Assessment of 1183 screen-detected, category 3B, circumscribed masses by cytology and core biopsy with long-term follow up data

Abstract

Discrete masses are commonly detected during mammographic screening and most such lesions are benign. For lesions without pathognomonically benign imaging features that are still regarded likely to be non-malignant (Tabar grade 3) reliable biopsy results would be a clinically useful alternative to mammographic surveillance. Appropriate institutional guidelines for ethical research were followed. Between Jan 1996 -Dec 2005 grade 3B discrete masses detected in the setting of a large, population based, breast cancer screening programme are included. Patient demographics, fine needle aspiration biopsy (FNAB), core and surgical biopsy results are tabulated. The final pathology of excised lesions was obtained. Information regarding interval cancers was obtained from the State Cancer Registry records and also through long term follow-up of clients in subsequent rounds of screening. A total of 1183 lesions, mean diameter of 13.3 mm ( ± 8.3 mm) and mean client age of 55.1 years ( ± 8.8 years) are included. After diagnostic work up, 98 lesions (8.3%) were malignant, 1083 were non-malignant and a final histologic diagnosis was not established in two lesions. In the 27 months after assessment, no interval cancers were attributable to these lesions and during a mean follow up of 54.5 months, available in 84.9% of eligible women, only one cancer has developed in the same quadrant as the original lesion, although the two processes are believed to be unrelated. FNAB performed in 1149 cases was definitive in 80.5% cases (882 benign, 43 malignant) with a negative predictive value (NPV) of 99.8% (880 of 882) and a positive predictive value (PPV) of 95.2% (40 of 42, both intraductal papillomas). Core biopsy was performed in 178 lesions, mostly for indefinite cytology. Core biopsy was definitive in 79.8% cases (57% benign 22% malignant) with a PPV of 100% and NPV of 99.0%. In experienced hands FNAB is an accurate first line diagnostic modality for the assessment of 3B screen-detected discrete masses, providing definitive results in 80.5% of cases. When used as a second line modality, core biopsy had a similarly high rate of definitive diagnosis at 79.8%. The stepwise approach to the use of FNAB and core biopsy would reduce substantially the proportion of cases requiring surgical diagnostic biopsy. Given the low probability of malignancy and the imperative to limit the morbidity associated with cancer screening, the demonstration of the reliability of FNAB as a minimally invasive but highly accurate test for this particular subset of screen-detected lesions has significant clinical utility.

3B circumscribed masses: to assess or not to assess?

“…Thus, our findings confirm the experience reported by Farshid et al (2008) that cyto-histological assessment of circumscribed 3B lesions increases the number of cancers detected.…”

“…We read with great interest the paper by Farshid et al (2008) recently published in the Br J Cancer.…”

“…In the screening at Verona, the global FNAC accuracy in defining breast lesions (PPV of 99.3%, NPV of 98.6%) (Manfrin et al, 2008) reflects Farshid et al (2008) data, confirming FNAC as a reliable first diagnostic tool for the assessment of breast lesions.…”

“…Using a stepwise approach to the use of FNAB and core biopsy in 1183 screen-detected category 3B lesions, Farshid et al (2008) have shown that 8.3% of these were, in fact, malignant.…”

“…In Verona, the breast cancer screening programme is designed in a way similar to that reported by Farshid et al (2008), as it is based on an integrated radio-pathologic programme with on-site pathologists who perform real-time immediate assessments of FNAC samples and discuss these results with the radiologists. A stepwise approach is similarly employed with FNAC as the firstline diagnostic modality and core biopsy as the second-line modality.…”