(ChemotherapyAdvisor) – Patients at high risk of breast cancer recurrence had tumors with more aggressive biological features — such as lack of pathologic complete response (pCR) — suggesting lumpectomy should be a consideration in those who receive radiation as a part of treatment, according to a presentation at the 13th Annual Meeting of the American Society of Breast Surgeons, held May 2 to 6 in Phoenix, AZ.

“Increasingly, women with stage 2 and 3 breast cancers are receiving neoadjuvant therapy. At the completion of neoadjuvant therapy, the majority of women can have breast conservation. The question often arises in the setting of modern neoadjuvant therapy, is breast conservation oncologically safe even in the setting of residual disease?” noted Elizabeth Cureton, MD, of the University of California San Francisco Medical Center.

The study, part of the I-SPY 1 trial, evaluated 206 women from 9 clinical centers with tumors ≥3cm, all of whom received neoadjuvant doxorubicin and cyclophosphamide followed by paclitaxel. Selection of surgical treatment — 90 underwent lumpectomy and 116, mastectomy — and the use of postoperative radiation therapy were at the discretion of the treating physician. The majority of patients (91%) were classified as biologically high risk based on a 70-gene expression profile. Mean tumor size was 6.9cm; tumors were hormone receptor positive (44%), HER-2/neu positive (24%), and triple negative (32%). Median follow-up was 3.9 years.

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Data were separated into those with and without pCR and by residual cancer burden 0 or 1 (complete or near-complete response) vs. 2 or 3 (less complete response) to determine whether surgical procedure and type of response (including no response) influenced the local recurrence rate.

Of 206 patients, 45 (21%) had a distant recurrence and 14 (6.8%), local recurrence. Of the 14 with local recurrence, 9 (64%) had synchronous distant metastases ≥2 years following diagnosis, 1 had a metastasis <2 years of local recurrence, and 4 have not had a distant recurrence.

Developing a local recurrence was significantly associated with developing a distant recurrence (P=0.00005), the investigators found. Stage (P<0.0001) and size (P<0.0001) at clinical presentation and nodal status at operation after neoadjuvant chemotherapy (P=0.0006) were significantly associated with recurrence. In women with lumpectomy vs. mastectomy, “local recurrence was closely associated with metastatic disease and seems to be another indication of aggressive tumor character, not the cause of the recurrence,” said Dr. Cureton. Women who did not respond well to neoadjuvant chemotherapy were also more likely to have disease recurrence.

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