Role of resection margins in patients treated with breast conservation surgery.

BACKGROUND: After breast conservation therapy (BCT), margin status is routinely evaluated to select patients who need reexcision. The aim of this study was to investigate how margin status and other clinicopathologic factors correlate with the presence of residual tumor at reexcision. METHODS: A series of 431 breast cancer patients who underwent BCT followed by reexcision were considered because they had positive or close (< or =3 mm) margins. At univariate and multivariate analysis the frequency of residual tumor in the reexcision specimens was associated with the status and width of resection margins and with a series of other clinicopathologic factors. RESULTS: Of the 382 evaluable patients, 253 had positive and 129 close margins. Residual tumor was found at reexcision in 51.8% positive-margin patients and 34.1% close-margin patients (P = .001). In the latter group tumor-margin distance (range, 0.08 to 3 mm) was not associated with the incidence of residual tumor (P = .134). On univariate analysis age < or =45 years (P = .006), intraductal histotype (P = .005), size > 2 cm (P = .010), positive axillary nodes (P = .031), and timing of reexcision (P = .044) were significantly associated with a higher frequency of residual tumor. All these factors, except tumor size, maintained a significant predictive value on multivariate analysis. CONCLUSIONS: In the presence of positive margins, relevant residual disease cannot be ruled out and further surgery is indicated. Close margins do not mandate reexcision because they may indicate either that the tumor has been radically excised or the presence of residual foci of a multifocal tumor, which are usually effectively treated by radiotherapy.

Sentinel lymph node metastasis from mammary ductal carcinoma in situ with microinvasion.

Axillary lymph node dissection (ALND) in patients with ductal carcinoma in situ with microinvasion (DCISM) of the breast was controversial, because of the relevant morbidity incurred by the procedure and the low incidence of axillary involvement. The introduction of the sentinel lymph node (SLN) biopsy as a minimally invasive procedure for axillary staging has prompted new interest in this issue. However, as DCISM is a rare type of cancer, data on the incidence of SLN metastasis are scarce. The aim of the present paper was therefore to assess the prevalence of SLN metastasis in a multi-institutional series of DCISM patients, in order to ascertain whether SLN biopsy might be justified as a standard procedure in the presence of microinvasive cancer. Between 1999 and 2004, 43 patients with a diagnosis of DCISM underwent SLN biopsy. Microinvasion was defined as one or more foci of invasion beyond the basal membrane, none exceeding 1mm. SLNs were examined following haematoxylin-eosin and immunohistochemical staining. SLN metastases were found in four out of 43 cases (9.3%). In one patient, SLN contained only micrometastasis. All four patients with positive SLN underwent complete ALND and in all these cases further metastatic axillary nodes were found. In conclusion, given the relevant incidence of nodal metastases and the low morbidity of the procedure, we believe that SLN biopsy should be considered in all patients with a diagnosis of DCISM. In cases of SLN involvement, even if micrometastatic, our policy is to perform a complete ALND.

Role of axillary sentinel lymph node biopsy in patients with pure ductal carcinoma in situ of the breast.

BACKGROUND: Sentinel lymph node (SLN) biopsy is an effective tool for axillary staging in patients with invasive breast cancer. This procedure has been recently proposed as part of the treatment for patients with ductal carcinoma in situ (DCIS), because cases of undetected invasive foci and nodal metastases occasionally occur. However, the indications for SLN biopsy in DCIS patients are controversial. The aim of the present study was therefore to assess the incidence of SLN metastases in a series of patients with a diagnosis of pure DCIS. METHODS: A retrospective evaluation was made of a series of 102 patients who underwent SLN biopsy, and had a final histologic diagnosis of pure DCIS. Patients with microinvasion were excluded from the analysis. The patients were operated on in five Institutions between 1999 and 2004. Subdermal or subareolar injection of 30-50 MBq of 99 m-Tc colloidal albumin was used for SLN identification. All sentinel nodes were evaluated with serial sectioning, haematoxylin and eosin staining, and immunohistochemical analysis for cytocheratin. RESULTS: Only one patient (0.98%) was SLN positive. The primary tumour was a small micropapillary intermediate-grade DCIS and the SLN harboured a micrometastasis. At pathologic revision of the specimen, no detectable focus of microinvasion was found. CONCLUSION: Our findings indicate that SLN metastases in pure DCIS are a very rare occurrence. SLN biopsy should not therefore be routinely performed in patients who undergo resection for DCIS. SLN mapping can be performed, as a second operation, in cases in which an invasive component is identified in the specimen. Only DCIS patients who require a mastectomy should have SLN biopsy performed at the time of breast operation, since in these cases subsequent node mapping is not feasible.