Recurrence Incidence and Optimal Surveillance After Complete Cytoreductive Surgery and Hyperthermic Intraperitoneal...

Area of Science:

• Oncology
• Surgical Oncology
• Cancer Research

Background:

• Optimal surveillance strategies for mucinous appendix cancer (MAC) following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) are not well-defined.
• Identifying critical postoperative time intervals with changing recurrence probabilities is essential for effective patient monitoring.

Purpose of the Study:

• To determine optimal surveillance intervals for mucinous appendix cancer (MAC) based on distinct recurrence risk periods after CRS/HIPEC.
• To analyze recurrence patterns according to histology: low-grade (LGMCP), high-grade (HGMCP), and signet-ring cell (SRC).

Main Methods:

• A prospective database of 385 stage IV MAC patients treated with CRS/HIPEC (1998-2024) was analyzed.
• A piecewise exponential recurrence-free survival model identified significant postoperative recurrence periods.
• Cumulative recurrence risk (CRR) was calculated per histology and period to model optimal surveillance frequency.

Main Results:

• Three recurrence risk periods were identified: 6-16 months, 16-48 months, and 48-120 months post-surgery.
• Cumulative recurrence risk (CRR) varied significantly by histology and period, with the highest rates observed in the earliest period.
• Recommended surveillance intervals varied: LGMCP (5.5-18 months), HGMCP (2-24 months), and SRC (2.5-24 months) across the identified periods.

Conclusions:

• Mucinous appendix cancer demonstrates distinct recurrence probabilities influenced by histology and specific post-CRS/HIPEC timeframes.
• A histology-tailored surveillance schedule, considering these key recurrence periods, is recommended for patients with MAC.