Table 2.
Hazard model for ipsilateral event-free survival*
| Covariate† | RR (95% CI) | P |
| Duration | 1.25 (0.90 to 1.73) | .18 |
| Duration2‡ | 0.99 (0.96 to 1.02) | .35 |
| Age, y | ||
| <40 | 8.41 (2.68 to 26.42) | <.001 |
| 40–49 | 3.20 (1.42 to 7.19) | .01 |
| 50–64 | 1.29 (0.61 to 2.70) | .51 |
| ≥65 | 1.00 (referent) | |
| Race | ||
| Non-black race | 1.00 (referent) | |
| Black race | 1.01 (0.49 to 2.12) | .97 |
| No. of comorbid conditions | ||
| <2 | 1.00 (referent) | |
| ≥2 | 2.33 (1.22 to 4.45) | .01 |
| Histologic subtype | ||
| Non-comedo histologic subtype | 1.00 (referent) | |
| Comedo histologic subtype | 2.05 (1.12 to 3.76) | .02 |
| Multifocality | ||
| Absent | 1.00 (referent) | |
| Present | 2.19 (0.92 to 5.23) | .08 |
| Treatment | ||
| Mastectomy | ||
| Negative margins (≥2 mm) | 0.03 (0.01 to 0.09) | <.001 |
| Close margins (<2mm) | 0.36 (0.07 to 1.81) | .22 |
| Positive margins | 1.98 (0.19 to 20.13) | .56 |
| BCS | ||
| Negative margins | 1.00 (referent) | |
| Close margins | 1.39 (0.71 to 2.73) | .33 |
| Positive margins | 3.38 (1.22 to 9.34) | .02 |
| Radiation therapy | 0.25 (0.14 to 0.46) | <.001 |
| Annual transitions (person-years) | 5445.00 | |
| Log pseudo-likelihood | −274.91 | |
| Pseudo R2 | 0.1558 | |
| Test of equivalence of BCS + RT and mastectomy§ | χ2 = 13.63 | <.001 |
*
N = 994 women; BCS = breast-conserving surgery; CI = confidence interval; RR = relative risk; RT = radiotherapy.
†
Other covariates not shown include year, census level percent black, census level percent below poverty, insurance status and type, histologic subtype, mammographic tumor size, presence of extensive ductal carcinoma in situ, nuclear grade, menopausal status, calcifications, tamoxifen use, and method of detection.
‡
Duration is time since treatment and duration2 is time since treatment squared.
§
Two-sided χ2 test with 1 df of BCS + RT = 0.