Top Line: Are outcomes from breast conservation therapy for multifocal breast cancer the same as those with unifocal breast cancer?
The Story: ACOSOG Z11102 was a single arm, phase 2 trial that described the outcomes of breast conservation therapy for patients with multifocal breast cancer. 204 patients with 2 (97%) or 3 foci of disease amenable to breast conservation and cN0-1 disease had lumpectomies followed by whole breast radiation and a boost. They had to have at least 2cm of normal tissue between foci and could have disease in no more than two quadrants. Standard fractionation was used (45-50 Gy) with a 10-16Gy boost to all lumpectomy cavities. At 5 years, the cumulative rate of local recurrence was 3.1%, and this was well below the acceptable threshold of 8% set for the trial. No patients had regional recurrence. An interesting finding was that among the small subset who didn’t have a pre-operative MRI, the rate of recurrence was 22.6%. That is likely because among patients who had preoperative MRI, 42% had a second or third foci detected by MRI but not mammogram or ultrasound.
TBL: ACOSOG Z11102 shows that breast conservation is feasible and a good treatment option for women with multifocal breast cancer. The risk of local recurrence is low with breast conservation therapy, but patients with multifocal disease likely benefit from preoperative MRI. | Boughey, J Clin Oncol 2023
The Story: ACOSOG Z11102 was a single arm, phase 2 trial that described the outcomes of breast conservation therapy for patients with multifocal breast cancer. 204 patients with 2 (97%) or 3 foci of disease amenable to breast conservation and cN0-1 disease had lumpectomies followed by whole breast radiation and a boost. They had to have at least 2cm of normal tissue between foci and could have disease in no more than two quadrants. Standard fractionation was used (45-50 Gy) with a 10-16Gy boost to all lumpectomy cavities. At 5 years, the cumulative rate of local recurrence was 3.1%, and this was well below the acceptable threshold of 8% set for the trial. No patients had regional recurrence. An interesting finding was that among the small subset who didn’t have a pre-operative MRI, the rate of recurrence was 22.6%. That is likely because among patients who had preoperative MRI, 42% had a second or third foci detected by MRI but not mammogram or ultrasound.
TBL: ACOSOG Z11102 shows that breast conservation is feasible and a good treatment option for women with multifocal breast cancer. The risk of local recurrence is low with breast conservation therapy, but patients with multifocal disease likely benefit from preoperative MRI. | Boughey, J Clin Oncol 2023