Elizabeth McIntyre understands more than most women why ovarian cancer has earned the chilling title of "the silent killer". When she was just 37, a routine scan showed up a cyst the size of an orange in one of her ovaries, which turned out to be malignant. What made the diagnosis so alarming, says McIntyre, was that she had no symptoms and felt fit and well. And while the cancer was able to be treated, if she'd had that scan just a few months later, the outcome could have been very different.

McIntyre, 48, a cardiac nurse at the Western Infirmary in Glasgow, says she was lucky to have had the cancer picked up early, and it was only because she'd had a cyst removed from her other ovary when she was 27, and which proved to be "borderline malignant", that she needed yearly check-ups. But not all ovarian cancers are as insidious and fast-growing as hers. Most of the time there will be early symptoms and it's a case of acting on them quickly before the cancer has spread beyond the ovaries and it's too late for an effective treatment.

However, ovarian cancer is notoriously difficult to diagnose because early symptoms can be vague and similar to those related to bowel or bladder problems. While it is a rare form of cancer, affecting women mostly over 45, it is one of the reasons older women may have a hysterectomy. It was announced last week that the Duchess of Cornwall, 59, is to have a hysterectomy, and while cancer appears to have been ruled out, she is at the age when ovarian cancer commonly strikes.

Leading cancer charities are hoping to reverse the difficulty of dealing with this disease during March, which is Ovarian Cancer Awareness Month. The campaign is being spearheaded by Ovarian Cancer Action, which is raising money to open the UK's first ovarian cancer research unit, and Ovacome, a support organisation for sufferers, which helped McIntyre. The awareness month is driving home the message that women must take heed of the early, persistent symptoms that could indicate cancer.

McIntyre, from West Kilbride, says that diagnosing the cancer early saved her life. When it was eventually operated on, surgeons found it had already spread to her bowel wall. This meant having a hysterectomy and six months of chemotherapy, which successfully wiped out the disease. Any more of a delay and the cancer may have spread further, with a more serious outcome. But fortunately, 10 years later, McIntyre is still cancer free.

"The trouble with this type of cancer is that the ovaries are deep in the pelvis, so you can't always feel a growth if you press your hand against your stomach," says McIntyre.

"From my experience I know that ovarian cancer can happen to anyone. Although my situation was more unusual, I am also living proof that if you spot it early, you will survive."

Ovarian cancer is the fourth most common cancer in British women, with around 7000 cases in the UK each year, and about 700 in Scotland. Some 60% of women who are diagnosed in the UK have ovarian cancer at the advanced stage. Only 30% of those diagnosed survive beyond five years, compared with 70% for breast cancer.

Dr Nadeem Siddiqui, a consultant gynaecological surgeon at Glasgow Royal Infirmary says: "With ovarian cancer, there is no definite symptom complex that you can say with clear confidence, if someone has the following symptoms, they definitely have this cancer. It just doesn't work like that.

"Symptoms are insidious but not specific: they creep up on you gradually and they can mimic the symptoms of irritable bowel syndrome, diverticular (bowel) disease, constipation or indigestion; and because a lot of the women affected are middle- aged, and they are putting on a bit of weight, they often attribute some of the symptoms to middle-age spread.

"The difficulty GPs have is picking the one woman who has ovarian cancer from the others who don't. The critical thing is the woman who presents herself as a new patient, someone the GP hasn't seen for a while, who's complaining of these vague symptoms yet doesn't have a history of irritable bowel syndrome, heartburn or menopausal symptoms - she's the woman who must be taken seriously and must be referred for further investigation."

Anna Chambers, from Gourock, lost her 57-year-old mother to ovarian cancer in 2003 after the disease was diagnosed too late. She says her mother, Mary, first noticed some symptoms four years earlier, but like many sufferers she put it down to the fact she was getting older and putting on weight.

"My mother told me about the symptoms before she went to the doctor, but symptoms can get confused with so many things. I would never have thought there was anything seriously wrong with her," says Chambers, 27, a marketing officer in Glasgow.

She says her mother would probably still be alive if there had been more awareness of the disease when she was first diagnosed in 1999.

"I still feel angry and very frustrated about her death because ovarian cancer is treatable if it's caught early - that's the hardest thing to deal with. There needs to be more awareness. There's been such a successful campaign with breast cancer, and that's the standard that should be set with all cancers."

Ovarian Cancer Action next month hopes to overturn the myth that early symptoms are too vague to be acted upon. The charity endorses a US study that offers a symptoms checklist. The study, published in the January edition of Cancer, the journal of the American Cancer Society, found that "any complaint of pelvic or abdominal pain, increased abdominal size or bloating, or difficulty eating, or feeling full, when it is present for more than 12 days a month and for less than one year, is 57% indicative of early disease and 80% indicative or advanced cancer, 90% for women over 50."

While simple guidelines like these may be life-saving for some women, the best method of early detection is yet to come.

"The way forward is through a general screening programme," says Dr Siddiqui. "It should screen for asymptomatic individuals, not even people at high risk of getting it because of family history; only 5% of sufferers will fall into this category."

At the moment, ultrasound screening is confined to those with suspected ovarian cancer, but it doesn't always identify a growth as being a malignancy and often surgery is the only way to investigate it conclusively. That can create its own risks.

One of the largest ovarian cancer screening studies is currently taking place at University College, London. It involves more than 200,000 women, and is looking at the use of ultrasound together with a blood test that detects a protein released by an ovarian tumour, as a means of screening. It will run until 2011.

In the meantime, Elizabeth McIntyre says women shouldn't panic but "they should be aware of their bodies and what's normal for them, and just persist in getting treatment."