Does the histological grade of early stage breast cancer effect outcomes of older women treated with breast conserving surgery?

This article was carried out to look at how histological grade (HG) impacts the outcomes of older women with early-stage (ES) breast cancer (BC) treated with breast-conserving therapy (BCS) with or without radiotherapy (RT). The authors found that the treatment of ESBC without RT resulted in a lower cancer-specific survival in higher-grade tumors. 

BC is one of the most common forms of cancer in women. Standard care is usually a combination of chemotherapy, surgery, and radiotherapy. BCS is the removal of the tumor only. It is an alternative to mastectomy (complete removal of the breast) in women with ES BC. BCS is associated with better psychological outcomes for patients.

HG is a description of a tumor based on how abnormal the cells look underneath a microscope. HG also describes how quickly these cancer cells may grow and spread. A higher grade usually indicates that a cancer is more aggressive and will spread faster. Previous studies have not examined the influence that HG has on outcomes of elderly women receiving BCS with or without RT. 

There were a total of 12 036 patients aged between 70 and 79 years examined for this article. All patients had ES BC and received BCS. 78% of patients also received RT. The average follow-up was 9.4 years long.

Overall, survival was higher in patients who received RT. After 5 years, 92.1% of the RT group and 83.5% of the non-RT group were alive. After 10 years, 74.4% of the RT group and 62.3% of the non-RT group were alive. 

In patients with grade 1 disease, there was no difference in survival rates with BC at 5 years (99% for both the RT and non-RT groups) and at 10 years (95% with RT and 96% without RT). However, in patients with higher-grade disease, RT was associated with a 42% increased survival with BC. Overall survival was also significantly improved (by 37%) in patients who received RT.

The authors found that treatment of ES BC with BCS and RT resulted in a better survival particularly in higher-grade tumors. 

This study was based on data from medical records. Information might have been missing. Many factors could have influenced the receipt of RT. This could have influenced the results.