High FIT results in CRC patients and 1-year mortality outcomes
High fecal immunochemical test (FIT) results in colorectal cancer (CRC) patients are strongly associated with significantly worse 1-year mortality outcomes, according to the study. Below is a detailed breakdown of the key findings related to high FIT results and 1-year mortality outcomes:
1. Mortality Rates in High-FIT Group (FIT ≥ 10 µg Hb/g) vs Low-FIT Group (FIT < 10 µg Hb/g):
All-cause mortality:
Elevated FIT group: 8.3% mortality within 1 year.
Lower FIT group: 2.8% mortality within 1 year.
This represents a nearly threefold increase in 1-year mortality in the elevated FIT group compared to the lower FIT group.
All-cause mortality rate:
Elevated FIT group: 87.21 deaths per 1000 person-years.
Lower FIT group: 28.41 deaths per 1000 person-years.
Non-CRC mortality:
Elevated FIT group: 92.4% of all deaths in this group were non-CRC related.
Non-CRC mortality rate: 74.79 per 1000 person-years in the elevated FIT group vs 27.72 per 1000 person-years in the lower FIT group.
CRC-specific mortality: While mortality due to CRC increased with higher FIT levels, the majority of excess deaths in the elevated FIT group were attributed to non-CRC causes.
2. Adjusted Risk of Mortality (High FIT vs Low FIT):
- After adjusting for factors such as age, sex, and year, patients with elevated FIT results (≥ 10 µg Hb/g) had:
- Nearly double the risk of all-cause mortality (adjusted hazard ratio [aHR]: 1.96).
- 1.7 times higher risk of non-CRC mortality (aHR: 1.70).
- These findings indicate that high FIT results are predictive of a systemic vulnerability to death beyond CRC alone.
3. Standardized Mortality Ratios (SMRs):
- For patients with FIT ≥ 10 µg Hb/g:
- SMR for all-cause mortality: 2.12 (indicating a more than twofold excess risk compared to the general population).
- SMR for non-CRC mortality: 1.86 (indicating significantly higher risk of non-CRC-related deaths).
4. Demographic and Subgroup Insights:
- Age: Younger symptomatic patients with elevated FIT results showed particularly pronounced relative increases in mortality risk, highlighting that high FIT is worrisome even in traditionally lower-risk age groups.
- Sex differences: Women with elevated FIT results demonstrated a greater relative risk of mortality compared to men, suggesting potential biological or diagnostic differences.
5. Possible Mechanisms for Elevated Mortality in High-FIT Patients:
- Elevated FIT results may signal underlying systemic health issues beyond CRC, such as:
- Cardiovascular disease.
- Other malignancies.
- Inflammatory conditions or other comorbidities.
- These conditions may contribute to the significantly higher non-CRC mortality observed in the elevated FIT group.
6. Clinical and Public Health Implications:
- Red flag for overall mortality risk: A positive FIT result in symptomatic patients should not be viewed solely as a marker of CRC risk but as an indicator of increased overall mortality risk.
- Comprehensive evaluation required: High-FIT patients should undergo urgent diagnostic workup and closer surveillance for both CRC and non-CRC conditions.
- Prognostic utility: FIT may serve as a biomarker of systemic disease burden, providing prognostic insights beyond its traditional role in CRC detection.
7. Limitations of the Study:
- The study was retrospective and conducted within a single regional healthcare system (Nottingham University Hospitals), which may limit generalizability to other populations. However, the large cohort size (49,889 adults) strengthens the robustness of the findings.
Summary:
High FIT results (≥ 10 µg Hb/g) in CRC patients are associated with significantly worse 1-year mortality outcomes, driven by both CRC-specific and non-CRC-related causes. The findings underscore the importance of interpreting elevated FIT results as a broad clinical red flag requiring comprehensive evaluation and management, not only for CRC but also for other underlying health risks.
