Mortality by laterality of the primary tumour among 55,000 breast cancer patients from the Swedish Cancer Registry
1990

Breast Cancer Mortality and Radiotherapy Effects

Sample size: 54617 publication Evidence: moderate

Author Information

Author(s): L.E. Rutqvist, H. Johansson

Primary Institution: Oncologic Centre, Radiumhemmet, Karolinska Hospital

Hypothesis

Radiotherapy for breast cancer can cause myocardial infarction.

Conclusion

Patients with left-sided breast cancer have a higher mortality due to myocardial infarction compared to those with right-sided tumours.

Supporting Evidence

  • Patients with left-sided tumours had a higher mortality due to myocardial infarction than those with right-sided tumours.
  • The relative risk for myocardial infarction was 1.09 for left-sided tumours compared to right-sided.
  • Previous studies suggested that radiotherapy can lead to increased cardiovascular deaths.

Takeaway

This study found that women with breast cancer on the left side are more likely to die from heart problems caused by radiation treatment than those with cancer on the right side.

Methodology

The study analyzed cause-specific mortality by laterality of the primary tumour among breast cancer patients reported to the Swedish Cancer Registry from 1970-1985.

Potential Biases

The study may underestimate the risk associated with radiation since not all patients received radiotherapy.

Limitations

The study could not distinguish between patients with bilateral breast cancer and those with other multiple tumours due to data integrity issues.

Participant Demographics

The study included 54,617 breast cancer patients from the Swedish Cancer Registry.

Statistical Information

P-Value

0.01

Confidence Interval

1.02-1.17

Statistical Significance

p<0.01

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