Increased Burden of Familial-associated Early-onset Cancer Risk among Minority Americans Compared to non-Latino Whites

Background The role of race/ethnicity in genetic predisposition of early-onset cancers can be estimated by comparing family-based cancer concordance rates among ethnic groups. Methods We used linked California health registries to evaluate the relative cancer risks for first degree relatives of patients diagnosed between ages 0-26, and the relative risks of developing distinct second primary malignancies (SPMs). From 1989-2015, we identified 29,631 cancer patients and 62,863 healthy family members. We calculated the standardized incident ratios (SIRs) of early-onset primary cancers diagnosed in proband siblings and mothers, as well as SPMs detected among early-onset patients. Analyses were stratified by self-identified race/ethnicity. Results Given probands with cancer, there were increased relative risks of any cancer for siblings and mothers [SIR=3.32;95% confidence interval (CI):2.85-3.85)] and of SPMs (SIR=7.27;95%CI:6.56-8.03). Higher relative risk of any cancer in siblings and mothers given a proband with solid cancer ( P <0.05) was observed for both Latinos (SIR=4.98;95%CI:3.82-6.39) and for non-Latino Blacks (SIR=7.35;95%CI:3.36-13.95) compared to non-Latino White subjects (SIR=3.02;95%CI:2.12-4.16). For hematologic cancers, higher familial risk was evident for Asian/Pacific Islanders (SIR=7.56;95%CI:3.26-14.90) compared to non-Latino whites (SIR:2.69;95%CI:1.62-4.20). Conclusions The data support a need for increased attention to the genetics of early-onset cancer predisposition and environmental factors in race/ethnic minority families in the US. Funding This work was supported by the V Foundation for funding this work (Grant FP067172). Key Messages We identified 29 631 cancer patients and their 62 863 healthy family members in California from 1989 to 2015. The risk of early-onset cancer in siblings and mothers was elevated by having a proband with cancer in the same family. The relative risk of early-onset cancers given a proband with solid cancer was higher for Latinos and Blacks when compared to non-Latino Whites.