IMPROVING DIAGNOSTIC DECISION MAKING FOR A RARE DISEASE: IDENTIFYING BARRIERS TO EARLY DIAGNOSIS OF SCHWANNOMATOSIS

Purpose: To investigate provider and system level factors contributing to delays in the diagnosis of schwannomatosis, a neurogenetic tumor predisposition syndrome

Method(s): We conducted a retrospective chart review of patients with definite or probable schwannomatosis seen in schwannomatosis specialty clinics at two U.S. academic medical centers.  All information in the electronic medical record system at these institutions was reviewed, including any scanned notes from external institutions.  Descriptive data including patient demographics, symptomology, and diagnostic procedures were extracted.   For a subset of patients, narrative summaries detailing key processes and events in each patient's diagnostic journey were generated by the first author.  We then applied qualitative thematic analysis to these summaries to understand clinicians' diagnostic decision-making and identify recurrent barriers to early diagnosis of schwannomatosis.

Result(s): Medical records of 40 patients (27 with definite and 13 with probable schwannomatosis) were analyzed.  The median age at first symptom was 32 years (range, 5 to 66 years), with a median of 9 years between first symptom and diagnosis (range, <1 year to 34 years.)  In our chart review, patients with probable schwannomatosis did not meet definite disease criteria because schwannomatosis specialty physicians did not think it was clinically necessary to obtain a tumor sample or an MRI required by published diagnostic criteria, or because patients were too young to confidently exclude other etiologies.

   Qualitative review of 21 patient narratives (from 17 definite and 4 probable cases) identified four barriers to early diagnosis of schwannomatosis and/or referral to specialty care (Table 1). Impaired information flow between medical institutions led to duplicative exams and unnecessary work-ups for alternate conditions. Clinicians' lack of awareness about schwannomatosis led to misdiagnosis of another tumor predisposition syndrome in 6 cases and of cancer in 2 cases.  A presenting symptom of pain often involved a prolonged diagnostic work-up and in 6 cases, misdiagnosis of pain etiology.  Finally, some patients were not referred for evaluation for tumor predisposition syndromes, even after multiple surgeries, because the tumors were pathologically benign and thus judged not to warrant follow-up.

Conclusion(s): Diagnostic delay is a significant problem in schwannomatosis.  However, there are remediable provider and system level barriers to early diagnosis.  Targeted education of medical professionals and improved sharing of medical records may reduce diagnostic delay in the future.