Increased Antimicrobial Use Precedes B-Cell Cancer Diagnosis by Up to a Decade, Danish Study Reveals

Key Insights

• A comprehensive Danish study of over 48,000 patients reveals significantly elevated antimicrobial use in multiple B-cell cancer types, particularly CLL, MM, MZL, and LPL, up to 10 years before diagnosis.
• Researchers identified three distinct patterns of infection risk, with some cancers showing gradual immune system deterioration over a decade, while others like follicular lymphoma displayed normal antimicrobial use until just before diagnosis.
• The study found penicillins and macrolides were the most commonly prescribed antimicrobials, with chronic lymphocytic leukemia patients showing increased use of both macrolides and antivirals for over a decade pre-diagnosis.

A large-scale Danish study has uncovered a significant correlation between increased antimicrobial use and subsequent B-cell cancer diagnoses, with some patients showing elevated prescription patterns up to a decade before their cancer diagnosis. The research, published in the British Journal of Cancer, analyzed data from over 48,000 patients across two cohorts, providing new insights into the relationship between infection patterns and B-cell malignancies.

Distinct Patterns of Antimicrobial Use Across Cancer Types

The study revealed three distinct patterns of antimicrobial usage among different B-cell cancers. Patients later diagnosed with chronic lymphocytic leukemia (CLL), multiple myeloma (MM), marginal zone lymphoma (MZL), and lymphoplasmacytic lymphoma (LPL) demonstrated significantly increased antimicrobial use for at least ten years before their diagnosis, compared to control groups.

In contrast, patients who developed follicular lymphoma (FL) showed normal antimicrobial usage patterns until the year preceding their diagnosis. Those with diffuse large B-cell lymphoma (DLBCL) exhibited a modest 10% increased risk of infections for up to 15 years before diagnosis, followed by a sharp increase in antimicrobial use during the final year.

Medication Patterns and Clinical Implications

Penicillins emerged as the most frequently prescribed antimicrobials, followed by macrolides. Notably, CLL patients showed elevated prescription rates for both macrolides and antivirals extending beyond a decade before their diagnosis. DLBCL patients exhibited similar patterns.

Study Methodology and Population

The research encompassed two distinct cohorts:

• A population cohort of 30,389 participants, identified through nationwide population and cancer registers
• A clinical cohort of 18,560 participants, drawn from nationwide clinical quality registers
• A control group of 435,846 individuals

Immune System Implications

The varying patterns of infection risk provide important insights into the relationship between immune system function and B-cell malignancies. The gradual increase in infection risk observed in CLL, LPL, MM, and MZL patients suggests progressive immune system deterioration, potentially linked to the developing malignancy.

Research Limitations

The study authors acknowledge several important caveats:

• Some B-cell malignancy symptoms may have been initially misdiagnosed as routine infections
• Elevated C-reactive protein levels in newly diagnosed lymphoma and MM patients could lead to antimicrobial prescriptions without true infection
• The analysis did not account for patient comorbidities

These findings suggest that patterns of antimicrobial use could serve as an early indicator of developing B-cell malignancies, potentially enabling earlier detection and intervention in high-risk patients.