目的

探讨定量和定性粪便免疫化学检测（FIT）技术在结直肠癌（CRC）及进展期腺瘤筛查中的应用价值。

方法

选取2023 年1 月至2024 年6 月淮南新华医院完成结肠镜检查的100例疑似CRC 患者为研究对象，所有受试者均在肠镜检查前留取粪便样本，使用定量FIT 与定性FIT进行检测，并以结肠镜＋病理诊断为金标准，比较定量FIT 与定性FIT 对CRC 及进展期腺瘤的检出率，比较不同截断值时定量FIT 与定性FIT 对CRC 和进展期腺瘤的敏感度、特异度、阳性预测值、阴性预测值。单因素分析进展性肿瘤组、息肉组、正常组患者的临床基本资料，以多因素Logistic回归分析进展性肿瘤的危险因素。

结果

结肠镜与病理检查结果显示，100 例研究对象中，确诊CRC 4 例（4.00%）、进展期腺瘤19 例（19.00%），定量FIT 检测CRC 与进展期腺瘤的检出率分别为4.00%与19.00%，定性FIT 检测CRC 与进展期腺瘤的检出率分别为2.00%与16.00%；当粪便血红蛋白截断值为20、50、100 ng/mL 时，定量FIT 诊断CRC 的敏感度由100%下降至66.67%，而定性FIT检测CRC 的敏感度为66.67%，低于定量FIT 截断值在20 ng/mL 时的敏感度。配对卡方检验的McNemar 检验结果显示，截断值为20 ng/mL 的定量FIT 检测与定性FIT 检测的一致性差异具有统计学意义（χ²=4.00，P=0.046）。截断值为50、100 ng/mL 的定量FIT 检测与定性FIT 检测一致性差异均无统计学意义（P＞0.05）。同样的血红蛋白浓度梯度，FIT 诊断进展期腺瘤的敏感度由20 ng/mL的76.00%下降至100 ng/mL 的57.14%，而定性FIT 检测进展期腺瘤的敏感度为50.00%，低于定量FIT 截断值在20 ng/mL 时的敏感度。配对卡方检验的McNemar 检验结果显示，不同截断值的定量FIT 检测与定性FIT 检测一致性差异均无统计学意义（P＞0.05）。

结论

定量FIT 对CRC 与进展期腺瘤的检出率更高，且20 ng/mL 粪便血红蛋白截断值的检测敏感度更高，其在判定CRC 时显著倾向于将更多的样本判定为阳性。

Objective

To explore the application value of quantitative and qualitative fecal immunochemical test (FIT) in screening colorectal cancer (CRC) and advanced adenoma.

Methods

A total of 100 patients with suspected CRC undergoing colonoscopy in Huainan Xinhua Hospital were enrolled as the research objects between January 2023 and June 2024.The stool samples were collected before colonoscopy for detection by quantitative and qualitative FIT.Taking colonoscopy+pathological diagnosis as the golden standard, detection rates of CRC and advanced adenoma by quantitative and qualitative FIT, as well as sensitivity, specificity, positive predictive values and negative predictive values of quantitative and qualitative FIT in the diagnosis of CRC and advanced adenoma under different cut-off values were compared.The basic clinical data of patients in progressive tumor group, polyp group and normal group were analyzed by univariate analysis, and risk factors of progressive tumor were analyzed by multivariate Logistic regression analysis.

Results

The results of colonoscopy and pathological examination showed that among the 100 patients, there were 4 cases (4.00%) with CRC and 19 cases (19.00%) with advanced adenoma.The detection rates of CRC and advanced adenoma by quantitative FIT were 4.00%and 19.00%, while which by qualitative FIT were 2.00% and 16.00%, respectively.When cut-off values of fecal hemoglobin were 20, 50 and 100 ng/mL, sensitivity of quantitative FIT in the diagnosis of CRC was decreased from 100% to 66.67%, the sensitivity of qualitative FIT for detecting CRC was 66.67%, lower than that of quantitative FIT under cut-off value of 20 ng/mL.The results of McNemar's test with paired chi-square test showed that when the cut-off value was 20 ng/mL, the difference in consistency between qualitative and quantitative FIT was statistically significant (χ²=4.00, P=0.046).When cut-off values were 50 and 100 ng/mL, the difference in consistency between qualitative and quantitative FIT was not statistically significant (P>0.05).Under the same hemoglobin concentration gradient, the sensitivity of FIT in the diagnosis of advanced adenoma was decreased from 76.00% (20 ng/mL) to 57.14% (100 ng/mL).The sensitivity of qualitative FIT for detecting advanced adenoma was 50.00%, lower than that of quantitative FIT under cut-off value of 20 ng/mL.The results of McNemar's test with paired chi-square test showed that the difference in consistency between qualitative and quantitative FIT was not statistically significant under different cut-off values (P>0.05).

Conclusion

The detection rates of CRC and advanced adenoma are higher by quantitative FIT, and detection sensitivity is higher when cut-off value of fecal hemoglobin is 20 ng/mL, it significantly tends to determine more samples as positive when judging CRC