Introduction

Tumor cells are known to express a unique isoform of the glycolytic enzyme pyruvate kinase, called pyruvate kinase isoenzyme type M2 (M2-PK). This study aims to evaluate the effectiveness of the M2-PK antigen rapid test, compared to the conventional fecal occult blood test (FOBT), for diagnosing colorectal neoplasms, including colorectal cancer (CRC) and advanced adenoma.

Aims & Methods

Participants screened by endoscopy in three South Korean referral hospitals (December 2020 - June 2023) were classified into three groups: CRC, advanced adenoma, and normal control. This study is parallel-design, [CYY1] comparing the fecal M2-PK antigen test (Schebo® M2-PK Quick^TM test, Biotech AG) to the FOBT for detecting CRC and advanced adenoma, using the normal control group as a reference. The study aimed to demonstrate the non-inferiority of the M2-PK antigen test for detecting CRC (non-inferiority margin: -15%) and its superiority in advanced adenoma group compared to FOBT.

Results

A total of 270 patients [CYY1] were analyzed. The sensitivity of CRC by M2-PK test was 0.88 and 0.75 in FOBT with margin difference of 0.13 [95% CI (0.02, 0.25), p=0.01]. In advanced adenoma group, sensitivity was 0.43 and 0.17, respectively. The M2-PK test showed a PPV of 0.73 (vs. 0.96 for FOBT) and an NPV of 0.82 (vs. 0.76 for FOBT) in the CRC group. For advanced adenoma, PPV and NPV were 0.51 (vs. 0.82 for FOBT) and 0.53 (vs. 0.55 for FOBT), respectively. The clinical specificity for colorectal neoplasms was 0.62 for the M2-PK test and 0.97 for FOBT.

Conclusion

The M2-PK antigen rapid test is non-inferior to FOBT for detecting CRC. While its sensitivity for advanced adenoma detection is higher than FOBT, further studies are needed to fully evaluate its role.

Introduction

Recently, some guidelines recommend conducting colorectal cancer (CRC) screening at ages younger than 50 years. However, there are few data on the preventive effect of colonoscopy at ages 40-49 years at the population level.

Aims & Methods

In this study, the risk of CRC according to the presence or absence of CSP in their 40s was evaluated in a retrospective cohort design using a nationwide database. Using the Korean National Health Insurance System data between 2004 and 2006, we constructed 1:5 colonoscopy cohort (CsC) and non-colonoscopy cohort (NCsC) at ages 40-49 years and followed through 2014. A total of 2,940,792 subjects were enrolled and CRC risk was evaluated after propensity score matching between CsC and NCsC based on age, sex, smoking, metabolic syndrome (MetS) and potentially relevant variables related CRC risk.

Results

Among 490,132 CsC subjects and 2,450,660 NCsC subjects at baseline periods in 40-49 ages, 689 (0.14%) and 9,440 (0.39%) cases of CRC were found during 10 years follow up period, respectively. According to age group, cumulative CRC incidences in early 40’s (40-44) were 0.10% in CsC and 0.25% in NCsC respectively. For late 40’s (45-49), those were 0.17% in CsC group and 0.49% in NCsC group, respectively. Compared with NCsC, the adjusted hazard ratios (aHRs) for CRC development in CsC group were 0.42 (men, 95% CI: 0.35-0.50) and 0.37 (women, 95% CI: 0.30-0.47) in early 40’s and 0.33 (men, 95% CI: 0.29-0.37) and 0.39 (women, 95% CI: 0.33-0.45) in late 40’s.

Conclusion

Overall, colonoscopy in their 40s significantly lowered the risk of colorectal cancer development by 58-67%. This cancer prevention effect of colonoscopy was different according to age and gender, and it was most effective in men in their late 40s, suggesting the rationales for optimization of age and gender to start colonoscopy.

Disclosure

Korea Health Technology R&D Project through the Korea Health Industry Development Institute, National Research Foundation of Korea grant and the National R&D Program for Cancer Control through the National Cancer Center funded by the Korea Ministry of Health & Welfare, Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education.