Comparison of surgical and oncological outcomes following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in upper and middle/lower rectal peritoneal metastases.

BACKGROUND

We aim to assess the surgical and oncological outcomes of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in upper rectal peritoneal metastases (U_PM) versus middle/lower rectal peritoneal metastases (ML_PM).

METHODS

Between January 2013 and March 2024, Data from 101 patients with rectal peritoneal metastases who underwent CRS with or without HIPEC were analysed (U_PM, n = 68; ML_PM, n = 33). Day-30 morbi-mortality, overall survival (OS) and recurrence-free survival (RFS) were compared.

RESULTS

Among 101 patients included, the median age was 58 years and 52.5% were women. Initial PCI score median was 6 [3; 13]. The U_PM group had longer surgery time (420 vs 370 min; p = 0.029). Surgical outcomes including postoperative complications, reoperation rate, ICU and hospital stays were not significantly different between U_PM and ML_PM groups. Severe complications (Dindo-Clavien 3-4) and death rates were similar between the two groups: (64.3% vs 75%; p = 0.399) and (1.5% vs 0%; p = 1.000); respectively. The 3-year and 5-year OS rates were 59.7% and 42% respectively and were significantly better for U_PM than for ML_PM patients: (68.1% vs 42.9%; p = 0.039) and (48.2% vs 32.2%; p = 0.044) respectively. Multivariable Cox proportional hazards analysis of survival up to 5 years identified ML_PM (HR = 1.93), PCI score (HR = 1.10) and HIPEC procedures with oxaliplatin (HR = 2.93) as significant risk factors of death. The 3 and 5-years RFS were similar between groups (p = 0.318) and (p = 0.376); respectively.

CONCLUSION

Patients presenting with upper rectal PM who underwent CRS with or without HIPEC have similar surgical outcomes except total surgery time and have significantly better OS at 3 and 5 years than patients with middle/lower rectal PM. RFS at 3 and 5 years was comparable between the two groups. Middle/Lower origin and PCI score were identified as significant risk factors of death. The primary tumor location of patients with rectal PM is an important factor that should not be underestimated. Larger prospective studies are required to confirm findings.