Clinical Significance and Interpretation of DIPSS Score in Patient Management
The Dynamic International Prognostic Scoring System (DIPSS) is a critical tool for risk stratification in myelofibrosis that guides treatment decisions, particularly regarding the timing of allogeneic hematopoietic cell transplantation (HCT). 1
What is DIPSS?
DIPSS is a prognostic scoring system used for patients with myelofibrosis (MF) that:
- Can be applied at any time during the disease course (unlike IPSS which is only used at diagnosis) 1
- Stratifies patients into four risk categories: low, intermediate-1, intermediate-2, and high risk 1
- Predicts overall survival with median survival of 135,95,48, and 27 months for the respective risk categories 1
Components of DIPSS
The score includes five key variables:
- Age > 65 years
- Hemoglobin < 10 g/dL
- Leukocyte count > 25 × 10^9/L
- Circulating blasts ≥ 1%
- Constitutional symptoms
DIPSS Plus: Enhanced Prognostic Model
DIPSS Plus is a refinement of DIPSS that incorporates three additional independent risk factors 1:
- Unfavorable karyotype
- Platelet count < 100 × 10^9/L
- Transfusion dependency
This enhanced model provides more precise risk stratification with median survivals of 185,78,35, and 16 months for low, intermediate-1, intermediate-2, and high-risk groups, respectively 2.
Clinical Applications of DIPSS
1. Treatment Decision-Making
- Low-risk patients: Observation or symptom-directed therapy is recommended 1
- Intermediate-1 risk: Consider ruxolitinib if symptomatic; allogeneic HCT may be considered in select cases 1
- Intermediate-2/High-risk: Allogeneic HCT should be strongly considered if the patient is a transplant candidate 1
2. Transplantation Decisions
- DIPSS strongly predicts post-transplant outcomes 3, 4
- Patients with high-risk DIPSS have significantly worse post-HCT survival (HR 4.11) compared to low-risk patients 3
- 5-year overall survival rates after HCT are approximately 78% for low/intermediate-1 risk versus 35% for high-risk patients 4
3. Monitoring Disease Progression
- DIPSS should be reassessed during follow-up to detect disease progression 1
- Changes in DIPSS score between days 3-7 better predict mortality than the score at diagnosis 5
Integration with Molecular Data
Recent evidence suggests that incorporating genetic information enhances prognostic accuracy:
- Screening for additional mutations (particularly ASXL1 and SRSF2) is recommended for comprehensive risk assessment 1
- The Genetically Inspired Prognostic Scoring System (GIPSS) may outperform DIPSS in certain patients, especially when the two models disagree 6
- Molecular assessment (at least ASXL1 mutation) is recommended for therapeutic decisions in selected MF patients, particularly when deciding on transplantation for intermediate-1 risk patients 1
Clinical Pitfalls and Considerations
- DIPSS-Plus is preferred for risk stratification of myelofibrosis, but IPSS should be used at diagnosis 1
- DIPSS can be used if karyotyping is not available 1
- While developed for primary myelofibrosis, DIPSS is commonly applied to post-polycythemia vera MF and post-essential thrombocythemia MF, though its validity in these contexts has been questioned 1
- Additional molecular marker monitoring is recommended for higher-risk patients 1
- Patients with intermediate-2 and high-risk disease by DIPSS who undergo allogeneic transplant have improved overall survival compared to those who do not 6
In summary, DIPSS provides essential prognostic information that directly impacts treatment strategy, transplant timing, and overall management approach in patients with myelofibrosis.