Use of Mastectomy for Overdiagnosed Breast Cancer in the United States: Analysis of the SEER 9 Cancer Registries
Table 1
Characteristics of breast cancer cases diagnosed at age ≥40 in 2013 and use of mastectomy.
Characteristic
Cases
Treated with mastectomy ()
Risk ratio (95 CI)
Total
26017
8802 (33.8%)
Stage, AJCC
0 (in situ)
5451
1439 (26.4%)
Ref.
I
10673
2988 (28.0%)
1.1 (1.0-1.1)
II
6353
2796 (44.0%)
1.7 (1.6-1.8)
III
1940
1306 (67.3%)
2.6 (2.4-2.7)
IV
1097
188 (17.1%)
0.6 (0.6-0.7)
NA
503
85 (16.9%)
0.6 (0.5-0.8)
Tumor size, cm
0.0-0.9
5236
1271 (24.3%)
Ref.
1.0-1.9
8172
2407 (29.5%)
1.2 (1.1-1.3)
2.0-2.9
4308
1655 (38.4%)
1.6 (1.5-1.7)
3.0-3.9
2033
911 (44.8%)
1.8 (1.7-2.0)
4.0-4.9
1100
563 (51.2%)
2.1 (2.0-2.3)
5.0+
2043
1280 (62.7%)
2.6 (2.4-2.7)
NA
3125
715 (22.9%)
0.9 (0.9-1.0)
Regional lymph nodes positive
0
14018
5177 (36.9%)
Ref.
1
2331
1043 (44.7%)
1.2 (1.2-1.3)
2+
2940
1760 (59.9%)
1.6 (1.6-1.7)
NA
6728
822 (12.2%)
0.3 (0.3-0.4)
Grade
I
5556
1488 (26.8%)
Ref.
II
10580
3693 (34.9%)
1.3 (1.2-1.4)
III
7683
3122 (40.6%)
1.5 (1.4-1.6)
IV
161
59 (36.6%)
1.4 (1.1-1.7)
NA
2037
440 (21.6%)
0.8 (0.7-0.9)
Molecular status
HER2− HR− (triple negative)
2064
830 (40.2%)
1.2 (1.1-1.2)
HER2− HR+
15049
5134 (34.1%)
Ref.
HER2+ HR−
867
395 (45.6%)
1.3 (1.2-1.4)
HER2+ HR+
1998
807 (40.4%)
1.2 (1.1-1.3)
NA
6039
1636 (27.1%)
0.8 (0.8-0.8)
Age, years
40-49
4392
1956 (44.5%)
Ref.
50-64
10284
3519 (34.2%)
0.8 (0.7-0.8)
65-84
10062
3003 (29.8%)
0.7 (0.6-0.7)
85+
1279
324 (25.3%)
0.6 (0.5-0.6)
Race
American Indian or Alaska Native
177
59 (33.3%)
1.0 (0.8-1.2)
Asian or Pacific Islander
2751
1024 (37.2%)
1.1 (1.1-1.2)
Black
2880
955 (33.2%)
1.0 (0.9-1)
White
20047
6724 (33.5%)
Ref.
Other and unknown
162
40 (24.7%)
0.7 (0.6-1)
NA, not available or not applicable; AJCC, American Joint Committee on Cancer; HR, hormone receptor status (negative if both estrogen and progesterone receptor status are negative, positive if either is positive); HER2, human epidermal growth factor receptor 2 neu status; CI, confidence interval; Ref., reference level. Risk ratios are from univariate analyses and were estimated by unconditional maximum likelihood.
