Table 4.

HRs for incidence of lymphedema for combinations of axillary surgery, chemotherapy, and radiation therapy compared with a reference group of no axillary surgery, radiation, or chemotherapy, adjusting for the potentially confounding patient and treatment factors specified in Table 3

Person-months of exposure (% of all person-months with that exposure)*
(A) ALND, no chemotherapy, no radiation: HR, 3.78 (95% CI, 2.17-6.58)2,265 (10.9)
(B) ALND, anthracycline, no radiation: HR, 5.46 (95% CI, 2.97-10.01)1,470 (7.1)
(C) ALND, no chemotherapy, radiation: HR, 4.67 (95% CI, 2.48-8.83)2,704 (13.0)
(D) ALND, anthracycline, radiation: HR, 4.61 (95% CI, 2.43-8.73)3.632 (17.5)
(E) SLNB, no chemotherapy, no radiation: HR, 0.30 (95% CI, 0.04-2.27)718 (3.5)
(F) SLNB, anthracycline, no radiation: HR, 4.06 (95% CI, 1.32-12.45)222 (1.1)
(G) SLNB, no chemotherapy, radiation: HR, 1.74 (95% CI, 0.70-4.37)1,714 (8.3)
(H) SLNB, anthracycline, radiation: HR, 4.09 (95% CI, 1.43-11.76)589 (2.8)
(I) Reference: No ALND or SLNB, no radiation, no chemotherapy: HR, 1.03,277 (15.8)

NOTE: Reported HRs are estimates from a model with risk factors nested (a method for examining interaction terms). With a reference group of subjects with no radiation, no chemotherapy, and no axillary surgery (no ALND or SLNB), each of the lettered results (A-H) must be contrasted with this reference (row I). Thus, for example, the reported HR for (A) 3.78 is the relative hazard of developing lymphedema in those having ALND versus having no axillary surgery (no ALND or SLNB), assuming that the patient had no chemotherapy or radiation.

  • *Total number of person-months in the model: 20,778. The number of person-months in the last column of the table totals to 16,591 because results for some treatment combinations with very few person-months of observation (e.g., chemotherapy but not anthracycline-based) are not shown in the table.

  • Anthracycline chemotherapy: any regimen containing anthracycline.

  • Radiation therapy: any radiation therapy regardless of extent.