About one fifth of female breast cancer patients who chose breast conserving surgery instead of mastectomy eventually need another operation, British researchers reported in the BMJ (British Medical Journal). The authors explained that their findings should help patients when deciding on how to go forward; whether to surgically remove the whole breast (mastectomy) or undergo breast conserving surgery (to have just part of the breast removed).

Of the 45,000 women who were diagnosed with breast cancer in England in 2008, 58% opted for breast conserving surgery instead of mastectomy.

According to the vast majority of studies, survival rates after mastectomy alone and breast conserving surgery combined with radiotherapy are similar.

However, not all tumors are easy to detect, and a number of breast conserving surgical procedures do not succeed in removing the whole tumor. In such cases the patient will eventually need to be operated on again; this could be a mastectomy or another breast conserving procedure.

The authors explained that there are few studies that focused on breast conserving surgery reoperation rates - reoperation rates were also unclear. So, lead researcher, Dr David Cromwell, Senior Lecturer in Health Services Research at the London School of Hygiene & Tropical Medicine, and team from around the country gathered data from the HES (Hospital Episode Statistics) database on 55,297 females who had breast cancer and chose breast conserving surgery in the National Health Service between 2005 and 2008. All the patients were adults.

They were specifically concentrating on reoperation rates within three months of the first breast conserving surgery. They made adjustments for patients' age, type of tumor, co-morbidity (presence of other diseases), and socioeconomic levels.

A total of 55,297 patients had breast conserving surgery:
  • 82% (45,793) had isolated invasive cancer
    18% of them needed a reoperation within three months

  • 12% (6,622) had isolated carcinoma in-situ (pre-cancerous disease)
    29.5% of them needed a reoperation within three months

  • 6% (2,882) had both types, invasive and in-situ breast cancers

  • Approximately 40% of reoperations were mastectomies
Reoperation rates were lower among women with comorbid diseases, as well as older patients. Women from deprived areas had slightly lower reoperation rates.

Invasive breast cancer is when the cancer cells break out from inside their place of origin, sometimes reaching the lymph nodes and eventually make their way to other parts of the body (metastasis). Non-invasive breast cancer is when the cancer cells are still inside their place of origin and have not broken out. "In situ" means "in its original place".

NHS trusts had different reoperation rates. The authors said the reasons for the variations need to be examined in another study, because this was not the focus of theirs. Possibly, NHS trusts have varying proportions of people opting for alternative treatments.

The researchers concluded that about half of all female breast cancer patients choose to have breast conserving surgery, but one fifth need another operation within three months.

Dr David Cromwell said:

"Breast conserving surgery with radiotherapy is as effective as mastectomy but if women choose conserving surgery, there is a risk of having another operation. Before this study, it was unclear what that risk was but now women can be better informed."
Professor Jerome Pereira, consultant breast surgeon at James Paget University Hospitals and contributing author, wrote:

"The important message from this national study is that nearly one in three women with pre-cancerous changes, in isolation or with invasive cancer, have a reoperation following breast conserving surgery. As clinicians, we need to inform women of these findings and help them to make decisions about their surgical treatment."

Written by Christian Nordqvist