How it's calculated
Five adverse risk factors (age >60, Ann Arbor stage III/IV, elevated LDH, ECOG ≥2, >1 extranodal site) are each scored 1 point, for a total of 0-5, stratifying risk in non-Hodgkin lymphoma.
Risk groups
| Score | Risk group | Approximate 5-year overall survival |
|---|---|---|
| 0-1 | Low | ~73% |
| 2 | Low-intermediate | ~51% |
| 3 | High-intermediate | ~43% |
| 4-5 | High | ~26% |
Clinical use
- Used to stratify prognosis in diffuse large B-cell lymphoma and other non-Hodgkin lymphomas at diagnosis, informing discussions about expected outcome and, in some settings, treatment intensity.
- Derived in the pre-rituximab era — the age-adjusted IPI (for patients under 60) and the more recently developed NCCN-IPI and R-IPI refine risk stratification for the modern immunochemotherapy era.
- Should be interpreted alongside histological subtype, molecular/genetic features (e.g. double-hit lymphoma), and response to initial treatment, not used in isolation to determine management.
- The age-adjusted IPI uses only stage, LDH, and ECOG performance status (omitting age and extranodal sites), and is sometimes preferred for younger patients.
Frequently asked questions
What is the IPI used for?
It stratifies prognosis at diagnosis in non-Hodgkin lymphoma (particularly diffuse large B-cell lymphoma) using five simple clinical and laboratory factors.
Is the IPI still accurate with modern treatment (rituximab-based regimens)?
The original IPI was derived before rituximab became standard; the NCCN-IPI and R-IPI were developed to better reflect outcomes in the rituximab era and may be preferred where available.
What counts as an 'extranodal site'?
Sites of lymphoma involvement outside the lymph nodes and spleen — such as bone marrow, liver, lung, or gastrointestinal tract — with more than one such site counting as an adverse factor.
Does a high IPI score mean a patient should get more aggressive treatment?
It informs prognostic discussion and can influence treatment intensity in some protocols, but decisions should incorporate histological subtype, molecular features, and patient factors, not the IPI alone.
References
- The International Non-Hodgkin's Lymphoma Prognostic Factors Project. A predictive model for aggressive non-Hodgkin's lymphoma. N Engl J Med. 1993;329(14):987-994.
- Zhou Z, et al. An enhanced International Prognostic Index (NCCN-IPI) for patients with diffuse large B-cell lymphoma treated in the rituximab era. Blood. 2014;123(6):837-842.