"If we assume ovarian cancers grow and spread at different rates, the best screening strategy available will only reduce the number of women dying from this cancer by 11 percent," said study team leader Dr Laura Havrilesky. "This is partially because the slower growing cancers are more likely to be caught by a screening test."
These findings suggest that strategies other than screening, such as prevention and better treatments, are necessary to significantly lower the number of deaths due to ovarian cancer each year-which is more than 15,000 women in the US alone (Int J Cancer, 2009; 124: 1918-25).
In the UK, according to Cancer Reseach UK (http://info.cancerresearchuk. org/cancerstats/types/ovary/), ovarian cancer is the fifth most common form of cancer in women and the fourth most common cause of cancer death. In 2007, more than 6700 new cases were diagnosed, which translates to 130 women every week.
Several teams of scientists around the world are now focused on trying to find ways to prevent this deadly disease. Happily, their findings so far suggest that there are a number of simple steps women can take that may reduce their risk of ovarian cancer.
o Get moving. Taking regular exercise can significantly slash the risk of a range of diseases, including cancer (Int J Clin Pract, 2010; 64: 1731-4).
Although only a few studies have looked at ovarian cancer in particular, one dis-covered that women who are physically active, either through work or in their spare time, have a significantly reduced ovarian cancer
risk compared with women who lead more sedentary lives (Int J Cancer, 2005; 117: 300-7).
Public health organizations now recommend at least 30 minutes of moderate-to-vigorous exercise on most days for cancer prevention.
o Stop smoking. Cigarette-smoking has been linked to certain types of ovarian cancer. According to
a review conducted by the Queensland Institute of Medical Research in Brisbane, Australia, current smokers have twice the risk of developing the mucinous type of ovarian cancer, which accounts for 12-15 per cent of all ovarian tumours. However, the good news is that stopping smoking will return the risk to normal in the long term (Gynecol Oncol, 2006; 103: 1122-9).
o Consider your diet. What you eat may have a role to play in ovarian cancer prevention. Another study from Brisbane-but by a different team of researchers-of more than 4000 women found that high intakes of poultry and fish may protect against ovarian cancer, while eating too much processed meat had the opposite effect (Am
J Clin Nutr, 2010; 91: 1752-63).
Yet another study based on 900 women in Zhejiang, China, found that ovarian cancer risk was lower with a higher consumption of fruit and vegetables, but increased with high intakes of fat, fried, cured and smoked food, and preserved (salted) vegetables (Br J Cancer, 2002; 86: 712-7).
Indeed, eating fresh vegetables, particularly the leafy green kind, appears to be especially helpful for reducing ovarian cancer risk. The Iowa Women's Health Study found a significant 56-per-cent epithelial ovarian-cancer risk reduction with frequent consumption of green leafy vegetables (Am J Epidemiol, 1999; 149: 21-31). A study from the Karolinska Institute in Stockholm, Sweden, reported a risk reduction of 10 per cent for each daily serving increase in vegetable consumption (Br J Cancer, 2004; 90: 2167-70).
Vegetables contain flavonoids-phytochemicals that have anti-oxidant, anti-inflammatory and anticancer properties-which may explain their protective effects.
In fact, studies have identified an association between dietary flavo-noids and ovarian cancer risk. One Italian study found that certain plant flavonoids (flavanols and isoflavones) were linked to a 40-
to 50-per-cent lower risk of having the disease (Int J Cancer, 2008; 123: 895-8). Flavonoids are also found in fruit, tea, wine, and other food and drinks derived from plant sources.
Another family of phytochemicals called 'carotenoids' may also help to prevent ovarian cancer. A study from Boston, MA, concluded that eating fruit, vegetables and other foods high in carotene and lycopene antioxidants-such as carrots and tomatoes-can reduce ovarian cancer risk (Int J Cancer, 2001; 94: 128-34).
o Drink tea. There is also evidence that women who drink tea are less likely to have ovarian cancer than non-tea-drinkers. A significantly reduced risk was seen in women who drank four or more cups of any type of tea-black, green or herbal-every day (Cancer Causes Control, 2010; 21: 1485-91). Green tea, however, may be especially good for you, as it contains high levels of catechins, a potent type of poly-phenol antioxidant known to have cancer-fighting effects (Curr Med Chem Anticancer Agents, 2002; 2: 441- 63). One case-control study conducted in China during 1999-2000 revealed a strong inverse relationship between drinking green tea and ovarian cancer (Cancer Epidemiol Biomarkers Prev, 2002; 11: 713-8).
o Avoid acrylamide. This chemical compound is a natural byproduct of cooking certain foods at high temperatures, and is found in a wide range of popular foods-especially high-carbohydrate foods that have been fried or baked. It has also been linked to ovarian cancer. Using data from the Netherlands Cohort Study on diet and cancer from more than 62,000 women, the risk of ovarian and endometrial cancers rose signifi-cantly with increasing dietary acrylamide intake. Among non-smokers, those who consumed the highest amounts of acrylamide had twice the risk of those cancers compared with those who had the lowest levels (Cancer Epidemiol Biomarkers Prev, 2007; 16: 2304-13).
Foods that contain acrylamide include crisps, chips, fried, baked or roasted potatoes, cereals, crispbreads and even coffee. Boil-ing, steaming and microwaving do not appear to produce acrylamide.
To reduce acrylamide levels in your diet, the US Food and Drug Administration (FDA) offers the following tips:
v Limit fried foods. Frying results in the highest acrylamide formation, followed by roasting potato pieces and baking potatoes whole.
v Soak raw potato slices in water for 15-30 minutes before frying or roasting, as this will reduce acryla-mide formation during cooking. (Be sure to dry soaked potatoes before frying to avoid splattering and fires.)
v Don't store potatoes in the fridge, as this can result in increased acrylamide levels during cooking.
v Cook cut potato products, such as chips, to a golden-yellow colour rather than brown. Brown areas tend to contain more acrylamide.
v Toast bread to a light-brown colour rather than a dark brown. Again, very brown areas should be avoided as they contain the most acrylamide.
v Limit coffee intake. The acryla-mide in coffee is formed when the beans are roasted, not when it's brewed and, so far, scientists have failed to find any effective ways to reduce acrylamide in coffee.
o Pass up HRT. Not only does hormone replacement therapy (HRT) cause heart disease and breast cancer in menopausal women, but researchers have also discovered that it increases the risk of ovarian cancer. A long-term Danish study, involving more than 900,000 women aged 50-79 years, found that the current use of hormones accounted for a 38-per-cent greater chance of developing ovarian cancer. This translates to one extra case every year for every 8300 women using HRT, or 140 additional cases during the eight-year follow-up, accounting for 5 per cent of all cases of ovarian cancer. What's more, HRT was associated with an increased risk of the disease regardless of how long it was taken, which formulation was used, how much oestrogen was included in the mix and what sort of delivery method was chosen (JAMA, 2009; 302: 298-305).
o Be wary of infertility drugs. There have been concerns that these drugs may increase the risk of ovarian cancer. One study of nearly 4000 women reported that the prolonged use of the 'selective oestrogen receptor modulator' (SERM) clomiphene more than doubled the risk of borderline or invasive ovarian tumours (N Engl J Med, 1994; 331: 771-6).
However, another study found no overall increased risk of ovarian cancer after the use of either gonadotrophins or clomiphene. However, when the researchers analyzed the differences in risk according to the type of ovarian cancer, they found a 67-per-cent greater risk of having serous ovarian cancer (the most wide-spread form) among clomiphene users, particularly in those who were followed for 15 years or more (BMJ, 2009; 338: b249).
Other research suggests that it's the state of female infertility itself that contributes to the increased cancer risk rather than infertility drugs. Clearly, more research is needed to resolve this important issue (Minerva Endocrinol, 2010; 35: 247-57).
o Avoid talc. There's evidence to suggest that women who use talcum powder in their genital area are more likely to develop ovarian cancer than those who don't. The theory is that the talc may be traveling up into the vagina to eventually make its way into the ovaries, where it can cause irritation and, potentially, inflammation that could lead to cancerous changes in the cells.
One study of nearly 500 women found a 50-per-cent greater ovarian cancer risk among women with perineal exposure to talc. Those who applied it directly to the genital area, or used it on a daily basis for more than 10 years, were found to have the highest risk estimates (Obstet Gynecol, 1992; 80: 19-26).
A more recent study also found a connection between talc use and ovarian cancer, particularly among women with a history of endometriosis, an inflammatory condition that has itself been independently linked to ovarian cancer (Int J Cancer, 2009; 124: 1409-15).
o Maintain a healthy weight. Some studies have found that being overweight could be increasing your chances of having ovarian cancer.
The results of the European Prospective Investigation into Cancer and Nutrition (EPIC) study showed that women who were obese had a significantly higher risk of this type of cancer, with obese postmenopausal women having the greatest risk of all (Int J Cancer, 2010; 126: 2404-15).
Signs to watch out for
Ovarian cancer is often referred to as 'the silent killer', as its symptoms can be so vague that most women are not diagnosed until the cancer has spread. However, there's growing evidence that the frequency and combination of certain symptoms may alert women and their doctors to the possibility of ovarian cancer, even in the early stages of the disease, when survival rates are higher (Cancer, 2007; 109: 221-7; JAMA, 2004; 291: 2705-12).
Diagnosing the disease can be tricky as symptoms often mimic those of more common and less serious conditions, such as digestive and bladder problems. Nevertheless, experiencing the following three symptoms on most days are suggestive of ovarian cancer:
o persistent pelvic and abdominal pain;
o increased abdominal size and persistent bloating, but not bloating that comes and goes; and
o difficulty eating and feeling full quickly.
Occasionally, other signs, such as urinary symptoms, changes in bowel habits, extreme fatigue and/or back pain, may also be experienced on their own or together with those mentioned above. So, if you do regularly have any of these symptoms and they're not 'normal' for you, consult your doctor. Although it's unlikely that your symptoms are due to a serious problem, it's important that you check them out.
To find out more and to download a symptom diary, visit the website of UK charity Ovarian Cancer Action at www.ovarian.org.uk.
WDDTY VOL. 21 NO. 11