For patients with early stage breast carcinoma, the ability to achieve complete tumor resection with breast conservation remains suboptimal despite advances in surgical, pathologic and imaging techniques. Currently re-excision rates to achieve clear margins in the United States range between 15-40%.The negative impacts of re-excision include delays in the completion of adjuvant therapies, increased infection rates, increased health care costs, increased mastectomy rates and negative psychological impacts on the patients. The principle of clear margins is imperative since presence of positive margins is associated with increased loco-regional recurrence, and the failure to maintain local control is associated with a decrease in long-term breast cancer specific survival.
In AMIGO, we are studying the use of novel intraoperative mass spectrometry and magnetic resonance imaging (MRI) as methods to reduce the rate of re-excision for breast cancer patients. AMIGO enables surgeons to incorporate existing and novel imaging technologies including intraoperative MRI and mass spectrometry, to efficiently and precisely guide treatment — before, during, and after surgery — without the patient or medical team ever leaving the operating room.
It is our hypothesis that utilizing intra-procedural mass spectrometry and breast MRI will allow for improved visualization and characterization of tumors and breast-tumor biomarkers that will be effective in assessing tumor margins and areas of residual disease. Ultimately we hope that implementation of these advanced imaging technologies during breast surgery will allow surgeons to achieve more precise excisions and successful first-surgery clear margin rates, ultimately hopefully obviating the need for further operations in patients undergoing breast-conserving therapy.
Breast Conserving Surgery Workflow in AMIGO
Diagnostic Imaging. 3D volume rendered MIP images showing the main mass and satellites. The presence of satellite tumors poses a difficulty in ensuring complete tumor resection.
Diagnostic Imaging. Color overlay by a Computer-aided software over the rapidly enhancing mass (invasive ductal cancer).
Preoperative. The patient comes into the AMIGO operating room and is placed under general anesthesia. A contrast enhanced 3D MRI then is performed while the patient is in supine position. In this case, an MRI is performed before and after contrast injection, delineating the tumor boundaries in relationship to fixed landmarks. Upon completion of the preprocedural MRI, the MRI machine leaves the room and the images are evaluated.
Intraoperative. The woman's breast is then prepared and draped in standard sterile fashion. Through palpation, the tumor is identified and surgical incisions marked.
Intraoperative. As part of the lymph node evaluation procedure, marcaine and 2cc of 1% methylene blue diluted with 3cc of saline are injected. The breast is then massaged so as to distribute the methylene blue to the lymphatics before beginning the incision between the pectorals and latissimus muscles, below the marked line.
Intraoperative. The methylene blue renders the sentinel lymph nodes detectable. The lymph nodes are then sent to pathology for evaluation. Then the lumpectomy is performed and the resected tumor is sent to pathology.
Intraoperative. The lumpectomy cavity is temporarily closed with a nylon suture.
Intraoperative. Before completing closure, the lumpectomy cavity is filled with exactly the volume of resected tumor and a 1cm margin. Finally, the incision is covered.
Postoperative. Immediately post-surgery, a second MRI scan (again, with contrast) is obtained while the patient is on the operating table. The purpose of this MRI is to examine the saline filled cavity to identify areas of enhancement that may be suspicious for residual carcinoma. Following the imaging, the MRI scanner leaves the operating room. A radiologist compares the resected tumor to an MRI of the second breast for possible areas of residual tissue. On the left side, the preoperative images are shown; on the right side, the new images are displayed.
Postoperative. Post-surgical post-contrast MRI showing the saline cavity filled with saline.
Postoperative. 3D volume rendered image showing the surgical cavity.
Re-excision. If suspicious remaining tissue is detected on the MRI images, the breast is reopened and the residual tumor removed.