Diagnosis of persistent ovarian carcinoma with three-step immunoscintigraphy

The diagnosis of recurrent ovarian carcinoma is usually determined at surgical re-exploration since the main non-invasive diagnostic tests have low accuracy. It would be desirable to have a high accuracy non-invasive diagnostic procedure. With this aim, we have assessed the utility of three-step immunoscintigraphy. Thirty patients were intravenously injected with biotinylated monoclonal antibodies MOv18 and B72.3, followed by avidin-streptavidin injection and finally by 111In-biotin. Tumour recurrences were imaged 2 h post radioactivity injection. All patients underwent surgical re-exploration 3-4 days after immunoscintigraphy; the presence of tumour in the area of immunoscintigraphic uptake was evaluated in the biopsied material. Twenty-one patients studied were true-positive, five were true-negative, four were false-positive and none was false-negative. The diagnostic accuracy, positive predictive value and negative predictive value were 87%, 84% and 100% respectively. If these findings are confirmed in a larger number of patients, we expect immunoscintigraphy to be introduced as a cost-effective procedure in the follow-up of patients who have received surgery for ovarian carcinoma, since it promises to reliably identify patients who do not require surgical re-exploration, and guide biopsies when they are indicated.