Thinking outside the box: a more efficient diagnostic approach in metastatic colorectal cancer
Authors: Andreas G Schreyer
Journal: The Lancet. Gastroenterology & hepatology (2019)

Early and correct tumour staging in newly diagnosed patients with colorectal carcinoma is the basis for optimised treatment pathways. Along with T and N staging, M staging for metastasis assessment is a fundamental feature of the stratification of further therapy. Various national and international guidelines try to highlight which diagnostic method, and especially which radiological imaging technique, ensures the best sensitivity and accuracy regarding metastasis detection in early diagnosis. Currently, most published studies compare dedicated advanced imaging methods performed by experts in their fields, such as PET-CT, with MRI. These studies are used to inform clinical guidelines and identify the optimal imaging methods used for staging. Evidence-based guidelines are important for a personalised and tailored approach to modern medicine, which still has to be economically optimised while providing the best possible quality of care. Diagnostic staging methods are based on the current literature, which recommends for example that patients with rectal carcinoma receive a pelvic MRI and a chest, abdominal, and pelvic CT, sometimes with an additional ultrasound examination of the liver before the other examinations. The use of multiple advanced imaging modalities to assess metastatic status means that several appointments usually need to be scheduled and often follow-up examinations are required. This can lead to additional anxiety for the patients and higher costs in the medical system, and therefore should be critically assessed. MRI has faced considerable backlash within the medical community due to relatively high costs and the problems involved in finding a timely slot for imaging because of the high demand for this method. This is why it is particularly important to think outside the box and look for new medical pathways and paradigms and not to be driven by prejudices. It could be more efficient to adapt the known therapeutic concept of hitting hard and early1Ferreira AJ Reis A Marcal N Pinto P Barbara C GI DPOC-Grupo de Interesse na Doença Pulmonar Obstrutiva CrónicaCOPD: a stepwise or a hit hard approach?.Rev Port Pneumol. 2016; 22: 214-221PubMed Google Scholar to diagnostic imaging to improve medical outcomes and economic performance. The results of the Streamline C trial, have now been published in The Lancet Gastroenterology & Hepatology.2Taylor SA Mallett S Beare S et al.Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed colorectal cancer: the prospective Streamline C trial.Lancet Gastroenterol Hepatol. 2019; (published online May 9.)http://dx.doi.org/10.1016/S2468-1253(19)30056-1Summary Full Text Full Text PDF Scopus (36) Google Scholar The trial compared whole-body MRI (WB-MRI)3Kosmin M Makris A Joshi PV Ah-See ML Woolf D Padhani AR The addition of whole-body magnetic resonance imaging to body computerised tomography alters treatment decisions in patients with metastatic breast cancer.Eur J Cancer. 2017; 77: 109-116Summary Full Text Full Text PDF PubMed Scopus (31) Google Scholar, 4Larbi A Dallaudiere B Pasoglou V et al.Whole body MRI (WB-MRI) assessment of metastatic spread in prostate cancer: therapeutic perspectives on targeted management of oligometastatic disease.Prostate. 2016; 76: 1024-1033Crossref PubMed Scopus (39) Google Scholar, 5Oliveri S Pricolo P Pizzoli S et al.Investigating cancer patient acceptance of whole body MRI.Clin Imaging. 2018; 52: 246-251Summary Full Text Full Text PDF PubMed Scopus (16) Google Scholar with the standard imaging pathway for patients with newly diagnosed colorectal cancer; an unorthodox and pragmatic new approach to finding an economically and medically optimised staging approach in real-world settings. 299 patients with newly diagnosed colorectal carcinoma—a sufficient number, for the first time in any trial of this type—were prospectively assessed in a real-world multicentre trial in 16 English hospitals. A multidisciplinary team made a therapeutic decision first based on the conventional modular diagnostic pathway and second after the findings of a WB-MRI. The conventional image approach and the WB-MRI were done in a regular hospital setting and not by dedicated specialists for the study. The authors measured the time taken for the patient to complete the whole staging process and the sensitivity and specificity of the two different approaches. The time to complete the staging was significantly shorter for WB-MRI (8 days) compared with conventional modular imaging (13 days). Additionally, the per-patient costs were lower (£216) in WB-MRI compared with the standard pathway (£285). Although the time taken for the staging was shorter and the economic costs lower for WB-MRI, the sensitivity (67% WB-MRI vs 63% standard pathway) and specificity (95% WB-MRI vs 93% standard pathway) did not differ between imaging pathways. Therefore, these findings, which were acquired in a realistic and pragmatic clinical setting, suggest that WB-MRI (traditionally considered to be the more costly approach) is the more economic and medically preferable method for staging pathways in patients with newly diagnosed colorectal carcinoma. This study has some limitations. First, it solely represents the English National Health Service with its national recommendations and cost calculations. Based on the details in the appendix of the study, further analysis of costs can be done to be applicable to other countries and medical systems. The real-world approach of this study highlights a key problem: eight of the 16 recruitment sites had no local radiological infrastructure to perform WB-MRI, which led to examination being done in another nearby hospital. Therefore, the infrastructure based on availability and technical expertise of advanced MRI scanners will be a fundamental prerequisite to changing to new, more efficient paradigms and diagnostic pathways. Overall, the study gives an important evidence-based argument and shows that new diagnostic imaging approaches and techniques, which are often thought of as more expensive and complex at first sight, can eventually change clinical pathways while being more time-efficient and cost-efficient. I declare no competing interests. Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed colorectal cancer: the prospective Streamline C trialWB-MRI staging pathways have similar accuracy to standard pathways and reduce the number of tests needed, staging time, and cost. Full-Text PDF Open Access