Table 6. Progression-free survival based on histology.

HR, hazard ratio; CI, confidence interval; Ref: reference; NA, not available; N, number of patients; MBC, metaplastic breast cancer

#Other histology in our study includes ductal carcinoma in situ micropapillary pattern, heterologous type with matrix production, high-grade metaplastic carcinoma, large cells with intermingling mature plasma cells, matrix-producing carcinoma, and sarcomatoid features, and metaplastic carcinoma.

Variable	Variable level	N	Number of events	Estimated median (month)	One-year rate	Two-year rate	Five-year rate	HR (95% CI)	p-value
Histology	Spindle cell	27	11	74.8	92% (73%-98%)	73% (51%-86%)	56% (33%-74%)	Ref
	Squamous	40	19	156.3	82% (67%-91%)	65% (48%-78%)	54% (37%-68%)	1.15 (0.55-2.42)	0.71
	Mixed MBC/mesenchymal	54	16	NA	88% (76%-95%)	76% (62%-86%)	66% (50%-78%)	0.69 (0.32-1.49)	0.34
	#Other	11	3	NA	91% (51%-99%)	82% (45%-95%)	72% (35%-90%)	0.54 (0.15-1.95)	0.35