Breast-conserving therapy may be option for multiple breast lesions

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Published: 13 Jan 2023
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Dr Judy Boughey - Mayo Clinic, Rochester, USA

Dr Judy Boughey speaks to ecancer as part of the SABCS 2022 meeting about a study looking at the impact of breast conservation therapy on local recurrence in patients with multiple ipsilateral.

She explains that this was a prospective trial enroling patients across 78 centres with patients with 2 or 3 sites of breast cancer enroled.

Dr Boughey reports that from 204 patients the estimated 5 year local recurrence rate found was 3.1%, which met the protocol defined endpoint of below 8%.

The Alliance Z11102 clinical trial was developed to look at the role of breast-conserving therapy in women with multiple ipsilateral breast cancer. Increasingly, as we are seeing patients diagnosed with breast cancer through the improvements in screening technology and diagnostic imaging, as well as increasing use of MRI, we are increasingly finding women that have more than one focus of disease within the breast, meaning that at the time of their diagnosis these patients may have two or three foci of disease. Historically the data has shown high rates of local recurrence if these patients are treated with breast-conserving therapy and that has resulted in many surgeons electing to recommend mastectomy for those patients. Some smaller, more recent, studies have shown the potential that local recurrence rates may be lower and may be more clinically acceptable and so the Alliance trial was designed as a prospective clinical trial to evaluate the local recurrence with the use of breast-conserving therapy in patients with two or three sites of breast cancer within one breast.

What was the methodology used?

This was a prospective clinical trial run through the Alliance for Clinical Trials in Oncology, so through the National Cancer Treatment Network in the United States. It enrolled patients across 78 centres and patients with two or three sites of breast cancer were eligible to be enrolled. This was a single arm prospective phase II clinical trial.

What were your findings?

We enrolled on the study a total of 204 patients who were eligible for analysis. What we found was that the estimated five year local recurrence rate was 3.1% and this met our protocol-defined endpoint of a clinically acceptable local recurrence rate at five years being below 8%.

How can these results impact the treatment of breast cancer?

The impact of this trial is going to be that the patients who are diagnosed with two or three foci of disease within their breast and they are considering their treatment options that hopefully the multidisciplinary team and the surgeons and the patients will be able to consider not only mastectomy but also to consider breast-conserving therapy as an option for these women. So that means that the woman can potentially choose between undergoing breast-conserving therapy which involves lumpectomy to resect both sets of disease followed by whole breast radiation and boosts to each of the lumpectomy sites or proceeding with mastectomy. That will remain a personal choice for the patient but it does mean to the patient that they will have more options than just being recommended mastectomy.

Is there anything else important to mention?

The vast majority of patients enrolled in this trial were over the age of 40, had clinically node negative disease and the vast majority had only two sites of breast cancer although the protocol did allow two or three sites of breast cancer. So the area where most of this will be incorporated into clinical practice will be in those patients that are clinically node negative, have two sites of cancer in their breast and that those patients can be considered for breast-conserving therapy.

A couple of interesting factors that we noted that were associated with local recurrence was the use of adjuvant endocrine therapy for those patients that had oestrogen receptor positive breast cancer. So that’s an important component of the discussion of consideration of breast-conserving therapy is that the patients will be considering being adherent with endocrine therapy in the adjuvant setting.

Furthermore, an unplanned analysis of this data showed that we had a small cohort of about 15 patients in the study that did not have a preoperative MRI. We did see a higher local recurrence rate in the patients without MRI than in the patients that did have a preoperative MRI. So for patients with two or three sites of breast cancer that are considering breast-conserving therapy, MRI may have a role to evaluate the extent of the disease in the breast and evaluate their candidacy for breast-conserving therapy.