Circulating CA125 in patients with peritoneal mesothelioma treated with cytoreductive surgery and intraperitoneal hyperthermic perfusion

Background: Recent phase I/II trials report encouraging results in selected patients with peritoneal mesothelioma (PM) treated with cytoreductive surgery (CRS) and intraperitoneal hyperthermic perfusion (IPHP). Circulating tumor markers have never been extensively investigated in the management of PM. We assessed the clinical role of markers in a large series of patients with PM undergoing CRS and IPHP. Methods: Clinical data on 60 patients with PM operated with the intention to perform adequate CRS (residual tumor nodules <= 2.5mm) and IPHP were prospectively collected. Marker levels were determined pre-operatively, post-operatively, and routinely during long-term follow-up. Baseline diagnostic sensitivity, accuracy in monitoring response to treatment or tumor progression and prognostic significance were determined. Results: Baseline diagnostic sensitivity was 53.3% for CA125, 0 for CEA, 3.8% for CA19.9 and 48.5% for CA15.3. Forty-six patients underwent adequate cytoreduction and IPHP; gross residual tumor was left after the operation in fourteen. Postoperatively, CA125 became negative in 21/22 patients with elevated baseline levels undergoing adequate CRS and IPHP, while remained elevated in 9/9 patients with persistent macroscopic disease. CA125 became positive in 12/12 patients with elevated baseline levels developing disease progression after adequate CRS and IPHP. Baseline CA125 showed borderline prognostic significance only among patients not previously treated with systemic chemotherapy. Conclusions: CA125 was elevated in the majority of patients with PM in the present series. Serial maker measurements paralleled tumor growth or regression after CRS and IPHP, suggesting the need of further studies to assess the role of CA125 in this clinical setting.