How the DLBCL International Prognostic Index (IPI) Works
The International Prognostic Index (IPI) was developed in 1993 by the International Non-Hodgkin's Lymphoma Prognostic Factors Project and remains the most widely used pretreatment prognostic tool for diffuse large B-cell lymphoma (DLBCL). It combines five simple, routinely available clinical variables into a single score from 0 to 5, and that score maps to a risk group with an associated historical survival estimate. This calculator applies the same five factors, reports the classic IPI score and risk group, and also shows the Revised IPI (R-IPI) category used in the rituximab era. This tool is for education only and does not replace a hematologist-oncologist's assessment.
The five IPI risk factors
- Age > 60 years — 1 point. Older age is associated with reduced tolerance of intensive chemotherapy and more comorbidities.
- Elevated serum LDH — 1 point if the measured LDH is above your laboratory's upper limit of normal (ULN). LDH reflects tumor cell turnover and burden.
- ECOG Performance Status ≥ 2 — 1 point. This measures functional capacity, from 0 (fully active) to 4 (completely disabled).
- Ann Arbor Stage III or IV — 1 point. Stage III/IV indicates disease on both sides of the diaphragm or with extranodal/organ involvement, versus more localized Stage I/II disease.
- More than 1 extranodal site — 1 point. Involvement of multiple sites outside the lymph nodes (e.g., bone marrow, liver, GI tract, CNS) signals more widespread disease.
From score to risk group and R-IPI
Add one point for each factor present to get a total IPI score of 0-5. In the original (pre-rituximab) cohort, four risk groups were defined: Low (0-1 points, ~73% 5-year overall survival), Low-Intermediate (2 points, ~51%), High-Intermediate (3 points, ~43%), and High (4-5 points, ~26%). Once rituximab-containing chemotherapy (R-CHOP) became standard, the four IPI groups stopped separating outcomes as cleanly, so Sehn and colleagues proposed the Revised IPI (R-IPI) in 2007, which regroups the same five factors into three bands: Very Good (0 factors, ~94% 4-year survival), Good (1-2 factors, ~79%), and Poor (3-5 factors, ~55%). Newer tools such as the NCCN-IPI refine the age and extranodal-site criteria further, but the classic IPI and R-IPI remain the most widely cited reference points in clinic notes and research papers.
Important limitations
The IPI is a population-level statistical tool built from data on many patients, not an individual prediction. It does not capture cell-of-origin subtype (germinal center B-cell vs. activated B-cell), MYC/BCL2 "double-hit" genetics, bulky disease, or response to initial treatment cycles, all of which also influence outcomes. Survival percentages shown here are historical averages from published cohorts and are for educational context only — always discuss your specific case, staging results, and treatment plan with your treating oncologist.