Performing a sentinel node biopsy prior to mastectomy and reconstruction gives best results

Altering the standard step-by-step procedure that takes women facing a mastectomy from diagnosis to surgery to reconstruction can improve the process and help in determining if immediate reconstruction is the best course of action, according to new research from the University of North Carolina at Chapel Hill.

Key to the new approach is the use of sentinel lymph node biopsy (SLNB) performed as an outpatient procedure a week or so prior to mastectomy, rather then doing the SLNB at the same operation as the mastectomy and reconstruction.

According to the new study published in the October issue of the American Journal of Surgery, particular problems may arise with performing SLNB at the same time as the mastectomy with immediate reconstruction.

SLNB involves the removal of some of the first "sentinel" lymph nodes into which cancerous cells from the breast might drain. Studies have shown SLNB to be an effective way to determine the spread of disease to the lymph nodes under the arm.

In current practice using SLNB, the sentinel node is quick-frozen; a pathologist then examines the node under a microscope. This method quickly gives a diagnosis of cancer spread while the surgeon is waiting to complete the procedure. The diagnosis is confirmed a few days after surgery by a more detailed study called a permanent section.

"If the pathologist does not see tumor in the lymph node on frozen section, there is still a chance that tumor may be found in the lymph nodes on final pathology," said lead study author Dr. Nancy Klauber-DeMore, assistant professor of surgery in UNC's School of Medicine and a member of the UNC Lineberger Comprehensive Cancer Center.

"There can be major consequences for a patient who has undergone immediate breast reconstruction if a metastasis is found on permanent section that was not recognized on frozen section."

There are two issues here, Klauber-DeMore said. The first is the need for another operation, axillary lymph node dissection, or removal of all the lymph nodes under the armpit. "Axillary lymph node dissection may present increased complications in a patient with a newly reconstructed breast."

The second is that some patients whose lymph nodes prove positive on final pathology may be recommended to undergo post-mastectomy radiation therapy. "And radiation can sometimes have adverse effects on the reconstruction that may lead to poorer cosmetic results, particularly if the reconstruction is with a tissue expander, a breast-shaped prosthetic that helps create a pocket for a breast implant," Klauber-DeMore said.

"That is why it would be optimal to know the final status of the sentinel node before committing the patient to a large operation, such as mastectomy and reconstruction."

In the study, 25 patients underwent outpatient sentinel node biopsy, the procedure taking generally less than an hour. The patients then went home. Two patients had cancer in both breasts; therefore, 27 SLNBs were performed. Patients returned for the final pathology results the following week.

"With the knowledge of the final pathology, the patient can make more informed decisions in discussion with the radiation oncologist and plastic surgeon, to determine whether or not the patient will need radiation after the mastectomy. This in turn will influence whether or not the patient should have immediate reconstruction," Klauber-DeMore said. "We also know definitively if the patient needs an axillary lymph node dissection at the time of mastectomy."

The study demonstrated that exact knowledge of positive versus negative sentinel lymph node prior to mastectomy helped physicians plan the optimal surgical procedure for the patient, the researchers said.

Of the 27 biopsies, nine patients (33 percent) had tumor-involved lymph nodes. All nine patients underwent an axillary lymph node dissection at the time of their mastectomy. Of these, three did not have immediate reconstruction because it was thought that would be detrimental, Klauber-DeMore said.

Of the remaining six node-positive patients, five underwent reconstruction with their own tissue instead of a tissue expander. In contrast, six of the 16 (37 percent) node-negative patients underwent reconstruction with a tissue expander.

"We conclude that performing a sentinel node biopsy as a staged procedure prior to definitive mastectomy and reconstruction gives the treating physicians more information to guide the patient regarding the best surgical procedure for them," Klauber-DeMore said.