IT was fatigue that made Sally Whiteman, aged 35, think something wasn't quite right with her health.

She stopped working out at the gym because she was too tired. Then she started losing weight.

When she finally noticed that her bowel habits were changing without reason, and that at times her rectum was even bleeding, she went to see her GP.

"I was sure her diagnosis of haemorrhoids, caused by stress and overwork — without any direct examination — wasn't right because of my age," says Sally, from Fforestfach.

"I was given suppositories to soothe the pain, but these had no effect, so for the next year I just carried on with my life."

Within a year, she had lost enough weight to drop two dress sizes. Eating was increasingly difficult, as she was frightened of the effect it would have.

Finally, a bout of food poisoning made her return to the doctor.

"This time, I saw a different GP who recognised my symptoms and referred me to the hospital to be tested for bowel cancer," she says. "I was devastated to receive the diagnosis, as I was so young and had always taken care of myself."

Sally, a Swansea bank cashier, is just one of the 37,500 men and women diagnosed annually in the UK, according to figures, making it the third most common cancer behind breast and lung cancer.

Bowel cancer affects the large bowel, made up of the colon and rectum, and is also known as colorectal or colon cancer. Nearly all diagnoses (97 per cent) are in people over the age of 50, so Sally's case is rare.

While bowel cancer is currently the second largest cause of cancer deaths, killing more than 16,000 people a year, 90 per cent of cases could be successfully treated if caught early enough.

Sally's symptoms are common, but they are not the only ones indicating trouble, says nurse adviser Mary Heynes, of Beating Bowel Cancer.

"These include bleeding from the rectum, mucous or blood in the stools, abdominal pain, a change in bowel habits (such as constipation or diarrhoea lasting more than two weeks), unexplained weight loss, tiredness, or, perhaps, a lump in the abdomen."

People who feel that they present with these symptoms should visit their GP, who can refer them to a gastroenterologist or colorectal surgeon. Blood tests, scans, X-rays and a colonoscopy could be carried out to investigate.

Annette Norman and her husband Neil, of Caswell in Swansea, have both been through the experience.

Neil, now 80, was successfully diagnosed and treated in 1986. Then, out of the blue, a couple of years ago, so was Annette.

"I didn't have any of the classic symptoms," she says.

"But I did notice a couple of things out of the norm and went to the doctor to tell him. I don't believe in hanging about.

"I was sent for a colonoscopy, diagnosed and treated. It had spread to my lymph nodes as well, but those were removed, and now I have regular blood checks and scans to make sure all is well."

The exact cause of bowel cancer remains unknown, says Ian Beaumont of charity Bowel Cancer UK , although it tends to affect older people.

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"Eight out of 10 cases occur in people over 60, but we don't know why exactly," he says.

Diet, lifestyle and family history are the three strongest factors in determining a person's susceptibility to bowel cancer.

Those at high risk are people with a family history of the disease, or who suffer from inflammatory bowel diseases (such as Crohn's disease or ulcerative colitis).

But a poor diet, sedentary lifestyle, smoking and excessive drinking are risk factors too.

"Being overweight can increase one's risk of bowel cancer, so it's important for people to maintain a healthy weight," says Mr Beaumont.

"The amount of red and processed meats like ham, bacon and sausage should also be limited, as they can take longer to process in the bowel."

According to a recent World Cancer Research Fund (WCRF) report, which linked a high consumption of red and processed meat with an increased risk of bowel cancer, such meat should be limited to only 80g per day, as it is believed to produce toxic metabolites in the bowel.

Excessive alcohol consum- ption is another risk factor, as research from WCRF suggests people who drink more than three alcoholic drinks per day may slightly increase their risk of bowel cancer. However, those who have a large (250 ml) glass of wine every day could reduce their bowel cancer risk by seven per cent just by swapping a normal wine (alcohol content of 14 per cent) to a low-alcohol one (of 10 per cent), says the WCRF. Regular exercise plus a diet rich in fibre and fresh fruit and vegetables is a good method of reducing risk.

Exercise moves food through your system quicker than if you're sedentary, as the food doesn't stagnate.

Bowel screening programmes targeted at those at highest risk of the cancer have been rolled out across Wales to help prevent the disease. It involves taking a stool test at home and is aimed at people aged 60 to 69.

Both Beating Bowel Cancer and Bowel Cancer UK are hoping screening will increase awareness of the disease.

"Bowel cancer is one of the most treatable cancers if caught early," says Mr Beaumont.

"If you don't have any symptoms, but blood is found in your stool, which is what the test looks for, then your chances of catching bowel cancer earlier are much higher."

Neil Norman, who had his cancerous polyps removed in 1986 a full 20 years after his first tell-tale signs that something might be wrong, says his delay meant he later had to have much of his intestine removed.

The former sales manager with Shell adds: "It was March 1 that I had the op. I count every day since then as my birthday!"

Annette's Singleton Hospital consultant is now delving through her husband's family for a genetic link, and has found some evidence to support the theory meaning the Normans's three children all now receive a regular colonoscopy test.

"I don't think we followed a particularly poor lifestyle prior to diagnoses although years ago we, like everyone else, probably ate more red and processed meat and white bread," adds Annette.

"We have changed our eating habits, eating more chicken and fish than we once did. Go and see your GP if you suspect there might be a problem. Don't delay: it simply isn't worth it."