Second primary breast cancers following an initial diagnosis of cancer in one breast: a methodological issue
2008

Methodological Issues in Second Primary Breast Cancers

Sample size: 13269 publication Evidence: moderate

Author Information

Author(s): Robinson D

Primary Institution: King's College London

Hypothesis

How does the removal of an organ affect the risk of second primary cancers?

Conclusion

Failing to account for mastectomies leads to an underestimation of the incidence ratios for ipsilateral breast cancers.

Supporting Evidence

  • Failure to correct for mastectomies leads to underestimation of standardized incidence ratios for ipsilateral tumors.
  • Expected numbers of subsequent ipsilateral and contralateral breast cancers are calculated differently based on mastectomy status.
  • An example shows that without correction, the SIR for ipsilateral breast cancer is lower than for contralateral tumors.

Takeaway

If a woman has breast cancer and has one breast removed, we need to be careful when counting how many times she might get cancer again in that breast.

Methodology

The study compares observed numbers of subsequent cancers with expected numbers based on general population incidence rates, adjusting for mastectomies.

Potential Biases

Potential bias in estimating cancer risk due to not correcting for mastectomies.

Limitations

The analysis may not account for all factors influencing cancer risk.

Participant Demographics

Women diagnosed with breast carcinoma in situ.

Digital Object Identifier (DOI)

10.1038/sj.bjc.6604718

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