NESS - Variability in Utilization of Neoadjuvant Chemotherapy in Treatment of Invasive Breast Cancer Eligible for Breast Conservation Therapy

Variability in Utilization of Neoadjuvant Chemotherapy in Treatment of Invasive Breast Cancer Eligible for Breast Conservation Therapy
*Jill K. Onesti¹, Ted A James², *Erin J Bowles³, *Heather S Feigelson⁴, *Adedayo A Onitilo⁵, *Richard M Single⁶, Laurence E McCahill⁷^,8
¹Grand Rapids Medical Education Partners, Rockford, MI;²University of Vermont College of Medicine, Burlington, VT;³Group Health Research Institute, Seattle, WA;⁴Kaiser Permanente Colorado, Denver, CO;⁵Marshfield Clinic, Weston, WI;⁶University of Vermont, Burlington, VT;⁷Saint Mary's Health Care, Grand Rapids, MI;⁸Van Andel Research Institute, Grand Rapids, MI

OBJECTIVE:
To determine variability in current practice management in neoadjuvant chemotherapy use to increase feasibility of breast conservation therapy (BCT).
DESIGN:
A multi-center cohort study of surgical outcomes for invasive breast cancer.
SETTING:
One academic and three HMO-Cancer Research Network institutions.
PATIENTS:
2595 female patients with biopsy proven invasive breast cancer and preoperative tumor size estimation without contraindication to BCT, identified from the Breast Cancer Surgery Outcomes (BRCASO) database of over 4000 patients.
INTERVENTIONS:
BCT and mastectomy related neoadjuvant chemotherapy use.
MAIN OUTCOME MEASURES:
(1)Rate of mastectomy by pre-operative tumor size. (2)Rate of failure for BCT by preoperative tumor size. (3)Rate of neoadjuvant chemotherapy by preoperative tumor size and institution.
RESULTS:
Final mastectomy rates were 22% for preoperative tumor size <30mm, 50% for tumors 30-39mm, and 78% for tumors >40mm (p<0.001). Conversion from initial partial mastectomy to mastectomy (BCT failure) occurred for 5% with tumors <30mm, 7.2% for tumors 30-39mm, and 25% for tumors >40mm (p<0.001). Overall neoadjuvant chemotherapy use varied by institution (8.4%, 6.5%, 2.5%, and 0.6%, p<0.001). Use by pre-operative tumor size is shown in Table 1.
CONCLUSIONS:
At centers favoring BCT for smaller tumors, a significant increase in final mastectomy incidence is seen in tumors >30mm. Overall neoadjuvant chemotherapy use is quite low, even for tumors >50mm, a size traditionally prompting neoadjuvant therapy. Use also remains very low for tumors with pre-operative size >30-50mm despite increases in failed BCT and mastectomy as the final procedure. Surgeons should consider neoadjuvant chemotherapy for tumors >30mm in patients desiring BCT.
Frequency (%) of Neoadjuvant Chemotherapy According to Preoperative Tumor Size by Institution
A B C D p Value
<10mm 2.4 1.4 0 0 0.036
10-20mm 5.8 3.6 0.7 0 0.0001
20-30mm 8.3 14.6 2.6 1.7 0.0018
30-40mm 11.4 8.3 7.7 0 0.0946
40-50mm 21.4 33.3 15.0 0 0.2056
>50mm 3.9 16.7 43.5 0 0.0004

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