Sarah was invited to take part in a breast cancer screening trial for women aged between 47 and 50.
During her mammogram, a tumour was found.
Throughout her treatment, Sarah found the endorphins released during exercise made her feel so much more positive, which was extremely important when dealing with an illness that not only affects you physically, but also mentally.
Now, firmly back on the road to recovery, Sarah and her husband are cycling 50 miles a day in preparation for Ride London, where they will be raising money for Breast Cancer Care.
The Ride London event takes place over three days from 28 to 30 July. You can find details of the BBC's live coverage of the event here, while the BBC Sport website will feature live text commentary of the Ride London 100 and 46 races and the men's elite London-Surrey Classic from 09:00 BST on Sunday.
And if you're inspired to try cycling yourself, check out our Get Inspired guide.