Abstract P3-14-01: Features of neoadjuvant and adjuvant chemotherapy in breast cancer – A population-based study on 39404 patients
Authors: von Minckwitz G , Kern P , Schneeweiss A , Gluz O , Harbeck N , Neumann M , Badiian M , Fries H , Rezai M 
Published: August 2014

Background: Neoadjuvant chemotherapy (NACT) is increasingly used globally in clinical trials for breast cancer patients. In Germany, NACT has been implemented as a standard option of care for almost a decade. In a population-based benchmark cohort study, the West German Breast Center (WBC) recorded approximately 50% of all breast cancer cases diagnosed in Germany between 2007 and 2010. We compare baseline and treatment pattern of patients treated either with adjuvant (ACT) or NACT.

Methods: Approx. 200 accredited breast centers treated 115169 primary breast cancer patients of whom 32609 received ACT and 6795 NACT. Pathological complete response (pCR) was stated if no invasive and no non-invasive tumor residues (ypT0 ypN0) were detected. Follow up information was available for 55% of patients.

Results: Use of NACT increased from 16.4% in 2007 to 19.1% in 2010 (p&lt;.0001). Patients treated with NACT were younger, had higher clinical nodal involvement, fewer lobular-invasive cancers, more undifferentiated, hormone-receptor-negative, and HER2-positive cancers, and more multicentric tumors compared to patients treated with ACT (all p&lt;0.002). 34% of patients in the NACT group had cT3/4 tumors compared to 7.7% of pT3/4 tumors in the ACT group. cN0 status was twice as frequent (70.6% vs 37.7%, p&lt;.0001) whereas pN0 status was reported less frequently (47.4% vs 51.4%, p&lt;0.0001) in the ACT and NACT group, respectively. Time between diagnosis and start of systemic treatment or surgery was in median 12 (range 1-902) and 22 (range 1-721) days in the ACT and NACT group, respectively (p&lt;.0001). 66.2% and 91.4% of patients received ACT and NACT with a taxane, respectively (p&lt;.0001). 9.7% and 37.5% of patients receiving treatment for &gt; = 18 weeks, respectively. 35.2% and 69.9% of patients with HER2-positive tumors received adjuvant or neoadjuvant trastuzumab, respectively (p&lt;.0001). 21.7% and 31.4% of patients were treated in ACT or NACT clinical trials, respectively (p&lt;.0001). Breast conservation was possible in 69.4% and 55.2% in the ACT and NACT group, respectively (p&lt;.0001). 30.5% and 37.5% needed two or more surgical interventions in the ACT and NACT group, respectively (p&lt;.0001).

Multivariable logistic regression analysis confirmed taxane- and trastuzumab-based treatment, study participation, age, histologic type, grading, and hormone-receptor status as independent predictors of pCR. pCR rate was not dependent on the time between diagnosis and start of treatment or the time between end of chemotherapy and surgery.

In univariate analysis patients receiving NACT showed a 4-year overall survival rate of 78%, compared to 92% in patients receiving ACT (p&lt;.0001). However, patients with a pCR after NACT showed a comparable survival to patients in the ACT group, whereas patients without a pCR showed a 4-year overall survival rate of 76%. In the hormone-receptor-positive/HER2-positive and even more in the triple-negative subgroup, survival of patients with a pCR appeared better than in patients with ACT.

Conclusion: In this population-based study, NACT was used in patients with unfavorable risk factors and was more intense than ACT. Outcome of patients with pCR after NACT was similar and in aggressive tumor subtypes even better than after ACT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-14-01.