Chronic stress helps cancer spread through the body, according to Australian-led research on mice.
It builds lymphatic "highways" that provide cancer cells with a faster and more efficient way to spread.
But the mice study found the effect may be blocked through the use of a common blood pressure drug, now being trialled in cancer patients to see if it can reduce the risk of the tumour spreading.
Previous work has linked stress to poor cancer survival in patients and with advanced stages of cancer progression in animals.
The lymphatic system helps carry immune cells through the body to fight illness, but it also plays a role in transporting cancer cells through the body.
Monash University's Dr Caroline Le and Dr Erica Sloan said their study, published in Nature Communications, indicates that chronic stress can be extremely detrimental to cancer patients.
High stress levels increase lymphatic activity, making the patient's own lymphatic system a more efficient and networked distributor of cancer cells.
Dr Le said the findings "suggest that blocking the effects of stress to prevent cancer spread through lymphatic routes may provide a way to improve outcomes for patients with cancer".
The researchers collaborated with clinicians at Melbourne's Peter MacCallum Cancer Centre and Milan's European Institute of Oncology.
The study showed that blocking neural signalling in patients, with drugs that are readily available and currently used to treat hypertension, regulates the function of lymphatic vessels to prevent the spread of cancer cells.
