Smooth muscle tumors of the gastrointestinal tract: analysis of prognostic factors.

BACKGROUND: The survival rates and therapeutic approaches to gastrointestinal leiomyoma and leiomyosarcoma vary widely. This review analyzes the clinical symptoms and signs, the results of the pathologic examination, and the DNA makeup of these tumors and determines the factors that affect the prognosis of patients who have leiomyosarcoma.
METHODS: Flow cytometric DNA analysis was performed in 80 patients with gastrointestinal smooth muscle tumors to establish the correlation of DNA ploidy with tumor size and stage and histologic grade. Using univariate and multivariate analyses, we investigated tumor size, histologic grade, association with gastrointestinal bleeding, DNA makeup, operative procedure, age, gender, and tumor necrosis as they affect the long-term survival of 45 patients with leiomyosarcoma. The Kaplan-Meier method was used to determine the survival rates and the log-rank method was used to compare survival rates between the two groups.
RESULTS: Between 1986 and 1992, operations were performed on the 80 gastrointestinal smooth muscle tumors--esophageal 1, stomach 32, intestinal 33, colonic 2, and rectal 12. The most common symptoms and signs were gastrointestinal bleeding (43.8%), abdominal mass (37.5%), and abdominal pain (21.3%), and the tumors were classified as leiomyoma 35, low-grade leiomyosarcoma 24, and high-grade leiomyosarcoma 21, according to the cellular atypia and mitotic rate. DNA ploidy correlated with histology grade (r = 0.70, p < 0.01) and tumor size (r = 0.31, p < 0.01) but not with localized or advanced tumors. Only one patient with leiomyoma died of liver metastasis during the follow-up period. In univariate analysis of the 45 patients with leiomyosarcoma, the survival rate was poor in men with tumor sizes greater than 5 cm, incomplete resections, advanced tumors, and high-grade tumors. With multivariate Cox regression analysis only advanced tumors (p < 0.01) and high-grade tumors (p < 0.01) were the independent factors that affected survival.
CONCLUSIONS: Leiomyosarcomas usually measure more than 10 cm. In univariate analysis the significant factors affecting the survival rate of patients with leiomyosarcoma are maleness, size greater than 5 cm, inadequate resection, and advanced-stage and high-grade disease. In multivariate Cox regression analysis advanced-stage and high-grade leiomyosarcoma are the only independent factors affecting survival. DNA ploidy correlates with the size and the grade of gastrointestinal smooth muscle tumors but not with tumor stage. DNA ploidy does not affect independently the survival of leiomyosarcoma.