Abstract P2-01-09: Application of the Z0011 criteria on Dutch breast cancer patients

Abstract

Abstract Background The American College of Surgeons Oncology Group reported a randomized controlled trial (Z0011-trial) among women with T1-2N0M0 breast cancer treated with breast conserving therapy. It showed that axillary lymph node dissection may be redundant in selected sentinel node positive patients. Though, it raises questions as to the general applicability of these results. Therefore, this study aims to examine the practice changing effect and the clinical relevance of the criteria described in the Z0011 trial, when applied to a Dutch population of patients diagnosed with invasive breast cancer. Methods This is a multicenter study including patients with T1-2N0-1M0 invasive breast cancer treated in either of the 10 different hospitals affiliated with the Dutch National Cancer Registry region South in the period between January 2007 and December 2012. All patients underwent a clinical examination, a mammography and sonographic examination of the breast and the ipsilateral axilla. Chi-square analyses or a Fisher’s exact test were used to assess differences in patient and tumor characteristics the Z0011 population and the Dutch cohort. A p-value of ≤0.05 was considered statistically significant. Results A total of 11,031 patients had invasive breast cancer, of whom 5368 patients were treated with breast conserving therapy. In 6.8% axillary status was determined by the ultrasound guided lymph node biopsy and in 93.1% axillary metastases were found trough the sentinel node procedure after a negative or inconclusive ultrasound. When applying the Z0011 criteria to our study population of node positive patients, 5.7% of all breast cancer patients, equalling 11.8% of patients receiving breast conserving therapy, met the Z0011 criteria. Conclusion These results suggest that when applying the Z0011 criteria to all node positive patients, including patients with a positive sentinel node and patients with a positive ultrasound guided lymph node biopsy, only in 5.7% of all invasive breast cancer patients could be spared an ALND and its morbidity. This is a small practice changing effect. Nevertheless, it is worthwhile to consider implementing the findings of Z0011 trial in daily clinical practice. Citation Format: Nicole C Verheuvel, Vivianne CG Tjan-Heijnen, Adri C Voogd, Rudi MH Roumen. Application of the Z0011 criteria on Dutch breast cancer patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-01-09.