Virtual colonoscopy: a novel imaging modality for colorectal cancer

Liquid biopsy as a perioperative biomarker of digestive tract cancers: review of the literature

Tissue biopsies are the gold-standard for investigating the molecular characterization of tumors. However, a "solid" biopsy is an invasive procedure that cannot capture real-time tumor dynamics and may yield inaccurate information because of intratumoral heterogeneity. In this review, we summarize the current state of knowledge about surgical treatment-associated "liquid" biopsy for patients with digestive organ tumors. A liquid biopsy is a technique involving the sampling and testing of non-solid biological materials, including blood, urine, saliva, and ascites. Previous studies have reported the potential value of blood-based biomarkers, circulating tumor cells, and cell-free nucleic acids as facilitators of cancer treatment. The applications of a liquid biopsy in a cancer treatment setting include screening and early diagnosis, prognostication, and outcome and recurrence monitoring of cancer. This technique has also been suggested as a useful tool in personalized medicine. The transition to precision medicine is still in its early stages. Soon, however, liquid biopsy is likely to form the basis of patient selection for molecular targeted therapies, predictions regarding chemotherapy sensitivity, and real-time evaluations of therapeutic effects.

Virtual colonoscopy compared with conventional colonoscopy for stricturing postoperative recurrence in Crohn's disease

BACKGROUND

The place of virtual colonoscopy (VC) in patients with Crohn's disease (CD) requiring endoscopic follow-up after surgery is unknown. The authors compared findings from VC versus conventional colonoscopy (CC) for assessing the postoperative recurrence of CD.

METHODS

Sixteen patients with ileocolonic anastomosis for CD were prospectively enrolled from January 2001 to January 2002. Recurrence was assessed by CC according to Rutgeerts et al. VC was performed with a computed tomography scanner, with images examined by three radiologists who were unaware of the endoscopic findings.

RESULTS

CC showed perianastomotic recurrence in 15 of 16 patients. Perianastomotic narrowing or stenosis was detected by VC in 11 of these 15 patients. There were 11 true positive, 1 true negative, 0 false-positive, and 4 false-negative findings (73% sensitivity, 100% specificity, 100% positive predictive value, 20% negative predictive value, 75% accuracy). Among the eight patients showing a rigid stenosis of the anastomosis not allowing passage of the colonoscope, VC detected narrowing or stenosis in seven patients.

CONCLUSIONS

The current findings suggest that although the widespread use of VC in CD is currently not indicated because of possible false-negative findings, this technique may represent an alternative to CC in noncompliant postsurgical patients with a rigid stenosis not allowing passage of the endoscope.

Virtual colonoscopy. Potential clinical applications of a new technique

The potential role of virtual colonoscopy is not limited to colorectal cancer screening, although that is its greatest potential. Same-day VC should be offered for patients undergoing an incomplete colonoscopy. Conversely, faster, more accurate interpretation by the radiologist on the same day as a VC should lead to the consideration by the gastroenterologist of same-day colonoscopy for patients with a suspicious, significantly sized polyp.