Breast cancer survivors face excess risk for second primary cancer in SEER analysis

  • Wei JL & al.
  • Int J Clin Oncol
  • 19 Mar 2019

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • Breast cancer survivors may face elevated risk for second primary malignancy (SPM), which is associated with poorer prognosis and may be driven by chemotherapy exposure.

Why this matters

  • Findings suggest the need for more screening for SPM among breast cancer survivors.

Study design

  • Retrospective cohort of 442,234 stage I-III breast cancer survivors (2000-20014).
  • Analysis compared breast cancer survivors with the general population through Standardized Incidence Rates (SIRs).
  • Funding: Source not disclosed.

Key findings

  • The overall incidence of SPM for all sites was 15% greater in breast cancer survivors than in the general population (SIR, 1.15; 95% CI, 1.14-1.16).
    • The most common SPMs were breast (33.4%), digestive system (16.9%), lung and bronchus (13.4%), genital system (10.4%), lymphatic and hematopoietic system (7.6%), urinary system (5.1%), and thyroid (3.3%).
  • Developing SPM (vs breast cancer with no SPM) was associated with worse breast cancer-specific survival and worse OS (both P<.001>
  • Chemotherapy exposure was associated with higher incidences of SPM for all sites except lymphoma (SIR, 0.80; 95% CI 0.72-0.88), myeloma (SIR, 0.85; 95% CI 0.71-1.01), and chronic lymphocytic leukemia (SIR, 0.57; 95% CI 0.43-0.74).

Limitations

  • Retrospective observational design.
  • Lack of detail on chemotherapy type.