The study identifies three key symptoms associated with ovarian cancer that should help clinicians decide whether to investigate further. Yet one of these symptoms is not included in current guidance for urgent investigation.
Ovarian cancer accounts for 4 per cent of all cancers in women and has the worst prognosis of all gynaecological cancers. Until recently, ovarian cancer was thought to have few symptoms and was often dubbed the “silent killer” but recent studies have shown that symptoms are common and that their early identification has the potential to improve prognosis.
Dr William Hamilton and colleagues in the Department of Community Based Medicine at the University of Bristol set out to identify key symptoms that could indicate ovarian cancer in women presenting to primary care. They also calculated the positive predictive value for each symptom (the chance that a woman with a particular symptom actually has ovarian cancer).
The study involved 212 women aged over 40 with a diagnosis of primary ovarian cancer and 1,060 healthy controls from 39 general practices in Devon, England.
Seven symptoms were associated with ovarian cancer: abdominal distension, urinary frequency, abdominal pain, postmenopausal bleeding, loss of appetite, rectal bleeding, and abdominal bloating. Some women presenting with the first three of these symptoms waited at least six months before the diagnosis was made.
All symptoms had positive predictive values below 1 per cent, except for abdominal distension, which had a positive predictive value of 2.5 per cent. This means that it carries the highest risk and warrants rapid investigation, say the authors. Yet persistent abdominal distension is not included in current guidance for urgent investigation. If it were, some women could have their diagnosis speeded up by many months.
The fact that symptoms are common and often reported is encouraging as it means there is some chance of identifying early ovarian cancer by using symptoms, say the authors. This study provides an evidence base for selection of patients for investigation, both for clinicians and for developers of guidelines, they conclude.
There is now increasing evidence that ovarian cancer is not a “silent killer” but one that presents with vague symptoms that have a low positive predictive value for cancer, writes Dr Robin Fox in an accompanying commentary.
This study adds to the evidence base derived from primary care of red flag symptoms for several cancers, and is important as most patients in the United Kingdom present initially to primary rather than secondary care, he writes.
The diagnosis of ovarian cancer will continue to be a challenge for primary care doctors, adds Joan Austoker from the University of Oxford, in an accompanying editorial.
She believes that more research is needed to improve our knowledge of the predictive value of different symptoms in ovarian cancer. In the meantime, what is important for both women and primary care doctors is that ovarian cancer can no longer be regarded as a silent killer, she says.
Risk of ovarian cancer in women with symptoms in primary care: population based case-control study by William Hamilton, Tim J Peters, Clare Bankhead and Deborah Sharp BMJ 2009;339:b2998