Tumor Response Classifications of International Workshop Criteria (1999)
| Classification | Criteria |
| Complete response | Total disappearance of all signs and symptoms of disease on clinical and radiographic evaluations |
| Regression of nodal masses to normal size in greatest transverse diameter (≤1.5 cm in nodes >1.5 cm before therapy, ≤1 cm in nodes 1.1–1.5 cm before therapy) | |
| Regression of spleen to normal size so as not to be palpable on physical examination | |
| Clear infiltrate on bone marrow aspiration and biopsy in sites that were previously involved | |
| Unconfirmed complete response | Fulfillment of complete-response requirements, except: |
| Presence of residual lymph nodes >1.5 cm that have regressed by >75% in sum of product of their greatest diameters (SPD) | |
| Bone marrow aspiration indeterminate for infiltration | |
| Partial response | Regression of 6 largest nodal masses by ≥50% in SPD |
| No increase in size of other nodes, liver, or spleen | |
| Regression of splenic and hepatic nodules by ≥50% in SPD | |
| No new sites of disease | |
| Stable disease | Results not meeting the criteria for partial response or progressive disease |
| Progressive disease | ≥50% increase in SPD of lymph node mass |
| Appearance of any new lesions |