What is the Myeloproliferative Neoplasm Symptom Assessment Form (MPN‑SAF) total symptom score, its scoring range, and the thresholds that define significant symptom burden and clinically meaningful improvement?

MPN-SAF Total Symptom Score (TSS)

The MPN-SAF TSS is a patient-reported outcome tool that scores 10 key symptoms on a 0-10 scale each, generating a total score ranging from 0-100, with ≥50% reduction defining a clinically significant symptom response. 1

Scoring Structure and Administration

• The MPN-SAF TSS is self-administered by patients, assessing their worst symptom severity over the past 24 hours 1

• Each of the 10 symptoms is scored from 0 (absent/as good as it can be) to 10 (worst imaginable/as bad as it can be) 1

• The TSS is calculated by summing all 10 individual symptom scores, yielding a total range of 0-100 points 1, 2

The 10 Assessed Symptoms

The MPN-SAF TSS evaluates these specific symptoms: 1, 2

• Fatigue (weariness, tiredness)
• Concentration problems
• Early satiety
• Inactivity
• Night sweats
• Itching (pruritus)
• Bone pain
• Abdominal discomfort
• Weight loss
• Fevers

Clinical Thresholds and Interpretation

• A symptom response requires ≥50% reduction in the MPN-SAF TSS from baseline 1

• Symptom responses <50% may still be clinically meaningful and justify continued therapy with ruxolitinib 1

• Mean baseline TSS scores vary by MPN subtype: essential thrombocythemia (18.7 points), polycythemia vera (21.8 points), and myelofibrosis (25.3 points), with myelofibrosis patients experiencing the highest symptom burden 2

Guideline-Recommended Applications

• The NCCN recommends using the MPN-SAF for baseline symptom burden assessment in all MPN patients 1, 3

• The 2013 IWG-MRT and ELN Response Criteria for myelofibrosis recommend the MPN-SAF TSS for monitoring symptom status during treatment 1

• Changes in symptom status should prompt evaluation of treatment efficacy and/or disease progression 1

Psychometric Properties and Validation

• The MPN-SAF TSS demonstrates excellent internal consistency with Cronbach's α = 0.83-0.89 2, 4, 5

• The TSS strongly correlates with overall quality of life (r = 0.59) and functional scales (r ≥ 0.50 for most domains) 2

• Factor analysis confirms a single underlying construct, validating the TSS as an appropriate unified scoring method 2

• The instrument has been validated in multiple languages including English, Italian, Swedish, Romanian, and Brazilian Portuguese 6, 4, 7

Common Pitfalls to Avoid

• Do not dismiss symptom improvements below the 50% threshold as clinically insignificant, as these may still represent meaningful benefit justifying therapy continuation 1

• Avoid relying solely on physician assessment of symptoms, as patient-reported outcomes via MPN-SAF TSS provide more accurate and comprehensive symptom burden evaluation 1, 3

• Do not use the MPN-SAF TSS in isolation for treatment decisions—integrate it with objective disease parameters including spleen size, blood counts, and bone marrow findings 1, 3