When Ruth Donaldson lost an eye to a rare form of cancer, the mum-of-four was the first person to start making jokes about pirates and eye patches.

Now the 45-year-old, who says her sense of humour has helped her cope since being diagnosed with ocular melanoma in October 2010, is planning to run Norwich's Race for Life in a pink pirate costume and eyepatch.

Mrs Donaldson, from Surlingham, will be accompanied by her very own swashbuckling pirate crew, comprised of her daughters Lauren, 23, Keeleigh, 21, and Sorcha, 19.

She first noticed something was wrong in July 2010 when she started losing the top part of her visual field while she was working as a students' union manager and sessional lecturer. She went to an optician, who referred her to the Norfolk and Norwich University Hospital. Eight weeks later she had an eye scan, was told the devastating news and referred to Barts Hospital in Londont.

Mrs Donaldson, who also has a son, Cullen, 25, said: 'The whole family lives within a few miles of each other so we are all very close. They couldn't believe how well I was taking it because I kept making quips about pirates and eye patches. In fact I was actually in shock, but I was being positive for them – it was my way of coping.

'You hear the word cancer and it sounds like a death sentence. My dad had died in 2009 of oesophageal cancer, and his bravery was an inspiration to me. I decided I had to adopt my dad's attitude and stand up to cancer. I said to Kenny, my husband: 'It can have my eye, but it can't have me'.'

Mrs Donaldson was given the option of having a radiation disc fitted to treat the cancer in her eye – a procedure that would also leave her blind in one eye. Or she could have her eye completely removed, which she chose because she felt this was her best chance.

She has adjusted well to life with a prosthetic eye, can drive again and wants to return to work.

Now she is urging others to join her at the Norfolk Showground on the weekend of May 19 and 20, in either the 10k event on Saturday morning, or the 5k events on Saturday afternoon and Sunday morning.

To join Norfolk versus cancer, enter Race for Life 5k or 10k at www.raceforlife.org or call 0871 641 1111.

Do you have a story about why you are taking part in Norwich's Race for Life? Contact health correspondent Kim Briscoe on 01603 772419 or email kim.briscoe@archant.co.uk