Table 1.

Clinical characteristics of patients with metastatic breast cancer and known germline-pathogenic BRCA1/2 mutations or novel BRCA1/2 variants.

Clinical Variable	cfDNA BRCA1/2 mutation absent (BRCA wild-type (WT)) (N=186)	cfDNA BRCA1/2 known germline-pathogenic mutation present (BRCA known germline-pathogenic mutant)* (N=9)	cfDNA BRCA1/2 novel variant mutation present (BRCA novel variant)* (N=20)	p value for difference between BRCA WT and BRCAknown germline-pathogenic mutant+	p value for difference between BRCA known germline-pathogenic mutant and BRCA novel variant+
Median age at metastatic breast cancer diagnosis	57 (48–65)	48 (46–52)	55 (52–67)	0.059	0.008
Tumor Subtype				0.023	0.022
HER2+	11 (5.9%)	0 (0%)	3 (15%)
HR+	134 (72%)	4 (44.4%)	14 (70%)
TNBC	24 (12.9%)	4 (44.4%)	1 (5%)
Unknown	17 (9.1%)	1 (11.1%)	2 (10%)
Number of prior lines of chemotherapy				0.98	0.26
0–1	124 (66.7%)	6 (66.7%)	17 (85%)
≥2	61 (32.8%)	3 (33.3%)	3 (15%)
Unknown	1 (0.5%)	0 (0%)	0 (0%)
First therapy post-cfDNA testing				0.32	0.42
Endocrine	57 (30.6%)	3 (33.3%)	7 (35%)
HER2 therapy	13 (7.0%)	0 (0.0%)	2 (10%)
Immunotherapy	14 (7.5%)	2 (22.2%)	2 (10%)
Chemotherapy	49 (26.3%)	3 (33.3%)	3 (15%)
Other	36 (19.4%)	0 (0.0%)	3 (15%)
None	13 (7.0%)	0 (0.0%)	2 (10%)
Unknown	4 (2.2%)	1 (11.1%)	1 (5%)

^*Patients with both known germline-pathogenic and novel variants present in cfDNA were included in the known germline-pathogenic category for these analyses.

⁺For the statistical analyses, the Wilcoxon rank-sum test (age variable) and Pearson chi-squared test (all categorical variables) were used.