Dec 11, 2015
The Breast Cancer Symposium eQ&A series discusses some of the unanswered questions posed by attendees of the 2015 Breast Cancer Symposium during panel discussions.
Kelly Hunt, MD, of The University of Texas MD Anderson Cancer Center, helped moderate a General Session during the 2015 Symposium on “Controversies in Surgery and Radiation Therapy.” Other speakers included:
- Jennifer Ruth Bellon, MD, Dana-Farber Cancer Institute
- Eun-Sil Shelley Hwang, MD, MPH, Duke University
- David Euhus, MD, Johns Hopkins Hospital
- Barbara L. Smith, MD, PhD, Massachusetts General Hospital
- Hani Sbitany, MD, UCSF Medical Center
- Alice Y. Ho, MD, MBA, Memorial Sloan Kettering Cancer Center
- David E. Wazer, MD, Tufts Medical Center
In the following article, Dr. Hunt addresses some of the questions that did not get asked during the panel discussion.
How do you follow women who have undergone nipple-sparing mastectomies in terms of imaging?
KH: Nipple-sparing mastectomy is essentially the same as skin-sparing mastectomy in that you do not perform routine surveillance imaging of patients after the procedure. Our intention in doing these procedures is to remove all of the breast tissue; the skin flaps, as we know, may have some small amount of breast tissue remaining. An estimated 2% to 5% of breast tissue remains after a skin-sparing or nipple-sparing procedure. But that is not enough breast tissue to allow for any specific imaging like mammography or MRI. I have seen some groups perform mammography or MRI; in general, the volume of breast tissue is so small that those types of imaging are not productive or useful.
With respect to patients who have a palpable abnormality after the procedure, my preference is performing an ultrasound first. Sometimes you will have patients with implant-based reconstruction who might have some textural abnormality in the implant or in the material used to cover the implant. Those features can usually be imaged with ultrasound to determine whether further assessment is needed and whether a biopsy is indicated.
In terms of patients who have autologous reconstruction, they can sometimes get fat necrosis within the reconstruction that will cause a palpable abnormality that feels similar to a breast mass or might be suspicious for recurrence. In that case, we would usually start with an ultrasound because fat necrosis has pretty typical features on an ultrasound evaluation. If there is a concern about the abnormality, you may want to further evaluate it with mammography or MRI after consultation with a breast imaging specialist.
In summation, we do not perform routine surveillance imaging for follow up. We only do imaging directed at any concern, any palpable abnormality or sudden change in the reconstructed breast.
How large is the periareolar incision for nipple sparing mastectomy? Are we were supposed to stay away from the areola?
KH: There are some surgeons who use periareolar incisions. These incisions have been associated with a slightly higher risk of nipple necrosis, but they can be used for patients, especially those who are having autologous reconstruction with free flaps using microvascular anastomosis to the internal mammary artery. In that case, you need more access medially so that you can get to the internal mammary vessels. From there, you can extend the periareolar incision medially in order obtain enough access.
The key is maintaining the vascularity within the skin envelope and the subdermal plexus, and also maintaining the vascularity along the medial part of the breast where the perforator vessels come in. If those vessels are maintained, then the risk of nipple necrosis should be minimal.
Another approach is using an inframammary fold incision. That incision, however, can make it challenging during autologous reconstruction for the plastic surgeon to reach an internal mammary vessel. The oncologic/breast surgeon and the plastic surgeon must coordinate with each other in order to try to ensure that access is going to be achievable for autologous reconstruction. If an implant-based reconstruction is planned, then it is often better to use an incision along the inframammary fold or even a lateral radial incision so that there is less risk of nipple necrosis.
There is tumor or ductal carcinoma in situ (DCIS) in the retroareolar biopsy margin, but when you take another margin and it is greater than 2 mm. In this case, do you need to resect the nipple? What is an acceptable negative margin?
KH: I think most clinicians would be satisfied as long as the margin is clearly negative. The width of the margin is not as much of an issue as the amount of disease in the tissue behind the nipple/areola complex. If there is extensive DCIS, I think there is concern about ductal extension up along the ducts to the nipple and perhaps a higher risk of recurrence within that ductal epithelium. In terms of a slightly close margin, within 1 mm to 2 mm, where there is only a small focus of DCIS, I think most would consider a negative margin acceptable. In that case, you don’t need to go back and resect the nipple to have more “negative” tissue.
What is recurrence rate after skin-sparing mastectomy with thick flaps? How often is breast tissue or axillary breast tissue left?
KH: This is a difficult question because each surgeon approaches the flap thickness in a slightly different manner. I think it is ideal to perform an anatomic resection just below the subdermal plexus where there is a clear plane between the breast tissue and the subcutaneous fat underneath the skin. There is an anatomic plane, so if the surgeon follows the plane while doing the skin-sparing mastectomy or nipple sparing mastectomy, then there should be minimal breast tissue regardless of the flap thickness. There is not an exact flap thickness to achieve, but more of an anatomic resection of the breast and leaving the subdermal plexus in place in order to have adequate blood supply to the skin.
In terms of axillary breast tissue, the surgeon should approach the axillary breast tissue the best they can through the incision in order to perform a complete resection. There is a clear anatomic plane between the axillary tissue and the breast, so surgeons should be able to resect all the axillary breast tissue.
There are not any contemporary studies that have tried to methodically evaluate what percentage of breast tissue has been left, but there is an MRI study where there was mathematical modeling to try to determine how much breast tissue would be left if the surgeon did a 5-mm flap behind the nipple versus a 10-mm flap thickness. You can use the MRI because the MRI can measure the amount of fibroglandular tissue versus fatty tissue and can estimate how much breast tissue would remain based on that flap thickness. That was more directed toward the thickness of the nipple/areolar tissue as opposed to the entire breast/skin envelope.
Do you advocate for intraoperative assessment of lymph nodes in sentinel lymph node biopsy after neoadjuvant chemotherapy for patients who presented as N1 prior to neoadjuvant chemotherapy?
KH: I prefer intraoperative assessment with frozen section analysis of the sentinel node after neoadjuvant chemotherapy because unless the patient is on protocol or a clinical trial, our standard is to perform an axillary lymph node dissection in these patients for regional control.
If the patient has a pathologic complete response, do they need to have a completion axillary node dissection? Do they need radiation? These questions are being studied in clinical trials. In a trial sponsored by the NRG Oncology group, for patients who start out as N1 that is biopsy proven and who then receive neoadjuvant chemotherapy, if they are clinically node-negative after chemotherapy and are node-negative by pathologic assessment of the sentinel nodes or axillary nodes, they are eligible to be randomly assigned to radiation versus no radiation. For patients whohave residual disease in the sentinel nodes based on frozen section examination or permanent histologic examination of the sentinel nodes, those patients are eligible for randomization in the Alliance A011202 trial to completion axillary dissection with radiation or radiation alone. We’re trying to see if we can eliminate axillary dissection to reduce morbidity but still maintain locoregional control because they will be receiving radiation therapy.