Overview about the current state of the art in TNM staging of gastric cancer using modern imaging techniques.

Material and methods

A review of the literature on TNM staging of gastric cancer using endoscopy, endoscopic ultrasonography (EUS), EUS-guided fine needle aspiration biopsy and tomographic imaging techniques, such as multidetector computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography CT (PET-CT) and PET-MRI as well as laparoscopy.

Results

Endoscopy is still the first-line diagnostic method and gold standard for early detection, histological diagnosis and exclusion of gastric cancer. The EUS technique is used to assess the extent of intramural infiltration (T staging). The determination of the exact N stage using EUS, multidetector CT or MRI remains a problem but can be improved by EUS-guided fine needle aspiration biopsy of paragastric lymph nodes if clinically necessary. Multidetector CT and MRI are used to detect extramural growth of gastric cancer, for diagnosis of local infiltration and of distant metastases (M staging). Laparoscopy is the method of choice for the diagnosis of peritoneal cancer not detectable by conventional imaging.

Conclusion

Following initial endoscopic diagnosis the TNM classification (cTNM) of gastric cancer can be carried out using endoscopy, EUS, CT and MRI; however, there are diagnostic loopholes in determination of the N staging and non-invasive detection of peritoneal cancer.

     

Evolution of imaging in rectal cancer: multimodality imaging with MDCT,MRI, and PET

Magnetic resonance imaging (MRI), multidetector computed tomography (MDCT), and positron emission tomography (PET) are complementary imaging modalities in the preoperative staging of patients with rectal cancer, and each offers their own individual strengths and weaknesses. MRI is the best available radiologic modality for the local staging of rectal cancers, and can play an important role in accurately distinguishing which patients should receive preoperative chemoradiation prior to total mesorectal excision. Alternatively, both MDCT and PET are considered primary modalities when performing preoperative distant staging, but are limited in their ability to locally stage rectal malignancies. This review details the role of each of these three modalities in rectal cancer staging, and how the three imaging modalities can be used in conjunction.     

CT and MR imaging in the evaluation and staging of lung cancer

Cancer of the lung is one of the most frustrating yet important challenges facing medicine today. Despite screening programs and education of the public concerning the established link of lung cancer and cigarette smoking, the overall incidence of lung cancer continues to rise. Improved imaging has led to more accurate staging. Expanded treatment has yielded improving survivals of certain specific tumors. Accurate diagnosis and staging of lung cancer is important in detecting therapy and prognosis. Computed tomography (CT) has been established as an important component of the staging process. More recently, applications of magnetic resonance imaging (MRI) are ideally suited to evaluate tumor extent and nodal disease. We reviewed the uses and limitation of CT and MRI. Compared with CT, the relatively low signal in the lung limits the detection of pulmonary nodules and other lung parenchymal diseases, and noise due to motion has been a frequent and significant problem in thoracic MRI. Because of its superior spatial resolution and ability to detect calcification, CT is better than MRI for the detection and evaluation of lung nodules and mediastinal adenopathy when assessing lung cancer. For the detection of mediastinal invasion or lymph node metastases, CT and MRI generally provide similar information. However, volume averaging problems, which may occur on trasaxial CT, can be avoided or clarified using MRI, and nodes can sometimes be more clearly distinguished from vessels using this technique. In the diagnosis of hilar masses or lymphadenopathy, CT and MR provide similar information in the majority of cases, but occasionally MR may more clearly indicate the presence or absence of a mass. Because of superb vascular imaging capability (without the need for exogenous contrast agents), exquisite soft tissue contrast, the ability to image the chest directly in multiple planes, and the potential to characterize certain tissues, MRI appears to be superior to CT in defining the extent of chest-wall invasion. In general, CT is superior to MRI as an all-around tool for imaging the wide range of thoracic abnormalities that can be present in patients with lung cancer. Limited availability, and longer examination time of MRI compared with CT has restricted the use of thoracic MRI. If MRI is used selectively as a secondary imaging study to answer specific questions raised or unanswered by CT, its value can be optimized.     

Literature review: Imaging in prostate cancer

Imaging plays an increasingly important role in the detection and characterization of prostate cancer (PC). This review summarizes the key conventional and advanced imaging modalities including multiparametric magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging and tries to instruct clinicians in finding the best image modality depending on the patient`s PC-stage. We aim to give an overview of the different image modalities and their benefits and weaknesses in imaging PC.Emphasis is put on primary prostate cancer detection and staging as well as on recurrent and castration resistant prostate cancer. Results from studies using various imaging techniques are discussed and compared. For the different stages of PC, advantages and disadvantages of the different imaging modalities are discussed. Moreover, this review aims to give an outlook about upcoming, new imaging modalities and how they might be implemented in the future into clinical routine.Imaging patients suffering from PC should aim for exact diagnosis, accurate detection of PC lesions and should mirror the true tumor burden. Imaging should lead to the best patient treatment available in the current PC-stage and should avoid unnecessary therapeutic interventions. New image modalities such as long axial field of view PET/CT with photon-counting CT and radiopharmaceuticals like androgen receptor targeting radiopharmaceuticals open up new possibilities. In conclusion, PC imaging is growing and each image modality is aiming for improvement.     

Bildgebung des Prostatakarzinoms

Prostatic carcinoma (PCa) is the most common life-threatening cancer in the Western world. In Germany about 40,609 new cases are expected per year. Mortality is 10%. The major goals of pretherapeutic imaging are determination of local intraprostatic tumor extent, presence of extracapsular extension (ECE), seminal vesicle invasion (SVI), invasion into neurovascular bundles and if so into surrounding tissues and organs. In addition, determination of presence and extent of nodal spread as well as distant metastases is required. Exact pretherapeutic staging is mandatory, because the choice of optimal tumor treatment is initiated in strict dependence on tumor stage and risk profile. Anatomic as well as functional molecular imaging of PCa has made significant progress in recent years. Transrectal ultrasonography (TRUS) is primarily used as the basic imaging test in PCa and to guide prostate biopsies. When prostate biopsies are negative but suspicion of PCa persists, MRI/MRS and C-11-/F-18-choline PET/CT may be helpful for localization of PCa, determining intraprostatic tumour extent – and if so – ECE, SVI, invasion into neurovascular bundles and to guide targeted biopsies. Lymphotrophic contrast agents are highly promising for accurate nodal staging of PCa, but are not yet available for clinical use. Thus, nodal staging with commonly available imaging modalities remains insufficiently sensitive and inadequately specific. Localization of local relapse of PCa with contrast-enhanced MRI and C-11-choline PET/CT has made significant progress and allows imaging of local recurrence of PCa in the majority of patients with a PSA >1 ng/ml.     

Improving the Treatment of Colorectal Cancer: The Role of EUS

The two most important factors for determining the risk of local failure and overall prognosis in colorectal carcinoma are nodal status and the depth of tumor penetration into or through the bowel wall. These features have traditionally been determined pathologically because the clinical-staging accuracy of other imaging modalities such as computed tomography (CT) has not proven sufficiently predictive of surgical staging. However, endorectal or endoscopic ultrasonography (EUS) can be used to preoperatively evaluate nodal involvement with an accuracy of up to 86% (median: 80%) and depth of tumor penetration through the bowel wall with an accuracy of up to 97% (median: 85%) for effective clinical staging. This high staging accuracy is useful in managing colorectal cancer. Through clinical evaluation of the initial stage of colorectal cancer with EUS, a patient's risk of disease recurrence can best be determined and patients stratified for the most appropriate treatment. EUS can be used to select patients with lesions that can be treated with local excision or sphincter-sparing surgery, often combined with radiation therapy, in situations otherwise requiring an abdominoperineal resection. EUS can also be used to preoperatively identify patients with locally advanced or unresectable disease. Chemoradiation can then be given preoperatively, when it appears to be better tolerated and more effective than postoperative treatment. Unresectable tumors can often be downstaged sufficiently to allow their excision. In resectable disease, EUS can also identify patients at high risk for recurrence who would benefit from adjuvant chemoirradiation. EUS for precise staging or for earlier diagnosis of recurrence will further improve the clinical outcome of patients with colorectal tumors as significant advances both in surgical techniques and in combined chemotherapy/ radiotherapy continue to be made and applied selectively in a stage-dependent manner.     

Effectiveness of preoperative staging in rectal cancer: digital rectal examination,endoluminal ultrasound or magnetic resonance imaging?

In rectal cancer, preoperative staging should identify early tumours suitable for treatment by surgery alone and locally advanced tumours that require therapy to induce tumour regression from the potential resection margin. Currently, local staging can be performed by digital rectal examination (DRE), endoluminal ultrasound (EUS) or magnetic resonance imaging (MRI). Each staging method was compared for clinical benefit and cost-effectiveness. The accuracy of high-resolution MRI, DRE and EUS in identifying favourable, unfavourable and locally advanced rectal carcinomas in 98 patients undergoing total mesorectal excision was compared prospectively against the resection specimen pathological as the gold standard. Agreement between each staging modality with pathology assessment of tumour favourability was calculated with the chance-corrected agreement given as the kappa statistic, based on marginal homogenised data. Differences in effectiveness of the staging modalities were compared with differences in costs of the staging modalities to generate cost effectiveness ratios. Agreement between staging and histologic assessment of tumour favourability was 94% for MRI (kappa=0.81, s.e.=0.05; kappa(W)=0.83), compared with very poor agreements of 65% for DRE (kappa=0.08, s.e.=0.068, kappa(W)=0.16) and 69% for EUS (kappa=0.17, s.e.=0.065, kappa(W)=0.17). The resource benefits resulting from the use of MRI rather than DRE was 67164 UK pounds and 92244 UK pounds when MRI was used rather than EUS. Magnetic resonance imaging dominated both DRE and EUS on cost and clinical effectiveness by selecting appropriate patients for neoadjuvant therapy and justifies its use for local staging of rectal cancer patients.     

Diagnostic Challenges in Prostate Cancer and 68Ga-PSMA PET Imaging: A Game Changer?

Prostate cancer (PC) is the most frequent solid tumor in men and the third most common cause of cancer mortality among men in developed countries. Current imaging modalities like ultrasound (US), computerized tomography (CT), magnetic resonance imaging (MRI) and choline based positron emission (PET) tracing have disappointing sensitivity for detection of nodal metastasis and small tumor recurrence. This poses a diagnostic challenge in staging of intermediate to high risk PC and restaging of patients with biochemical recurrence (PSA >0.2 ng/ml). Gallium-68 labeled prostate specific membrane antigen (68Ga-PSMA) PET imaging has now emerged with a higher diagnostic yield. 68Ga-PSMA PET/CT or PET/MRI can be expected to offer a one-stop-shop for staging and restaging of PC. PSMA ligands labeled with alpha and beta emitters have also shown promising therapeutic efficacy for nodal, bone and visceral metastasis. Therefore a PSMA based theranostics approach for detection, staging, treatment, and follow-up of PC would appear to be highly valuable to achieve personalized PC treatment.     

Imaging of distant metastases of prostate cancer

The detection of distant metastases at the initial diagnosis of prostate cancer (PCa) establishes the treatment approach and has a prognostic value, nevertheless it is not well established. Since proposed staging approaches often contradict each other, we aimed to compare the current imaging techniques for staging of advanced PCa, including future applications of the most innovative methods. Conventional imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) have been employed for metastatic staging (both N and M staging) of men with high-risk PCa, but surgical pelvic dissection remains the gold standard for N staging. However, functional MRI by using diffusion-weighted imaging, MR lymphography (MRL) with ultra-small paramagnetic iron oxide particles (USPIO), and hybrid PET/MRI imaging showed both high sensitivity and high specificity for nodal staging and depicting metastases. The standard of practice for M staging in PCa includes the radionuclide bone scan and targeted X-ray film, but their performance has generally been poor. Recently, MRI showed promising results with applications in both local and distant staging. Finally, with the development of new PET tracers, PET/CT and PET/MRI offer a combination of excellent pharmacokinetic characteristics, functional information, and precise anatomic localization and morphological correlation of tumor lesions.     

The wind of change in the therapy of lung cancer

Total mesorectal excision has been established as a standard surgical procedure for rectal cancer. MRI is now routinely used for preoperative staging of rectal cancer and provides accurate assessment of the tumor relative to the circumferential margin, that is, the mesorectal fascia. This identifies patients at risk of local recurrence and those likely to benefit from neoadjuvant therapy. Compared with CT and ultrasound, MRI is more reliable for the evaluation of the extent of locoregional disease, planning radiation therapy, assessing postoperative changes and pelvic recurrence. The evaluation of nodal metastases remains a challenge with routine MRI. In this review, we describe the role of MRI in staging rectal cancer as well as highlight some limitations and recent advances to overcome these.     

Pre-operative staging of gastro-oesophageal junction carcinoma: Comparison of endoscopic ultrasound and computed tomography

Fifteen patients with carcinoma of the gastro-oesophageal junction were pre-operatively staged with endoscopic ultrasound (EUS) and computed tomography (CT). The accuracy of tumour and nodal staging using both modalities was compared to the final histological staging of the resected specimens. In staging depth of tumour growth, EUS was significantly more accurate (87% of lesions correctly staged) than CT (40% correctly staged). In staging nodal involvement, EUS was again significantly more accurate (73% correctly staged) than CT (33%). Two-thirds of the lesions were traversable with the endoscopic probe, but most of the nontraversed lesions were correctly staged on EUS. In this study, CT has performed poorly as a staging modality for carcinoma at the gastro-oesophageal junction. Other studies have shown CT to be less accurate at this location than at other oesophageal sites. The orientation of the gastro-oesophageal junction, lack of surrounding fat planes, proximity of adjacent organs and patient motion contribute to the poor staging performance of CT at this location. In contrast, EUS has been an accurate staging modality at the gastro-oesophageal junction in this study and compares well with other studies evaluating EUS in the more proximal oesophagus. Endoscopic ultrasound is therefore a necessary modality if accurate pre-operative staging of gastro-oesophageal junction carcinoma is to be achieved.     

Testicular tumors: Oncologic imaging and diagnosis

The extreme radiosensitivity of testicular seminomas plus recent advances in chemotherapy for nonseminomatous tumors and for advanced seminomas have made long term survival possible in the large majority of patients with testis cancer. Since choice of therapy is determined by tumor histology and extent of disease, accurate clinical staging is critical. Computed tomography (CT) of the abdomen and chest is the imaging procedure of choice for staging testis cancer. Clinical staging accuracy of 80 to 90% can be achieved using CT in combination with radioimmunoassays for β-HCG and AFP. Ultrasonography (US), while less sensitive and specific than CT for determining nodal status, may be useful in thin patients with sparse retroperitoneal fat; in addition US may play an important role in detecting occult testicular neoplasms and in assessing primary tumor extent within the scrotum. Lymphangiography should be reserved for Stage I patients in whom elective treatment of the retroperitoneum is not planned. Follow-up should include serial radioimmunoassays for serum AFP and β-HCG and periodic CT examinations of the abdomen and chest. Technical improvements in CT scanners and further experience with the use of tumor markers should help refine our ability to stage and manage patients with testicular tumors. In addition, nuclear magnetic resonance (NMR) imaging and radionuclide imaging following injection of radioactively labelled antibodies to AFP and β-HCG are new techniques which offer great promise for the future.     

New diagnostic imaging of gastointestinal tumors: a preliminary study of three-dimensional tumor structure and volumetry

BACKGROUND: The aim of the present report was to present preliminary results of the pre-operative evaluation of three-dimensional tumor structure and volumetry using three-dimensional computed tomography (3-D CT) and three-dimensional endoscopic ultrasonography (3-D EUS). MATERIALS AND METHODS: Diagnostic imaging was performed for 2 patients (one with gastric cancer, one with a rectal tumor) using virtual endoscopy, 3-D CT for the patient with gastric cancer and 3-D EUS for the patient with the rectal tumor, for the pre-operative evaluation of tumor structure and volumetry. Computer-generated image analysis of resected tumors was also performed. RESULTS: The gastric tumor was successfully visualized using 3-D CT and the rectal tumor was successfully visualized using 3-D EUS. The values obtained for volume of the stomach tumor, calculated using 3-D CT and resected materials, were 15.1 cm3 and 11.4 cm3, respectively. The values obtained for volume of the rectal tumor, calculated using 3-D EUS and resected materials, were 2.3 cm3 and 3.9 cm3, respectively. CONCLUSION: The present findings demonstrate that clinically useful results can be obtained by using 3-D CT and 3-D EUS for the pre-operative evaluation of 3-D tumor structure and volumetry of gastrointestinal tumors. We expect that further studies of these methods will lead to the establishment of new diagnostic criteria for gastrointestinal tumors based on tumor volume in the near future.     

Staging and preoperative evaluation of upper gastrointestinal malignancies

Esophageal and gastric cancers are distinct carcinomas of the upper gastrointestinal tract, although the distinction between them becomes less clear at the gastroesophageal junction (GEJ). Increasingly accurate staging is possible based on newer radiographic and surgical techniques such as positron emission tomography (PET), laparoscopy and thoracoscopy, laparoscopic ultrasound, and endoscopic ultrasound (EUS). For both cancer types, tumor classification is determined by depth of penetration of the primary tumor into the gastric or esophageal wall. For esophageal cancer, primary tumor anatomic position-upper, mid, and lower esophagus-is used to define the local nodal basin. Metastases in nodes outside the local basin are considered to be distant (M) rather than regional (N). In gastric cancer, the region of nodal metastasis has been abandoned in favor of the number of lymph nodes containing metastasis, which predicts outcome more accurately-patients with more than 15 positive lymph nodes have an outcome comparable to those with M disease. Increasing consideration is being given to the subclassification of tumors near the GEJ into types based on anatomical position, although this staging scheme ("Adenocarcinoma of the EsophagoGastric junction" or AEG type) has not yet been universally adopted. We review the current pathologic staging systems for esophageal and gastric cancers, the clinical staging approaches for these diseases, and the controversy surrounding classification of tumors of the GEJ.     

Pancreatic cancer–Endosonography

EUS is the most sensitive imaging procedure for the detection of small solid pancreatic masses and is accurate in determining vascular invasion of the portal venous system. Even compared to the new CT-techniques EUS provides excellent results in preoperative staging of solid pancreatic tumors. Compared to helical CT-techniques EUS is less accurate in detecting tumor involvement of superior mesenteric artery. EUS staging and EUS-guided FNA can be performed in a single-step procedure, to establish the diagnosis of cancer. There is no known negative impact of tumor cell seeding due to EUS-FNA. Without FNA EUS and additional methods are not able to reliably distinguish between inflammatory and malignant masses.     

胰腺癌:超声内镜检查

EUS is the most sensitive imaging procedure for the detection of small solid pancreatic masses and is accurate in determining vascular invasion of the portal venous system. Even compared to the new CT-techniques EUS provides excellent results in preoperative staging of solid pancreatic tumors. Compared to helical CT-techniques EUS is less accurate in detecting tumor involvement of superior mesenteric artery. EUS staging and EUS-guided FNA can be performed in a single-step procedure, to establish the diagnosis of cancer. There is no known negative impact of tumor cell seeding due to EUS-FNA. Without FNA EUS and additional methods are not able to reliably distinguish between inflammatory and malignant masses.