Ovarian cancer screening - light at the end of the tunnel?
A diagnosis of cancer is scary enough, but women have good reason to fear a diagnosis of ovarian cancer almost above all others. While ovarian cancer is the fifth most common cancer among women in the UK, it's one of the most deadly.
Breast cancer rates are much higher - over 48,000 women are diagnosed with this most common cancer every year in the UK, and rates have increased by more than 50% in the last 25 years. But survival rates for breast cancer have improved dramatically in recent years, with more than 80% of women surviving for at least 5 years from diagnosis (compared to 50% in the 1970s) and twice as many women as in the 1970s surviving for 10 years.
Sadly, the same improvements have not been seen with ovarian cancer. While about 7,100 women are diagnosed with ovarian cancer a year in the UK, 4,200 die from it each year. One of the reasons for this is that many women have advanced cancer by the time they are diagnosed. There are early warning signs, but some women don't seek help early because they put their symptoms down to other conditions like irritable bowel syndrome, or IBS. But IBS rarely develops for the first time in anyone over 50, and it usually starts before you're 40.
The 'red flag' symptoms include:
- Persistent bloating
- Feeling full quickly or loss of appetite
- Persistent stomach or pelvic pain
- Needing to pass water more often.
These symptoms need checking out if they're persistent (they don't come and go) or if you get them frequently over any length of time, especially on more than 12 days a month.
There are also screening tests - one is an ultrasound scan of the pelvis, which can pick up growths on the ovary. The other is a blood test called Ca125.
It's crucial to be certain that screening tests save lives before jumping in with whole population screening. The UK breast screening programme is estimated to save 1,300 lives a year, but at a cost of 4,000 women having unnecessary surgery. That's because screening can throw up 'false positive' results, where initial screening suggests cancer might be present but none is found on further testing. Screening can also miss cancers (so-called false negative results), which might mean people being lulled into a false sense of security and ignoring symptoms.
Just four years ago, a 10-year American study of almost 40,000 women, given a Ca125 blood test annually for the first six years and a yearly ultrasound for the remaining four, failed to show any improvements in survival from ovarian cancer in the screened group. Worse still, there were over 3,000 'false positive' results among the screened women. More than 1,000 women underwent unnecessary surgery and 222 had 'major complications' from treatment for a condition that wasn't there.
The difference between this trial and previous ones is that it tracked trends in Ca125 for each woman. This allowed the researchers to personalise the results, deciding on what constituted a raised level based on the woman's previous results rather than using a single cut-off point. As a result, about a quarter of women found to have cancer were diagnosed in the earliest stages - currently, three quarters of women first present with symptoms when their cancer has reached an advanced stage.
But there is still no guarantee that getting a diagnosis and treatment earlier using this approach translates into lives saved - final figures on survival rates of the trial are expected at the end of this year. Doctors would also need to weigh up how much over-treatment from false positives will result - and there's no doubt that there will be false positives. Then there would be the question of whom to screen. While ovarian cancer can occur at any age, the highest number of cases is seen in women in their 60s and the risk increases with age. Start too young and complications of the resultant unnecessary treatment could cost more lives than it saves.
This means that even if screening is introduced, it will almost certainly start too old to benefit women like Angelina Jolie, who carry the faulty BRCA gene. So there's a very long way to go before we conquer this deadly disease, or even see the sort of revolutions in treatment we've achieved for breast cancer. But every little helps, and this might just help more than a little.