The American Society of Peritoneal Surface Malignancies (ASPSM) Multiinstitution Evaluation of the Peritoneal Surface Disease Severity Score (PSDSS) in 1,013 Patients with Colorectal Cancer with Peritoneal Carcinomatosis

Background: Extensive clinical experience suggests that hyperthermic intraperitoneal chemotherapy (HIPEC) may play an important role in the management of colorectal cancer patients with peritoneal carcinomatosis (CRCPC). However, there remains no established nonsurgical process to rationally select patients for this management, either for inclusion/stratification in clinical trials or as a component of standard of care. The Peritoneal Surface Disease Severity Score (PSDSS) was introduced as a basis to improve patient selection.

Methods: The American Society of Peritoneal Surface Malignancies conducted a retrospective review of 1,013 CRCPC patients. The PSDSS was evaluated on 3 specific criteria obtained before surgery (symptoms, extent of peritoneal dissemination, and primary tumor histology). Overall survival was analyzed according to four tiers of disease severity, and a comparison was made between patients who underwent cytoreductive surgery + HIPEC and those who did not.

Results: The PSDSS was calculated on 884 patients (87 %). The median survival of 275 patients not undergoing CRS/HIPEC based on their PSDSS—I (n = 8), II (n = 80), III (n = 55), and IV (n = 132)—was 45, 19, 8, and 6 months, respectively. The median survival of 609 patients who underwent CRS/HIPEC based on their PSDSS—I (n = 75), II (n = 317), III (n = 82), and IV (n = 135)—was 86, 43, 29, and 28 months, respectively.

Conclusions: These data support that the PSDSS, undertaken before surgery, is capable of defining CRCPC populations who have a statistically defined high or considerably lower likelihood of long-term survival after CRS/HIPEC. The PSDSS can be quite useful in the decision to enter CRCPC patients into, and their stratification within, clinical trials.