Maximum reduction in sum of perpendicular diameters (SPDs). Shown are the 37 patients who had follow-up scans available for bidimensional measurements. Two additional patients had no follow-up scans because of early withdrawal for pneumonia and refusal after hip fracture and were considered to be nonresponders for response rate determination. One patient had progressive disease but bidimensional measurements were not available for the new lesions. PD, progressive disease; SD, stable disease.