Surgical management of gastrointestinal stromal tumor (GIST)-Induced sarcomatosis (GISTOSIS)

The optimal management of intra-abdominal dissemination of gastrointestinal stromal tumor (GISTosis) remains unclear. We performed a multi-institutional retrospective review of patients undergoing cytoreductive surgery (CRS) to evaluate overall (OS) and recurrence-free survival (RFS), and the impact of clinical and pathological factors.

From 2000 to 2021, 49 patients with GISTosis from 10 Spanish institutions were identified; 37 underwent CRS. Clinical and pathological data were collected, and OS/RFS were calculated using Kaplan-Meier analysis.

Among 37 patients, 53.8% were female, 56.7% under 57 years old, and 67.5% ECOG 0. GISTosis was synchronous in 37.8%. Mean peritoneal cancer index (PCI) was 17.6. At diagnosis, 16.2% had metastases. Neoadjuvant therapy followed by adjuvant tyrosine kinase inhibitors (TKI) was used in 48.6%. Complete cytoreduction (CC-0) was achieved in 83.7%, and 21.6% received HIPEC. Major complications occurred in 13%, with 2.7% postoperative mortality. After 85.6 months' median follow-up of, recurrence occurred in 24.3% (median time to recurrence was 0.97 years). RFS at 1, 3, and 5 years was 81.1%, 75.6%, and67.6%; OS was 97.2%, 86.1% and 77.8%.

CRS for GISTosis, especially with adjuvant TKI, yields favourable long-term outcomes in well-selected patients.