Removing a malignant tumor from a cancer is not enough to prevent its spread (metastasis) to other organs. Researchers at Tel Aviv University recommend treatment to stimulate the immune system to minimize physiological stress that can prevent metastases and save cancer patients’ lives.

In a comprehensive study, the researchers – Prof. Shamgar Ben-Eliyahu from the School of Psychological Sciences and Sagol School of Neuroscience and Prof. Oded Zmora from Shamir (Assaf Harofeh) Medical Center in Tzrifin – found that the time period of a surgery for tumor removal is critical for metastases development. The article just published in the prestigious journal Nature is entitled: “Harnessing cancer immunotherapy during the unexploited immediate perioperative period,”

Immunotherapeutic therapy is a medical treatment that activates the immune system. One such treatment, for example, involves the injection of substances with similar receptors to those of viruses and bacteria into the patient’s body. The immune system recognizes them as a threat and activates itself, thus it can prevent a metastatic disease.

“Surgery for the removal of the primary tumor is a mainstay in cancer treatment, however the risk of developing metastases after surgery is estimated at 10% among breast cancer patients, at 20% to 40% among colorectal cancer patients and at 80% among pancreas cancer patients,” Ben-Eliyahu explained.

When the body is under physiological stress such as a surgery, or even psychological stress, groups of hormones called prostaglandin and catecholamine are being produced in large quantities, he continued. “These hormones suppress the immune system cells’ activity, and thus indirectly increase the development of metastases. These hormones also help tumor cells left after the surgery to develop into life-threatening metastases, so exposure to those hormones cause tumor tissues to become more aggressive and metastatic.”

Although surgery is usually successful in completely removing
the primary tumor, the authors wrote, most patients continue
to harbor minimal residual disease in the form of dormant or active micro-metastases and/or scattered single tumor cells in the circulation and/or the lymphatic system. In clinical trials, improvements in disease-free survival and/or overall survival have been observed with interventions restricted to the immediate period after surgery, thus suggesting that perioperative factors have substantial effects on the progression of metastases.

Such intervention to reduce physiological stress and activate the immune system in the critical period before and after the surgery can prevent development of metastases, which would otherwise be discovered months or years later, he stressed.

Ben-Eliyahu’s research contradicts the assumption – widespread in the medical community – that it is not recommended to give cancer patients immunotherapeutic treatment in the month before and after the surgery, just as oncologists recommend postponing chemotherapy and radiotherapy for a month.