Locoregional Control from Complete Peritoneal Cytoreduction in Patients with Extraperitoneal Colorectal Cancer...

Area of Science:

• Surgical Oncology
• Gastrointestinal Oncology
• Cancer Metastasis Research

Background:

• Colorectal cancer with peritoneal metastases (CRC-PM) presents a significant challenge in locoregional disease control.
• The presence of concurrent extraperitoneal metastases (EPM) in CRC-PM patients complicates treatment strategies and prognostic assessment.
• Complete cytoreductive surgery (CRS) is a cornerstone treatment for peritoneal disease, but its role in the setting of EPM requires further elucidation.

Purpose of the Study:

• To evaluate the efficacy of complete cytoreductive surgery (CRS) in achieving locoregional disease control for patients with colorectal cancer and peritoneal metastases (CRC-PM) who also have concurrent extraperitoneal metastases (EPM).
• To compare oncologic outcomes, including progression-free survival (PFS), peritoneal progression-free survival (p-PFS), and overall survival (OS), between CRC-PM patients with and without EPM.
• To identify prognostic factors and patient subgroups that may benefit from CRS in the presence of EPM.

Main Methods:

• A retrospective institutional study identified patients who underwent complete cytoreductive surgery (CC-0/1 CRS) for CRC-PM.
• Patients were categorized into two groups: those with peritoneal disease only (PDO) and those with concomitant EPM.
• Entropy balancing was employed to address covariate imbalance between groups, followed by weighted Cox proportional hazards modeling to analyze survival outcomes (PFS, p-PFS, OS). Subgroup analyses were conducted to explore prognostic factors.

Main Results:

• Of 83 patients, 31 (37.4%) had EPM, most commonly involving the liver or lung.
• Unadjusted analyses showed similar overall survival (OS) and peritoneal progression-free survival (p-PFS) between groups, but longer progression-free survival (PFS) in the PDO group.
• After entropy balancing, patients with EPM exhibited significantly worse OS (HR 2.12) and PFS (HR 2.7) but comparable p-PFS (HR 1.10). Subgroup analyses indicated similar OS and p-PFS for patients with PDO and those with single-site liver or lung EPM.

Conclusions:

• Complete cytoreductive surgery (CRS) can achieve durable locoregional disease control even in the presence of extraperitoneal metastases (EPM) in colorectal cancer patients.
• While CRS manages peritoneal disease effectively, the presence of EPM is associated with poorer overall survival and progression-free survival outcomes compared to patients with peritoneal disease only.
• Patients with single-site liver or lung EPM may represent a favorable prognostic subgroup benefiting from CRS, warranting further investigation.