Abstract
BackgroundIn the UK, the cancer antigen 125 (CA125) test is recommended as a first-line investigation in women with symptoms of possible ovarian cancer.AimTo compare time between initial primary care CA125 test and diagnosis, tumour morphology, and stage in women with normal (<35 U/ml) and abnormal (≥35 U/ml) CA125 levels prior to ovarian cancer diagnosis.Design and settingRetrospective cohort study using English primary care and cancer registry data.MethodAssociations between CA125 test results and test-to-diagnosis interval, stage, and ovarian cancer morphology were examined.ResultsIn total, 456 women were diagnosed with ovarian cancer in the 12 months after having a CA125 test. Of these, 351 (77%) had an abnormal, and 105 (23%) had a normal, CA125 test result. The median test-to-diagnosis interval was 35 days (interquartile range [IQR] 21–53) for those with abnormal CA125 levels, and 64 days (IQR 42–127) for normal CA125 levels. Tumour morphology differed by CA125 result: indolent borderline tumours were less common in those with abnormal CA125 levels (n = 47, 13%) than those with normal CA125 levels (n = 51, 49%) (P<0.001). Staging data were available for 304 women with abnormal, and 77 with normal, CA125 levels. Of those with abnormal CA125 levels, 35% (n = 106) were diagnosed at an early stage, compared to 86% (n = 66) of women with normal levels. The odds of being diagnosed with early-stage disease were higher in women with normal as opposed to abnormal CA125 levels (odds ratio 12.2, 95% confidence interval = 5.8 to 25.1, P<0.001).ConclusionDespite longer intervals between testing and diagnosis, women with normal, compared with abnormal, CA125 levels more frequently had indolent tumours and were more commonly diagnosed at an early stage in the course of the disease. Although testing approaches that have greater sensitivity might expedite diagnosis for some women, it is not known if this would translate to earlier-stage diagnosis.
Highlights
Ovarian cancer is the 6th most common cancer to affect UK women, with over 7,000 women diagnosed each year.[1]
Keywords Ovarian cancer, Cancer antigen 125, CA125, early diagnosis, diagnostic intervals, general practice. How this fits in CA125 is widely used as an initial test for ovarian cancer in symptomatic women in primary care, but a recent study reported that CA125 levels were normal in 23% of women prior to diagnosis
We found that women with normal CA125 results take longer to receive a diagnosis following testing, they are more likely to be diagnosed with less aggressive more curable forms of disease and at an earlier stage than women with abnormal CA125 results
Summary
Ovarian cancer is the 6th most common cancer to affect UK women, with over 7,000 women diagnosed each year.[1]. Most women with ovarian cancer are diagnosed after presenting with symptoms in primary care, but ovarian cancer symptoms, such as bloating and abdominal pain, are non-specific and individual symptoms have relatively low positive predictive values (PPVs) for the disease.[5,6] In 2011 the guideline-producing body for England, Wales and Northern Ireland, the National Institute for Health and Care Excellence (NICE), advocated testing for the serum biomarker CA125 in women with symptoms of possible ovarian cancer in primary care.[7] NICE recommended that women with an elevated CA125 (>35U/ml) should undergo ultrasound testing; they did not provide guidance on the follow-up or investigation of women with ‘normal’ (
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