Exercise may improve the outlook for prostate cancer patients by affecting blood vessels in their tumours, a study suggests.
Researchers found that men who walked at a fast pace before being diagnosed with the disease had tumours containing larger and more regularly shaped blood vessels.
Better-formed tumour blood vessels may in turn inhibit cancer aggressiveness and promote better responses to treatments, the scientists believe.
Physically active men with prostate cancer have a lower risk of recurrence and death from the disease than those living sedentary lives, but until now the reason has remained a mystery.
The study looked at 572 prostate cancer patients taking part in a US lifestyle and health investigation called the Health Professionals Follow-up Study.
Men with the fastest walking pace prior to diagnosis had eight per cent more regularly shaped tumour blood vessels than the slowest walkers.
“Prior research has shown that men with prostate tumours containing more regularly shaped blood vessels have a more favourable prognosis compared with men with prostate tumours containing mostly irregularly shaped blood vessels,” said lead scientist Dr Erin Van Blarigan, from the University of California at San Francisco.
Activity and walking pace were assessed every two years as part of the study, starting in 1986.
In a summary of their work the researchers concluded: “Brisk walking may be associated with more regularly shaped vessels in prostate tumours. Normalisation of tumour vasculature may in turn inhibit tumour aggressiveness and improve response to anticancer therapies.
“Future studies should investigate whether increasing brisk walking after diagnosis is associated with favourable changes in tumour vasculature.”