During the gynaecological oncology session, Sean Kehoe also presented on his research in epithelial ovarian cancer and the potential to prevent its occurrence.
Ovarian cancer is one of the most common forms of cancer in women, namely in post-menopausal women and is associated with the highest number of deaths. 75% of women with ovarian cancer will only present when the disease has spread beyond the ovaries making it challenging to treat. Stage 3 diagnosis is most common and 40% of women in this phase will unfortunately succumb to the condition within 5 years. Prevention is key.
The fact most women present at stage 3 is different to other forms of cancer, the majority such as breast, colonic and prostate cancer all present early (in stage 1), leaving more time for treatment. Sean suggests it’s essential to look at and understand the primary source of each condition so that you can try to drive a stage shift with treatment/action.
It is well documented that there is a direct relationship between number of ovulatory cycles and risk of developing ovarian cancer. In the last decade there has been a review into the source of ovarian carcinoma, driven by research that looked at post-menopausal ovarian cysts and detected the absence of any carcinoma cells. Research from Callahan MJ et al demonstrated that the source of malignancies is actually the fallopian tube. Data shows that in women who have had their fallopian tubes removed there is a lower risk of high grade ovarian carcinoma.
BRCA mutations account for 15% of occurrences of ovarian cancer in women. A woman who is a BRCA1 carrier has an increased ovarian cancer risk from age 40 whilst BRCA2 carriers have increased risk from the age of 50. This is usually managed by prophylactic surgery which is highly successful in reducing ovarian cancer risk by 80-90% in BRCA carriers.
But what about removing the fallopian tubes, the source of ovarian cancer? This would have the added benefit of preventing women from going through premature menopause. Initial data suggests that primarily removing the tube and then having an additional operation later in life to remove the ovaries can be a successful method to reduce ovarian cancer risk but more evidence is needed.
What about for the general population? There is less data about the use of surgery in the wider population. Initial meta-analysis suggests that removal of tubes could work, but long term data needs to be collected from patients to see if this reduces risk of ovarian cancer. For now oral contraceptives are known to reduce ovarian cancer risk, with data showing that this can protect women for over 20 years after they take the pill.
And what about screening? A large randomised trial published in JAMA 2011 showed no stage shift or reduction in ovarian cancer mortality as a result of screening. Sean suggests this is because we are currently screening the wrong organ. To date there is no evidence that screening reduces death from ovarian cancer. As we now have strong evidence that many ovarian cancers arise from the fallopian tube, screening for pre-invasive or early stage fallopian tube cancers now becomes the new challenge.
Until we have concrete data on the effectiveness of screening, we must pursue with surgical and hormonal preventive measures. With more data the hope is that screening can be used to help significantly reduce ovarian cancer risk.
What do you think about the prospect of screening? Leave us a comment in the box below.