Table 1

Study sample characteristics

N 7533
Age (years), median, SD (IQR)65.21, 11.72 (58–74)
ICD9-CM code, N (%)
174.0 Nipple and areola97 (1.29)
174.1 Central portion407 (5.40)
174.2 Upper-inner quadrant690 (9.16)
174.3 Lower-inner quadrant437 (5.80)
174.4 Upper-outer quadrant2638 (35.02)
174.5 Lower-outer quadrant490 (6.50)
174.6 Axillary tail19 (0.25)
174.8 Other specified sites of female breast791 (10.50)
174.9 Malignant neoplasm of breast (female), unspecified1765 (23.43)
196.3 Secondary malignant neoplasm of lymph nodes1801 (23.91)
198.81 Secondary malignant neoplasm of breast19 (0.25)
  • ICD9-CM, international classification of diseases-clinical modification.