Prognostic value of preoperative serum C-reactive protein level for survival in mucinous appendix cancer treated with complete CRS/HIPEC

Background

The role of systemic inflammation, a significant prognostic factor in various malignancies, is underexplored in mucinous appendix cancer (MAC). We assessed how inflammation, expressed by preoperative serum C-reactive protein (CRP), correlates with survival across MAC histopathologies managed with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

Methods

This retrospective cohort study included MAC patients with peritoneal dissemination, who had complete CRS/HIPEC (CC-0/1) (1998–2023). Preoperative serum CRP cut-off was defined with the minimum p-value approach and time-dependent receiver operating characteristic analysis. Survival was analyzed using the Kaplan-Meier method and Cox regression.

Results

Of 273 patients, 163 had low-grade and 110 had high-grade MAC. CRP cut-off was 2.00 mg/dL. Among low-grade, 132 patients had CRP<2 and 31 had CRP≥2. In high-grade, 87 patients had CRP<2 and 23 had CRP≥2. Median follow-up was 86 (95%CI: 48–124) months. In low-grade MAC, 5-year progression-free survival (PFS) was 88.5 % in CRP<2 and 53.9 % in CRP≥2 (p < 0.001), while 5-year overall survival (OS) was 89.2 % and 85.4 %, respectively (p = 0.018). In high-grade tumors, 5-year PFS was 46.5 % in CRP<2 and 19.3 % in CRP≥2 (p = 0.011), while 5-year OS was 56.5 % and 45.3 %, respectively (p = 0.291). Multivariate Cox regression showed a strong association of CRP≥2 with worse PFS (HR 5.10; 95%CI: 2.46–10.58) and OS (HR 3.18; 95%CI: 1.22–8.28) in low-grade MAC only.

Conclusions

Elevated pre-CRS/HIPEC serum CRP was associated with worse PFS and OS in low-grade, but not in high-grade MAC. These findings highlight CRP's utility in prognosis assessment and can be useful in identifying target MAC subgroups for studying anti-inflammatory agents.