I spent most of my teenage years using olive oil to get a tan…at 45 I was diagnosed with the same skin cancer that Fergie now has

I was lying in bed reading when my eyes were drawn to a small mole on the back of my left calf. Something was wrong, even if it wasn't big.

I had never noticed this mole before. If you looked closely, there was a black spot in it, as if a small amount of black ink had been dripped onto a brown spot.

This was ten years ago, when at age 45 I was busy embracing middle age. With more than a dozen best-selling novels to my name, I was married for the second time and had four children between the ages of 11 and 14, and two stepchildren at home. Then I went to a doctor and her diagnosis of malignant melanoma changed everything.

Last week the Duchess of York, 64, expressed her shock at being diagnosed with the same thing, and I understand how much she is reeling.

The duchess's cancerous birthmark was discovered while she was undergoing reconstructive surgery after breast cancer. But I think I might not have found mine if a friend hadn't given me CDs by a blues singer named Eva Cassidy.

I was surprised that I had never heard of this woman with the voice of an angel. I soon discovered her sad story. Eva Cassidy had a birthmark on her back removed at the age of 30. It was melanoma, but, she was told, melanoma in situ, meaning the disease had not spread.

Three years later she was in the hospital again, this time with hip pain. They discovered that her original melanoma had spread and was now in her shoulder and lungs. Eva died shortly afterwards, in 1996, at the age of 33.

I got those CDs the day I saw my birthmark. If my head hadn't been full of Eva Cassidy's story, I doubt I would have felt like there was something wrong with the birthmark on the back of my leg.

Like most of us over 50, my risk of developing skin cancer was not increased by my childhood. I grew up when sunny days were scarce in London, which meant we were unaware of the risks. On the rare occasions when the sun was strong enough to produce a tan, there was no sunscreen; I even used olive oil and an aluminum foil pad for browning.

During the summer holidays with my parents in Spain, Portugal and France, among others, little was taken. We were of the generation where children were sent out to find a friend and play in the pool for hours while the parents relaxed with a book.

After breakfast or lunch we were not allowed to go into the pool for an hour because of the possibility of 'cramps', which we were told could cause us to drown. So there we sat, my brother and I, under the full glare of the sun, without sunscreen, counting the minutes until we could dive back into the pool. By the end of the first day my fair skin had invariably turned a bright scarlet red, occasionally blistering my shoulders and back. This meant swimming for a few days in a T-shirt and then playing in the sun again. Still without sunscreen.

If only we had known that even one blistering sunburn in childhood or adolescence doubles the risk of skin cancer.

If only we had known that my uncle would eventually die of melanoma, and that one in ten people diagnosed have a close family member with the disease.

I remember the photos in the newspapers of Sarah Ferguson on a lounge chair, roasting her alabaster skin under a hot Mediterranean sun. I'm sure she knew as little as the rest of us.

I was always afraid of cancer, but skin cancer was something I never thought about.

After I found the mole on my leg, I went to my dermatologist, who examined it with a magnifying glass. Her usual light-hearted attitude changed and she became serious when she told me she was going to remove it and send it for a biopsy.

I was on the train returning from a meeting in New York when she called. “It's skin cancer,” she said. 'Malignant melanoma.'

I remained calm, but the world around me slowed down. I thought I was listening, but later realized I hadn't heard a word after she said “melanoma.” Melanoma is the rarest skin cancer and the deadliest. Melanocytes are the cells in our skin that make a brown pigment called melanin. These are the cells that are activated when we sunbathe and tan. Melanoma occurs when those melanocytes grow out of control.

Despite accounting for only one percent of skin cancer cases, melanoma causes 80% of skin cancer deaths. And the incidence is increasing: it is the fastest growing cancer in the world. Mortality rates depend on the stage at which the disease is detected – early enough the cure rate can be 100 percent – ​​and there are now immunotherapy treatments that can dramatically change the outcome for people diagnosed with stage IV, which was once always fatal.

But it is still a deadly cancer that requires real vigilance. My own melanoma was caught early, but not quite early enough. It had mitosis, meaning it had already begun to divide and multiply and had already spread to the deep layers of the skin. It meant not only having a chicken breast-sized piece of my calf removed under general anesthesia, leaving me with a six-inch scar, but a sentinel lymph node biopsy in the groin to check it hadn't spread.

The wait was endless. First the waiting for the operation, and then the waiting for the results. No matter how optimistic you are, no matter how much you want to believe that you are doing well, the word cancer is loaded.

As I waited, I became aware of my own mortality. The world became brighter and more beautiful. Sarah Ferguson is surrounded by her family, and I too found myself staring at my loved ones, especially my children, as I swallowed them, just in case.

There were times when I was scared. Whenever I found myself in a pit of doom, I immediately thought of three things I could be grateful for. It helped. It kept me focused on the positive and the good.

No matter how powerful and strong we feel in life, cancer immediately makes us powerless. It's terrifying to be at his mercy and not know the outcome. The only choice I had was acceptance: I would take whatever steps the doctors told me to do, while praying for the willingness to accept whatever outcome.

In the melanoma world, the ABCDEs are crucial. Anyone who has ever been sunburned, who has used UV tanning beds, who has a history of melanoma in the family, or who simply has a number of moles should check themselves and know what to look for:

A stands for asymmetry: One half of a mole or mole does not match the other.

B is for border: The edges are irregular, ragged, notched or blurred.

C stands for Color: The color is not the same everywhere and can contain different shades of brown or black, sometimes with pink, red, white or blue spots.

D stands for Diameter: The spot is larger than 6 millimeters in diameter (about ¼ inch – the size of a pencil eraser), although melanomas can be smaller.

E is for Evolve: The mole changes size, shape or color.

My surgery was successful and I received the results after the lymph node biopsy results. Ten years later I am cancer free.

I have my entire body's skin checked every six months, but now that I've reached the 10-year mark, I can postpone that to a year.

I don't sunbathe anymore. I spend about 20 minutes in the sun every day without sunscreen because vitamin D is essential and few of us get enough, but if you see me with a tan, I guarantee it's from a bottle.

Know your body, know your moles. Pay attention to changes and use a sunscreen with a high factor. For a cancer this deadly, we all need to check our skin regularly.

It's bad luck that she was diagnosed with melanoma so soon after being diagnosed with breast cancer, but the Duchess of York can take comfort in the fact that it was detected early.

Let's hope she's back on her feet, with SPF50 and a hat, by the time the spring sun arrives.