April 11 (UPI) -- The wound healing process that follows breast cancer treatment surgeries may trigger a spread of the disease in the following months, researchers said Wednesday.
The immune system stops restraining cancer cells that have strayed away from the original tumor site as it works to heal the surgical scar, allowing cancer cells to grow into new tumors within the first 18 months following a lumpectomy or mastectomy, according to a study published in Science Translational Medicine.
"The systemic inflammatory response induced after surgery promotes the emergence of tumors whose growth was otherwise restricted by a tumor-specific T cell response," the study's abstract states.
Massachusetts Institute of Technology biologist Robert Weinberg, the paper's senior author, said the cause for the spread is not the actual surgery, but the post-surgical wound response.
"It is provoking already disseminated cells to begin to grow into clinically detectable metastases," Weinberg said.
According to the study, days of anti-inflammatory therapy prevented the spread in mice by keeping the immune brake engaged.
"Perioperative anti-inflammatory treatment markedly reduces tumor outgrowth in this model, suggesting that similar approaches might substantially reduce early metastatic recurrence in breast cancer patients," the study states.
Hanna Dillekas, a researcher at Haukeland University Hospital in Norway, said the study in mice accurately reflects the process in the human body.
"The pieces fit really well together -- what we see in humans and what they have demonstrated in mice," Dillekas said.
A small, separate study showed breast cancer patients who were treated with the anti-inflammatory drug ketorolac in the days following surgery were five times less likely to have the cancer spread than those who didn't receive the medication.
Surgeons tend to avoid administering anti-inflammatory drugs during and after surgery because it can lead to bleeding problems, but as modern advances allow such problems to be controlled researchers have begun testing drugs such as aspirin to decrease the likelihood of cancer recurrence after surgery.