Background: Several lines of evidence suggest that cytokines released as a result of wound healing might reactivate dormant breast cancer metastases. To test this, we examined if accidental trauma or surgery, unrelated to the original cancer, might stimulate the growth of dormant micrometastases and be related to an increase in the recurrence rate in the period after the event.
Methods: To test this hypothesis, we used data from the ATAC [Arimidex (anastrozole), tamoxifen alone or in combination] trial and coded the data for women who have experienced trauma or surgical procedures unrelated to the cancer. For the initial analysis, we considered recurrences occurring 2-24 months after the traumatic event and also between 2 and 12 months after trauma. In a secondary analysis, we also looked at recurrences in the first 2 months after event.
Results: The hazard ratio (HR) for recurrence 2-24 months after event was 0.96 [confidence interval (CI) 0.86-1.07, P = 0.48]; for 2-12 months, it was 0.96 (CI 0.82-1.11, P = 0.58) and for 0-2 months, the HR was 0.87 (CI 0.54-1.38 P = 0.87).
Conclusion: Trauma was not associated with an increased rate of breast cancer recurrence in the 24-month window after the event in this large study.