Nonpalpable breast lesions : challenges in diagnosis and treatment

The aim of this thesis was to address pitfalls and concerns of the diagnostic evaluation of nonpalpable breast lesions, in an attempt to further improve preoperative diagnostic assessment, as well as surgical strategies of nonpalpable breast lesions. Chapter 1 presents an overview of current methods in preoperative diagnostic assessment and treatment of nonpalpable breast lesions. Results of stereotactic large-core needle biopsy (SLCNB) in current practice (2000-2002) are described and compared to results of the controlled study setting during COBRA (COre Biopsy after RAdiological localisation; 1997-2000) in chapter 2. Data on all (n=955) patients scheduled to undergo SLCNB in current practice was assembled. At follow-up of women with benign diagnoses at SLCNB who no longer needed to undergo surgical excision, we found that no malignancies were missed. The follow-up was, however, limited (mean, 20.0 months; 5.8-34.0). 96% of patients was treated according to COBRA guidelines. In chapter 3, we studied differences in cancer prevalence between women referred through the national screening program and a non-screening group, to assess whether the validity of SLCNB differed between these patient groups. The prevalence of carcinoma differed significantly, yet the accuracy of SLCNB did not. Therefore SLCNB appears accurate in diagnosing nonpalpable breast lesions both in screening and non-screening patients. In chapter 4, we describe a subgroup of lesions for which surgical excision with SNB may be considered as the first diagnostic and therapeutic procedure. SLCNB is preferred in all other cases. Seeding of biopsy needle tracks with viable malignant cells is evaluated in chapter 5. We conclude that needle tracks can be found, and displaced tumourcells can be recognised. Excising and evaluating the entire needle track is not always possible, should not be recommended as a routine, since radiotherapy is advised for all types of locally excised breast cancer. When ductal carcinoma in situ (DCIS) is diagnosed at SLCNB, invasive cancer is found in ~17% of excision specimens. These so called ‘DCIS-underestimates’ generally cause extension of treatment. In chapter 6, we evaluated DCIS-underestimates in detail and assessed reasons for missing the invasive component at SLCNB. A variety of radiological and histopathological reasons contribute to the DCIS-underestimate rate. Approximately half of these are potentially avoidable. Chapter 7, presents a critical review of the currently available literature on the accuracy of vacuum-assisted biopsy and compare it to published data on 14G automated-needle biopsy. Chapter 8 describes the surgical treatment results for patients diagnosed with DCIS at SLCNB. We sought preoperative determinants predicting which patients would eventually undergo mastectomy. These determinants were a history of breast cancer, mammographic lesions characterised by calcifications, measuring >17mm and classified as BI-RADS 5. Knowledge of these determinants may guide the initial surgical procedure to be more aggressive. In Chapter 9 we compared the outcomes of surgical treatment of nonpalpable breast cancer diagnosed preoperatively with SLCNB in two surgical training hospitals, and conclude that with adequate supervision, the experience of the first operating surgeon does not seem to affect the possibility of a radical resection. Chapter 10 is a general discussion

Is stereotactic large-core needle biopsy beneficial prior to surgical treatment in BI-RADS 5 lesions?

Introduction. Due to screening mammography, more nonpalpable mammographic lesions warrant histological evaluation. Stereotactic large-core needle biopsy (SLCNB) has been shown to be as effective in diagnosing these lesions as diagnostic surgical excision, and has become the preferred diagnostic procedure for most mammographic lesions. Since radiologically malignant BI-RADS 5 lesions are almost always carcinoma, some centers advocate prompt diagnostic surgical excision for these lesions instead of SLCNB. For some patients this diagnostic surgical intervention may serve as definitive treatment. We set out to find a subgroup of mammographic BI-RADS 5 lesions for which surgical biopsy might be preferable. Methods. Of 1644 consecutive nonpalpable lesions referred for SLCNB between April 1997 and May 2002, 238 were classified as BI-RADS 5. We assessed the number of carcinomas and the surgical interventions performed. Outcomes were compared between various types of mammographic lesions: density with calcifications, density without calcifications, and calcifications only. Different theoretical strategies for diagnostic work-up of BI-RADS 5 lesions were explored. Results. Carcinoma was found in 229/238 lesions (96%). Most mammographic densities were invasive cancer (97%), while calcifications only showed the highest risk for DCIS (51%). In our study ( current practice) all lesions were scheduled to first undergo SLCNB. A scenario was proposed where all lesions with only a density would be scheduled directly for sentinel node biopsy (SNB) and tumour excision (n = 154; 65%), while other lesions would still be scheduled for SLCNB. When we compared this scenario to current practice, four out of 238 patients (<2%) would be 'overtreated' with SNB. Conclusions. Our findings confirm a high predictive value of malignancy for BI-RADS 5 lesions ( 96%). Surgical excision is therefore imperative for all BI-RADS 5 lesions, irrespective of SLCNB results. For BI-RADS 5 lesions presenting as mammographic densities only, we propose to consider surgical excision with SNB to be the first diagnostic and therapeutic procedure. SLCNB is preferred in all other cases