Women stand a better chance of surviving breast cancer if they don’t have a mastectomy, a major study has found.

Those aged over 50 who have only the lump removed, followed by radiotherapy, are almost a fifth more likely to survive the illness than patients who lose the whole breast.

Many women diagnosed with breast cancer choose to have a mastectomy thinking it will remove the tumours as quickly as possible and give them the best chance of survival.

But the results of a ten-year research project by academics show that a  less radical form of treatment – breast conservation surgery – is more effective.

It involves taking away the affected lump and then administering high doses of radiotherapy over a course of five or six weeks to ensure any remaining cancerous cells are killed.

Researchers from Duke University in North Carolina looked at the records of 112,154 women diagnosed with breast cancer between 1994 and 2004.

Around 55 per cent had breast conservation surgery and 44 per cent had a mastectomy.

The study, published in the journal Cancer, shows that women who had breast conservation surgery were 13 per cent more likely to survive the illness. But the results were even more promising in women over 50 whose survival odds were 19 per cent higher than those who had mastectomies.

It also found that women of all ages who had breast conservation surgery were a fifth less likely to die from other causes such as heart disease.

This study looked only at women diagnosed with breast cancer early – known as stages one or two. It did not include patients with advanced forms of the illness.

Experts believe radiotherapy may be far more effective at killing all cancerous cells than removing the entire breast.

Lead researcher Dr E Shelley Hwang, of the Duke Cancer Institute in North Carolina, said: ‘Our findings support the notion that less invasive treatment can provide superior survival to mastectomy in stage one or stage two breast cancer.

‘Given the recent interest in mastectomy to treat early stage breast cancers, despite the research supporting lumpectomy, our study sought to further explore outcomes of breast-conserving treatments in the general population comparing outcomes between younger and older women.’

Sally Greenbrook, senior policy officer at UK charity Breakthrough Breast Cancer, said: ‘We welcome these significant findings, as we have known for some time that lumpectomy and radiotherapy is as effective as mastectomy for some women.

‘These findings go further to suggest that lumpectomy with radiotherapy could be better than mastectomy in early stage invasive breast cancer.

‘We know, through speaking to women with breast cancer every day, how difficult it is to choose between a mastectomy and a lumpectomy.

This study provides further reassurance allowing women to be more confident when making this decision.

‘More research is needed to confirm these results, and we urge anybody concerned to speak to their surgeon so they can make an informed decision, as every choice is personal.’

Radiotherapy is given to women immediately after surgery and the course of treatment normally lasts five or six weeks. But many women are put off by the side effects which include chest pain, tiredness, lowered immune system and heart problems.

Around 50,000 women are diagnosed with breast cancer in the UK every year. One in eight women will get the disease at some point in their lifetime.

Thanks to medical advances the survival odds are far higher than other forms of cancer and 80 per cent of patients live beyond five years.