Outcomes of Patients with No Calcium Yield in Stereotactic-guided Breast Biopsy for Microcalcifications: Ten-year Experience

Abstract

Objectives: To look at the outcomes of patients who underwent stereotactic-guided breast biopsy for microcalcifications without specimen yielding calcium, so as to facilitate management.

Methods: In this retrospective study, records of all patients who underwent stereotactic-guided breast biopsy for microcalcifications from 2001 to 2010 in the Department of Radiology, Kwong Wah Hospital, were reviewed. Information including radiological grading, pathology, and outcomes in those without calcium in their specimen was retrieved.

Results: In all, 2028 stereotactic-guided biopsies for microcalcifications were performed in the relevant period. The number of biopsy specimens with radiography showing calcium was 60 (3%), whereas 32 (53%) of the latter specimens also yielded no calcium when examined pathologically. Regarding these patient specimens without calcification, pathologically 4 (13%) showed malignancy, 2 (6%) showed atypical ductal hyperplasia, 23 (72%) showed a benign pathology, and 3 (9%) were reported as specimen insufficient. The six patients with biopsy showing malignancy or atypical ductal hyperplasia underwent surgery. Regarding the 23 patients with benign pathology, 10 had microcalcifications radiologically graded as R2 (probably benign), 6 were of R3 (indeterminate) grade, and 7 were of R2-3 grade. Two patients graded R3 had surgery that yielded malignant pathology. Among patients with insufficient specimens, one had R2 microcalcifications and two were graded R3; one of the latter had surgery that yielded malignancy. For the remaining 23 patients, they either had follow-up mammograms establishing stability, or surgical excision or repeat biopsy showing benign pathology. False-negative rate in R3 group without specimen calcification was high (38%).

Conclusion: For R3 (indeterminate) microcalcifications without specimen yielding calcium in the stereotactic biopsy, repeat biopsy is advised even if the initial pathology appears benign. For R2 and R2-3 microcalcifications without specimen yielding calcium, follow-up mammography is advised.

Alternate abstract:

目的：探討接受立體定向引導下乳腺活檢微小鈣化病變但標本無鈣化的病人結果，以幫助病人治療。

方法：回顧研究2001至2010年期間在廣華醫院放射科，所有接受立體定向引導下乳腺活檢微小鈣化的患者紀錄。從中篩取標本中無鈣化的患者紀錄，並找出其放射學等級、病理和結果。

結果：研究期間共有2028個立體定向引導下乳腺活檢微小鈣化病變的標本。X光檢查過的標本中60例（3%）有鈣化，其中32例（53%）病理結果無鈣化。在這些無鈣化的標本中，病理學結果顯示惡性腫瘤有4例（13%）、導管非典型增生2例（6%）、良性病變23例（72%）、標本不足3例（9%）。6例惡性腫瘤和導管非典型增生的患者接受手術治療。23例良性病變中，經影像學證實出現微小鈣化而屬R2級別（可能良性）的有10例，屬R3級別（不確定）的有6例，屬R2-3級別的有7例。兩名R3級別的患者接受手術後發現有惡性腫瘤。標本不足的患者中，1例有R2級微小鈣化，2例有R3級，其中一例R3級手術發現為惡性腫瘤。其餘23名患者中，部份有跟進乳房X線攝影檢查以確定其穩定性，或者進行手術切除或重複活檢以確定為良性病變。沒有標本鈣化的R3級別的假陰性率偏高（38%）。

結論：對於微小鈣化屬R3級別（不確定）但立體定向活檢標本中無鈣化的病例來說，即使最初病理學結果呈良性，仍建議重複活檢。至於微鈣化屬R2和R2-3級別但標本中無鈣化的病例，則建議作乳房攝影X線檢查隨訪。