The 40-year-old podcaster, known as Bowel Babe online, shared a photo on Instagram of herself with her brother Benjamin and his new fiance after they spent a day at the races.
Dame Deborah, who is receiving end-of-life care at home for bowel cancer, admitted that living in “limbo land” has been very stressful but she is grateful for whatever extra time she gets.
In photos shared to her social media, the campaigner can be seen beaming while wearing a navy dress with white polka dots and a large woven hat while attending Ascot Racecourse.
She wrote: “Yesterday was really special as with a lot of effort and help I actually made it to @ascotracecourse once again.
“I honestly have to pinch myself that I’ve been well enough each day to do something like this. Another favourite I’d had in mind and a fab milestone to say ‘ain’t dead yet!'”
The presenter of the BBC podcast You, Me And The Big C thanked Ascot for helping to make the experience “seamless and achievable” for her.
She also revealed that she picked three winners in a row at the event which left her “bouncing off the ceiling”.
Dame Deborah, who continues to outlive her life expectancy diagnosis, added that amidst the activities she still finds herself “living in limbo land, not really knowing what the future holds and for how long”.
She said: “It’s a very stressful, uncertain place to be because when I was discharged from hospital over a month ago I was given days, maybe a week to live. And I felt like it.
“But as we all know life doesn’t go according to plan, so I’m just grateful for what ever extra time the powers that be have decided to grant me.
“So despite the unnerving tears, I look at the sunshine, smile, and think, wow, life is a funny thing isn’t it!! Better enjoy it!”
The campaigner, who was diagnosed with bowel cancer in 2016, has been increasing awareness for years and has raised more than £6.7 million for Cancer Research UK, Bowel Cancer UK and the Royal Marsden Cancer Charity through her Bowelbabe fund on JustGiving.
Other famous faces spotted at the annual Ascot race include TV judge Robert Rinder, who wore a black suit and top hat with a grey waistcoat and tie.
Lizzie Cundy, Lady Victoria Hervey, Terry Scott and Yuan Li were also in attendance.