Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal neoplasms of the digestive system, representing 1%-2% of gastrointestinal malignancies [1,2]. They are primarily located in the stomach (50%) and small bowel (25%) [[1], [2], [3]]. Surgical resection is the main treatment for localized GISTs, though recurrence rates can be as high as 40% [[4], [5], [6], [7]]. Before tyrosine kinase inhibitors (TKIs) like imatinib were introduced in 2002, survival for unresectable or metastatic GISTs was limited, with a median survival of about 1.5 years [2,[4], [5], [6],8]. Imatinib has improved survival significantly, with response rates of 45%-68%, and median survival of 3.9-4.8 years [[9], [10], [11], [12], [13]]. However, 15% of patients are resistant to imatinib initially [[14], [15], [16]], and over 80% develop resistance after 20-24 months due to secondary mutations [14,17,18]. Second-line (sunitinib) and third-line (regorafenib) TKIs show less favourable results [[19], [20], [21]]. Surgical resection of residual disease in imatinib-responding patients may help delay resistance and improve survival [[22], [23], [24], [25]]. A multidisciplinary approach with cytoreductive surgery (CRS) and systemic therapy is used for liver metastases to improve disease control and survival [[22], [23], [24], [25]].

Disseminated peritoneal sarcomatosis (PS) from GISTs, or GISTosis, has a poor prognosis and is often considered incurable [26,27]. For this, TKIs or supportive care are recommended, with surgery reserved for complications [26,27]. The success of CRS for liver metastases raises questions about its possible benefits for GISTosis [28]. Few studies have focused on GISTosis as a distinct patient cohort [[29], [30], [31], [32]], and only two studies have analysed it in the TKI era [33,34], with limited cases. As a result, evidence-based management of GISTosis is unclear, and treatment recommendations are based on expert consensus [[37], [38], [39], [40]]. The 5-year OS remains uncertain, as the optimal therapeutic approach and key prognostic factors have yet to be fully identified [[29], [30], [31], [32]]. This study aimed to assess the outcomes of surgical resection in GISTosis patients through a national survey in Spanish specialized centres and identify prognostic factors to guide therapeutic decisions.