Accelerated partial breast irradiation using only intraoperative electron radiation therapy in early stage breast cancer.

BACKGROUND: We report the results of a single-institution, phase II trial of accelerated partial breast irradiation (APBI) using a single dose of intraoperative electron radiation therapy (IOERT) in patients with low-risk early stage breast cancer. METHODS AND MATERIALS: A cohort of 226 patients with low-risk, early stage breast cancer were treated with local excision and axillary management (sentinel node biopsy with or without axillary node dissection). After the surgeon temporarily reapproximated the excision cavity, a dose of 21 Gy using IOERT was delivered to the tumor bed, with a margin of 2 cm laterally. RESULTS: With a mean follow-up of 46 months (range, 28-63 months), only 1 case of local recurrence was reported. The observed toxicity was considered acceptable. CONCLUSIONS: APBI using a single dose of IOERT can be delivered safely in women with early, low-risk breast cancer in carefully selected patients. A longer follow-up is needed to ascertain its efficacy compared to that of the current standard treatment of whole-breast irradiation.

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.