Multivariate analysis of CPCC or MAI for correlation with RFS in breast cancer subgroups by Cox proportional hazard regression model.

The co-variables of age at diagnosis (groups 1–5), T stage (T1, T2 or T3), N stage (N0, N1, N2 or N3), institution (KCCH or IIPH), and year of surgical resection (2000, 2001, 2002, 2003, 2005 or 2006) were used in the multivariate analysis, treating each co-variable as a categorical variable.
*Luminal A subgroup: cases with hormone receptor (HR)-positive and HER2-negative status.
**HER2-positive subgroup: cases with HER2-positive status with or without HR positivity.
***Triple-negative subgroup (TN): HR-negative and HER2-negative status.
†P for linear trend.