The study comprised 799 patients: 751 female (94%) and 48 male (6%) patients, with 636 (80%) of the patients being over 50 years old. In this population, 221 (29%) of the female and 22 of the 48 male patients had an abnormal result (fig 1).
Because ovarian cancer was not relevant to the male population these patients were excluded from all further analyses. An indication for CA125 use in the female patients was apparent in 672 (89%) of cases (fig 2). A suspicion of ovarian cancer only accounted for 259 (34%) of the CA125 tests performed. A large proportion of CA125 tests—327 (44%)—were undertaken to investigate patients with a wide range of signs and symptoms (table 1).
When the CA125 concentration was correlated with the final diagnosis in patients having a CA125 measurement for suspicion of malignancy/ovarian cancer only 39 (20%) of the abnormal results in the female population were the result of ovarian cancer. The sensitivity of CA125 for ovarian cancer in female patients in this population was 88.6%, but with a specificity of only 72.0%. Patients without ovarian cancer had another malignancy in 48 cases (26%)—such as breast, bowel, or lung—or had benign ovarian pathology (26 cases; 14%), benign gynaecological conditions, particularly leiomyoma (18 cases; 9%), or hepatobiliary disease (12 cases; 6%) (fig 3). When the CA125 results over 1000 kU/litre were analysed the specificity of CA125 increased to 99.1%. Ovarian cancer was diagnosed in 23 of 28 cases, but there were five patients who had a CA125 concentration above 1000 kU/litre in the absence of ovarian cancer. There were three cases of metastatic disease from the breast, gallbladder, and an unknown primary tumour, and there were two cases of cirrhotic liver disease. However, increasing the cut off value to over 1000 kU/litre caused a fall in the sensitivity of CA125 for ovarian cancer to 52.3%.
The radiological investigations performed on the female population being investigated for suspicion of malignancy/ovarian cancer were reviewed (fig 4). Ultrasonography was the most frequently used modality, with 310 patients (53%) having a pelvic ultrasound as their sole investigation and 91 (16%) undergoing this test in conjunction with computerised tomography scanning. Urgent (within two weeks) diagnostic laparoscopy was performed in seven cases, five of which were preceded by a transvaginal ultrasound scan. One patient was investigated with magnetic resonance imaging. The likelihood of the ovaries being imaged increased with a rising CA125 result, except for patients with a CA125 between 500.1 and 1000 kU/litre. No imaging was performed in 134 (23%) cases; however, 108 (81%) of these had a normal CA125 result.
In this study population, 44 patients were diagnosed with first presentation of a malignant ovarian cancer. In 36 of these, the indication for a CA125 measurement was that they fell into the category of suspicion of ovarian cancer. The CA125 concentrations of these patients were examined and showed a wide distribution of results, with 23 patients having more than 1000 kU/litre but five having less than 30 kU/litre.
Additional serum tumour markers taken at the time of the index CA125 result showed that 422 (56%) of the female population had CA125 taken in isolation, unlike the male population in which the figure was 10 cases (20%). Of the 57 patients who were below 40 years old, only four had an HCG and AFP performed, one patient had AFP alone, and another HCG alone.
Screening for ovarian cancer only accounted for 24 patients in the audit. Ten of the tests were ordered in primary care, with gynaecologists responsible for seven cases and general surgeons for four cases. Imaging of the ovaries with transvaginal ultrasonography was performed in 13 of the 24 patients being screened.
The final analysis concentrated on the departments ordering CA125 measurement. Rheumatology, care of the elderly medicine, and haematology were grouped together as “other medical specialities” and orthopaedics and urology as “other surgical specialities”. Gynaecologists were the most frequent users of CA125, but accounted for only 278 (36%) of all the tests ordered on female patients. Many other specialities, in particular—general surgery (109 tests; 15%), primary care (89 tests; 12%), and general medicine (78 tests; 10%)—were responsible for most of the remainder (fig 5).
In the male population, general medicine and general surgery initiated most of the requests for CA125—16 tests (33%) and 10 tests (21%), respectively.