Equal survival outcomes for BCT and mastectomy, trials often exclude elderly patients or patients with existing disease other than breast cancer (comorbidity).

‘Breast conserving therapy is at least as good as mastectomy and that some patients might benefit more than others from BCT in the future.’

Although randomised trials initiated in the 1980s have shown equal survival outcomes for BCT and mastectomy, trials often exclude elderly patients or patients with existing disease other than breast cancer (comorbidity). Studies with large, population-based groups, including comorbidity and those who are elderly, can add to the knowledge based on these trials and provide outcome that is more widely applicable and reflect daily practice. Several recent population-based studies showed a survival advantage for BCT. However, these studies tended to lack long-term follow-up, evaluated limited patient numbers, had differences in medication after surgery between both groups and lacked the data on cause of death that are needed to evaluate breast cancer-specific survival. All this could have led to the introduction of confounding factors such as severity of disease or death due to other causes, the researchers say. 




In the current study, a number of prognostic factors such as age, stage, comorbidity, hormonal receptor and HER2 status, and differences in systemic treatments (medication after surgery) were included and considered as possible explanations for the previously reported survival differences between BCT and mastectomy. This enabled the identification of possible prognostic factors that might, in future, predict which patients could benefit most from BCT.
"We looked at two different groups in order to allow us to compare long-term outcomes in a more historical versus a more recent cohort, evaluating patients that had been able to benefit from more sophisticated diagnostics and therapies. A considerably superior survival, both specific to breast cancer and from any cause of death, was found for BCT in the early stage T1-2N0-1M0 cancers in both time cohorts," says Prof Siesling.
To identify patients who could possibly benefit most from BCT, both time cohorts were divided into subgroups. Evaluation of T1-2N0-1M0 cancers, which are at a stage when metastasis to distant organs has not yet occurred, in both groups showed a considerable advantage for BCT in patients with increasing age, those with comorbidity, and those who did not receive chemotherapy.
"Although this study is based on retrospective data with much detailed data, and residual confounding factors cannot be ruled out completely, we believe that this information will have potential to greatly improve shared treatment decision-making for future breast cancer patients in those aged over 50 years and those with comorbidity," says Prof Siesling.
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Source-Eurekalert