Skip to main content
SSO 2024 Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Presentation Icons
Recorded for On-Demand Viewing
Recorded for On-Demand Viewing
Back

Peritoneal Surface Malignancies

E345: Novel scoring system to assess the response to PIPAC therapy in patients with peritoneal cancer

Introduction:

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a promising treatment option for patients with peritoneal cancers. During PIPAC, a laparoscopy is performed and chemotherapy is applied to the abdominal cavity as an aerosol under pressure. This allows for direct targeting of peritoneal lesions. PIPAC was shown to be safe and well tolerated for patients with peritoneal cancers of various origins. However, one of the main challenges of PIPAC remains the objective assessment of treatment response. Here, we present a modified scoring system, QARP (Quantitative Assessment of Regression in Peritoneal cancer), to assess the histological regression in peritoneal cancer biopsies following PIPAC treatment.

Methods: Peritoneal biopsies from 27 patients with peritoneal metastases undergoing PIPAC were obtained. The percentage of tumor cells and/or regressive changes was determined for each tumor focus and a score from 0 to 5 was assigned:


  • 0 - no residual tumor cells with regressive changes present;

  • 1 - 1 to 25% viable tumor cells per tumor focus with regressive changes present;

  • 2 - 26 to 50% viable tumor cells per tumor focus with regressive changes present;

  • 3 - 51 to 75% viable tumor cells per tumor focus with few regressive changes;

  • 4 - more than 75% viable tumor cells per tumor focus with minimal or no regressive changes.



Results:

The median age of patients included in this study was 62. There were 13 male (48.1%), 14 female (51.9%) patients. The primary cancer origins were esophagogastric in 8 (29.6%), colorectal in 10 (37.0%), pancreatic in 5  (18.5%), biliary in 3 (11.1%) and appendiceal in 2 patients (7.4%). Regressive changes within the peritoneal biopsies were determined by QARP for each PIPAC cycle. 9 patients showed improvement in QARP scores over time and 5 patients had stable low QARP scores (QARP 0 or 1) in every procedure. These patients were labelled as “QARP responders”. 13 patients had either stable high QARP scores (QARP 4) or worsening scores over time. These patients were labelled as “QARP non-responders”. PCI scores for each patient and procedure were compared with QARP scores. QARP and PCI showed a weak, but significant, positive correlation (r=0.32; p=0.007), i. e. higher QARP scores correlated with higher PCI scores. Survival times for QARP responders and QARP non-responders, were plotted on a Kaplan-Meier graph. The survival curves cross at 15 months and there is no significant difference in overall survival for both groups (p=0.43; log-rank).

Conclusions:

QARP proved to be a useful tool for quantifying treatment response after PIPAC and correlated with the macroscopic cancer burden.

Learning Objectives:

  • Upon completion, participant will be able to describe the basic steps of a PIPAC procedure.
  • Upon completion, participant will be able to list the established methods for quantification of response to therapy in peritoneal cancer.
  • Upon completion, participant will be able to describe the key aspects of our novel QARP score as a measure of treatment response in peritoneal cancer.