Post-operative wall shear stress in the superior mesenteric artery: Biomarker of long term outcome in patients with residual disease after incomplete cytoreductive surgery for pseudomyxoma peritonei

Background: After incomplete cytoreductive surgery (CRS), the assessment of pseudomyxoma peritonei (PMP) progression remains challenging. The objective was to assess the efficacy of wall shear stress (WSS) measured in superior mesenteric artery (SMA) to predict PMP progression in the postoperative setting to propose additional treatments.

Methods: In a prospective study, 52 patients with PMP had Doppler-ultrasound examination of the SMA with WSS calculation within one year after CRS with a mean follow-up of 43.3 ± 18.3 months. Patients were categorized according to the completeness of CRS and clinical outcome: Group-1 (n = 19): complete CRS and no recurrence, group-2 (n = 20): incomplete CRS with slowly progressive disease (alive at 2 years without severe clinical symptoms), group-3 (n = 13): incomplete CRS and severe clinical symptoms or dead within two years. Results of WSS were compared between groups and to 24 healthy subjects.

Results: WSS measured in the SMA was superior in Group-3 (19.6 ± 8.2 dynes/cm²) than in Group-2 (9.2 ± 1.8 dynes/cm², p = 1.10^-6), Group-1 (10.4 ± 2.8 dynes/cm², p = 8.10^-5), and healthy patients (8.7 ± 2.8 dynes/cm², p = 9.10^-7). One year after surgery, among patients with incomplete CRS a cut-off value of 12.1dynes/cm² allowed distinguishing patients without from those with severe disease progression with a sensitivity of 100% and a specificity of 100% (p < 1.10^-4) AUC = 1.000 [95%CI: 0.897-1.000].

Conclusion: Post-operative assessment of the WSS in the SMA in patients with incomplete CRS for PMP should be considered as biomarker of tumor progression in the postoperative setting. Therefore, WSS could be useful to target patients needing adjuvant systemic chemotherapy one year after CRS.