Angus McIndoe gives an overview on the latest thinking on ovarian cancer, its diagnosis and treatment. Ovarian cancer is called a silent killer. The symptoms are vague, and often confused with
other diseases. Ovarian cancer usually presents at an advanced stage when it has already
spread around the abdomen. Interestingly, we now believe that many ovarian cancers start
in the fallopian tubes.
Ovarian Cancer Symptoms
The symptoms of ovarian cancer are not specific, and are similar to other abdominal
conditions, such as irritable bowel syndrome. Women diagnosed with ovarian cancer have
usually seen their GP three or four times before the diagnosis is made.
Ovarian Cancer Tests
If you feel you have some of the symptoms of ovarian cancer, the best test is an ultrasound
scan done by an expert.
An MRI scan can be helpful in difficult cases
The CA125 blood test is not very useful as a diagnostic test, as it can be wrongly positive
when there is no cancer, and wrongly negative when there is cancer. Ovarian Cancer Risk
Ovarian cancer can run in families, and is usually associated with breast cancer. The chances of being in a cancer family are increased if the cancers cluster more with first degree relatives and with younger age of diagnosis.
The most common genes associated with an increased risk of breast and ovarian cancer are
the BRCA 1 & 2 genes, but other rarer genes may also be associated with an increased risk.
We do not fully understand all the genetic links associated with these diseases. Men who have the BRCA 1 or 2 genes are at increased risk of testicular cancer and prostate cancer, particularly at a young age. They are also at increased risk of male breast cancer. A full genetics screen can be run for all know ovarian or breast cancer genes.
Screening for Ovarian Cancer
Two approaches have been used for screening for ovarian cancer. A blood test using the
CA125 tumour marker has been tested in a very large study in the UK but the results are not
reported yet. Unfortunately, wrongly positive results are common, particularly in women
before the menopause. Wrongly negative results are also common in women with early
ovarian cancer. A single blood test didn’t seem to be very helpful but a series of blood tests
showing a steady rise was more indicative of ovarian cancer.
Ultrasound scanning is very accurate at detecting ovarian cancer. The difficulty with this
approach is that surprisingly, within a few months of a normal scan, an advanced ovarian
cancer can be diagnosed.
In women at high risk of developing ovarian cancer, risk reducing surgery may preferable to
screening. Where this is not acceptable, ultrasound screening can be undertaken every 6 or
12 months, with CA 125 blood tests as well. Risk Reducing Surgery for Ovarian Cancer
The best way to reduce the risk of ovarian cancer is to remove the ovaries and tubes. This is
a very big decision for a young woman, but as women approach the menopause this may
become an easier decision. Removing the ovaries and tubes reduces the risk of ovarian
cancer by about 95%. This a relatively minor procedure that can be completed as a day case.
Unfortunately, most insurance companies in the UK will not pay for risk reducing surgery,
although they are committed to pay for treatment if you develop a cancer.
Ashkenazi Jewish risk of BRCA mutations
Ashkenazi Jews have a particularly high risk of carrying BRCA mutations. Studies have shown that screening using family history alone misses 56% of carriers of BRCA mutations, and that screening on a populations basis is very cost effective in this population. Cost-effectiveness of population based BRCA testing with varying Ashkenazi Jewish ancestry. With this in mind, all Ashkenazi Jews should consider BRCA genetic testing.
We now believe that many ovarian cancers start as precancerous abnormalities in the fallopian tubes. In women at increased risk of ovarian cancer at a young age, it may be that
removing the fallopian tubes will significantly reduce the risk of ovarian cancer. Studies have
not yet been completed to confirm the effectiveness of this procedure, but it is likely to be
much better than screening, and is a relatively minor procedure that can be completed as a
day case.
Surprisingly, most ovarian cancers start in the fallopian tubes. Precancerous changes have
been found in the fallopian tubes of women at high risk of ovarian cancer, and these
abnormalities are also found in women who have developed cancer. The precancerous
changes, called STIC (Serous Tubal Intraepithelial Carcinoma) persist for many years before
they spread to become invasive ovarian carcinoma. We think that only when these changes
become malignant with the ability to spread to other tissues, that the tumours spread to the
ovaries. At the same time, as the cancerous cells spread to the ovaries, they also have the
ability to spread to other tissues within the abdominal cavity.
Treatment of Ovarian Cancer
Surgery is the primary treatment for ovarian cancer. The operation should aim to remove all
visible tumour. If the tumour is at an early stage, this may be a relatively straightforward
operation, involving the removal of the ovaries, fallopian tubes, uterus and the omentum, a
fatty sheet that extends from the lower edge of the stomach. The omentum is one of the
first places an ovarian cancer will spread to, and so it is removed as part of staging the
ovarian cancer.
If the tumour is more advanced, it will have spread around the abdominal cavity and surgery
may be a more complex procedure, carefully stripping disease off surfaces of abdominal
organs, and sometimes removing some of the bowel or other organs.
An independent prognostic factor for survival from ovarian cancer is the quality of surgery.
Chemotherapy is used to kill all the individual cells or groups of cells that cannot be
removed by surgery. This may be given before surgery to make the surgery less complicated
to perform, or more usually after surgery, to mop up any invisible disease left behind.
Chemotherapy usually involves 6 cycles of treatment spread at an interval of 3 weeks.