Table 3.
Patient factors associated with conventional schedule chemotherapy vs. dose dense chemotherapy
| Characteristic | Among those receiving drug combinations with dose-dense and conventional administration schedules | Minimally adjusteda | Fully adjustedb | |||
|---|---|---|---|---|---|---|
|
| ||||||
| Dose dense chemotherapy (N, %) | Conventional schedule chemotherapy (N, %) | PRatio | 95% CI | PRatio | 95% CI | |
| TOTAL | 2789 (60) | 1896 (40) | - | - | - | - |
| Sociodemographics | ||||||
| Age at diagnosis (years) | ||||||
| 18-39 | 358 (74.3) | 124 (25.7) | REF | - | REF | - |
| 40-49 | 838 (63.7) | 478 (36.3) | 1.28 | 1.09, 1.49 | 1.24 | 1.06, 1.45 |
| 50-64 | 1,313 (58.5) | 931 (41.5) | 1.47 | 1.27, 1.71 | 1.44 | 1.24, 1.67 |
| 65-74 | 268 (45.4) | 322 (54.6) | 2.00 | 1.71, 2.24 | 1.99 | 1.70, 2.33 |
| 75+ | 12 (22.6) | 41 (77.4) | 2.89 | 2.29, 3.66 | 2.97 | 2.35, 3.75 |
| p-trend<0.001 | p-trend<0.001 | |||||
| Race and ethnicity | ||||||
| Non-Hispanic White | 1,534 (59.2) | 1,057 (40.8) | REF | - | REF | - |
| Non-Hispanic Black/AA | 211 (54.1) | 179 (45.9) | 1.15 | 1.03, 1.28 | 1.11 | 0.99, 1.24 |
| Non-Hispanic Asian | 518 (61.6) | 323 (38.4) | 1.01 | 0.92, 1.10 | 1.00 | 0.91, 1.09 |
| Hispanic | 478 (59.9) | 320 (40.1) | 1.08 | 0.99, 1.18 | 1.04 | 0.95, 1.14 |
| Other | 48 (73.8) | 17 (26.2) | 0.94 | 0.65, 1.37 | 0.86 | 0.60, 1.24 |
| global p=0.08 | global p=0.32 | |||||
| Neighborhood level SES | ||||||
| Median Household Income c | ||||||
| Q1: <$66,392 | 691 (55.9) | 546 (44.1) | REF | - | REF | - |
| Q2: $66,392-<$89,107 | 679 (58.8) | 476 (41.2) | 0.91 | 0.84, 0.99 | 0.90 | 0.83, 0.98 |
| Q3: $89,107-<$117,278 | 723 (60.3) | 476 (39.7) | 0.86 | 0.79, 0.94 | 0.84 | 0.77, 0.92 |
| Q4: ≥$117,278 | 696 (63.6) | 398 (36.4) | 0.74 | 0.68, 0.81 | 0.73 | 0.67, 0.80 |
| p-trend<0.001 | p-trend<0.001 | |||||
| Patient characteristics | ||||||
| BMI at diagnosis (kg/m2) | ||||||
| <18.5 | 27 (55.1) | 22 (44.9) | 1.09 | 0.80, 1.48 | 1.07 | 0.78, 1.47 |
| 18.5-<25 | 838 (59.4) | 572 (40.6) | REF | - | REF | - |
| 25-<30 | 923 (61.7) | 572 (38.3) | 0.95 | 0.88, 1.03 | 0.93 | 0.86, 1.01 |
| 30-<35 | 545 (57.9) | 396 (42.1) | 1.05 | 0.96, 1.14 | 0.99 | 0.91, 1.09 |
| ≥35 | 456 (57.7) | 334 (42.3) | 1.06 | 0.97, 1.17 | 1.01 | 0.92, 1.11 |
| p-trend=0.12 | p-trend=0.79 | |||||
| Diabetes | ||||||
| No | 2,552 (60.0) | 1,698 (40.0) | REF | - | REF | - |
| Yes | 237 (54.5) | 198 (45.5) | 1.11 | 1.01, 1.23 | 1.09 | 0.99, 1.20 |
| CVD | ||||||
| No | 2,718 (59.6) | 1,843 (40.4) | REF | - | REF | - |
| Yes | 71 (57.3) | 53 (42.7) | 0.98 | 0.82, 1.18 | 0.96 | 0.80, 1.15 |
| Renal impairment | ||||||
| No | 2,785 (59.6) | 1,884 (40.4) | REF | - | REF | - |
| Yes | 4 (25.0) | 12 (75.0) | 1.61 | 1.15, 2.24 | 1.55 | 1.11, 2.17 |
| Hepatic impairment | ||||||
| No | 2,727 (59.5) | 1,853 (40.5) | REF | - | REF | - |
| Yes | 62 (59.0) | 43 (41.0) | 1.03 | 0.83, 1.28 | 1.03 | 0.83, 1.26 |
| Neutropenia | ||||||
| No | 2,735 (59.4) | 1,867 (40.6) | REF | - | REF | - |
| Yes | 54 (65.1) | 29 (34.9) | 1.06 | 0.81, 1.39 | 1.08 | 0.83, 1.41 |
| Thrombocytopenia | ||||||
| No | 2,761 (59.4) | 1,886 (40.6) | REF | - | REF | - |
| Yes | 28 (73.7) | 10 (26.3) | 0.74 | 0.45, 1.22 | 0.74 | 0.44, 1.25 |
| Tumor/cancer characteristics | ||||||
| Year of diagnosis | ||||||
| Early (2005-2011) | 1,108 (44.4) | 1,385 (55.6) | REF | - | REF | - |
| Late (2012-2019) | 1,681 (76.7) | 511 (23.3) | 0.42 | 0.39, 0.46 | 0.44 | 0.41, 0.48 |
| Stage | ||||||
| Stage I | 449 (46.1) | 525 (53.9) | REF | - | REF | - |
| Stage II | 1,687 (60.2) | 1,117 (39.8) | 0.71 | 0.67, 0.76 | 0.71 | 0.67, 0.76 |
| Stage IIIA | 653 (72.0) | 254 (28.0) | 0.52 | 0.47, 0.58 | 0.51 | 0.46, 0.58 |
| p-trend<0.001 | p-trend<0.001 | |||||
| Grade | ||||||
| Grade 1 | 239 (51.4) | 226 (48.6) | REF | - | REF | - |
| Grade 2 | 1,086 (57.4) | 805 (42.6) | 0.96 | 0.87, 1.05 | 0.95 | 0.86, 1.05 |
| Grade 3 | 1,464 (62.9) | 865 (37.1) | 0.88 | 0.80, 0.97 | 0.90 | 0.81, 1.00 |
| p-trend=0.002 | p-trend=0.03 | |||||
| Hormone-receptor status | ||||||
| ER− and PR− | 875 (64.1) | 491 (35.9) | REF | - | REF | - |
| ER+ and/or PR+ | 1,914 (57.7) | 1,405 (42.3) | 1.22 | 1.13, 1.32 | 1.22 | 1.13, 1.32 |
| HER2 status | ||||||
| HER2− | 2,554 (62.1) | 1,560 (37.9) | REF | - | REF | - |
| HER2+ | 235 (41.2) | 336 (58.8) | 1.43 | 1.33, 1.55 | 1.50 | 1.38, 1.62 |
| Surgery type | ||||||
| Mastectomy | 1,579 (64.0) | 888 (36.0) | REF | - | REF | - |
| Breast conserving surgery | 1,210 (54.6) | 1,008 (45.4) | 1.09 | 1.02, 1.16 | 1.11 | 1.04, 1.19 |
a
Minimally adjusted: Age, stage, study site, year of diagnosis. Outcome is conventional regimen (as 1) versus dose dense regimen (as 0).
b
Fully adjusted: age, income, renal impairment, diabetes, year of diagnosis, HER2, stage, grade, hormone receptor status, surgery type, study site. Outcome is conventional regimen (as 1) versus dose dense regimen (as 0).
c
Median neighborhood household income: calculated at neighborhood level
Abbreviations: SES, socioeconomic status; BMI, body mass index; ER: estrogen receptor; PR: progesterone receptor; HER2, human epidermal growth factor receptor-2; CVD, cardiovascular disease