A new international study suggests that breast cancer screening could save lives even when the disease is diagnosed at its most advanced stage.
Researchers found that women whose stage IV breast cancer was discovered through routine screening had a far better chance of long-term survival compared with those whose cancer was found after symptoms appeared.
The study, conducted by scientists from King’s College London, Queen Mary University of London, and the University of Southern Denmark, analyzed how the method of detection affects survival at different stages of breast cancer.
The findings were published in the Journal of the National Cancer Institute (JNCI).
Stage IV breast cancer is the most serious form of the disease.
At this stage, cancer has spread from the breast to other parts of the body, such as the bones, liver, lungs, or brain. Survival rates are typically low, and treatment often focuses on controlling the disease rather than curing it.
However, the new research revealed a striking difference.
Women with stage IV cancer detected through screening had about a 60% chance of surviving 10 years after diagnosis. In contrast, fewer than 20% of women whose stage IV cancer was discovered outside screening survived that long.
Researchers believe screening may catch cancers earlier in their spread, even if they have technically reached stage IV.
These cancers may still be limited enough for doctors to attempt surgery or other aggressive treatments.
The study found that screened patients were more likely to undergo surgical removal of tumors, suggesting their disease may have been less widespread than in other stage IV cases.
Breast cancer screening programs use mammograms—low-dose X-rays of the breast—to detect tumors before symptoms appear. Many countries offer routine screening for women in middle age, as early detection is known to improve outcomes for earlier-stage cancers.
To conduct the study, researchers linked Danish national screening records from 2010 to 2019 with death records up to 2022.
They compared survival rates among women with breast cancer based on whether their cancer was detected through screening, found outside screening, or diagnosed in women who had never participated in screening programs.
Interestingly, for stages I, II, and III breast cancer, survival rates were similar regardless of how the cancer was detected. The biggest difference appeared only in stage IV cases, where screened patients had outcomes resembling those of stage III patients.
They were about three times more likely to live another decade than women with stage IV cancer found outside screening.
Lead author Dr. Amy Tickle said the results offer reassurance that even late-stage cancer can have better outcomes if detected during routine screening. The findings also highlight the importance of attending scheduled screening appointments.
Experts say the study provides new evidence that screening programs remain valuable, not only for early detection but also for improving outcomes in some advanced cases. Encouraging participation in screening could help reduce breast cancer deaths and allow doctors to treat the disease more effectively at all stages.
