The Value of the 8th Edition of American Joint Committee on Cancer Pathological Prognostic Staging on the Selection of Postmastectomy Radiotherapy for T1–2N1 Breast Cancer

Table 1

Clinicopathological characteristics of the patients with and without PMRT before PSM and after PSM.

Variables		Before PSM (%)				After PSM (%)
	Total	PMRT	Non-PMRT		Total	PMRT	Non-PMRT
Age (years)
<50	936 (58.0)	470 (63.2)	466 (53.5)	<0.001	765 (61.3)	377 (60.4)	388 (63.2)	0.523
≥50	679 (42.0)	274 (36.8)	405 (46.5)		483 (38.7)	247 (39.6)	236 (37.8)
Menopausal status
Premenstrual	968 (60.0)	498 (66.9)	476 (57.6)	<0.001	794 (63.6)	396 (63.5)	398 (63.8)	0.993
Postmenstrual	637 (40.0)	246 (33.1)	395 (45.4)		454 (36.4)	228 (36.5)	226 (36.2)
Histological subtype
Infiltrating ductal carcinoma	1563 (96.8)	718 (96.5)	845 (97.0)	0.804	1205 (96.6)	604 (96.8)	601 (96.3)	0.969
Lobular carcinoma	13 (0.8)	7 (0.9)	6 (0.7)		11 (0.9)	5 (0.8)	6 (1.0)
Other	39 (2.4)	19 (2.6)	20 (2.3)		32 (2.5)	15 (2.4)	17 (2.7)
Pathological grade
Well differentiated	44 (2.7)	16 (2.2)	28 (3.2)	0.100	33 (2.6)	16 (2.6)	17 (2.7)	0.821
Moderately differentiated	731 (45.3)	322 (43.3)	409 (47.0)		564 (45.2)	277 (44.4)	287 (46.0)
Poorly differentiated/undifferentiated	840 (52.0)	406 (54.6)	434 (49.8)		651 (52.2)	331 (53.0)	320 (51.3)
Tumor stage
T1	567 (35.1)	241 (32.4)	326 (37.4)	0.035	444 (35.6)	207 (33.2)	237 (38.0)	0.076
T2	1048 (64.9)	503 (67.6)	545 (62.6)		804 (64.4)	417 (66.8)	387 (62.0)
ER status
Positive	1229 (76.1)	548 (73.7)	681 (78.2)	0.033	927 (74.3)	452 (72.4)	475 (76.1)	0.136
Negative	386 (23.9)	196 (26.3)	190 (21.8)		321 (25.7)	172 (27.6)	149 (23.9)
PR status
Positive	1141 (70.7)	522 (70.2)	619 (71.1)	0.69	868 (69.6)	419 (67.1)	449 (72.0)	0.065
Negative	474 (29.3)	222 (29.8)	252 (28.9)		380 (30.4)	205 (32.9)	175 (28.0)
HER2 status
Positive	470 (29.1)	239 (32.1)	231 (26.5)	0.013	386 (30.9)	201 (32.2)	185 (29.6)	0.741
Negative	1145 (70.9)	505 (67.9)	640 (73.5)		862 (69.1)	423 (67.8)	439 (70.4)
Number of involved LN
1	1023 (63.3)	382 (51.3)	641 (73.6)	<0.001	777 (62.3)	380 (60.9)	397 (63.6)	0.597
2	375 (23.2)	221 (29.7)	154 (17.7)		311 (24.9)	160 (25.6)	151 (24.2)
3	217 (13.5)	141 (19.0)	76 (8.7)		160 (12.8)	84 (13.5)	76 (12.2)
The 7th AJCC staging
IIA	567 (35.1)	241 (32.4)	326 (37.4)	0.035	444 (35.6)	207 (33.2)	237 (38.0)	0.076
IIB	1048 (64.9)	503 (67.6)	545 (62.6)		804 (64.4)	417 (66.8)	387 (62.0)
The 8th AJCC staging
IA	314 (19.4)	135 (18.1)	179 (20.6)	0.434	250 (20.1)	111 (17.8)	139 (22.3)	0.267
IB	583 (36.1)	270 (36.3)	313 (35.9)		460 (36.9)	237 (38.0)	223 (35.7)
IIA	362 (22.4)	162 (21.8)	200 (23.0)		248 (19.9)	121 (19.4)	127 (20.4)
IIB	253 (15.7)	123 (16.5)	130 (14.9)		199 (15.9)	105 (16.8)	94 (15.1)
IIIA	103 (6.4)	54 (7.3)	49 (5.6)		91 (7.2)	50 (8.0)	41 (6.6)
Adjuvant chemotherapy regimen
Anthracycline-based	176 (10.9)	124 (14.2)	52 (7.0)	<0.001	133 (10.7)	51 (8.2)	82 (13.1)	0.026
Taxane-based	233 (14.4)	148 (17.0)	85 (11.4)		162 (13.0)	77 (12.3)	85 (13.6)
Anthracycline and taxane combination-based	1195 (74.0)	593 (68.1)	602 (80.9)		946 (75.7)	492 (78.8)	454 (72.8)
Other	11 (0.7)	6 (0.7)	5 (0.7)		7 (0.6)	4 (0.6)	3 (0.5)
Endocrine therapy
Yes	1212 (75.0)	569 (76.5)	643 (73.8)	0.219	916 (73.4)	465 (74.5)	451 (72.3)	0.370
No	443 (25.0)	175 (23.5)	268 (26.2)		332 (26.6)	159 (25.5)	173 (27.7)
Targeted therapy
Yes	204 (12.6)	117 (15.7)	87 (10.0)	0.001	174 (13.9)	105 (16.8)	69 (11.1)	0.003
No	1411 (87.4)	627 (84.3)	784 (90.0)		1074 (86.1)	519 (83.2)	555 (88.9)