Joanna Crosier before the surgery

Here Joanna Crosier, 32, an IT consultant, from Swansea, explains how she discovered she had skin cancer.

"I was very aware of being careful in the sun. I had lived in Australia from the age of nine to 18.

It's a big thing over there. They are a lot more aware than we are over here. I was not one of those people that sunbathed a lot.

I did sport outdoors but usually wore sunscreen. I had got burned from time to time. What happened certainly came as quite a shock.

A couple of years ago I noticed something I thought was just a spot on my forehead. But it kind of changed over time. It did not go away quickly like a normal spot.

It changed into a scab, like a chicken pox spot that had been knocked off. It was pinkish. I didn't think anything of it. I did not get it checked by GP.

Absolute shock

It was quite small at first but over time started getting bigger. If I went out in the sea or sun it would flare up a bit and go red.

It was quite unsightly. I was covering it up with make-up. People started to notice and ask 'what's on your forehead?'. That's when I decided to get it checked.

I went to see my GP. They did not tell me what they thought it was. They just said I should probably go and see a specialist at hospital.

The specialist told me it was skin cancer. She suspected it was a basal cell carcinoma. I needed a biopsy.

Joanna has been left with very little scarring following surgery

I was absolutely shocked. It was the words 'skin cancer'. One of my father's best friends had died of skin cancer.

I did initially feel quite frightened but they gave me an information sheet and I looked it up on the internet.

It is the most common form of skin cancer and is not known to be life-threatening. It's usually treatable by removal and you don't need chemotherapy.

I saw another specialist who sent me to see plastic surgeon to get it removed. It was all very quick after that.

All the specialists said they were really surprised someone my age had got this. It normally happens to older people. The surgeon who removed it had only seen two or three cases in people of my age.

Now I still go in the sun and I've actually been on a diving holiday since. But I use the highest factor sunscreen you can get.

I would not lie out in the sun, I cover up and wear a hat. I would say to others make sure you wear lots of sunscreen and don't let yourself get burned.

I'm ok now and I'm lucky, thanks to the surgeon, that I don't have a bigger scar.

This month I'm running the London marathon for Cancer Research.