Detection of progressive disease by method of examination. In 77% of the patients, PD was detected clinically by physical examination and/or blood count, in 9% by CT scan, in 6% by ultrasound, and in 1% the detection method was not evaluable because the reference result was missing. In 6% of the patients PD, as documented by the treating physician, could not be confirmed by the strict algorithm according to the NCI-WG criteria and were therefore assessed as stable disease.