Predictors of progression in high-grade appendiceal or colorectal peritoneal carcinomatosis after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

Background: Long-term survival of patients with appendiceal or colorectal peritoneal carcinomatosis (PC) may be achieved by combining cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Unfortunately, such favorable outcomes are realized in a minority of patients. Given the morbidity of the CRS/HIPEC and the uncertain role of postresection systemic therapy, it is important that prognostic factors in high-grade PC be clearly defined.

Methods: This single center, retrospective, cohort study examined the outcomes of CRS/HIPEC performed on patients with high-grade PC secondary to appendiceal or colorectal adenocarcinoma between 2007 and 2013. Cox regression analysis was utilized to evaluate the association between potential prognostic factors [age, sex, primary site, lymph node (LN) status, peritoneal cancer index (PCI) score, completeness of cytoreduction score (CC score), number of visceral resections, and systemic chemotherapy] and progression-free survival (PFS).

Results: A total of 70 patients with high-grade appendiceal or colorectal PC underwent CRS/HIPEC during the study period; 82.9 % underwent complete (CC-0) cytoreduction with a median PFS of 9.7 months. Positive LNs at the time of CRS/HIPEC were predictors of worse PFS on univariate and multivariate analysis. No association was demonstrated between pre- or post-HIPEC systemic chemotherapy and PFS.

Conclusions: High-grade PC secondary to appendiceal or colorectal adenocarcinoma can be managed with CRS/HIPEC. The number of LN metastases at the time of CRS/HIPEC is the strongest predictor of progression and must be considered when determining patient eligibility for this aggressive treatment.