Cancer patients who have radiotherapy after breast-conserving surgery have a lower risk of recurrence and a better chance of beating the illness, according to a study released on Friday.

An overview of 78 trials into the benefits of radiotherapy, which kills cancer cells left in the breast after the tumor has been removed, showed the five-year risk of the cancer returning dropped from 26 percent to seven percent in women receiving the treatment.

The odds of dying from the disease 15 years after diagnosis fell from 36 to 31 percent.

“It has been known that radiotherapy is beneficial in stopping the cancer growing again locally but it has not previously been seen that after breast-conserving surgery, radiotherapy improved survival from breast cancer mortality or from overall mortality,” said Dr Sarah Darby.

“That’s a new finding,” the professor of medical statistics at the University of Oxford in England added in an interview.

MASTECTOMY PATIENTS

Radiotherapy also brought an overall improvement in survival in patients who had had a mastectomy - removal of the breast - and whose cancer had spread to the lymph nodes in the armpit.

But the researchers, who reported their findings in The Lancet medical journal, said the treatment was not appropriate for mastectomy patients whose cancer had not spread beyond the breast.

“This study provides the first really definite evidence that, for women who’ve had breast-conserving surgery and for women whose cancer has spread to the armpit, radiotherapy reduces the long-term risk of dying from the disease,” said Dr Richard Peto, a co-author of the report.

“The improvement is small but definite and it adds to the improvement in long-term survival produced by chemotherapy and hormone therapy,” he added in a statement.

Breast cancer is one of the most common cancers in women. More than a million cases occur worldwide each year, according to the International Agency for Research on Cancer (IARC) in Lyon, France.

Although most cases of the disease develop in women over 50 years old, a small percentage are in women in the 30s or younger. Australian pop singer Kylie Minogue was diagnosed with the disease earlier this year at the age of 36.

Breast cancer is treated with surgery and radiotherapy, chemotherapy and hormone treatment, or a combination of them, depending on the cancer and stage of the illness.

Factors which can increase a woman’s risk of the breast cancer include having a mother or close relative with the disease, inherited mutations in the BRCA1 or BRCA2 genes, an early puberty, late menopause and not having any children.