Differential Biopsy Patterns Influence Associations between Multivitamin Use and Prostate Cancer Risk in the Selenium...

Area of Science:

• Oncology
• Epidemiology
• Preventive Medicine

Background:

• Multivitamin (MVI) use is prevalent, yet its impact on prostate cancer risk remains debated.
• Conflicting evidence exists regarding whether MVI use influences prostate cancer incidence.

Purpose of the Study:

• To evaluate the association between multivitamin (MVI) use and prostate cancer risk using data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT).
• To investigate potential biases in prostate cancer risk assessment due to differential screening and biopsy patterns related to MVI use.

Main Methods:

• Utilized Cox proportional hazards models to assess MVI use associations with total, low-, and high-grade prostate cancer risk.
• Employed longitudinal data to analyze screening and biopsy patterns.
• Developed methods to estimate prostate cancer probability for men with positive screening but no biopsy to account for differential biopsy acceptance.

Main Results:

• Initial analyses of observed biopsy data indicated a 19-21% increased risk of high-grade prostate cancer with current and long-term MVI use.
• Identified that MVI users were more likely to undergo earlier on-study biopsies, suggesting potential detection bias.
• After adjusting for differential biopsy patterns, the association between MVI use and prostate cancer risk was attenuated and no longer statistically significant.

Conclusions:

• Biopsy acceptance patterns in the SELECT trial varied by MVI use.
• Observed associations between MVI use and prostate cancer risk may be biased by differential biopsy ascertainment.
• Analytical adjustments using detailed screening and biopsy data can mitigate bias in risk factor associations.