Antibiotics may not be safe during immunotherapy treatment.
Cancer patients who took antibiotics during immunotherapy treatment lived about half as long as those who avoided the drugs, a new UK study of more than 300 people has found.
Researchers said the new work underscores the importance of taking antibiotics only when medically necessary, and shows general practitioners should coordinate closely with oncologists when treating patients on cutting edge treatments.
“Clearly, we need to treat serious or life threatening infections with antibiotics,” said a co-author, Nadina Tinsley of the Christie NHS Foundation, where the research was conducted. “The challenge is striking the right balance.” The research was presented at the American Society of Clinical Oncology in Chicago, the world’s largest annual cancer conference.
Researchers studied 303 patients who underwent cancer treatment with immunotherapy called checkpoint inhibitors. These drugs work by activating the body’s immune system against cancer cells.
However, researchers believe bacteria in the digestive system play a role in activating the body’s immune system, by encouraging activity in the toxin-rich gut. There, the body “recruits” t-cells to keep harmful bacteria at bay. Researchers believe antibiotics “clear the gut” of those bacteria, which take weeks to recover, and may cause t-cells to be less active.
“There are lots of toxins in our gut,” said Tinsley, “and they will recruit the immune system to be active, and there will be more white blood cells.” Without those bacteria, the immune system may be less active overall, diminishing the effects of immunotherapies. Infections are a common complication for cancer patients.
Researchers looked at patients between January 2015 to March 2017 at the Christie NHS Foundation Trust, and studied 303 patients with melanoma, non-small cell lung cancer and renal cancer. About one-third of all the patients received antibiotics either two weeks before or six weeks into their cancer therapy. The study is retrospective.
|Read on: Antibiotics greatly reduce effectiveness of immunotherapy for cancer – study | Society | The Guardian|