Outcome of elevated CA125 values from primary care following implementation of ovarian cancer guidelines

Ovarian cancer presents later in the UK compared to economically similar countries. National guidance suggests measuring CA125 in primary care as a means of bringing patients to specialist attention.

To investigate the outcome of CA125 values measured in accordance with this policy.

Examination of the laboratory records of female patients from the usual catchment population of one general hospital in whom CA125 was measured from primary care in a calendar year.

Those with values >35 u/ml were identified. Electronic records within the hospital were interrogated to identify what further evaluation had been undertaken whether ovarian or primary peritoneal cancer had been diagnosed or what other pathology was identified. We also reviewed the CA125 measurement history of patients diagnosed over 3 years by any route.

One hundred and sixty-four new cases of CA125 ≥35 u/ml were found. Further information was available for 152 of them. Sixteen had ovarian or primary peritoneal cancer and 16 had other cancers. In 50 no cause for the abnormality was found. The remainder had various non-malignant conditions. The specificity for carcinoma of ovary/primary peritoneal carcinoma was 95.4% [95% confidence interval: 94.8-96.0). In a 3-year period, 65 patients were diagnosed with ovarian or primary peritoneal cancer, 5 had values of CA125 between 20 and 35 u/ml shortly before diagnosis.

The CA125 level is a useful diagnostic test for ovarian cancer which has been embraced by primary care but higher sensitivity for earlier disease will require strategies to improve the specificity.