Table 3. Comparison of BCSM Using Combination of Laterality with Primary Tumor Site.
| Specific Location | BCSM | Pairwise* | ||
| HR [95% CI] | P1 value | HR [95% CI] | P2 value | |
| LUO | 1.000 [Reference] | 0.968 [0.908–1.033] | .329 | |
| LUI | 1.250 [1.189–1.313] | <.0001 | 1.210 [1.124–1.303] | <.0001 |
| LLI | 1.372 [1.290–1.459] | <.0001 | 1.329 [1.233–1.443] | <.0001 |
| LLO | 1.136 [1.072–1.203] | <.0001 | 1.100 [1.016–1.191] | .019 |
| LCEN | 1.144 [1.078–1.215] | <.0001 | 1.108 [1.022–1.202] | .013 |
| RUO | 1.005 [0.972–1.039] | .755 | 0.974 [0.913–1.038] | .415 |
| RUI | 1.242 [1.180–1.307] | <.0001 | 1.202 [1.115–1.297] | <.0001 |
| RLI | 1.288 [1.204–1.377] | <.0001 | 1.247 [1.143–1.360] | <.0001 |
| RLO | 1.145 [1.079–1.216] | <.0001 | 1.109 [1.022–1.203] | .013 |
| RCEN | 1.033 [0.968–1.101] | .329 | 1.000 [Reference] | |
Abbreviations: BCSM = breast cancer-specific mortality; HR = hazard ratio; CI = confidence interval; LUO = left upper outer quadrant of breast; LUI = left upper inner quadrant of breast; LLI = left lower inner quadrant of breast; LLO = left lower outer quadrant of breast; LCEN = left central portion quadrant of breast; RUO = right upper outer quadrant of breast; RUI = right upper inner quadrant of breast; RLI = right lower inner quadrant of breast; RLO = right lower outer quadrant of breast; RCEN = right central portion quadrant of breast.
*Pairwise comparisons were conducted to clarify the difference on HR at different specific location. P1 value, using LUO as the reference, indicated same prognosis for patients with tumors at LUO, RUO and RCEN which were better than any other location. From another point of view, P2 value, using RCEN as the reference, indicated a little bit worse prognosis for patients with tumors at LCEN, LLO, RLO and the poorest prognosis for patients with tumors at LUI, LLI, RUI, RLI.