Radiotherapy after surgery cuts long-term risk of breast cancer recurrence

By Sophie Ramsey

BMJ Group News

What do we know already?

Radiotherapy after breast-conserving surgery is a recommended treatment for women with early breast cancer. Breast-conserving surgery removes the tumour and its surrounding tissue, leaving the breast otherwise intact. Radiotherapy to the breast then aims to kill any cancer cells left behind.

Many studies have shown that this combination of treatments reduces the risk that a woman’s cancer will return in the years following her surgery. However, its long-term effects, both in terms of breast cancer recurrence and survival, are less clear.

Researchers have now pooled the findings of 17 long-term studies comparing women who had radiotherapy after breast-conserving surgery with women who had surgery alone. This is the largest review of studies done to date, including more than 10,000 women with early breast cancer.

What does the new study say?

Women who had radiotherapy after breast-conserving surgery were much less likely to have their cancer come back over the next 10 years. Overall, 19 percent of women had their cancer return after radiotherapy, compared with 35 percent who had surgery alone - nearly halving the risk.

This drop in risk held relatively steady when researchers looked separately at women with a higher and lower chance of breast cancer recurrence, based on factors including their age, the size of their tumour, and whether or not they had additional treatments.

For every four cancers halted through radiotherapy, one less woman dies of breast cancer, researchers estimate.

Another interesting finding was that, regardless of whether women had radiotherapy, their risk of dying from causes other than breast cancer was about the same 15 years after treatment. This suggests that serious risks associated with radiotherapy (notably, a raised chance of other cancers) didn’t lead to more deaths.

How reliable is the research?

This is the largest review of long-term studies ever done on radiotherapy after breast-conserving surgery, and its findings should be quite reliable.

However, it’s worth noting that all of the women in the studies were treated from the 1970s to the 1990s, when the diagnosis and treatment of early breast cancer was less advanced than it is now. This could mean that the benefits of radiotherapy might be somewhat different for women having the treatment today.

What does this mean for me?

These findings confirm and expand what we know about the benefits of radiotherapy after breast-conserving surgery, showing a large drop in breast cancer recurrence 10 years after treatment and a moderate decline in breast cancer deaths after 15 years.

This is good news if you’ve had radiotherapy for early breast cancer, or are considering the treatment. You may also be reassured to know that women who had radiotherapy were no more likely to have died of other causes after 15 years than those who did not have this treatment.

However, some women do get side effects from radiotherapy, although serious problems are fairly rare. If you have any questions about the benefits and risks of this treatment, be sure to discuss these with your doctor.