Predictive Value of Faecal Immunochemical Test for Screening of Colorectal Malignancy: A Single Centre Prospective Study
Z. M. Raihan Kabir *
Kapasia Health Complex, Gazipur, Bangladesh.
Mahmud Hasan
Department of Surgery, Shaheed Tajuddin Ahmed Medical College and Hospital, Gazipur, Bangladesh.
Tarek Hasan
OSD, DGHS, Mohakhali, Dhaka, Bangladesh.
Munsur Miah
OSD, DGHS, Mohakhali, Dhaka, Bangladesh.
Moshe Dayen Halder
Department of Urology, Dhaka Medical College and Hospital, Dhaka, Bangladesh.
Saoda Islam
Department of Orthopaedics and Traumatology, Sher-E-Bangla Medical College and Hospital, Barishal, Bangladesh.
Sarmin Rahman
Vita Skin Centre, Gulshan, Dhaka, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
Background: Colorectal malignancy (CRC) is the third most prevalent cancer worldwide, with an estimated one million new cases and a half million deaths each year. This study discusses the predictive value of faecal immunochemical test (FIT) for colorectal malignancy as a screening tool.
Method: This prospective observational study was conducted among high risk patients of colorectal malignancy seeking treatment in Department of Colorectal Surgery, Bangladesh Medical University (BMU) from August, 2015 to August, 2017 over a period of 24 months. Prevalence of colorectal malignancy among FIT-positive patients were identified and diagnostic performance of FIT (sensitivity, specificity, positive predictive and negative predictive value and positive and negative likelihood ratio) were analyzed. A p-value less than 0.05 was considered as statistically significant.
Results: A total number of 150 patients were enrolled in the current study after fulfilling the inclusion and exclusion criteria. 114(76%) patients had colonoscopy positive pathological lesions. Among these 114 patients, 60(40.00%) had colonic adenoma and 24(16%) had CRC. Besides,30 (20%) patients had non neoplastic lesions (hemorrhoids, anal fissure etc.) and 6(4.0%) patients had inflammatory bowel disease. The fecal immunochemical test (FIT) was positive for CRC in 16.67% patients (n = 25) of the study population. The sensitivity of FIT for detecting colorectal malignancy was 91.67%, while specificity was 95.24%. The positive predictive value (PPV) and negative predictive value (NPV) were 90.48% and 91.89% respectively. Diagnostic accuracy was 94.67%. Positive Likelihood ratio was 2.17 while Negative likelihood ratio was 0.64. Logistic regression analysis revealed that a positive FIT was independently associated with increased odds of colorectal malignancy (OR: 8.50, 95% CI 5.20–13.90, p<0.001).
Conclusion: FIT is a valuable, noninvasive tool for CRC screening and triage, with high NPV and acceptable PPV in appropriate populations. FIT serves as an effective first-line screening modality, particularly in resource-limited settings. Future research should focus on optimizing thresholds and integrating FIT with other biomarkers to enhance diagnostic accuracy.
Keywords: Predictive value, faecal immunochemical test, colorectal malignancy.