Lower tumour mutation burden (HR 3.08; 95%CI 1.06–8.93; p = 0.0386) and HER2-negative BM (HER2neg) (HR 7.75;95%CI 1.97–30.40; p = 0.0033) were associated with longer BM-iPFS; HER2neg BM (HR 3.44; 95%CI 1.03–11.53; p = 0.0449) and KRASmut BM (HR 0.31; 95%CI 0.12–0.80; p = 0.0153) conferred longer BM-PFS. Here, ERBB2 is linked to neoplasm.