KAREN Clark is only too well aware of the importance of cancer research.

She has been successfully treated for breast cancer and is now determined to live life to the full.

The 51-year old and two teams of supporters – the Dirty Birds and Bosom Buddies, will taking part in the Pretty Muddy obstacle course at Stanmer Park tomorrow.

Karen, from Saltdean, only had her cancer picked up after her health was closely monitored in Europe.

Her mum, Audrey Woodward, survived breast cancer nearly 40 years ago, which meant Karen was at a higher risk of developing the disease.

While living in Belgium, Karen underwent annual mammograms.

She returned to Britain in 2013 and moved to Saltdean.

She was approaching her 50th birthday and waited for an invitation for her first mammogram. But it didn’t arrive.

Although she was well and there was no sign of anything untoward, Karen went to her GP, explained the family history and was referred for a mammogram.

The new mammogram didn’t show any problem but Karen had taken the results of her previous mammograms with her.

After comparing the two, doctors called Karen back to explain they had noticed a significant difference between the two.

Further investigation revealed two small grade three tumours hidden deep in her breast tissue, known as ductal carcinoma in situ (DCIS).

Karen, a legal secretary, said: “The frightening thing was that without those old records, they wouldn’t have spotted any problem. I feel really lucky.

“In 16 months those tumours had developed and I could have gone several years without them being discovered.

“They were so ‘hidden’ that when they operated, they had to put a wire in so the surgeon could find the tumours.

“That’s why I want to make people aware that you don’t always have a lump with breast cancer.”

Karen, now 51, underwent a lumpectomy, chemotherapy, which finished in January, four weeks of radiotherapy and is now taking Tamoxifen and Herceptin.

She said: “I’m slowly regaining my stamina so decided to take on the challenge of the Pretty Muddy event at Brighton.

“There are two teams of friends taking part – I’m in the Bosom Buddies and there is another one called the Dirty Birds. We’ll all have matching t-shirts and I’m going to spray my hair pink.

This weekend also features 5km and 10km Race for Life events today and organisers are hopeful hundreds of thousands of pounds will be raised for the charity.

One of those taking part will be Loti Jackson, 29, from Lindfield.

She has herself a challenge of running 300 miles for the charity, culminating in the final mile at today’s Race for Life.

She has also had first-hand experience of the disease after being diagnosed with skin cancer in 2012.

She became aware of safe sun messages when she was working in public relations and one of her clients was a fake tanning company.

She had a couple of moles she was concerned about and eventually got them checked out.

One turned out to be cancerous and Loti needed an operation to remove it, leaving her with a tiny scar.

Loti now raises money for the charity and helps spread the message about the dangers of using sun beds.

In an interview she said: “I’m also lucky I was working on a sun awareness campaign.

"I had used sunbeds a couple of times in the past but it was a very long time ago before I knew how dangerous they are.

“I also knew moles could change into skin cancer but I wasn’t aware of the severity of the situation until I worked on that campaign.

“As soon as I was told I had skin cancer I vowed to tell my story wherever I could to make people aware of the signs and symptoms and urge them to get them checked out. I’ve even fallen out with friends who still use sunbeds – I don’t understand why people would take the risk – it’s not worth it. I wouldn’t wish what I went through on my worst enemy.

“I’m now an expert at fake tans and I get a much better colour than I would if I lay out in the sun for a week.”

To support Loti, visit justgiving.com/fundraising/lotis300miles.

Cancer Research UK spokesperson for Sussex Lynn Daly said: “ Every day, around 130 people are diagnosed with cancer in the South East.

“That’s why we need women of all shapes and sizes to pull on their leggings, lace up their trainers and show their support.

“Race for Life events are not competitive. They are not about being fit or fast. Taking part is about being part of a collective force of powerful women - of all ages - leading the charge against cancer.

“Last year, 18,000 women took part in Race for Life in the South East and raised a fantastic £1.1m.”

“There are different events to choose from - with 5k, 10k and Pretty Muddy – so there’s something to suit everyone. We’re asking women to pick the event that puts fire in their bellies and sign up as soon as possible.”

Money raised through Race for Life allows Cancer Research UK’s doctors, nurses and scientists to advance research which is helping to save the lives of men, women and children across the South East.

Ms Daly said: “One in two people in the UK will be diagnosed with cancer at some stage in their lives. Thanks to advances in research more people are surviving than ever before, but there’s still more work to be done. The fight is on and we’re rallying women across Kent to join us at the starting line.

“We know women in Sussex are ready to limber up, stride out and take on the challenge so we urge them to sign up now and help bring us one step closer to the day when all cancers are cured.”