Rectal aberrant crypt foci (ACF) as a predictor of benign and malignant neoplastic lesions in the large intestine

Abstract

Background: The importance of ACF is not fully explained, however, their number may be a good predictor of synchronous and metachronic adenoma or other polyps whose removal reduces the risk of CRC. Due to the epidemiological and genetic association of ACF with pre-cancer lesions, they may be a potential CRC biomarker. The aim of our study was to show that the number and type of rectal ACF may be a good predictive factor for the presence of polyps located proximally from the splenic flexure and that the type and number of ACF can correlate with the number and specific types of polyps in the large intestine.

Methods: The study included 131 patients who underwent colonoscopy combined with rectal mucosa staining with 0.25% methylene blue. The number of rectal ACF was determined and bioptats were sampled for histopathological examination to assess the type of ACF. Endoscopic ACF assessment criteria given by L. Roncucci were used. The obtained material was subjected to statistical analysis using probability distribution, U-test, t-student test, and chi ² as well as the Statistica 7.1 software package.

Results: The study population was divided into three subgroups according to the number of ACF observed, i.e. ACF < 5, 5-10 and > 10. ACF < 5 were found in 35 patients (29.41%), 5-10 ACF in 70 (58.82%) and ACF > 10 in 14 individuals (11.76%). The study revealed the presence of normal ACF (p = 0.49), hyperplastic ACF (p = 0.34), dysplastic ACF (p = 0.11), and mixed ACF (p = 0.06). A single type of ACF was most commonly observed (n = 88, p = 0.74). In the researched group a larger number of ACF is concurrent with adenomas and hyperplastic polyps. The number of ACF clearly correlates with the dysplasia advancement in the adenoma and the number of polyps found.

Conclusions: Rectal ACF are a useful marker for the presence of cancerous lesions in the proximal and distal sections of the large intestine.

Keywords: Benign and malignant neoplastic lesions; Large intestine; Rectal ACF.

Fig. 1

Probability of polyps occurence in a large intestine depending on the type of ACF in the rectum. 1- no polyp, 2- one polyp, 3-two polyps, 4- three and more polyps Red line- ACF < 5, Green line 5 < ACF < 10, Blue line-ACF > 10

Fig. 2

The probability of developing polips. 1-adenoma, 2- hyperplastic polyp, 3-serated polyp, 4- no polypsBlue- ACF < 5, Red-5 < ACF < 10, Green-ACF > 10

Fig. 3

Probability of adenoma size depending on the number of rectal ACF (up to 10 mm). Blue line ACF < 5, Red line-5 < ACF < 10, green line ACF > 10

Fig. 4

Probability occurrence of a type of dysplasia in the adenoma, depending on the number of ACFs in the rectum (ACF > 10)

Fig. 5

Distribution of the type of dysplasia in the adenoma depending on the number of ACF in the rectum. Red line- high dysplasia. Blue line- low dysplasia

Fig. 6

The probability of occurence of dysplastic ACF. Red- Dysplastic ACF

Fig. 7

The probability of polyps distribution in all sections of the large intestine. 1-rectum 2- sigmoid colon, descending colon 3- transverse colon 4- ascending colon, caecum 5- no polypserie 1(blue)-normal ACF, serie 2(red)- hyperplastic ACF, serie 3(green)-dysplastic ACF, serie 4(violet)-mixed ACF

Fig. 8

The probability distribution of different types of polyps depending on the type of rectal ACF. blue-ACF normal, red- ACF hyperplastic, green- ACF dysplastic, violet- ACF mixed

Fig. 9

Relative distribution of the probability of CRC in different sections of the large intestine depending on the ACF rectal class. 1- ACF normal 2-ACF hyperplastic 3-ACF dysplastic 4- sum of events (1 + 2 + 3) Blue- rectum red- sigmoid colon + descending colon, green- transverse colon + ascending colon + caecum, violet- sum of events Series 1- conditional probability of rectal cancer for different types of ACF Series 2-conditional probability of CRC in sigmoid and descending colon for ACF types Series 3-conditional probability of CRC occurrence in the “right colon” for ACF types Series 4-conditional probability of CRC in different sections of the large intestine