One in five women with breast cancer who has part of the breast removed, rather than the whole breast, ends up having another operation, a BMJ study suggests.The reoperation rate increases to one in three for women whose early-stage cancer is difficult to detect.In England, 58% of women with breast cancer have breast-conserving surgery.Women should be told of the risk of further operations when choosing surgery, researchers say.The study, led by researchers from the London School of Hygiene and Tropical Medicine and published in the British Medical Journal, looked at data collected on 55,297 women with breast cancer in England.They all underwent breast-conserving surgery, rather than a mastectomy, on the NHS between 2005 and 2008. All the women were aged 16 or over.They then looked at procedures carried out in the three months following the first breast operation.The researchers took tumour type, age, socio-economic deprivation and other health problems into account.When combined with radiotherapy, the study says that breast-conserving surgery is as effective as mastectomy, particularly for patients with an obvious, invasive tumour.'Emotional distress'However, because some pre-invasive cancers called 'carcinoma in situ' are difficult to detect, because they don't form a lump, breast conserving-surgery may not remove the cancer completely.This could result in another operation.The study says that additional operations put women's lives on hold while they wait for more surgery. It can delay their return to work, cause emotional distress and result in the need for reconstructive surgery to the breast.Out of the 55,297 women who underwent breast-conserving surgery, 45,793 (82%) were suffering from isolated invasive cancer, 6,622 (12%) had isolated carcinoma in situ (pre-cancerous disease), and 2,882 (6%) had both types of cancer.Another operation was more likely among women with pre-cancerous disease (29.5%) compared with those with isolated invasive disease (18%).Around 40% of women who had a reoperation underwent a mastectomy.Further results suggest that a repeat operation is less likely in older women and women from more deprived areas.'Empowering patients'Prof Jerome Pereira, study author and consultant breast surgeon at James Paget University Hospitals in Great Yarmouth, said the findings would help women to make decisions about their treatment."Patients should feel reassured that clinicians can now advise them more clearly."We all have a different attitude to risk but this is empowering patients to make the right decision for themselves."Prof Pereira said the study results would help surgeons too."This research focuses surgeons and challenges us to try and reduce reoperation rates."We need to refine imaging techniques to make this happen - and this opens up more areas for more research."'Increase survival'Ramsey Cutress, Cancer Research UK breast cancer surgeon at the University of Southampton, said it was standard practice to discuss the possibility of further surgery with patients."It's important for patients to fully understand the pros and cons of surgery. The ultimate aim of these repeat operations after breast-conserving surgery is to reduce the chance that breast cancer will return in the breast, and increase survival from the disease."Rates of breast cancer recurrence are also reduced by other treatments such as radiotherapy, hormone therapy and chemotherapy where appropriate."There is an ongoing need to better identify those at high risk of breast cancer recurrence, and to carefully select those who would benefit the most from further surgery."