BACKGROUND: Pressurized Intraperitoneal Aerosol chemotherapy (PIPAC) is a local treatment for peritoneal metastasis (PM). Prospective data are scarce and evaluation of treatment response remains difficult. This study evaluated the use of the Peritoneal Regression Grading score (PRGS) and its prognostic value.
PATIENTS AND METHODS: This was a prospective, controlled phase II trial in patients with PM from gastrointestinal, gynaecological, hepatopancreatobiliary, primary peritoneal, or unknown primary cancer. Patients in performance status 0-1, with a non-obstructed gastrointestinal tract, and a maximum of one extraperitoneal metastasis were eligible. Colorectal or appendiceal PM had PIPAC with oxaliplatin, other primaries had PIPAC with cisplatin and doxorubicin. Biopsies were taken at each PIPAC and evaluated using the PRGS. Quality-of-life questionnaires were reported at baseline and after three PIPACs.
RESULTS: One hundred ten patients were treated with 336 PIPACs (median 3, range 1-12). One hundred patients had prior palliative chemotherapy and 45 patients received bidirectional treatment. Complete or major histological response to treatment (PRGS 1-2) was observed in 38 patients (61%) who had three PIPACs, which was the only independent prognostic factor in a multivariate analysis. The median overall survival (mOS) from PIPAC 1 was 10 months, while patients with PM from gastric, colorectal, and pancreatic cancer had a mOS of 7.4, 16.7, and 8.2 months, respectively. Global health scores were significantly reduced, but patients were less fatigued, nauseated, constipated, and had better appetite after three PIPACs.
CONCLUSIONS: PIPAC with oxaliplatin or cisplatin and doxorubicin was able to induce a major or complete histological response during three PIPACs, which may provide significant prognostic information, both at baseline and after treatment.