The earliest detection was 41 months before a scan confirmed the diagnosis.
Lead researcher Dr Isaac Garcia-Murillas, from the ICR, said: “Breast cancer cells can remain in the body after surgery and other treatments but there can be so few of these cells that they are undetectable on follow-up scans.”
He added that the cells can cause patients to relapse many years after their initial treatment.
Dr Garcia-Murillas said the study lays the groundwork for better post-treatment monitoring and potentially life-extending treatment.
Researchers tested blood samples at the point of diagnosis, and then again following surgery and chemotherapy.
These tests were then repeated every three months for the next year and every six months for the next five years.
Dr Simon Vincent, director of research, support, and influencing at Breast Cancer Now – which part-funded the study – said: “Early detection is one of our greatest weapons against breast cancer and these initial findings, which suggests new tests could be able to detect signs of breast cancer recurrence over a year before symptoms emerge, are incredibly exciting.”
Though acknowledging that the research was still in its early stages, he said catching breast cancer recurrence earlier means treatment is much more likely to destroy the cancer and stop it from spreading to other parts of the body and becoming incurable.
Dr Vincent continued: “With around 11,000 people dying every year in the UK from secondary breast cancer, breakthroughs like these are urgently needed so that we can stop people losing their lives to this devastating disease.”
It is unclear when the test could become widely available.
The news follows several developments in cancer research in the past week.
It comes after saliva tests carried out at home were found to be better at identifying men at higher risk of prostate cancer than standard blood tests.
And on Friday it was announced that thousands of NHS cancer patients in England are expected to get access to trials of a new type of treatment using personalized vaccines to fight their disease.
But on Monday a cancer charity said the number of melanoma skin cancer cases in the UK was expected to hit record levels.