Table 6.

Variability in unilateral mastectomy use (compared to BCS) explained by patient, disease and area characteristics

Variable	%
Tumor size	43
Stage 0 (DCIS)	24
Positive lymph nodes	14
Breast reconstruction rates	5
Health insurance	3
Comorbidities	2

Percent of variation explained by each characteristic based on change in logistic regression pseudo-R2, with and without each characteristic. Only variables that changed the pseudo R² by ≥2% are shown here. The full model included all characteristics shown in Table 3, and had a pseudo R² of 0.0495, c-statistic 0.64, n= 1,651,924