With some patients who receive neoadjuvant chemotherapy for breast cancer, the subsequent magnetic resonance imaging (MRI) scan shows no further evidence of tumor tissue. Do these patients still need surgery to remove the former tumor tissue?

Certain patients with breast cancer are given neoadjuvant chemotherapy (NCT) before the tumor is surgically removed. In some cases, the tumor can no longer be detected by imaging methods following the NCT. Nevertheless, the original tumor tissue is removed from these patients to ensure complete tumor resection. It is thought that this surgery may actually be unnecessary for some of these patients, since the tumor has been completely destroyed by the NCT. This can be demonstrated by a tumor biopsy after the NCT. If the biopsy reveals that there is no longer any tumor tissue in a patient after NCT, surgery could be avoided.

Vacuum-assisted biopsy before tumor surgery

The SAKK 23/18 trial will examine this hypothesis. In cases where an MRI scan shows no or almost no tumor tissue in breast cancer patients following NCT, a vacuum-assisted biopsy (VAB) will be carried out before tumor surgery. An analysis of the tissue samples obtained in this way should show whether any tumor tissue is still present in these patients.

Process for participation in the trial

• The VAB will be carried out shortly before tumor surgery, which takes place within six weeks of the last NCT.
• The patient will then undergo surgery, as in the standard therapy.
• In contrast to patients who are not recruited to the trial, the participants will have both the VAB and tumor surgery (the other patients will only have surgery).

420 patients are expected to be included in the trial.