Ultrasound-guided breast-sparing surgery to improve cosmetic outcomes and quality of life. A prospective multicentre randomised controlled clinical trial comparing ultrasound-guided surgery to traditional palpation-guided surgery (COBALT trial).

BACKGROUND: Breast-conserving surgery for breast cancer was developed as a method to preserve healthy breast tissue, thereby improving cosmetic outcomes. Thus far, the primary aim of breast-conserving surgery has been the achievement of tumour-free resection margins and prevention of local recurrence, whereas the cosmetic outcome has been considered less important. Large studies have reported poor cosmetic outcomes in 20-40% of patients after breast-conserving surgery, with the volume of the resected breast tissue being the major determinant. There is clear evidence for the efficacy of ultrasonography in the resection of nonpalpable tumours. Surgical resection of palpable breast cancer is performed with guidance by intra-operative palpation. These palpation-guided excisions often result in an unnecessarily wide resection of adjacent healthy breast tissue, while the rate of tumour-involved resection margins is still high. It is hypothesised that the use of intra-operative ultrasonography in the excision of palpable breast cancer will improve the ability to spare healthy breast tissue while maintaining or even improving the oncological margin status. The aim of this study is to compare ultrasound-guided surgery for palpable tumours with the standard palpation-guided surgery in terms of the extent of healthy breast tissue resection, the percentage of tumour-free margins, cosmetic outcomes and quality of life. METHODS/DESIGN: In this prospective multicentre randomised controlled clinical trial, 120 women who have been diagnosed with palpable early-stage (T1-2N0-1) primary invasive breast cancer and deemed suitable for breast-conserving surgery will be randomised between ultrasound-guided surgery and palpation-guided surgery. With this sample size, an expected 20% reduction of resected breast tissue and an 18% difference in tumour-free margins can be detected with a power of 80%. Secondary endpoints include cosmetic outcomes and quality of life. The rationale, study design and planned analyses are described. CONCLUSION: The COBALT trial is a prospective, multicentre, randomised controlled study to assess the efficacy of ultrasound-guided breast-conserving surgery in patients with palpable early-stage primary invasive breast cancer in terms of the sparing of breast tissue, oncological margin status, cosmetic outcomes and quality of life. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NTR): NTR2579.

Sentinel node biopsy for nonpalpable breast tumors requires a preoperative diagnosis of invasive breast cancer.

A sentinel node biopsy done at the time of initial tumor resection allows for a one-stage surgical procedure. In addition, sentinel node identification may be impaired when done after a previous tumor excision. This study evaluates the sentinel node biopsy in patients with nonpalpable breast cancer and assesses whether a sentinel node biopsy for mammographically suspect breast lesions is justified when preoperative needle biopsy is inconclusive for invasive malignancy. A sentinel node biopsy was done in 67 patients with nonpalpable breast lesions after injection of radioactive tracer (intraparenchymal in 35 and subdermal in 32) and blue dye (para-areolar). A preoperative core needle biopsy was positive for malignancy in 42 patients. Thirteen patients had positive cytology or ductal carcinoma in situ (DCIS). In 12 patients the needle biopsy was nondiagnostic, but the lesions remained highly suggestive of malignancy on mammography. Sentinel node biopsy was successful in 64 patients (96%). In these, the sentinel node was both radioactive and blue in 58 patients (91%). Only 4 of 13 patients with positive cytology or DCIS on preoperative needle biopsy and only 5 of 12 patients without a preoperative diagnosis had an invasive cancer after resection. Sentinel nodes were positive for nodal metastases in 9 of 49 patients (18%) with a successful sentinel node biopsy for invasive malignancy. None of the eight patients with DCIS had nodal metastases. The sentinel node procedure avoids the potential morbidity of an axillary dissection in more than 80% of patients with nonpalpable breast cancer. A sentinel node biopsy for mammographically detected suspect breast lesions is not justified without a preoperative histologic diagnosis of invasive breast cancer.