Introduction: The present study was undertaken to define the clinical differences between leiomyosarcomas (LMS) occurring within the abdomen and retroperitoneum and gastrointestinal stromal tumors (GIST).
Methods: It was a retrospective, single-institution review of patients treated for intra-abdominal and retroperitoneal GIST and LMS from July 1, 1982 through August 1, 1999.
Results: A total of 561 patients, 239 with GIST and 322 with LMS, were identified. Patients with GIST were older, with a median age of 58 years versus 54 years in the LMS group (P < .01). The majority of patients with GIST were male (58%), whereas 68% of LMS patients (excluding gender-specific sites) were female (P < .01). The 5-year disease-specific survival for GIST and LMS were 28% and 29%, respectively. The presentation status and ability to achieve a complete surgical resection were the main independent predictors of outcome for both GIST and LMS. Local and distant recurrence was common in both. The pattern of distant recurrence differed: 50% of all first-site GIST recurrences involved the liver, whereas 30% of all LMS first-site recurrences involved the lungs.
Conclusions: Although the two patient populations appear to be distinct, their clinical courses are similar. The pattern of distant spread follows the known patterns of hematogenous dissemination. Complete surgical resection is the cornerstone of treatment for primary GIST and LMS and in selected patients with local and distant recurrence.