PROGNOSTIC IMPORTANCE OF DNA FLOW CYTOMETRIC VARIABLES IN RHABDOMYOSARCOMAS

Aim-To determine whether DNA ploidy patterns and S phase fraction offe r prognostic information in patients with rhabdomyosarcoma (RMS). Meth ods-DNA flow cytometry was performed on formalin fixed, paraffin wax e mbedded samples from primary tumours, and metastatic deposits or recur rences in 70 patients. DNA histogram analysis was done using a semi-au tomated cell cycle analysis program. Results-Of the 70 primary tumours , 23 were DNA diploid, 32 DNA aneuploid, eight DNA multiploid, and sev en DNA tetraploid. The prognosis for DNA aneuploid patterns was favour able, intermediate within the group of DNA tetraploid tumours and poor among patients with DNA diploid and DNA multiploid tumours (p = 0.009 ). In multivariate analysis (Cox regression model) DNA ploidy was an i mportant independent prognostic factor, along with TNM stage, localisa tion, and histopathological classification. Ten out of 32 patients wit h a high S phase fraction (>15%) with primary RMS achieved long term s urvival in contrast to 20 out of 29 patients with a low S phase fracti on (less-than-or-equal-to 15%) (p = 0-008). In 24 cases the DNA ploidy of cases of relapse was analysed. Of the 15 cases, in which stem line changes had occurred, 13 died of disease. No stem line changes were n oted in nine cases and in this group four patients died of disease (p = 0-02). Conclusions-Assessment of DNA ploidy and S phase fraction in primary RMS and evaluation of stem line changes in cases of relapse ar e important variables in predicting prognosis.