In the second study, Professor Pierce and her collaborators from the USA, Australia, Spain, and Israel found that patients treated with BCT had significantly higher rates of cancer recurring in the breast (23.5%) than did patients who had mastectomy (5.5%) at 15 years. But when they looked at patients who had received chemotherapy as well as BCT, they found that the risk of recurrence was much reduced and the overall risk with this treatment was not significantly different from the mastectomy group (11.9%). And despite the higher rates of local recurrence in the BCT group, other risks - metastasis, breast cancer-specific survival, and overall survival - were similar.

When they compared rates of developing cancer in the unaffected breast, which exceeded 40% in both groups, the researchers found that the use of radiotherapy after surgery did not increase risk in comparison with those women who did not receive radiation treatment.

Although there have been many trials comparing breast conserving surgery and radiotherapy with mastectomy in women with non-hereditary cancer, data on those women with the inherited form of the disease are limited and this has made it difficult for patients and doctors alike to know how best to proceed. Ideally, the researchers say, such studies should be randomised, but because treatments for patients who carry the BRCA1/2 mutation are so individualised and the decision-making so complex, a randomised trial is unlikely.

"To the best of my knowledge, ours is the first multi-institutional systematic comparison of BCT versus mastectomy in BRCA1/2 carriers," Professor Pierce will tell the conference. "It will provide important data to patients trying to decide what will be the best treatment for their hereditary breast cancer, as well as to the doctors advising them.

"If a woman with BRCA1/2-associated breast cancer is considering breast conserving surgery and radiotherapy, our findings show that she will have fewer recurrences in the breast if chemotherapy is also used. And our conclusion that 15-year outcomes of BCT and mastectomy are similar should reassure recently diagnosed women who may find the thought of an immediate mastectomy overwhelming. We strongly encourage patients to discuss local therapy options with their doctors before starting treatment."

Source: ECCO-the European CanCer Organisation