In patients with mastocytosis, mast cells expand and accumulate throughout the skin, bone marrow, and internal organs, such as the gastrointestinal tract.1 The uncontrolled growth of these abnormal mast cells results in skin lesions with diffuse thickening in its cutaneous form (which affects mostly children) and in skin lesions, liver or spleen enlargement, and in bone-marrow involvement in the systemic form (occurring more often in adults).1
Mastocytosis is classified as a neoplasm, but it may also be associated with other hematologic neoplasms or sarcomas. The course of mastocytosis may be indolent or aggressive, and it can have a significant impact on a patient’s quality of life.2
The ability to gauge mastocytosis treatment success may be optimized with patient-reported assessments of their own symptoms and signs. However, a validated patient-reported outcomes tool specific to mastocytosis does not currently exist. A team of allergists, immunologists, and dermatologists from Germany and the United States sought to test a new patient-reported outcomes measure for assessing mastocytosis disease control.
Their newly developed tool, called the Mastocytosis Control Test (MCT), was generated through interviews with 10 adult patients (80% female; disease duration, 60% ≤ 8 yr) with nonadvanced indolent systemic mastocytosis. All interviewed patients were surveyed using a 5-point Likert scale to calculate the frequency, importance, understandability and comprehensibility, and completeness for the entire potential MCT item set.
The individual items were then reviewed for inclusion in the final MCT tool by an expert panel of dermatologists specializing in mastocytosis treatment and a patient advocate. The result was a preliminary questionnaire covering 6 items. The final instrument was composed of 5 items (Table), each with five potential ratings, yielding potential total scores of 0 to 20 points; the higher the score, the greater the level of disease control.
| TABLE: THE FIVE-ITEM MASTOCYTOSIS CONTROL TOOL | |
|---|---|
| Item Number | Description |
| 1 | Strength of symptoms in the past 2 weeks (response range, very strong to no symptoms) |
| 2 | Effect of the unpredictability of symptoms on the patient in the past 2 weeks (very much to not at all) |
| 3 | Extent of sadness/frustration as a result of mastocytosis in the past 2 weeks (very much to not at all) |
| 4 | Effect of mastocytosis on daily life in the past 2 weeks (very much to not at all) |
| 5 | Rating of how well mastocytosis was controlled in the past 2 weeks because of changes in behavior or in therapy (not at all to completely) |
| Adapted from Siebenhaar F, Sofi S, Neising S, et al. The mastocytosis control test: A patient-reported outcome measure assessing disease control. J Allergy Clin Immunol Pract. 2025;13:647-657. doi: 10.1016/j.jaip.2024.11.021. | |
The researchers conducted a validation of the MCT as part of a study comprising 240 patients with mastocytosis. In this investigation, the patients completed a larger questionnaire (including the MCT) at study baseline and on study day 14 (to evaluate test-retest reliability). Beyond the MCT, the study questionnaire inquired about demographics and disease duration, and included the Short-Form 12 survey, global assessments of disease severity and control over the past 2 weeks, the Mastocytosis Activity Score, and other assessments. This greater data collection allowed the researchers to test how closely the results of the MCT correlated with results obtained from these other tools. They also evaluated the internal consistency of the instrument (correlating the relationship of its various items), the known-groups validity (whether MCT values would increase with a patients’ increasing level of disease control), and the screening accuracy of the MCT (to determine whether patients’ symptoms were truly well controlled or poorly controlled).
One hundred one patients completed the validation surveys in full. Of this cohort, 61% were female, 70% were between 20 and 59 years of age, with 83% reporting a disease duration of up to 25 years. These patients had cutaneous (8%) or various types of systemic disease (92%).
After analysis of the validation phase surveys, the researchers determined that the MCT demonstrated strong correlations with the other tools completed by the 101 patients. The Pearson correlation coefficient was reported to be –0.873 between the MCT and MC-QoL survey (this was higher than for correlation between the MCT and the generic SF-12 survey). The MCT also showed high internal consistency, with a Cronbach-alpha coefficient of 0.941. In terms of known-groups validity, they found that MCT scores did correspond with the patients’ level of disease control. The area under the receiver operating characteristics (ROC) curve was 0.907 for the MCT, demonstrating that it was sufficiently sensitive for distinguishing patients with poorly versus well-controlled disease. Finally, the test–retest reliability of the MCT, based on test results obtained 2 weeks apart, was high, with variance of the agreement for the total MCT score being 91%.
The investigators point out that the MCT “is the first disease-specific patient-reported outcomes measure to assess the control of mastocytosis from the patient’s perspective.” They believe that this reliable, validated, and simple tool can be useful in everyday practice, for measuring control of mastocytosis. As a result, they believe the MCT may also be useful in clinical trials of mastocytosis therapies.
Source: Siebenhaar F, Sofi S, Neising S, et al. The mastocytosis control test: A patient-reported outcome measure assessing disease control. J Allergy Clin Immunol Pract. 2025;13:647-657. doi: 10.1016/j.jaip.2024.11.021.
References
- Valent P, Akin C, Sperr WR, et al. New insights into the pathogenesis of mastocytosis: Emerging concepts in diagnosis and therapy. Ann Rev Pathol Mech Dis. 2023;18:161-186. doi: 10.1146/annurev-pathmechdis-031521-042618.
- Mastocytosis. National Organization for Rare Disorders. September 12, 2024. Accessed April 11, 2025. https://rarediseases.org/rare-diseases/mastocytosis/.