Prognosis of gastrointestinal stromal neoplasms: role of flow-cytometry and classical clinical and histological prognostic factors

BACKGROUND: Biological behavior of gastrointestinal stromal tumours (GIST) is still dificult to predict. The aim of this study was to analyze the prog nostic valve of DNA study by flow cytometry in addition to the classical cl inicopathologic parameters. PATIENTS AND METHODS: 82 GIST were investigated to assess by multivariable analysis the prognostic significance of classical morphologic and clinical features and DNA flow-cytometric analysis. RESULTS: Features significantly correlated with bad prognosis were: pain, r ecurrences, metastasis, small intestine tumours, invasion of adjacent tissu es, size > 6 cm, infiltrative pattern, high cellularity, high-grade of atyp ia, mitosis count > 2/50 high powered field, necrosis, DNA aneuploid-hyperp loid or near-diploid, S and SG(2)M-phase of aneuploid/s population/s > 11% and average S-phase > 11%, Multivariable analysis showed that mitotic activ ity was the only independent variable indicating poor prognosis. CONCLUSIONS: In this series of GIST mitosis count was the only independent prognostic factor, being more important than flow-cytometric variables like DNA ploidy and cellular cycle values.