Prognostic value of circulating tumor markers in patients with Pseudomyxoma Peritonei treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Background: Encouraging results have been recently reported in selected patients affected by pseudomyxoma peritonei (PMP) treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The selection factors predicting clinical outcome are still a matter of clinical investigation. We assessed the prognostic reliability of serum tumor markers in a large series of patients with PMP undergoing CRS and HIPEC. Methods: Sixty-two patients with PMP were operated on at a single institution with the intent of performing adequate CRS (residual tumor nodules <= 2.5mm) and HIPEC. Baseline and serial marker measurements were prospectively collected and tested by multivariate analysis with respect to adequate cytoreduction, overall (OS) and progression-free (PFS) survival, along with the following variables: age, sex, performance status, prior surgical score, histological subtype, prior systemic chemotherapy, disease extent, completeness of cytoreduction. Results: Baseline diagnostic sensitivity was 72.6% for CEA, 58.1% for CA19.9, 58.7% for CA125, 36.1% for CA15.3. Fifty-three patients underwent adequate CRS and HIPEC; gross residual tumor was left after surgery in nine. Adequate CRS was performed in 19/27 patients with elevated and in 19/19 with normal baseline CA 125 (P = .0140). The other markers were unable to predict the completeness of CRS by univariate analysis. Baseline elevated CA19.9 was an independent predictor of reduced PFS; inadequate CRS and aggressive histology were independent prognostic factors for both reduced OS and PFS. Conclusion: Normal CA125 correlated to the likelihood to achieve adequate CRS, which is a significant prognostic factor for PMP. Increased baseline CA19.9 was an independent predictor of worse PFS after CRS and HIPEC.