Cancer experts are also discussing studies that show that weight loss programs can change the biological make-up of breast tissue cells - helping survivors reduce their cancer risk.
Researchers at the Concord Cancer Centre have analysed data from 110 breast cancer survivors and will present their findings at the Clinical Oncology Society of Australia Annual Scientific Meeting.
The study found that 66% of breast cancer survivors were overweight and obese, and only one in three were meeting physical activity guidelines.
Dr Melinda Irwin, Professor of Epidemiology from Yale University, is an international expert in weight loss and cancer survival. She says that emerging research is showing the importance of maintaining a healthy weight after cancer treatment.
"My research has suggested that losing weight can actually change biological markers in serum and breast tissue of women with breast cancer and may reduce the risk of recurrence," says Dr Irwin.
"For instance, our study found that C-reactive protein, a marker of chronic inflammation and associated with breast cancer mortality, is reduced by 30% when women reduce their weight by around 5%.
"We also see the insulin pathways within the breast tissue change in ways that we know are linked to lower cancer risk and mortality."
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