Breast-conserving surgery is a treatment that proves "insufficient" in many cases for women who have had a cancer scare, the National Cancer Registry has said.
Almost a fifth of Irish women who had breast-conserving surgery between 2002 and 2008 needed an additional operation, and two-thirds of those who had a second operation went on to have a total mastectomy.
Breast-conserving surgery is increasingly used for breast cancer treatment and is the preferred option for women with small breast lumps.
National Cancer Registry director Dr Harry Cumber said the large number of second operations was down to the nature of the cancer itself, which can often conceal itself in minute quantities in the breast, rather than being the result of error on the part of surgeons.
“When a surgeon goes in to remove the cancer, they will have done scans. Afterwards, histologically, they may find that a very small amount of the cancer had spread further than they thought it would.”
Results relating to 16,551 women diagnosed with invasive breast cancer were examined. Some 8,318 had had breast-conserving treatment.
Of these, 17 per cent had had one or more subsequent re-operations and, of that subsection, 62 per cent had had a total mastectomy.
The registry found that the women who had had first surgery in a hospital treating a large number of breast cancer patients were less likely to have a second operation.
Similarly, women treated by a surgeon with a high breast cancer caseload were less likely to have a second operation, and were less likely to have a mastectomy if they did have a second operation.
Dr Cumber said the results showed that hospitals and surgeons who were more experienced in the surgery had better outcomes.
The survey covered operations carried out in Irish hospitals before the centres of excellence came into place in 2009. All the breast-conserving surgery done in public hospitals now is performed in the eight cancer centres of excellence.
