In multivariate analysis ( in @ patients with RECIST SD ; median OS , @ years ) , absolute change in mean positive pixels at spatial scaling filter of @ mm , change in tumor size , and baseline serum lactate dehydrogenase ( LDH ) level were predictors of OS ( hazard ratio -LSB- HR -RSB- = @ for decrease in mean positive pixels at spatial scaling filter of @ mm vs increase , p = @ ; HR = @ for > @ % increase in tumor size vs otherwise , p = @ ; and HR = @ for every @ IU/L increase in baseline LDH level , p = @ ) .