Table 3. Percent of initial mastectomy and neoadjuvant therapy according to tumor size by institution.

	Institution 1		Institution 2		Institution 3		Institution 4		P value
Pre-operative tumor size	Initial mastectomy	NAC	Initial mastectomy	NAC	Initial mastectomy	NAC	Initial mastectomy	NAC	Initial mastectomy	NAC
0-10 mm	7.3	2.4	16.4	0.0	16.2	0.0	8.6	2.9	0.0199	0.0135
>10-20 mm	9.2	5.8	21.2	0.3	27.2	0.7	24.1	3.6	<0.0001	<0.0001
>20-30 mm	21.5	8.3	35.4	1.1	27.9	2.6	21.6	13.5	0.0477	0.0005
>30-40 mm	34.1	11.4	58.6	1.4	40.4	7.7	63.6	0.0	0.0318	0.1068
>40-50 mm	57.1	21.4	76.2	4.7	50.0	15.0	80.0	40.0	0.2952	0.2050
>50 mm	88.5	3.9	81.8	0.0	78.3	43.4	60.0	20.0	0.4900	<0.001
P value	<0.0001	0.022	<0.0001	0.045	<0.0001	<0.0001	<0.001	0.002

Abbreviations: NAC: neoadjuvant chemotherapyOverall, initial surgery was PM for 60 (2.7%) patients and and TM for 51 (7.2%) patients who received NAC (P<0.0001). Of the 60 patients whose initial surgery was PM, achievement of BCT occurred in 53 patients (88.3%) and 7 (11.7%) required further surgery (P=0.0905). Utilization of NAC increased with clinical tumor size, yet less than 16% of tumors >50 mm in clinical size were treated with NAC (Table 1). Larger tumors were noted to have an increasing initial TM rate compared to smaller tumors (Figure 1), with the initial TM rate >80% for tumors with clinically estimated size >50 mm. Increasing utilization of NAC for increasing tumor size was also noted when NAC use was analyzed according to each individual institution (Table 3). Interestingly, however, three of the four institutions had lower rates of NAC for tumors >50 mm compared to tumors 40-50 mm at each respective institution. The frequency of BCT failure also increased with increasing clinical tumor size, reaching 29% in tumors >50 mm in size (Figure 2).