Diagnosing intra-abdominal malignancy

Cytology testing of ascitic fluid may be of limited usefulness in the detection and management of malignancy. Initial assessment should instead concentrate on a thorough history with examination, which should then direct any further laboratory assessment, with cell count and differential, albumin, and culture being mandatory. Additionally serum albumin should be obtained to calculate the serum-ascites albumin gradient as an important determinate of the differential count.

A literature search and retrospective audit was conducted for a major English teaching hospital. Of 276 samples sent for assessment, 45 female and three male specimens were found to contain malignant cells. Of these, 85% (n = 41) were ovarian in origin. Of the remaining 228 specimens (from 84 male and 108 female patients), 220 were reported to have no evidence of malignancy and eight to be inadequate. In this group, the results of 35 (19%) patients were found to be false negatives, and their cancer was detected by radiological investigations.

In the management of ovarian cancer, ascitic fluid collected during the operation is important for staging and is of prognostic value. For other intra-abdominal malignancies ascites is associated with a poorer prognosis.

The study results have led to the following recommendations. Firstly, cytology samples should be sent only for women as this is the only group of patients to show a sizeable detection rate and a positive result that could alter management.

Secondly, if history and examination are not conclusive or suspicious of malignancy, ascitic and serum albumin should be measured in the initial paracentesis to aid diagnosis, rather than sending “routine” cytology.

Thirdly, early ultrasound should be undertaken in suspected malignant ascites, rather than waiting for the cytology result.