title: Population based study on sentinel node biopsy before or after neoadjuvant chemotherapy in clinically node negative breast cancer patients: Identification rate and influence on axillary treatment.
abstract: The timing of the sentinel lymph node biopsy (SNB) is controversial in clinically node negative patients receiving neoadjuvant chemotherapy (NAC). We studied variation in the timing of axillary staging in breast cancer patients who received NAC and the subsequent axillary treatment in The Netherlands. Patients diagnosed with clinically node negative primary breast cancer between 1st January 2010 and 30th June 2013 who received NAC and SNB were selected from the Netherlands Cancer Registry. Data on patient and tumour characteristics, axillary staging and treatment were analysed. Two groups were defined: (1) patients with SNB before NAC (N=980) and (2) patients with SNB after NAC (N=203). Eighty-three percent of patients underwent SNB before NAC, with large regional variation (35-99%). The SN identification rate differed for SNBs conducted before and after NAC (98% versus 95%; p=0.032). A lower proportion of patients had a negative SNB when assessed before NAC compared to after (54% versus 67%; p=0.001). The proportion of patients receiving any axillary treatment was higher for those with SNB before NAC than after (45% versus 33%; p=0.006). In conclusion, variation exists in the timing of SNB in clinical practice in The Netherlands for clinically node negative breast cancer patients receiving NAC. The post-NAC SN procedure is, despite some lower SN identification rate, associated with a significantly less frequent axillary treatment and thus with less expected morbidity. The effect on recurrence rate is not yet clear. Patients in this registry will be followed prospectively for long-term outcome.
authors: Department of Research, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, The Netherlands. Electronic address: m.vanderheiden@iknl.nl.
authors: M
authors: M
authors: van der Heiden-van der Loo
authors: Department of Research, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, The Netherlands.
authors: L
authors: L
authors: de Munck
authors: Department of Medical Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors: G S
authors: GS
authors: Sonke
authors: Department of Surgery, Diakonessenhuis Utrecht, Utrecht, The Netherlands.
authors: T
authors: T
authors: van Dalen
authors: Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: P J
authors: PJ
authors: van Diest
authors: Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: H J G D
authors: HJ
authors: van den Bongard
authors: Julius Center of Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: P H M
authors: PH
authors: Peeters
authors: Department of Surgery, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors: E J T
authors: EJ
authors: Rutgers
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001365:Axilla / Q000473:pathology* / Q000528:radiation effects; D001943:Breast Neoplasms / Q000188:drug therapy / Q000453:epidemiology / Q000473:pathology; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D015182:Lymphatic Irradiation / Q000706:statistics & numerical data; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Axillary lymph node dissection; Breast cancer; Neoadjuvant chemotherapy; Sentinel node biopsy; Staging