The invisible worm: ovarian cancer
BMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b2072 (Published 04 June 2009) Cite this as: BMJ 2009;338:b2072
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Gill Reeve is, very understandably, searching for ways in which her ovarian cancer could have been diagnosed sooner. She suggests her GPs might have measured her Ca125 level earlier. They agree, saying that they should have a “much lower threshold” for requesting pelvic ultrasound and Ca125 in women with “vague abdominal symptoms”.
We would all dearly wish to have an easy way to diagnose ovarian cancer early, but is Ca125 helpful? SIGN says “no studies were identified that assessed the usefulness of the measurement of serum CA125 in women with vague abdominal symptoms hence the guideline development group cannot recommend the routine measurement of CA125" (1). Measuring Ca125 in women with very common and non-specific symptoms is tantamount to population screening and my understanding is that trials of screening for ovarian cancer using Ca125 have not shown a benefit.
As a GP myself, I would very much value expert guidance on Ca125. Patients with vague symptoms, who could have serious disease but almost certainly don’t, form a large part of my workload. Currently I almost never request Ca125 as a fishing exercise in such people, believing it to be too inaccurate and non-specific. Am I wrong? If I should be using the test frequently, what should I do with patients who have raised levels, bearing in mind the large variety of possible cancer and non-cancer diagnoses, plus the likelihood of there being no disease at all?
1. http://www.sign.ac.uk/guidelines/fulltext/75/section3.html#section312
Competing interests:
None declared
Competing interests: No competing interests
Not silent....
Dear Editor,
We wonder when the term “silent killer” for ovarian cancer will
finally be consigned to history.1 If it were truly silent, then general
practitioners could hardly be blamed for missing it. The truth is that it
is far from silent – rather the noise it makes is difficult to interpret.
Recent studies of newly diagnosed women show that symptoms are common, and
are reported to GPs.2 3 Although these symptoms are generally non-
specific, it seems GPs can at least identify a significant proportion of
women requiring investigation. In the GP records of a recent cohort from
Devon, soon to be published in the BMJ, 196 of the 212 women with primary
ovarian cancer had either a symptom of this recorded, or had a mass noted,
before diagnosis. 88 (42%) were referred for investigation on the same day
as the first symptom was recorded, with a further 36 (12%) within the next
week. This leaves a minority of women who experience diagnostic delays in
primary care – and who would benefit from a lowering of the threshold for
investigation.
However, we are concerned that CA125 could be used indiscriminately. No
study of its performance has been performed in primary care. In a recently
reported UK screening trial, 8.6% of women had an initially elevated
CA125.4 Most of these were normal on repeat testing, but these figures
mean that CA125 used in a low-prevalence setting of primary care would
generate many false-positives for each true positive. The potential
adverse effects of a false-positive test for ovarian cancer are major: not
just the emotional considerations, but the risk that peace of mind may
only be achievable by biopsy, or even oophrectomy. False-positive
ultrasound scanning was less common in the screening trial, and we believe
it should remain the primary care investigation of choice.
William Hamilton, general practitioner and consultant senior lecturer
Alison Round, general practitioner
Debbie Sharp, general practitioner and professor
References
1. Reeve G, Mackay-Thomas S. The invisible worm: ovarian cancer
10.1136/bmj.b2072. BMJ 2009;338(jun04_2):b2072-.
2. Tate A, Martin A, Murray-Thomas T, Anderson S, Cassell J. Determining
the date of diagnosis - is it a simple matter? The impact of different
approaches to dating diagnosis on estimates of delayed care for ovarian
cancer in UK primary care. BMC Medical Research Methodology 2009;9(1):42.
3. Bankhead C, Collins C, Stokes-Lampard H, Rose P, Wilson S, Clements A,
et al. Identifying symptoms of ovarian cancer: a qualitative and
quantitative study. BJOG 2008;115:1008-1014.
4. Menon U, Gentry-Maharaj A, Hallett R, Ryan A, Burnell M, Sharma A, et
al. Sensitivity and specificity of multimodal and ultrasound screening for
ovarian cancer, and stage distribution of detected cancers: results of the
prevalence screen of the UK Collaborative Trial of Ovarian Cancer
Screening (UKCTOCS). Lancet Oncol. 2009;10:327-340.
Competing interests:
None declared
Competing interests: No competing interests