eP285 - Stage 4 Colorectal Cancer with Liver and Peritoneal Metastases: Curative or Palliative Resection?

Purpose/Background: Peritoneal carcinomatosis (PC) develops in 15% of patients with primary colorectal cancer (CRC) while liver metastases (LM) has been observed in 35% of CRC patients. When both PC and LM are present, the prognosis tends to be poor. Treatment is typically systemic chemotherapy with surgery reserved for palliation. The objectives of our study are to determine the incidence of PC in patients who undergo colorectal resection and hepatic metastasectomy and whether any subsequent operation performed to address the peritoneal metastases improved survival.Methods/Interventions: A retrospective review was performed for all primary CRC patients with LM who underwent surgical resection from 2010 to 2020 within our integrated healthcare system. Patients with evidence of other distant metastases were excluded. Age, gender, race, hospital length of stay, location and histology of the primary tumor, complications, chemotherapy use, and survival were examined. A univariate analysis compared the demographics, surgical outcomes, and complications between groups. An unpaired two-sample T-test was used for continuous variables, and a chi-squared analysis was used for categorical variables. Primary endpoints included the incidence of PC in patients with CRC metastatic to the liver, whether patients with PC were offered debulking surgery, and if there was a survival benefit to cytoreduction. Secondary endpoints included risk factors for the development of PC.Results/Outcomes: 113 CRC patients with LM underwent synchronous or staged primary colon and liver resections. 10 patients had developed PC (8.8%, median follow-up 44.8 mo). 5 patients appeared to have peritoneal disease at the time of surgical resection (4 synchronous, 1 staged) while the other 5 patients developed PC later (median time 19.2 mo). 7 PC patients underwent debulking surgery with 1 patient receiving hyperthermic intraperitoneal chemotherapy. 5 of these patients were treated with curative intent while the remaining 2 patients underwent palliative debulking to relieve bowel obstructions. Of the 3 patients who did not undergo debulking, 2 patients had extensive peritoneal implants, and 1 patient declined further surgical intervention. Among the 10 PC patients, 6 patients only had peritoneal recurrence while 4 patients developed additional new sites of distant metastasis. There were no significant differences in terms of age, gender, race, location of primary tumor, tumor pathology, timing to surgery, staged vs synchronous resection, post-operative complications, and administration of systemic chemotherapy and immunotherapy. PC patients had a significantly shorter survival compared to patients without PC (median survival 19.7 mo vs 39.2 mo, P=0.028). Among those with carcinomatosis, there was no significant survival benefit to R0 surgical debulking compared to no debulking although there are still 2 survivors (40%) in the R0 group versus none in the control group (p=0.21). When palliative debulking was included in the analysis, there are 3 total survivors (42.9%, p=0.18).Conclusion/

Discussion: Colorectal cancer with metastasis exclusively to the liver demonstrates peritoneal spread at an incidence of 8.8% during a median follow-up of 44.8 months. There were no obvious risk factors for the development of peritoneal carcinomatosis. Locoregional control with curative or palliative surgical debulking may offer improved survival for these patients with stage 4 disease although future studies with larger data sets will need to be obtained and further analyzed.Study DesignThis table demonstrates which of the 10 patients with peritoneal carcinomatosis underwent curative or palliative surgical debulking and whether or not there was a survival benefit for this type of locoregional control in metastatic colorectal cancer