Impact of Aggressive Histology and Location of Primary Tumor on the Efficacy of Surgical Therapy for Peritoneal Carcinomatosis of Colorectal Origin

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) for peritoneal carcinomatosis (PC) of colorectal origin increases survival (OS) compared to systemic chemotherapy alone. Signet ring histology demonstrates aggressive behavior with poor survival. We sought to determine whether CRS/HIPEC increases survival in this subset of patients.

We reviewed 67 patients with PC of appendiceal (AP, n = 37) or colorectal origin (CRC, n = 30) with signet cell histology from a prospective database between May 2001 and August 2011. Survival analysis and multivariate Cox regression were used to determine prognostic factors for survival.

Complete CRS (CC-0/1) was achieved in 77 % (CRC) and 73 % (AP) of patients. Progression-free survival (PFS) and OS were 9 and 12 months in CRC and 12 and 21 months in AP patients. In the CRC group, univariate predictors of poor survival included female gender, age, American Society of Anesthesiologists score, preoperative albumin, completeness of cytoreduction, and morbidity. In a multivariate Cox regression model, incomplete cytoreduction (CC-2/3) and female gender were joint significant predictors of poor survival. In the AP group, significant univariate predictors of poor survival included higher EBL and PCI score. In a multivariate Cox regression model, blood loss of >500 ml and a body mass index of <25 kg/m² were joint significant predictors of poor survival.

AP signet cell tumors demonstrate a more favorable outcome than CRC signet cell tumors after CRC/HIPEC for carcinomatosis, suggesting an underlying difference in biology. CRS/HIPEC does not confer survival benefit in colorectal signet ring carcinomatosis unless complete cytoreduction can be achieved, whereas appendiceal signet ring carcinomatosis may benefit, regardless of resectability.