Temporal analysis of women aged ≤40 years demonstrates a trend of decreasing LR between 1988 and 2010 from 9.8% (95% CI: 7.1–12.5) to 3.3% (95% CI: 0.6–6.0, p = 0.006) [233], and a retrospective study analyzing 565 women aged ≤40 years reported no significant difference in LR between the BCS and mastectomy groups after adjusting for hormone receptor, tumour size, lymph node status, and HER2 status [234]. The gene discussed is ERBB2; the disease is neoplasm.