Breast cancer incidence and early diagnosis in a family history risk and prevention clinic: 33-year experience in 14,311 women.

PURPOSE: Women at increased familial breast cancer risk have been offered screening starting at an earlier age and increased frequency than national Screening Programmes for over 30 years. There are limited data on longer-term largescale implementation of this approach on cancer diagnosis. METHODS: Women at our institution at ≥ 17% lifetime breast cancer risk have been offered enhanced screening with annual mammography starting at age 35 or 5-years younger than youngest affected relative, with upper age limit 50 for moderate and 60 for high-risk. Breast cancer pathology, stage and receptor status were assessed as well as survival from cancer diagnosis by Kaplan-Meier analysis. RESULTS: Overall 14,311 women were seen and assessed for breast cancer risk, with 649 breast cancers occurring in 129,119 years follow up (post-prevalent annual incidence = 4.55/1000). Of 323/394 invasive breast cancers occurring whilst on enhanced screening, most were lymph-node negative (72.9%), T1 (≤ 20 mm, 73.2%) and stage-1 (61.4%), 126/394 stage2-4 (32%). 10-year breast cancer specific survival was 91.3% (95% CI 87.4-94.0) better than the 75.9% (95% CI 74.9-77.0) published for England in 2013-2017. As expected, survival was significantly better for women with screen detected cancers (p < 0.001). Ten-year survival was particularly good for those diagnosed ≤ 40 at 93.8% (n = 75; 95% CI 84.2-97.6). Women with lobular breast cancers had worse 10-year survival at 85.9% (95% CI 66.7-94.5). Breast cancer specific survival was good for 119 BRCA1/2 carriers with 20-year survival in BRCA1:91.2% (95% CI 77.8-96.6) and 83.8% (62.6-93.5) for BRCA2. CONCLUSIONS: Targeted breast screening in women aged 30-60 years at increased familial risk is associated with good long-term survival that is substantially better than expected from population data.