Attending surgeon Fondazione IRCCS Istituto Nazionale dei Tumori, Milano (Italy) Milano, Lombardia, Italy
Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Participants should be aware of the following financial/non-financial relationships:
Dario Baratti: I do not have any relevant financial / non-financial relationships with any proprietary interests.
Introduction: Systemic metastases from pseudomyxoma peritonei (PMP) have been occasionally documented, but the true metastasizing potential of PMP has never been thoroughly investigated. We assessed incidence, impact on prognosis, treatments, and outcomes of systemic metastases after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).
Methods: A prospective database of 327 patients undergoing CRS/HIPEC for PMP of appendiceal origin was reviewed. PMP was graded according to the Peritoneal Surface Oncology Group International (PSOGI) classification. Haematogenous metastases, and non-regional lymph-node involvement were considered as systemic metastases.
Results: After a median follow-up of 74.8 months (95% confidence interval [CI]=68.0-94.8), systemic metastases occurred in 21 patients. Of them, 11patients were affected by low-grade PMP, and 10 by high-grade PMP; surgical cytoreduction was macroscopically complete in 9 patients, and near complete in 12 (residual disease ≤2.5mm). Metastatic disease involved the lung (n=12), bone (n=1), liver (n=4), distant nodes (n=3), both lung and distant nodes (n=1). Systemic metastases independently correlated with PSOGI histological subtypes (P=0.001), and incomplete cytoreduction (P=0.026). Median OS was 139.0 months (95%CI=56.6-161.9) for patients who experienced systemic metastases, and 213.8 months (95%CI=148.7-not reached) for those who did not (P=0.159). Eleven patients had curative-intent surgery for their systemic metastases. Eight of them are presently alive at a median of 52.5 months (range 2.0-112.7). Seven are disease-free at a median of 27.4 months (range 2.0-110.4) after surgical resection of metastatic disease. At multivariate analysis, PSOGI histological subtypes (P=0.001), completeness of cytoreduction (P=0.001), and preoperative systemic chemotherapy (P=0.020) correlated with poorer survival. Systemic metastases did not (P=0.861).
Conclusions: After CRS/HIPEC, systemic metastases occur in a small but clinically relevant number of patients with PMP, and the risk increases with incomplete cytoreduction and aggressive histology. In selected patients, surgical resection of metastatic disease can result in long survival.
Learning Objectives:
Upon completion, participant will be able to define the risk for the occurrence of systemic metastases in patients with pseudomyxoma peritonei treated by citoreductive surgery and hyperthermic intraperitoneal chemotherapy
Upon completion, participant will be able to define clinical management of systemic metastases in patients with pseudomyxoma peritonei treated by citoreductive surgery and hyperthermic intraperitoneal chemotherapy
Upon completion, participant will be able to define the nature of a disease entity still poorly understood, such as pseudomyxoma peritnei, as a disseminating but also potentially metastasizing condition
