Impact of Method of Detection of Breast Cancer on Clinical Outcomes in Individuals Aged 40 Years or Older

Purpose To determine the impact of method of detection (MOD) on breast cancer stage, treatment, and breast cancer-related mortality in patients aged 40 years or older. Materials and Methods This retrospective observational cohort study included consecutive female individuals aged 40 years or older diagnosed with breast cancer at a tertiary referral center between January and December 2016. Odds ratios (ORs) and 95% CIs were computed using logistic regression modeling to determine the impact of MOD (screen-detected vs symptom-detected) on pathologic stage (American Joint Commission on Cancer, eighth edition), surgical treatment, and chemotherapy, with Cox regression to find the hazard ratio (HR) and 95% CI for mortality. Significance level was set at a <i>P</i> value less than .013 using Bonferroni correction. For subgroup analyses, patients were divided into categorical age groups: 40 to 49 years, 50 to 59 years, 60 to 74 years, and 75 years or older. Results A total of 821 patients (mean age [±SD], 62.5 years ± 12.2) were included; mean duration of follow-up was 6.7 years. Symptom-detected cancers (50.1% [411 of 821]) were more frequent in less-screened age groups (72.9% [97 of 133] in women aged 40-49 years and 70.4% [95 of 135] in those aged ≥75 years) compared with screened age groups (49.5% [106 of 214] in those aged 50-59 years and 33.3% [113 of 339 in those aged 60-74 years]). The odds of advanced cancer (stage IIA or greater) were 6.60 higher (95% CI: 4.96, 8.77; <i>P</i> < .001) with symptom detection (32.5% [267 of 821]) compared with screen detection (10.2% [84 of 821]). Symptom-detected cancers had higher HR of breast cancer-related death (HR, 1.63 [95% CI: 1.17, 2.28]; <i>P</i> = .004), higher odds of mastectomy (OR, 2.20 [95% CI: 1.63, 2.96]; <i>P</i> < .001), and the same odds of chemotherapy, adjusted for age and stage at diagnosis. Multivariable analysis found that higher tumor stage was associated with symptom detection (OR, 6.40 [95% CI: 4.74, 8.70]; <i>P</i> < .001), greater risk of chemotherapy (OR, 1.97 [95% CI: 1.39, 2.78]; <i>P</i> < .001), and age at diagnosis (OR, 1.02 [95% CI: 1.01, 1.03]; <i>P</i> = .001). Conclusion Screen-detected breast cancer in patients aged 40 years or older was associated with lower odds of advanced cancer, mastectomy, and breast cancer-related death compared with symptom-detected cancer. <b>Keywords:</b> Breast Screening, Guidelines, Breast Cancer, Treatment <i>Supplemental material is available for this article.</i> © RSNA, 2025.