Understanding rare cancers in Hispanic/Latinx populations: Insights from the MyPART natural history study of rare solid tumors

Abstract PURPOSE: Rare cancers (<15 cases per 100,000 people/year) are poorly understood, particularly in Hispanic/Latinx populations. The My Pediatric and Adult Rare Tumor (MyPART) network conducts a Natural History Study of Rare Solid Tumors (NHSRT) to better understand rare tumor biology and develop effective therapeutic strategies. We analyzed NHSRT Hispanic/Latinx participants. METHODS: Patients of any age with rare solid tumors are eligible. All participants complete medical and family history forms, patient-reported outcomes (PRO) and provide saliva for DNA. Tumors undergo comprehensive molecular analysis and are discussed in a molecular tumor board. A subset of participants is invited to NIH Clinical Center (NIHCC) to undergo a clinical evaluation, genetic counseling, blood collection, and imaging studies, as indicated. Spanish-speaking participants are offered a medical interpreter. Forms are only available in English. RESULTS: Between January 2019 and December 2020, 16 of 200 participants identified as Hispanic/Latinx. Additionally, two international patients, a 15-year-old from Panama with Medullary Thyroid Carcinoma (MTC) who underwent total thyroidectomy with lymphadenectomy, and a 19-year-old from Mexico with Fibrolamellar Carcinoma (FLC) who underwent left hepatectomy and lymphadenectomy were enrolled later and received surgical treatment at NIHCC, which was not accessible in their home countries. Tumor types were neuroendocrine tumors (NET) (n=7), wild-type gastrointestinal stromal tumors (wt-GIST) (n=4), adrenocortical carcinoma (ACC) (n=1), MTC (n=3), and FLC (n=1). Two participants were relatives of patients with an SDHA mutation. Females accounted for 66% of the cohort; the median age was 35 years (range 15-69), enrolled from five US states and five countries. Nine patients used interpreter services. The median time from diagnosis to enrollment was 5.3 years. Half had metastatic disease at diagnosis. At enrollment, 57% of cases with local disease at diagnosis had progressed to metastasis, and 20% showed no evidence of disease. Twelve patients had successful tumor sequencing, and eight were found to have Pathogenic/Likely Pathogenic (Path/LP) variants. MEN1, SMAD4, and LZTR/RPS6KB2 in NET; SDHC in GIST; CDKN2B loss in ACC; DNAJB1-PRACA fusion in FLC; and RET mutations in MTC. Of 12 participants with germline mutation testing, Path/LP variants were found in 10, including SDHA, SDHC, and MUTYH in GIST patients and their relatives; PMS2 and RET in MTC; MEN1 and PALB2 in NET; SLC26A2, OTOF, XPC, and DNAH8 in ACC. CONCLUSION: Enrollment and comprehensive data collection were feasible, granting access to specialty care unavailable to several participants. Hispanic/Latinx representation was low, indicating recruitment challenges and the need for targeted strategies. Remote enrollment facilitated international participation. Making all forms available in Spanish is a priority. Ongoing analysis with over 500 NHRST participants will yield further insights. Citation Format: Juan C. Fierro Pineda, Shadin Ahmed, Karlyne Reilly, Robin Lockridge, Margarita Raygada, Barbara Thomas, John Glod, Abby Sandler, Brigitte Widemann, Mary Frances Wedekind Malone. Understanding rare cancers in Hispanic/Latinx populations: Insights from the MyPART natural history study of rare solid tumors [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C097.