Uptake of cascade tests in relatives of patients undergoing cancer precision medicine in Japan.

Cascade testing program derived from secondary findings in cancer precision medicine (tumor-only + germline confirmation)

In a retrospective analysis of 862 patients undergoing comprehensive tumor genomic profiling in Japan, 11.2% had presumed germline pathogenic variants, and 22 confirmed germline variants were identified (BRCA2×10, BRCA1×6, APC, ATM, BAP1, CDK4, CDKN2A, MSH2, RAD51C). Among 43 eligible relatives, 69.8% underwent cascade testing, with 33.3% testing positive. The median interval from disclosure to cascade testing was 50 days. These findings confirm the feasibility of germline cascade testing derived from tumor-only precision medicine programs in Japan.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

A 69.8% cascade testing uptake rate is a solid performance in the Japanese context, where cultural considerations around family genetic disclosure are significant. These data validate the integration of germline confirmation testing into cancer precision medicine pathways and highlight the need for active follow-up of young untested relatives (aged 14–34 years identified in this cohort).

Clinical impact : 2/3 · Evidence strength : 2/3 · Novelty : 1/2 · Sample size : 1/1 · Journal quality : 1/1 → Total : 7/10