Abstract B114: Core biopsy in breast cancer diagnosis: The provincial evaluation of utilization and relationship with treatment outcomes
Authors: Cho Kristy KM , Wilson Christine , Tyldesley Scott , Speers Caroline 
Published: May 2015

Purpose:To determine:

1) The proportion of women in British Columbia (BC) who have a pre-operative diagnosis of breast cancer by image-guided core biopsy;

2) Whether women who have a pre-operative radiological diagnosis of breast cancer with core biopsy have fewer breast surgeries as part of their initial therapy;

3) Whether local/ locoregional relapse is lower in women who have had a pre-operative diagnosis of breast cancer with a core biopsy versus an open biopsy;

4) Whether there is regional variation in the use of pre-operative core biopsies versus open biopsies in the diagnosis of breast cancer in B.C.

5) Whether the risk of pN0i+ on sentinel node biopsy (SNB) is reduced when the initial diagnosis of breast cancer is made on core biopsy versus open biopsy.

Methods: All B.C residents diagnosed with breast cancer in 2006 were reviewed. The women were divided into groups according to the method of diagnosis- pre-operative core needle biopsy, operative biopsy (open biopsy or other surgery), versus other diagnosis. Core biopsies were further divided into image-guided versus clinically-directed core. Women with denovo metastatic disease, locally advanced disease, prior or synchronous invasive or insitu breast cancer, Paget's, alone or with insitu disease, patients with surgical procedures performed out of province, patients diagnosed on death certificate/ autopsy only, and cases without pathology were all excluded.

Results: 3130 patients diagnosed in 2006 were identified in the BC Cancer Agency Registry. After exclusions, 2589 patients were included in the study cohort. 32% of patients had diagnosis made on an open surgical procedure, and 68% were diagnosed on a non-open biopsy, of which, 80% were image-guided core biopsies. Seventy-five percent of women with an image-guided core had one or less surgical procedure compared to only 26% of women whose diagnosis was made by surgery, despite the image-guided core biopsy group having larger, more invasive tumors and increased nodal positivity. The type of biopsy did not impact the prevalence of pN0i+ on SNB, or local and locoregional relapse rate. Regionally, Vancouver Coastal and Vancouver Island Health Authority, which are more densely populated urban centres, had the highest proportion of patients diagnosed by core biopsy, 70.3% and 75.4% respectively, and the sparsely populated Northern Health Authority had the lowest proportion at 46.7%.

Conclusions: Core biopsies for breast cancer diagnosis are under-utilized in British Columbia and show significant regional variation. Although core biopsy diagnosis does not impact rate of pN0i+ on nodal biopsy or locoregional relapse rates, it is associated with substantially fewer breast/nodal surgeries. More resources are required to promote the use of CNB to providers and patients.

Citation Format: Kristy KM Cho, Christine Wilson, Scott Tyldesley, Caroline Speers. Core biopsy in breast cancer diagnosis: The provincial evaluation of utilization and relationship with treatment outcomes. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B114.