Comparison of the differential effect of participation in breast cancer screening program versus opportunistic screening or symptomatic detection on tumour characteristics.

Objectives: The success of a breast cancer screening program is highly dependent on adherence. We aimed to compare the differential effect of participation in breast cancer screening program versus opportunistic screening or symptomatic detection on tumour characteristics.

Methods: We included women referred to our Breast Centre in 2015-2021: 321 from the breast cancer screening group (group 1) and 422 through opportunistic screening or due to symptomatic detection (group 2). We compared data on sociodemographics, breast cancer detection, clinical features and tumour characteristics.

Results: A total of 10.6% of women in group 1 had breast symptoms and 63.8% had breast signs, with group 2 presenting higher proportions (57.6 and 77.8%, respectively, P < 0.001). The median tumour size in group 1 was smaller compared with group 2 (14 vs 17 mm, P < 0.001). A total of 8.7% of women in group 1 had nodal involvement whereas in group 2 the proportion corresponded to 19.0% (P < 0.001). No women in group 1 were diagnosed with metastasis, while metastases were found in 2.4% of those from group 2 (P = 0.005). There were no significant differences in molecular subtype of invasive tumours between the two groups.

Conclusion: The tumour characteristics of women who participated in the breast cancer screening program showed in almost all characteristics more favourable results in comparison with the group who underwent opportunistic screening or sought care due to symptoms. The lower clinical stage observed in those referred from the organised program reaffirms that it is an effective measure for early detection, diagnosis, and treatment.