Rates of intervention and cancer detection on initial versus subsequent whole body MRI screening in Li-Fraumeni Syndrome.

Li-Fraumeni Syndrome (LFS) is a hereditary cancer predisposition syndrome with up to 90% lifetime cancer risk. Cancer screening, including annual whole-body MRI (WBMRI), is recommended due to known survival advantage, with cancer detection rate of 7% on initial screening. Intervention and cancer detection rates on subsequent screenings are unknown. Clinical data for pediatric and adult LFS patients (n=182) were reviewed, including instances of WBMRI screening and interventions based on screening results. For each WBMRI screening, interventions including biopsy and secondary imaging, as well as rate of cancer diagnosis, were analyzed comparing initial versus subsequent WBMRI. Of the total cohort (n=182), we identified 68 adult patients and 50 pediatric patients who had undergone at least two WBMRI screenings, with a mean of 3.8+1.9 (adults) and 4.0+2.1 (pediatric) screenings. Findings on initial screening led to an imaging or invasive intervention in 38% of adults and 20% of children. On follow up, overall intervention rates were lower for adults (19%, p=0.0026) and stable for children (19%, p=NS). Thirteen cancers were detected overall (7% of adult and 14% of pediatric scans), on both initial (pediatric: 4%, adult: 3%) and subsequent (pediatric: 10%, adult: 6%) screenings. Rates of intervention after WBMRI screening decreased significantly in adults between first and subsequent exams and remained stable in pediatric patients. Cancer detection rates were similar on screening (3-4% initial, 6-10% subsequent) for both children and adults. These findings provide important data for counseling LFS patients about screening outcomes.