Effect of rehydration on guaiac-based faecal occult blood testing in colorectal cancer screening
1993

Rehydration Improves Colorectal Cancer Screening

Sample size: 12848 publication Evidence: moderate

Author Information

Author(s): G. Castiglione, M. Biagini, A. Barchielli, G. Grazzini, A. Mazzotta, P. Salvadori, L. Scillone, S. Ciattol

Primary Institution: Centro per lo Studio e la Prevenzione Oncologica

Hypothesis

Does rehydration of guaiac-based faecal occult blood tests improve their effectiveness in colorectal cancer screening?

Conclusion

Rehydrated guaiac-based tests significantly increase the detection rates of colorectal cancer and adenomas without reducing the positive predictive value.

Supporting Evidence

  • The positivity rate for rehydrated tests was significantly higher at 5% compared to 3.1% for unhydrated tests.
  • Detection rates for cancer were 0.37% for rehydrated tests versus 0.15% for unhydrated tests.
  • Detection rates for adenomas were 1.06% for rehydrated tests versus 0.72% for unhydrated tests.
  • Positive predictive values for cancer were 8.9% for rehydrated tests and 5.8% for unhydrated tests.
  • Positive predictive values for adenomas were 25.5% for rehydrated tests and 26.7% for unhydrated tests.

Takeaway

This study found that adding water to a test for blood in poop helps find more cases of cancer and polyps, which is important for catching problems early.

Methodology

The study compared the diagnostic accuracy of unhydrated and rehydrated guaiac tests in a population-based screening program.

Potential Biases

Potential selection bias due to low attendance rates, although consistent across groups.

Limitations

The study was not randomized and did not record the symptomatic status of participants.

Participant Demographics

Subjects aged 40-70, with 3,145 females and 2,774 males in the rehydrated group, and 3,131 females and 3,998 males in the unhydrated group.

Statistical Information

P-Value

P <0.001

Statistical Significance

p<0.05

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