Many breast cancer patients who undergo partial breast removal need to have follow-up surgery.
New research published in the British Medical Journal by scientists at the London School of Hygiene and Tropical Medicine found that when combined with radiotherapy, breast-conserving surgery in patients with obvious invasive tumours can be as effective as full removal.
However, having studied the medical records of 55,000 women they observed that in cases of carcinoma in situ, partial removal of tissue often failed to remove all of the cancerous material from the breast and patients needed a secondary operation with 40 per cent opting for a mastectomy.
Lead author Dr David Cromwell said: "Before this study, it was unclear what that risk was but now women can be better informed."
According to Cancer Research UK, breast cancer is the most common form of the disease in Britain, but around 85 per cent of sufferers survive for at least five years after diagnosis.