Table 3.
Univariate and multivariable analysis: impact of various clinical and biological factors and of fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET-CT) findings on disease-specific survival*
| Variable | No. (%) | Univariate analysis | Multivariable analysis | |||||
|---|---|---|---|---|---|---|---|---|
| Reference category | Log rank P | RR(95% CI) | Cox P | Reference category | RR(95% CI) | Cox P | ||
| Clinical N+ disease | 156 (82.5%) | Clinical N0 disease | .71 | 1.32 (0.30 to 5.72) | .71 | † | † | † |
| Inflammatory cancer | 31 (16.5%) | Noninflammatory breast cancer | <.001 | 4.85 (2.00 to 11.73) | <.001 | Noninflammatory breast cancer | 2.03 (0.75 to 5.52) | .17 |
| Grade 3 breast cancer | 92 (48.5%) | Grade 1 or 2 breast cancer | .28 | 1.61 (0.67 to 3.90) | .29 | † | † | † |
| Phenotype‡ER-positive/HER2-negative tumors§HER2-positive tumors§ TNBC§ | 98|| (52.0%)37|| (19.5%)52|| (27.5%) | ER-positive/HER2-negative tumors§ | <.001 | 10.42 (0.09 to 1.80)4.48 (1.82 to 11.00) | -.24.001 | ††Non-TNBC§ | ††18.58 (5.24 to 65.85) | ††<.001 |
| Distant metastases on PET-CT | 47 (25.0%) | No distant metastases on PET-CT | <.001 | 8.41 (3.33 to 21.27) | <.001 | No distant metastases on PET-CT | 26.60 (6.60 to 102.62) | <.001 |
* The analysis was performed in patients with clinical stage IIB and higher breast cancer and full information (N = 189). All statistical tests were two-sided. CI, confidence interval; ER = estrogen receptor; HER2 = human epidermal growth factor receptor 2; RR = relative risk; TNBC = triple-negative breast cancer.
† Corresponding variables were discarded from the multivariable Cox proportional hazard model because they were not significant in the univariate analysis.
‡ Stratified univariate Cox proportional hazard model was considered for the corresponding variables.
§ Tumors were considered ER positive if more than 10% of cells showed staining by immunohistochemistry. The same criterion was used for progesterone receptor. Tumors were considered to overexpress HER2 (HER2-positive) if more than 30% of invasive tumor cells showed definite membrane staining resulting in a so-called fishnet appearance. TNBC is negative for estrogen and progesterone receptors and is without HER2 overexpression.
|| Phenotype was undetermined in 2 of the 189 patients.