Recurrence of breast cancer after more than 10 years is an important indicator of survival

Barcelona, Spain: Recurrence of breast cancer in the same area as the original tumour remains the strongest, independent prognostic factor for subsequent metastasis and death, even for patients who have been free of disease for a very long time, according to research presented today (Wednesday) at the seventh European Breast Cancer Conference (EBCC7).

Dr Sven Mieog, MD, a research fellow at Leiden University Medical Centre (Leiden, The Netherlands) will tell the conference that in women treated with breast conserving treatment for early stage breast cancer, a locoregional recurrence remained the most important prognostic factor after a disease-free interval of five years. Moreover, after a disease-free interval of ten years, locoregional recurrence remained the sole independent prognostic factor.

"In patients who were free of disease for more than ten years after primary treatment, locoregional recurrence had a significant impact on both disease-free survival and overall survival," he said. "The increased risk of metastases after a recurrence was approximately four times higher than if there had been no recurrence, and the risk of dying after a recurrence was around eight times higher. However, these levels of increased risk need to be treated with caution because, with the longer time interval between the primary cancer and the recurrence, the number of events goes down, making these calculations less certain, although they remain important for clinicians when deciding on the best treatments."

Dr Mieog and his colleagues pooled data from 7,749 early stage breast cancer patients taking part in four trials run by the European Organisation for Research and Treatment of Cancer (EORTC). The average length of follow-up was 10.9 years and three different analyses looked at: 1) all the patients, 2) only patients without further cancer after at least five years, and, 3) patients without further cancer after at least 10 years.

In the analysis of all patients, locoregional recurrence, tumour size, whether the cancer had spread to the lymph nodes, young age, oestrogen receptor status and treatment with chemotherapy were all independent prognostic factors with a significant impact on long-term outcome, with locoregional recurrence being the strongest factor.

In the second analysis looking at patients who were disease-free after at least five years, locoregional recurrence was the strongest independent prognostic factor for overall survival and metastases-free survival. In the third analysis looking at patients who were disease-free after at least ten year, locoregional recurrence was the only independent prognostic factor.

Dr Mieog said: "These findings suggest that even after a long, event-free interval, locoregional recurrence seems to be associated with distant disease rather than a cause of subsequent distant disease."

Dr Jos A. van der Hage, MD PhD, a surgical oncologist at The Netherlands Cancer Institute (Amsterdam, The Netherlands) who collaborated with Dr Mieog but was unable to attend EBCC7, explained: "Locoregional recurrence is a well-known risk factor for subsequent distant disease and death. The nature of this relationship is not clear. However, most recurrences are not causes of subsequent disease spread but rather a symptom of disease progression, associated with a high likelihood of simultaneous metastases.