The Finnish Medical Journal recently reported that breast cancer screening in Finland will expand from women aged 50-69 to 45-74 (Alanko et al., 2026). The change follows updated European Commission recommendations and evidence from the Finnish Cancer Registry showing that broader screening is cost-effective.
As screening expands and more cancers are detected earlier, a key question emerges: which breast cancer patients benefit the most from early detection?
Recent research points to patients with a novel subtype known as “HER2-low” breast cancer (Hollmén et al., 2026). HER2 is a receptor found in breast cancer cells. Tumors with high expression of HER2 (also known as HER2-positive breast cancer) are more aggressive, but treatable with therapies that target HER2. More recently, patients with lower levels of HER2 expression, also known as HER2-low, have also been shown to benefit from these treatments.
Despite this, HER2-low breast cancer remains poorly understood.
In our study, we compared HER2-low and HER2-negative breast cancers. We found that HER2-low tumors were associated with more favorable features: fewer co-existing illnesses, less aggressive tumor biology and more frequent detection via screening mammography with no prior symptoms. In contrast, HER2-negative patients more often presented with symptoms, such as a breast lump, and were diagnosed later in subsequent imaging. Notably, among patients with stage II disease, HER2-low patients had a higher survival rate than HER2-negative patients.
These findings highlight why screening matters.
Expanding screening is not just about detecting more cancers, but detecting them earlier — especially those that would otherwise progress and cause apparent symptoms. Broader screening may increase detection of HER2-low tumors before symptoms appear, while also enabling earlier diagnosis of more aggressive HER2-negative cancers.
Expanding screening only makes a difference if people take part. So when invited, attend your screening and stay aware of any changes in your breasts.
Milla Hollmén
A newly graduated doctor currently working as a doctoral researcher studying biomarkers in breast cancer.
References:
- Alanko, J., Hukkinen, K., Ipatti, P., Lagercrantz, S., & Salminen, A. (2026). Rintasyöpää seulotaan jatkossa nykyistä enemmän. Lääkärilehti. https://www.laakarilehti.fi/tieteessa/katsausartikkeli/rintasyopaa-seulotaan-jatkossa-nykyista-enemman/
- Milla Hollmén, Eliisa Löyttyniemi, Eeva Juhanoja, Pia Vihinen, Maria Sundvall, Characterization of real-world clinical and pathological differences between HER2-0
- and HER2-low localized breast cancer, Cancer Treatment and Research Communications (2026), doi: https://doi.org/10.1016/j.ctarc.2026.101204
