Radial Scars without Atypia Diagnosed at Imaging-guided Needle Biopsy: How Often is Associated Malignancy Found at Subsequent Surgical Excision, and do Mammography and Sonography Predict which Lesions are Malignant?

Anna Linda; Chiara Zuiani; Alessandro Furlan; Viviana Londero; Rossano Girometti; Piernicola Machin; Massimo Bazzocchi

Disclosures

Am J Roentgenol. 2010;194(4):1146-1151. 

In This Article

Materials and Methods

The institutional review board granted permission for this retrospective cohort study, which was performed in a large university referral hospital for breast diseases.

Patient Selection

The study coordinator reviewed the histologic results of 4,458 consecutive imaging-guided needle biopsies of the breast performed at our institution from January 2000 to May 2008. Of these, 3,845 (86.3%) were performed under sonographic guidance, 607 (13.6%) were performed under stereotactic guidance, and six were performed under MR guidance (0.1%). Seventy-nine lesions (1.8%) diagnosed as radial scars at percutaneous biopsy were identified.

The inclusion criteria for this study were, first, radial scar diagnosed as the highest-grade lesion at pathologic evaluation of biopsy specimens in the absence of any other high-risk lesion (i.e., atypical ductal hyperplasia or lobular neoplasia), DCIS, or invasive carcinoma; second, diagnostic surgical excision performed at the department of surgery at our hospital (it is our standard policy to recommend surgical excision of radial scars independently of the preoperative diagnostic judgment); and, third, pathologic analysis of percutaneous biopsy and surgical specimens performed at the department of pathology at our hospital. The exclusion criteria were, first, associated DCIS or invasive breast cancer in the same breast; and, second, absence of final pathology after surgical excision because of patient refusal to undergo the surgical procedure or referral to an outside hospital. Sixty-two lesions in 62 women (age range, 19–76 years; mean age, 51 years) were included in our study group. The other 17 lesions were excluded: 14 as a result of absence of final pathology and three because of association with breast cancer in the same breast.

Clinically, four women (6%) had mastalgia and 58 women (94%) had no specific symptoms. Of these 58 asymptomatic patients, five were being followed up for previous breast neoplasm and the remaining 53 were being screened for breast cancer.

Imaging and Biopsy Techniques

All 62 patients underwent mammographic examination. Images were obtained in two standard planes: mediolateral oblique and craniocaudal. Dedicated full-field equipment (Digital Device, Giotto IMS Srl) was used.

Whole-breast sonography of all 62 women was performed using a broadband 5–12—MHz linear array transducer (HDI 5000, Advanced Technology Laboratories/Philips Healthcare), a broadband 10–13—MHz linear transducer (Technos, Esaote), or a broadband 12–15—MHz linear array transducer (iU22, Advanced Technology Laboratories/Philips Healthcare). We usually perform whole-breast sonography rather than targeted sonography guided by mammographic or clinical findings. All examinations were performed by one of four attending radiologists, each of whom had more than 10 years' experience in breast imaging at the time of the study.

Percutaneous biopsy was performed using stereotactic or sonographic guidance according to the judgment of the attending radiologist. In none of these cases was percutaneous biopsy performed under MR guidance. The biopsy procedures were performed by radiologists with 10–20 years' experience in breast imaging.

In 43 of 62 lesions (69%), biopsy was performed under sonographic guidance using an automated biopsy gun (Magnum Biopsy Instrument, Bard) or a semiautomated biopsy gun (Precisa, Hospital Service SpA) with a 14-gauge, 15-cm-long needle (total running, 23 mm). A mean of five core samples (range, 3–8) were obtained per lesion.

Nineteen lesions (31%) that were not visible on ultrasound were biopsied under stereotactic guidance using a digital prone table (Mammobed, Giotto, IMS Srl) and a directional vacuum-assisted biopsy device (Mammotome, Biopsy/Ethicon Endo-Surgery) with an 11-gauge needle. On average, 12 cores samples (range, 9–18) were obtained per lesion. In patients with mammographically detected microcalcifications, a specimen radiograph was obtained to confirm the presence of calcifications in each sample and a clip was left to mark the biopsy site.

Imaging Interpretation

All soft-copy mammographic and sonographic images were retrieved for retrospective independent interpretation by two radiologists with more than 10 years' experience in breast imaging. The radiologists were aware of the study purpose but were blinded to the histologic diagnoses. Mammographic and sonographic images were presented randomly to each reader in separate sessions. Any discrepancy in opinion was resolved by consensus.

With regard to mammography, the presence of a mass, including a mass with microcalcifications, or of microcalcifications or architectural distortion, including architectural distortion with microcalcifications, was noted.

On the basis of sonography findings, lesions were classified as circumscribed or noncircumscribed masses.

Reference Standard

The study coordinator reviewed the surgical pathology report for each lesion and classified it according to the highest-grade lesion in one of the following categories: malignant (DCIS or invasive carcinoma), high risk (radial scar, atypical ductal hyperplasia, flat epithelial atypia, or lobular neoplasia), or benign (proliferative changes without atypia, other benign lesions). The final pathology results served as the reference standard.

Statistical Analysis

Data were entered into a computerized spreadsheet (Excel, Microsoft).

The underestimation rate of malignancy of percutaneous biopsy was calculated according to the reference standard.

For statistical evaluation of the differences in mammographic and sonographic appearances, radial scars eventually proved to contain malignant lesions were compared with radial scars without associated malignancy. The Fisher's exact test was used, and a p value of less than 0.05 was considered statistically significant.

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