Long-term outcomes of elderly patients with peritoneal metastases of colorectal origin after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Introduction: Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) were reportedly safe for the elderly. However, long-term survival data in this subgroup of patients are scarce. Our aim was to evaluate the peri-operative and long-term outcomes of CRS + HIPEC in colorectal peritoneal metastases (CRC-PM) in patients ≥70 years of age. Material and methods: We retrospectively analyzed our combined institutional databases for patients who underwent CRS + HIPEC for CRC-PM. Clinical and pathological characteristics, as well as overall survival (OS) and progression-free survival (PFS) were compared between the groups. Tumor extent was measured by the peritoneal carcinomatosis index (PCI) and completeness of cytoreduction by the CCR score. Major morbidity was defined according to Clavien-Dindo classification. Results: The dataset of 159 patients included 33 elderly and 126 non-elderly patients. Clinical characteristics between the groups differed only in medical comorbidities (Charlson comorbidity index 10 vs. 7, P < 0.001) and delivery of post-HIPEC adjuvant treatment (12.5% vs. 43.8%, P = 0.004). Overall PCI and CCR0 rates were similar between the groups, as were length of stay and major morbidity and mortality rates. Long-term outcomes in the elderly group were lower than those of the non-elderly (median OS: 21.8 vs. 40.5 months, P < 0.001; median PFS: 6 vs. 8 months, P = 0.02, respectively). Conclusions: CRS + HIPEC in selected elderly patients can be safe in terms of postoperative morbidity and mortality. However, despite the same surgical extents and radicality, their long-term outcomes are inferior, possibly due to under-usage of systemic chemotherapy.