ปัจจัยที่ส่งผลต่อการเกิดผลบวกลวงในการตรวจคัดกรองมะเร็งลำไส้ใหญ่และไส้ตรงด้วยวิธี FIT (Fecal Immunochemical Test) ในอำเภอสองพี่น้อง จังหวัดสุพรรณบุรี

Kesanan Prajumsukh

Authors

Kesanan Prajumsukh Somdej Phrasangkharaj XVII hospital

Keywords:

การตรวจคัดกรองมะเร็งลําไส้, การตรวจหาเลือดแฝงในอุจจาระ, การส่องกล้องทางเดินอาหารส่วนล่าง, มะเร็งลำไส้ใหญ่และไส้ตรง, ผลบวกลวง

Abstract

Objective: To identify factors associated with false-positive results in colorectal cancer screening using the fecal immunochemical test (FIT). A false positive was defined as a positive FIT with no colorectal cancer or advanced adenoma detected on colonoscopy.

Methods: We conducted a retrospective observational case–control study of medical records for FIT-positive individuals aged 50–75 years between January 2023 and December 2024 who subsequently underwent colonoscopy (n = 294). Collected variables included age, sex, comorbidities, medication use, smoking, and colonoscopic findings. Descriptive statistics were used to summarize baseline characteristics. Univariable and multivariable logistic regression analyses were performed to identify predictors of false-positive FIT.

Results: Among 294 participants (mean age 60.89 ± 6.13 years; 59.9% female), the most common comorbidity was dyslipidemia (57.8%). Colonoscopy findings were normal in 43.5% of participants; colorectal cancer was detected in 2.4%; advanced adenoma in 7.1%; and non-advanced adenoma in 26.5%. Overall, 266 cases (90.5%) were classified as false positive. In multivariable analysis, female sex was independently associated with false-positive FIT (adjusted OR 3.08; 95% CI 1.26–7.54; p = .014). Hemorrhoids showed a positive trend with false positivity but did not reach statistical significance.

Conclusions: This study found that the false-positive rate of FIT was relatively high, and female sex was significantly associated with false-positive FIT results. Individuals with hemorrhoids also showed a relatively high tendency toward false-positive results, although this association did not reach statistical significance. Therefore, in these groups, a higher fecal hemoglobin cut-off value may be considered to help reduce unnecessary colonoscopy referrals, while carefully balancing the risk of increasing false-negative FIT results.

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รังสรรค์ ฤกษ์นิมิตร, พินิจ กุลละวณิชย์, สมบัติ ตรีประเสริฐสุข, สุพจน์ พงศ์ประสบชัย, ทวี รัตนชูเอก, ศิริบูรณ์ อัตศรัณย์, และคณะ. การศึกษาการใช้ Asia-Pacific colorectal cancer risk score และการตรวจหาเลือดแฝงในอุจจาระ (fecal immunochemical test) ในการช่วยตรวจคัดกรองเนื้องอกลำไส้ใหญ่ในประเทศไทย. กรุงเทพมหานคร; สถาบันวิจัยระบบสาธารณสุข: 2560.

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