Breast cancers more likely to spread after surgery finds study

By Dr. Ananya Mandal, MDApr 12 2018

Breast cancer patients are more likely to experience a return and spread of their cancer within 18 months after a mastectomy or removal of the breast tumour along with healthy breast tissues. The reason for this or this association has been hitherto unexplained. According to a new study from MIT and the Whitehead Institute, the process of healing of the surgical scar after surgery is the cause for spread of the cancer.

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Normally the body’s immune system prevents the spread of the cancer from the breast to other tissues in the body. When the healing from the scar is ongoing after a surgery, the immune system is too busy to stop the spread of the cancer cells to other parts of the body. This means that the cancer cells are transported to distant sites in the body and the cancer thus progresses. This study appeared in the latest issue of the journal Science Translational Medicine this Wednesday.

According to senior author Robert Weinberg, who is a biologist at the Massachusetts Institute of Technology, it is not the surgery itself that is leading to this phenomenon but the “post-surgical wound response.” This wound response provokes the already disseminated cells to grown and become distant tumours called metastases.

Weinberg explains that when a surgical scar is healing, the immune system works overtime to send in cells that promote repair, prevent infections and promote blood vessel growth. These mechanisms are also seen when a cancer is growing. As the immune system is busy repairing the surgical wound, he said, the cancer cells fuelled by the very same immune system go unchecked to other parts of the body where they act as seeds for new and dangerous tumours. These are called secondary tumours and are far more dangerous that the primary ones in the breast says Weinberg. For example when the tumours have spread to the brain, lungs or liver, they are more likely to become life threatening sooner than when they are confined to the breast.

Researchers explain that it was believed earlier that the surgery was causing the spread of the cancer cells to other parts of the body due to handling. But Weinberg explains that along with the tumour a substantial amount of healthy breast tissues are also removed. So it is not possible for the surgery alone to be spreading the cancer. Jordan Krall, the first author of the paper and a former postdoc in the lab of Weinberg says that this is the first evidence of the phenomenon that was happening after mastectomies.

Taking anti-inflammatory drugs may be one of the solutions suggest the authors. The team of researchers looked at the phenomenon in mice and found that if the patient was given anti-inflammatory drugs such as Meloxicam, the immune system continued to exert its control and prevent the spread of the cancer to other parts of the body. More studies are necessary to see if these drugs are actually successful to a significant extent, but as of now this is an exciting find say researchers. Earlier smaller studies have shown that anti-inflammatory drugs like Ketorolac after mastectomy could prevent spread of the cancer. More research on this is necessary to extrapolate the results in humans say the authors of the study.