Prognostic significance of serum LDH in Ewing's sarcoma of bone

The pretreatment serum lactic dehydrogenase (SLDH) levels of 618 patients w ith Ewing's sarcoma of the extremities (136 metastatic at presentation and 482 localized) were analyzed to evaluate whether the enzyme level had a cli nical value in predicting the course of the disease. The percentage of pati ents with increased SLDH was significantly higher in the metastatic group t han in the group of patients with localized disease (68% vs 32%; P<0.0001). In the latter group treated with neoadjuvant chemotherapy the 5-year disea se-free survival rate was significantly higher in patients with normal pret reatment SLDH than in those with high levels (65% vs 41%; P<0.0001). The ti me to relapse was significantly shorter for patients with elevated SLDH tha n in patients with normal values of the enzyme. The site of the tumor was s ignificantly related with the stage of the disease, and for patients with l ocalized disease, with the disease survival rate, at the multivariate analy ses site of the tumor and SLDH levels were independently related with the s tage of disease and with prognosis. These data demonstrate that in Ewing's sarcoma of bone pretreatment SLDH have a prognostic value and should be con sidered in the comparison of the results achieved with different therapies and in planning new randomized clinical therapeutic trials.