Diagnostic performance of fecal immunochemical test and sigmoidoscopy for advanced right-sided colorectal neoplasms.

BACKGROUND: Colorectal cancer screening effect on right-sided colorectal neoplasia is limited. We compared fecal immunochemical test and simulated sigmoidoscopy diagnostic accuracy for advanced right-sided neoplasia detection. METHODS: We analyzed 1,292 individuals with complete screening colonoscopy with a fecal immunochemical test determination before colonoscopy. Sigmoidoscopy and "hybrid strategy" (sigmoidoscopy or fecal hemoglobin concentration ≥ 20 µg hemoglobin/g) diagnostic yield were simulated according to UK Flexible Sigmoidoscopy, Screening for COlon REctum (SCORE), and Norwegian Colorectal Cancer Prevention (NORCCAP) trials criteria to complete colonic examination. We compared sensitivity and specificity of both strategies and of "hybrid strategy" for advanced right-sided neoplasia with McNemar test. RESULTS: An advanced right-sided neoplasia was detected in 47 (3.6 %) subjects. A fecal hemoglobin concentration ≥ 20 µg hemoglobin/g was determined in 6.6 % of the subjects and 10.1, 12.7, and 23.5 % met UK, SCORE, and NORCCAP criteria, respectively. Fecal immunochemical test was statistically more specific than sigmoidoscopy strategies (93.8 %, UK 90.3 %, SCORE 87.7 %, NORCCAP 77.8 %; p < 0.001). In contrast, fecal immunochemical test sensitivity for advanced right-sided neoplasia (17 %) was not statistically different than UK (21.3 %; p = 0.7) or SCORE (23.4 %; p = 0.5), although it was inferior than NORCCAP strategy (42.5 %; p < 0.001). Adding fecal immunochemical test to sigmoidoscopy increased number of positives (8.5-25.7 %), sensitivity (10-30 %), and significantly reduced advanced right-sided neoplasia specificity (p < 0.001). CONCLUSIONS: Fecal immunochemical test and sigmoidoscopy diagnostic yield for advanced right-sided neoplasia are low. Fecal immunochemical test is more specific than sigmoidoscopy but less sensitive than sigmoidoscopy according to NORCCAP criteria.

Thyroid Pathology Findings in Cowden Syndrome: A Clue for the Diagnosis of the PTEN Hamartoma Tumor Syndrome.

OBJECTIVES: PTEN hamartoma tumor syndrome (PHTS) is a hereditary disorder caused by germline inactivating mutations of the PTEN gene. PHTS includes Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome. We describe how the peculiar pathologic and immunohistochemical thyroid features lead pathologists to suggest PHTS. METHODS: A 28-year-old white Spanish woman had a multinodular goiter. Total thyroidectomy was performed after fine-needle aspiration biopsy. Microscopic, immunohistochemical, and molecular analyses of the thyroid lesions were realized. RESULTS: The thyroid was multinodular, showing one papillary microcarcinoma, five follicular adenomas, three adenolipomas, 46 tiny adenomatous nodules (microadenomas), scattered foci of adipose tissue, and lymphocytic thyroiditis. Tumors were positive for thyroglobulin, thyroperoxidase, pendrin, cyclin D1, and p27 but negative for calcitonin and PTEN. A germline heterozygous deletion of one adenine at nucleotide 827 in exon 8 of the PTEN gene was confirmed. No BRAF, NRAS, or KRAS somatic mutations were detected in the papillary microcarcinoma, follicular adenoma, adenolipomas, or microadenomas. Negativity for PTEN was also found in the colonic tubulovillous adenoma and the storiform collagenoma. CONCLUSIONS: Pathologists play a crucial role in recognizing pathologic thyroid findings associated with PHTS for selecting patients for genetic testing.

Fecal immunochemical test accuracy in average-risk colorectal cancer screening.

AIM: To assess the fecal immunochemical test (FIT) accuracy for colorectal cancer (CRC) and advanced neoplasia (AN) detection in CRC screening. METHODS: We performed a multicentric, prospective, double blind study of diagnostic tests on asymptomatic average-risk individuals submitted to screening colonoscopy. Two stool samples were collected and the fecal hemoglobin concentration was determined in the first sample (FIT1) and the highest level of both samples (FITmax) using the OC-sensor™. Areas under the curve (AUC) for CRC and AN were calculated. The best FIT1 and FITmax cut-off values for CRC were determined. At this threshold, number needed to scope (NNS) to detect a CRC and an AN and the cost per lesion detected were calculated. RESULTS: About 779 individuals were included. An AN was found in 97 (12.5%) individuals: a CRC in 5 (0.6%) and an advanced adenoma (≥ 10 mm, villous histology or high grade dysplasia) in 92 (11.9%) subjects. For CRC diagnosis, FIT1 AUC was 0.96 (95%CI: 0.95-0.98) and FITmax AUC was 0.95 (95%CI: 0.93-0.97). For AN, FIT1 and FITmax AUC were similar (0.72, 95%CI: 0.66-0.78 vs 0.73, 95%CI: 0.68-0.79, respectively, P = 0.34). Depending on the number of determinations and the positivity threshold cut-off used sensitivity for AN detection ranged between 28% and 42% and specificity between 91% and 97%. At the best cut-off point for CRC detection (115 ng/mL), the NNS to detect a CRC were 10.2 and 15.8; and the cost per CRC was 1814€ and 2985€ on FIT1 and FITmax strategies respectively. At this threshold the sensitivity, NNS and cost per AN detected were 30%, 1.76, and 306€, in FIT1 strategy, and 36%, 2.26€ and 426€, in FITmax strategy, respectively. CONCLUSION: Performing two tests does not improve diagnostic accuracy, but increases cost and NNS to detect a lesion.

Characteristics of adenomas detected by fecal immunochemical test in colorectal cancer screening.

BACKGROUND: Fecal immunochemical test (FIT) diagnostic accuracy for colorectal adenoma detection in colorectal cancer screening is limited. METHODS: We analyzed 474 asymptomatic subjects with adenomas detected on colonoscopy in two blinded diagnostic tests studies designed to assess FIT diagnostic accuracy. We determined the characteristics of adenomas (number, size, histology, morphology, and location) and the risk of metachronous lesions (according to European guidelines). Finally, we performed a logistic regression to identify those variables independently associated with a positive result. RESULTS: Advanced adenomas were found in 145 patients (75.6% distal and 24.3% only proximal to splenic flexure). Patients were classified as low (59.5%), intermediate (30.2%), and high risk (10.3%) according to European guidelines. At a 100-ng/mL threshold, FIT was positive in 61 patients (12.8%). Patients with advanced adenomas [odds ratio (OR), 8.8; 95% confidence interval (CI), 4.76-16.25], distal advanced adenomas (OR, 6.7; 95% CI, 1.9-8.8), high risk (OR, 20.1; 95% CI, 8.8-45.8), or intermediate risk lesions (OR, 6; 95% CI, 2.9-12.4) had more probabilities to have a positive test. The characteristics of adenomas independently associated were number of adenomas (OR, 1.22; 95% CI, 1.04-1.42), distal flat adenomas (OR, 0.44; 95% CI, 0.21-0.96), pedunculated adenomas (OR, 2.28; 95% CI, 1.48-3.5), and maximum size of distal adenomas (mm; OR, 1.24; 95% CI, 1.16-1.32). CONCLUSIONS: European guidelines classification and adenoma location correlates with the likelihood of a positive FIT result. IMPACT: This information allows us to understand the FIT impact in colorectal cancer prevention. Likewise, it should be taken into account in the development of new colorectal adenomas biomarkers.

Diagnostic accuracy of fecal immunochemical test in average- and familial-risk colorectal cancer screening.

BACKGROUND: There is little information about the fecal immunochemical test (FIT) in familial-risk colorectal cancer (CRC) screening. OBJECTIVES: The objective of this article is to investigate whether FIT diagnostic accuracy for advanced neoplasia (AN) differs between average and familial-risk (first-degree relative) patients. METHODS: A total of 1317 consecutive participants (595 familial) who collected one stool sample before performing a colonoscopy as a CRC screening test were included. FIT diagnostic accuracy for AN was evaluated with Chi-square test at a 20 µg hemoglobin/g of feces cut-off value. Finally, we determined which variables were independently related to AN. RESULTS: An AN was found in 151 (11.5%) patients. The overall accuracy was not statistically different between both cohorts for AN (88.4%, 91.7%; p = 0.051). At the cut-off stablished, differences in FIT sensitivity (31.1%, 40.6%; p = 0.2) or specificity (96.5%, 97.3%; p = 0.1) were not statistically significant. Finally, independent variables such as sex (male) (odds ratio (OR) 2.1, 95% confidence interval (CI) 1.4-3.1), age (50-65, >65 years) (OR 2.1, 95% CI 1.1-4.3; OR 2.7, 95% CI 1.2-6.1), previous colonoscopy (OR 0.4, 95% CI 0.2-0.9) and FIT ≥20 µg/g feces (OR 17.7, 95% CI 10.8-29.1) were associated with AN diagnosis. CONCLUSIONS: FIT accuracy for AN detection is equivalent in average and familial-risk CRC screening cohorts.