Colorectal cancer screening

Identification of familial colorectal cancer and hereditary colorectal cancer syndromes through the Dutch population-screening program: results ofa pilot study

OBJECTIVES

In 2014, a population-screening program using immuno-faecal occult blood testing (I-FOBT) has started in the Netherlands. The aims of this study were to evaluate the proportion of individuals in the Dutch screening program with a positive I-FOBT that fulfill the criteria for familial colorectal cancer (FCC) and to evaluate the proportion of participants that needs genetic counseling or colonoscopic surveillance.

MATERIAL AND METHODS

This retrospective observational study was performed in two large hospitals. Individuals aged between 55 and 75 years with a positive I-FOBT that underwent colonoscopy were included. A detailed family history was obtained in all individuals.

RESULTS

A total of 657 individuals with a positive I-FOBT test underwent colonoscopy. A total of 120 (18.3%) participants were found to have a positive family history for CRC, 20 (3.0%) fulfilled the FCC criteria, 4 (0.6%) the Bethesda guidelines and 1 (0.2%) participant the Amsterdam criteria. Multiple adenomas (>10) were found in 21 (3.2%) participants. No cases of serrated polyposis were identified. Based on these criteria and guidelines, a total of 35 (5.3%) required referral to the clinical geneticist and the relatives of 20 (3.0%) participants should be referred for surveillance colonoscopy.

CONCLUSION

Obtaining a detailed family history at the time of intake of participants with a positive I-FOBT in the Dutch surveillance program increased the identification of participants with familial CRC.

Randomized Comparison of Surveillance Intervals in Familial Colorectal Cancer

PURPOSE

Colonoscopic surveillance is recommended for individuals with familial colorectal cancer (CRC). However, the appropriate screening interval has not yet been determined. The aim of this randomized trial was to compare a 3-year with a 6-year screening interval.

PATIENTS AND METHODS

Individuals between ages 45 and 65 years with one first-degree relative with CRC age < 50 years or two first-degree relatives with CRC were selected. Patients with zero to two adenomas at baseline were randomly assigned to one of two groups: group A (colonoscopy at 6 years) or group B (colonoscopy at 3 and 6 years). The primary outcome measure was advanced adenomatous polyps (AAPs). Risk factors studied included sex, age, type of family history, and baseline endoscopic findings.

RESULTS

A total of 528 patients were randomly assigned (group A, n = 262; group B, n = 266). Intention-to-treat analysis showed no significant difference in the proportion of patients with AAPs at the first follow-up examination at 6 years in group A (6.9%) versus 3 years in group B (3.5%). Also, the proportion of patients with AAPs at the final follow-up examination at 6 years in group A (6.9%) versus 6 years in group B (3.4%) was not significantly different. Only AAPs at baseline was a significant predictor for the presence of AAPs at first follow-up. After correction for the difference in AAPs at baseline, differences between the groups in the rate of AAPs at first follow-up and at the final examination were statistically significant.

CONCLUSION

In view of the relatively low rate of AAPs at 6 years and the absence of CRC in group A, we consider a 6-year surveillance interval appropriate. A surveillance interval of 3 years might be considered in patients with AAPs and patients with ≥ three adenomas.

Colosigmoid junction: morphohistologic, morphometric, and endoscopic study with identification of colosigmoid canal with sphincter

To study the anatomical structure of the colosigmoid junction, 15 cadaveric specimens were studied morphologically, another 15 histologically, and a morphometric study was done in 10 specimens. Specimens consisted of the descending colon, sigmoid colon, and the colosigmoid junction. Histologic specimens were stained with hematoxylin and eosin and Masson's trichrome stain. Morphometric studies used an image analysis system. The colosigmoid junction was investigated endoscopically in 18 healthy volunteers. A narrow segment having a mean length of 5.2 +/- 1.1 cm was identified both externally and internally between the descending and sigmoid colon. We called this segment the colosigmoid canal. Mucosal folds were found crowded in the colosigmoid canal, the lower end of which formed a nipple and was surrounded by a fornix. Histologically, the colosigmoid canal mucosa showed multiple folds. Its circular muscle was thicker than that of the descending or the sigmoid colon and confirmed morphometrically. The longitudinal muscle was thicker in only 4 of 10 specimens. Both the narrowing and the mucosal crowding were verified endoscopically. The colosigmoid junction is the narrow segment between the descending and the sigmoid colon. Histologic, morphometric and endoscopic studies indicated the presence of a sphincter in the colosigmoid canal. A colosigmoid sphincter is suggested to control the passage of colonic contents from the descending colon to the colosigmoid canal as well as to prevent reflux of sigmoid contents into the descending colon.

Cancer characteristics in Swedish families fulfilling criteria for hereditary nonpolyposis colorectal cancer

BACKGROUND & AIMS

The present study quantified the prevalence of families that fulfill the Amsterdam or Bethesda criteria for hereditary nonpolyposis colorectal cancer (HNPCC) in the whole Swedish population and investigated the extent to which tumors in the classified families are HNPCC-related.

METHODS

The families of the Swedish Family-Cancer Database with at least 4 generations (N = 566,877) were classified according to the Amsterdam and the Bethesda criteria. Survival methods were used to assess the risk of cancer in the classified families, the prognosis of cancer patients, and the risk of subsequent malignancies after colorectal adenomas and after colorectal/endometrial adenocarcinomas.

RESULTS

The Bethesda criteria identified 0.9% of all Swedish families and 11.2% of patients with colorectal cancer. Families that fulfilled the Bethesda criteria showed increased risks of cancer in the colorectum, endometrium, small bowel, ovary, stomach, bile ducts, renal pelvis, and ureter; members of Bethesda criteria families were at decreased risks of lung and cervical cancers. The prognosis of cancer in the ureter, renal pelvis, stomach, ovary, and colorectum, but not in the endometrium, was better in Bethesda criteria than in nonclassified families.

CONCLUSIONS

Most malignancies in the classified families reflect typical features of HNPCC (association with subsequent malignancies, accelerated adenoma-carcinoma sequence, and better survival). The data presented in this study should help to define surveillance strategies for members of families that fulfill the criteria for HNPCC testing.