Factors associated with all-cause mortality
| Factor | Crude | Adjusted | ||
|---|---|---|---|---|
| HR (95% CI) | p value | HR (95% CI)* | p value | |
| O-BAS | ||||
| No | Ref. | Ref. | ||
| Yes | 0.41 (0.39 to 0.43) | 0.72 (0.68 to 0.76) | ||
| Screening status | < 0.0001 | < 0.0001 | ||
| Symptomatic | Ref. | Ref. | ||
| OBSP-screened | 0.30 (0.27 to 0.33) | 0.72 (0.66 to 0.79) | ||
| Non-OBSP-screened | 0.43 (0.40 to 0.46) | 0.67 (0.62 to 0.72) | ||
| Sociodemographic | ||||
| Age (per 10-yr increment) | 1.62 (1.59 to 1.65) | 1.49 (1.46 to 1.51) | ||
| Sex | ||||
| Female | Ref. | Ref. | ||
| Male | 2.29 (1.91 to 2.74) | 1.43 (1.18 to 1.74) | ||
| Neighbourhood income quintile† | < 0.0001 | < 0.0001 | ||
| Highest | Ref. | Ref. | ||
| Mid-high | 1.18 (1.09 to 1.28) | 1.13 (1.04 to 1.23) | ||
| Middle | 1.29 (1.19 to 1.40) | 1.15 (1.06 to 1.25) | ||
| Mid-low | 1.45 (1.34 to 1.56) | 1.18 (1.09 to 1.28) | ||
| Lowest | 1.71 (1.58 to 1.84) | 1.29 (1.19 to 1.40) | ||
| Neighbourhood immigrant density† | < 0.0001 | < 0.0001 | ||
| Least dense | Ref. | Ref. | ||
| Mid-dense | 0.88 (0.83 to 0.93) | 0.97 (0.91 to 1.04) | ||
| Most dense | 0.84 (0.79 to 0.90) | 0.93 (0.85 to 1.03) | ||
| Rurality† | ||||
| Urban | Ref. | Ref. | ||
| Rural | 1.09 (1.00 to 1.16) | 0.94 (0.86 to 1.03) | ||
| Distance to closest O-BAS (per 100-km increment)‡ | 1.17 (1.04 to 1.30) | 0.90 (0.77 to 1.05) | ||
| Clinical | ||||
| Charlson Comorbidity Index | < 0.0001 | < 0.0001 | ||
| Missing | 0.73 (0.69 to 0.77) | 0.87 (0.82 to 0.92) | ||
| 0 | Ref. | Ref. | ||
| 1 | 1.75 (1.63 to 1.88) | 1.33 (1.23 to 1.44) | ||
| 2 | 2.79 (2.52 to 3.08) | 1.66 (1.50 to 1.85) | ||
| ≥ 3 | 4.56 (4.15 to 5.02) | 2.55 (2.31 to 2.82) | ||
| Previous breast cancer relative to diagnosis, yr | < 0.0001 | < 0.0001 | ||
| Never | Ref. | Ref. | ||
| ≤ 5 | 2.06 (1.68 to 2.52) | 1.65 (1.34 to 2.03) | ||
| 5–10 | 1.55 (1.36 to 1.77) | 1.10 (0.95 to 1.26) | ||
| ≥ 10 | 1.39 (1.26 to 1.53) | 0.98 (0.88 to 1.08) | ||
| Previous other cancer relative to diagnosis, yr | < 0.0001 | < 0.0001 | ||
| Never | Ref. | Ref. | ||
| ≤ 5 | 2.26 (2.04 to 2.50) | 1.63 (1.46 to 1.82) | ||
| 5–10 | 1.72 (1.47 to 2.01) | 1.27 (1.08 to 1.49) | ||
| ≥ 10 | 1.74 (1.55 to 1.96) | 1.25 (1.11 to 1.42) | ||
| Cancer | ||||
| Laterality | < 0.0001 | 0.01 | ||
| Right | Ref. | Ref. | ||
| Left | 1.00 (0.95 to 1.05) | 0.96 (0.91 to 1.01) | ||
| Bilateral | 1.84 (1.50 to 2.27) | 1.26 (1.02 to 1.56) | ||
| Cancer stage | < 0.0001 | < 0.0001 | ||
| 0 | 1.31 (0.79 to 2.18) | 0.94 (0.55 to 1.61) | ||
| 1 | Ref. | Ref. | ||
| 2 | 2.12 (1.97 to 2.28) | 1.80 (1.66 to 1.94) | ||
| 3 | 4.62 (4.27 to 5.01) | 4.10 (3.77 to 4.46) | ||
| 4 | 18.4 (17.0 to 19.9) | 13.0 (11.9 to 14.2) | ||
| Unknown | 7.68 (6.96 to 8.46) | 3.72 (3.30 to 4.19) | ||
| Histology | < 0.0001 | < 0.0001 | ||
| Ductal | Ref. | Ref. | ||
| Lobular | 1.13 (1.04 to 1.23) | 0.89 (0.82 to 0.98) | ||
| Ductal and lobular | 1.03 (0.91 to 1.16) | 0.99 (0.88 to 1.13) | ||
| Adenocarcinoma | 2.07 (1.84 to 2.33) | 0.99 (0.86 to 1.06) | ||
| Mucinous | 0.79 (0.64 to 0.97) | 0.88 (0.72 to 1.09) | ||
| Other | 2.53 (2.26 to 2.71) | 1.22 (1.12 to 1.31) | ||
| Hormone receptor profile | < 0.0001 | < 0.0001 | ||
| ER−, PR−, HER2− | Ref. | Ref. | ||
| ER−, PR−, HER2+ | 0.62 (0.55 to 0.70) | 0.50 (0.44 to 0.57) | ||
| ER−, PR+, HER2− | 1.07 (0.81 to 1.42) | 1.23 (0.93 to 1.63) | ||
| ER−, PR+, HER2+ | 0.76 (0.47 to 1.23) | 0.47 (0.29 to 0.75) | ||
| ER+, PR−, HER2− | 0.76 (0.69 to 0.85) | 0.62 (0.55 to 0.69) | ||
| ER+, PR−, HER2+ | 0.64 (0.55 to 0.75) | 0.52 (0.44 to 0.61) | ||
| ER+, PR+, HER2− | 0.40 (0.37 to 0.43) | 0.37 (0.34 to 0.40) | ||
| ER+, PR+, HER2+ | 0.42 (0.37 to 0.48) | 0.39 (0.34 to 0.44) | ||
| Missing | 0.95 (0.88 to 1.03) | 0.53 (0.48 to 0.58) | ||
| Topography | < 0.0001 | < 0.0001 | ||
| Upper–outer quadrant | Ref. | Ref. | ||
| Overlapping lesion | 1.26 (1.18 to 1.36) | 1.09 (1.02 to 1.17) | ||
| Breast NOS | 2.80 (2.61 to 3.01) | 1.41 (1.30 to 1.52) | ||
| Lower–outer quadrant | 1.03 (0.94 to 1.14) | 1.05 (0.95 to 1.15) | ||
| Upper–inner quadrant | 0.90 (0.83 to 0.98) | 0.97 (0.89 to 1.06) | ||
| Lower–inner quadrant | 1.05 (0.93 to 1.17) | 1.02 (0.91 to 1.14) | ||
| Central portion | 1.40 (1.26 to 1.55) | 1.05 (0.94 to 1.17) | ||
| Nipple | 1.28 (1.09 to 1.50) | 0.90 (0.76 to 1.06) | ||
| Axillary tail | 2.37 (1.91 to 2.93) | 1.48 (1.18 to 1.84) | ||
Note: CI = confidence interval, ER = estrogen receptor, HER2 = human epidermal growth factor receptor-2, HR = hazard ratio, NOS = not otherwise specified, O-BAS = OBSP-affiliated breast assessment site, OBSP = Ontario Breast Screening Program, PR = progesterone receptor, Ref. = reference category.
↵* n = 49 383 patients and 6402 events; all estimates are adjusted for O-BAS status, screening status, age, neighbourhood income quintile, neighbourhood immigrant density, rurality, distance to the closest O-BAS, Charlson Comorbidity Index, previous breast cancer, laterality, cancer stage, hormone receptor profile, topography, year of diagnosis and level of geography (Local Health Integration Network).
↵† Adapted from Statistics Canada Postal Code Conversion File and Postal Code Conversion File Plus (June 2017), which is based on data licensed from Canada Post Corporation.16 We used the patient’s postal code at diagnosis.
↵‡ Hazard ratios reflect the risk of death for every 100-km increase in Euclidean distance to the patient’s closest O-BAS. We used the patient’s postal code at diagnosis.