Lobular Neoplasia in Breast Core Needle Biopsy Specimens Is Associated With a Low Risk of Ductal Carcinoma In Situ or Invasive Carcinoma on Subsequent Excision

Andrew A. Renshaw, MD; Robert P. Derhagopian, MD; Pilar Martinez, MD; Edwin W. Gould, MD

Disclosures

Am J Clin Pathol. 2006;126(2):310-313. 

In This Article

Discussion

The goal of this study was to determine the true rate of DCIS and IC in subsequent excisions for LN alone on core needle biopsy. We were puzzled that our experience with this situation was so different from that reported by other centers. To help resolve the issue, we set out to prospectively obtain a very large number of patients from our center with LN on core needle biopsy and thoroughly correlate the previous and subsequent tissue diagnoses in these women. Our results show that many of these women (30%) will have DCIS or IC in the same or opposite breast before or after the biopsy of LN. However, few of them will have DCIS or IC in the subsequent excision. The rate of this finding is much less than that seen in other centers and much less than that seen for ADH and LN at our center. Indeed, the rate of DCIS and IC found in this study is well within the reported false-negative rate for core needle biopsy reported in the literature (1.2%-9.1%).[18,19,20]

In addition, the specific pathologic features of the needle biopsy and excision specimens suggest that these cases may represent false-negative interpretations of the needle biopsy (case 1), an incidental finding not associated with the biopsy site itself (case 2), and false-negative sampling in the biopsy (case 3). Our results strongly suggest that although women with LN clearly have a high risk of IC and DCIS in the same and the opposite breasts, previously and subsequently, subsequent excision of cases with LN alone on core needle biopsy identifies extremely few of these cases and is not necessarily warranted in all cases. In addition, women who undergo excision of the biopsy site are still at risk for development of DCIS or IC.

There are several possible explanations for the differences we report. First, the current series is by far the largest series of cases reported to date. It is possible that the rate of DCIS and IC in previous reports may be less if more cases had been followed up.

Second, this is only the second report[1] to identify cases prospectively. It is possible that cases identified retrospectively may be biased toward patients who had other reasons to obtain a subsequent excision.

Third, few of the previous studies distinguished clearly between tumors found in the biopsy site itself and tumors found in subsequent excisions of other sites in the same breast.[6] It is possible that some of the subsequent cases of DCIS and IC reported by others may not necessarily have been associated with the biopsy site.

Fourth, our pathology department exhaustively samples all core needle biopsy specimens, thus reducing the chance that a lesion that was sampled by the radiologist is not seen by the pathologist.[17] The amount of processing in previous studies has been variably reported. However, we still believe, as suggested in our earlier report,[12] that the primary reason we do not find DCIS and IC in subsequent excision specimens relates to our radiologists. Although we have been unable to determine a satisfactory way to assess the amount of tissue removed at the time of biopsy, it is clear in comparison with core biopsy specimens received in consultation from other centers that our radiologists obtain more tissue. We believe that the large amount of tissue obtained at the time of the biopsy significantly reduces the chance of missing a significant lesion and most likely accounts for the very low incidence of DCIS and IC in the subsequent excisions.

This scenario is similar to that described for high-grade prostatic intraepithelial neoplasia in prostate biopsy specimens.[21] When only 6 biopsy specimens were obtained routinely, high-grade prostatic intraepithelial neoplasia was associated strongly with carcinoma on repeated biopsy. However, when more tissue was obtained, the risk of carcinoma in subsequent biopsies is no more than that seen in men with a benign initial diagnosis. In contrast, atypical foci "suspicious" for carcinoma in prostate biopsy specimens remain strongly associated with a risk of carcinoma in subsequent biopsies, regardless of the amount of tissue obtained in the initial biopsy. This would be analogous to ADH, which has been shown to be a risk factor in breast cores in virtually all studies to date. If sampling should prove to be the reason for the differences in the preceding results, then following the rate of IC and DCIS after a diagnosis of LCIS may be a useful quality control method for breast core biopsies.

Regardless of the reasons, our results show that the significance of LN on core needle biopsy specimens does seem to differ at different centers. In centers with appropriate follow-up information, routine excision of all biopsy sites for LN may not always be necessary.

Although LN is associated strongly with IC and DCIS overall (30%), excision of the biopsy site for women with LN alone on core needle biopsy has a very low rate of IC and DCIS (3%). Women who undergo excision of biopsy sites are still at risk for subsequently developing IC.

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