MRI of Rectal Cancer Provides the Data to Improve Survival Odds

New findings revealed that preoperative evaluation using magnetic resonance imaging (MRI) is crucial in helping provide an optimized treatment strategy for rectal patients by predicting local recurrence and disease-free survival.

Rectal cancer, which accounts for one-third of all colorectal cancers, currently is a leading cause of cancer death in the Western World. The five-year study was conducted across 11 hospitals and research institutes across the United Kingdom, tracking 374 patients diagnosed and being treated for rectal cancer.

The research published the December 2013 issue Journal of Clinical Oncology set out to qualify the prognostic relevance of high-resolution magnetic resonance imaging (MRI) assessment of circumferential resection margin (CRM). Its usefulness in evaluating the risk of local recurrence has not been earlier validated.

The benefits were distinctly noticeable, rates of recurrence for patients with MRI-clear CRM were only 7% compared to 20% in the case of MRI-involved CRM. Furthermore, a five-year overall survival rate of 62% was showed in patients with MRI-clear CRM, compared to 42% in patients with MRI-involved CRM, independent of the type of treatment received by patients. From this, it is possible to conclude that by using this pre-op assessment method, patients could be identified who have a significant risk of local recurrence, which can in turn be prevented by preoperative down-staging of MRI detected high risk tumors and improved surgery.

The study’s goal was to compare the prognostic significance of using preoperative MRI assessment of CRM compared with the existing and widely used “staging” systems such as the American Joint Committee on Cancer (AJCC) TNM stage model and other clinical variables. The pre-op MRI assessment proved to be superior to TNM in predicting local recurrence, disease free survival, and overall survival. The researchers believe that MRI CRM status, instead of assessing the AJCC TNM, should be used when informing patients regarding the risks of local recurrence and treatment decisions such as pelvic radiotherapy.

Furthermore, although computed tomography (CT) imaging scan, endoluminal ultrasound (EUS), and MRI have all shown to be acceptable in terms of tumor and node staging, neither a CT nor EUS is capable of assessing the potential circumferential margin.

Dr. Gina Brown, the report’s author, consultant radiologist and reader in gastrointestinal cancer imaging at the Royal Marsden NHS [National Health Service] Foundation Trust (London, UK), commented, “The research found that it is highly beneficial in terms of patient outcome to predict local recurrence by adopting MRI preoperative imaging, helping to inform treatment decisions both amongst multidisciplinary teams and patients. If an MRI predicts that complete removal of the tumor can be achieved with at least 1 mm of clear margin, this should largely eliminate the risk of local recurrence in patients.”

Prof. Bill Heald, from the Pelican Cancer Foundation (Basingstoke, UK), noted, “Predicting recurrence by preoperative imaging would enable more intensive preoperative treatments as well as providing a surgical ‘roadmap’ to avoid breaching the tumor. This is a significant breakthrough and reinforces our belief here at the Pelican Cancer Foundation that investment in research is vital: advances in diagnosis and treatments are making a real difference to bowel cancer patients and helping to save thousands of lives each year in the UK alone.”

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Royal Marsden NHS Foundation Trust