A Monotonous Population of Elongated Cells (MPECs) in Colorectal Adenoma Indicates a High Risk of Metachronous Cancer

Risk factors for metachronous colorectal cancer or polyp: A systematic review and meta-analysis

BACKGROUND AND AIM

We conducted a systematic review and meta-analysis to identify personal, lifestyle, and tumor-related risk factors for metachronous colorectal cancer (CRC) and polyp.

METHODS

Relevant studies were identified by searching MEDLINE, Web of Science and Cochrane Central Register through 15 May 2016. Estimates for associations were summarized using random effects models.

RESULTS

Fifty-five studies were included in the review. For individuals who had a CRC resection, having a synchronous polyp was a risk factor for metachronous CRC or polyp (relative risk [RR], 2.04; 95% confidence interval [CI], 1.48-2.82) and having a synchronous CRC (RR, 1.90; 95% CI, 1.25-2.91) and proximally located CRC (RR, 2.12; 95% CI, 1.24-3.64) were risk factors for metachronous CRC. For individuals who had a polypectomy, larger size (RR, 4.26; 95% CI, 2.11-8.57) or severe dysplasia of the initial polyp (RR, 5.15; 95% CI, 2.02-13.14), and having a synchronous polyp (RR, 2.52; 95% CI, 1.35-4.73) were risk factors for metachronous CRC; and a family history of CRC (RR, 1.90; 95% CI, 1.26-2.87), having a synchronous polyp (RR, 2.47; 95% CI, 1.74-3.50) and a larger size (RR, 1.49; 95% CI, 1.03-2.15) and proximal location of the initial polyp (RR, 1.20; 95% CI, 1.02-1.40) were risk factors for metachronous polyp. Meta-regression showed duration of follow-up was not a source of heterogeneity for most associations. There was no evidence that lifestyle factors were associated with metachronous CRC or polyp risk.

CONCLUSION

A comprehensive list of risk factors identified for metachronous CRC or polyp may have important clinical implications.

Endoscopy, morphology, morphometry and molecular markers: predicting cancer risk in colorectal adenoma

The evaluation of short- and long-term risk for developing cancer in patients with colorectal adenomas is controversial. Good, reliable predictors of cancer risk in any adenoma are currently lacking and are limited to adenoma size, number and histologic type. In fact, the evaluation of any adenoma or precancer lesion (e.g., hyperplastic polyps, serrated adenoma or aberrant crypt foci) within the colorectum may be assessed by a number of techniques ranging from direct visualization through the endoscope, to microscopic assessment, and to evaluation at the molecular level. Emerging techniques may yield improved methods of adenoma risk-assessment in the near future. For one, newer endoscopy technologies include chromoendoscopy or endocytoscopy, which now render endoscopists able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time - thus, bringing the microscope to the patient's bedside. This new era in endoscopic imaging is dubbed 'histoendoscopy'. Further, while traditional views of classifying protruding and sessile lesions include those of Haggitt, the sm-classification, the Japanese and the so-called Vienna classifications to evaluate neoplasia, the development of new molecular techniques may give way to new methods of classifying preneoplasia and precancerous lesions. This review discusses some pros and cons of risk evaluation technologies in the colorectal tract by endoscopy, microscopy, and quantitative and molecular features. The morphometry-based studies performed over the past decades for the quantitative assessment of cellular and nuclear features within adenomas have failed to yield results amenable for clinical translation and are unlikely to improve further and gain widespread use with current technology. Rather, emerging knowledge of pathway-specific markers through the outlining of a molecular classification will likely be the basis for improved detection and diagnosis. The emerging genomic and proteomic technologies allowing for noninvasive tests to detect (asymptomatic) cancer and neoplasia are discussed. Lastly, the importance of recognizing bias and pitfalls and the adherence to guidelines for biomarker research are addressed.

Metachronous cancer development in patients with sporadic colorectal adenomas-multivariate risk model with independent and combined value of hTERT and survivin

BACKGROUND AND AIMS

Accurate, long-term risk predictors for colorectal cancer development in patients with sporadic adenomas are lacking. We sought to validate biomarkers predictive of metachronous colorectal cancer (mCRC) in patients with sporadic colorectal adenomas, using 374 consecutive patients from a large defined population.

MATERIALS AND METHODS

Risk evaluation was performed for patient and adenoma risk factors (morphometric longest nuclear axis and immunohistochemical markers survivin, human telomerase reverse transcriptase (hTERT), beta-catenin, p16INK4a, p21CIP1, and cyclin D1). Diagnostic accuracy was assessed by receiver-operating characteristics curve analysis, and uni- and multivariate survival analysis was performed.

RESULTS/FINDINGS

Of the 374 patients, 26 (7%) developed mCRC with a median of 5.6 years (range 2-19) from index adenoma. Independent risk factors included age greater than or equal to 60 years, proximal location, multiplicity (greater than or equal to three adenomas), and high-grade neoplasia, with high-grade intraepithelial neoplasia and proximal location as the strongest on multivariate analysis (hazard ratio [HR] of 4.1 and 5.2, respectively; both p< 0.05). The molecular markers hTERT (HR 11.3, 95% confidence interval [CI] 3.9-33.1; p < 0.001) and survivin (HR 7.0, 95% CI 2.4-20.5; p < 0.001) were independent predictors for mCRC, and proximal location (4 of 16 = 25% with mCRC) was the only clinical one. The value of hTERT and survivin were retained in the validation set. Survivin and hTERT together yielded high mCRC risk when both were positive (15 of 51 = 29%; HR 14.3, 5.6-36.5), modest with one positive (survivin 4 of 90 = 4.4%; hTERT 4 of 60 = 6.7%), and no risk with both negative (0 of 144 = 0%).

INTERPRETATION/CONCLUSION

hTERT and survivin are the best risk predictors for long-term, mCRC development in patients with sporadic colorectal adenomas.