Detection of lymph node metastases with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging in oesophageal cancer: a feasibility study.

AIM: In this feasibility study we investigated whether magnetic resonance imaging (MRI) with ultrasmall superparamagnetic iron oxide (USPIO) can be used to identify regional and distant lymph nodes, including mediastinal and celiac lymph node metastases in patients with oesophageal cancer. PATIENTS AND METHODS: Ten patients with a potentially curative resectable cancer of the oesophagus were eligible for this study. All patients included in the study had positive lymph nodes on conventional staging (including endoscopic ultrasound, computed tomography and fluorodeoxyglucose-positron emission tomography). Nine patients underwent MRI + USPIO before surgery. Results were restricted to those patients who had both MRI + USPIO and histological examination. Results were compared with conventional staging and histopathologic findings. RESULTS: One patient was excluded due to expired study time. Five out of 9 patients underwent an exploration; in 1 patient prior to surgery MRI + USPIO diagnosed liver metastases and in 3 patients an oesophageal resection was performed. USPIO uptake in mediastinal lymph nodes was seen in 6 out of 9 patients; in 3 patients non-malignant nodes were not visible. In total, 9 lymph node stations (of 6 patients) were separately analysed; 7 lymph node stations were assessed as positive (N1) on MRI+USPIO compared with 9 by conventional staging. According to histology findings, there was one false-positive and one false-negative result in MRI + USPIO. Also, conventional staging modalities had one false-positive and one false-negative result. MRI + USPIO had surplus value in one patient. Not all lymph node stations could be compared due to unforeseen explorations. No adverse effects occurred after USPIO infusion. CONCLUSION: MRI+USPIO identified the majority of mediastinal and celiac (suspect) lymph nodes in 9 patients with oesophageal cancer. MRI+USPIO could have an additional value in loco-regional staging; however, more supplementary research is needed.

Chemoprevention for colon cancer: new opportunities, fact or fiction?

Colorectal cancer (CRC) is still a disease with a high incidence and mortality. Prevention of (pre-) cancerous lesions of CRC by endoscopic screening is promising, but costs are high and identification of high-risk populations is difficult. Since screening both average-risk and high-risk populations for CRC has its logistic and financial limitations, new primary prevention strategies are sought. Substantial evidence has shown that non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors can reduce the incidence and mortality of CRC. However, long-term use of NSAIDs is associated with substantial gastrointestinal toxicity and may cause an exacerbation in IBD patients. Selective COX-2 inhibitors, with a better toxicity profile and no flare-up in IBD disease activity, are therefore attractive candidates for prevention. Chemoprevention with low-dose aspirin can be considered for individuals carrying a high risk for CRC. Folate supplementation is beneficial to the folate-depleted patients, since significant risk reductions for CRC are reported. Moreover, it might be applicable to the general population because it is safe, inexpensive and protects against vascular diseases. In line with drugs beneficial for multiple disease entities, statins have recently been proposed to reduce CRC risk. Ursodeoxycholic acid has been shown to decrease the incidence of colonic dysplasia in patients with ulcerative colitis and PSC and possibly reduces recurrence rates of polyps in general. Unfortunately, prospective randomized trials, in both high-risk and general population, are not available and the evidence is still controversial. Furthermore, cumulative epidemiological and observational data suggest the potential role of hormones as a chemoprotective agent. An increase in CRC in females with an early menopause, as well as a decrease of CRC in women with hormone replacement therapy justify further research into this issue. In IBD patients, both the severity and duration of the inflammation are the most evident risk factors for the development of dysplasia and subsequently cancer. Remission of inflammation, clinically, endoscopically and histologically, in IBD is the major goal. Long-term use of 5-aminosalicylates (5-ASA) has been shown to decrease the incidence of CRC and may hold the best promise as a chemoprotective agent in IBD. In parallel with primary prevention strategies in vascular medicine, the aim might be to postpone adenoma formation, for instance for 10 years, thereby achieving a significant risk reduction for CRC. In current practice, folate supplementation along with low-dose aspirin use in high-risk patients may be most attractive candidates, while future studies will have to clarify the role of these and other chemoprotective agents.