Evaluation of a standardized protocol of intracavitary recombinant interferon alpha-2b in the palliative treatment of malignant peritoneal effusions. A prospective pilot study.

OBJECTIVE

Several schedules with variable doses of intracavitary interferon have been proposed for the management of metastatic peritoneal effusions. This prospective pilot study evaluated the efficacy of a standardized schedule of intraperitoneal interferon alpha(2b).

METHODS

In 41 cancer patients with malignant ascites a 9-french intraperitoneal catheter was placed under sonographic guidance, and ascites was drained until abdominal ultrasound showed complete absence of effusion. Interferon alpha(2b), 6 or 9 million units (body weight <or= or >50 kg, respectively), was then administered via the tube, which was clamped for 6 h. 6 courses were given at 4-day intervals. In comparison with pretreatment levels, the 30-day response was classified as complete (CR) = no fluid recurrence, partial (PR) = fluid recurrence <50% and no response (NR) = >50%. Responders were monitored until fluid recurrence requiring paracentesis.

RESULTS

12 patients had CR, 15 PR, 14 NR. Global response (GR) was 65.9%. In ovarian cancer, GR was 75% and was not influenced by the quantity of the pretreatment daily fluid production. In the other cancers, a pretreatment fluid production <or=500 ml/day was associated with a significantly higher response (p < 0.05). Patients not showing response within the first 3 courses did not respond after the next courses. 60-day GR was 41.5%, 90-day GR was 26.8%. The mean time to fluid reaccumulation was 70.5 +/- 75.3 versus 11.4 +/- 4.4 days before treatment (p < 0.001). The survival of responders was 38-394 days (mean 131), and the average duration of response was 101 days.

CONCLUSION

This protocol could be reasonably applied to ovarian cancer patients and to patients with other cancers having a fluid production of <or=500 ml/day, and it should be stopped if no response is observed after 3 courses of treatment.