Houston: Scientists have developed a simple blood test which they say could lead to early diagnosis of breast cancer and predict whether a patient faces high risk of relapse or death following treatment.
The study carried out by a team from the University of Texas` MD Anderson Cancer Centre builds on previous work that identified tumour cells circulating in the blood of patients suffering from spreading (metastatic) breast cancer.
Tumours are generally thought of as spreading through the lymphatic system rather than the bloodstream, so this earlier research, the scientists said, represented a significant departure from the usual means of cancer diagnosis and characterisation, `The Lancet Oncology` reported today.
"The presence of one or more circulating tumour cells (CTCs, in the blood) predicted early recurrence and decreased overall survival," they said.
The Texas team, led by Prof Anthony Lucci from Department of Surgical Oncology, investigated whether circulating tumour cells (CTCs) could be found in the blood of patients at an earlier stage of disease, where the cancer has not spread beyond its original location (non-metastatic).
They also looked at how the presence of CTCs affected survival rates and progression of the disease by studying 302 patients with early-stage breast cancer.
The researchers identified CTCs in the blood of 24 per cent of the study group.
They also found that CTCs presence accurately predicted both progression-free survival and overall survival, with 15 per cent of the patients tested positive for CTCs relapsing, and 10 per cent dying during the study period (Feb 2005 to Dec 2010), as compared to just three per cent and two per cent, respectively, of patients who did not test positive for CTCs.
For patients with a higher concentration of CTCs, the correlation with survival and progression rates was even more dramatic, with 31 per cent of them dying or relapsing during the study period, the researchers found.
The findings raise hope that in future, blood tests could be used to provide improved diagnosis and treatment for early-stage breast cancer patients, they said.
Currently, diagnosis of early-stage breast cancer often relies on lymph-node removal, which can have unpleasant side-effects. CTCs analysis does not appear in current guidelines for the assessment of cancer patients.
"These studies identified that both progression-free and overall survival were worse in patients with one or more circulating tumour cells... The growing body of published work, including our study, suggests that assessment of circulating tumour cells might provide important prognostic information in these patients," said Prof Lucci.
"If the presence of circulating tumour cells were to contribute independently to the currently available prognostic factors, this information might be useful in disease staging and in identifying patients who might benefit from additional adjuvant therapies."
The research remains at an early stage and further work will be needed before CTCs can be used to guide clinical decision making, the researchers added.