Breast cancer is the most commonly diagnosed cancer worldwide, affecting over 2 million women each year. The most important predictor of both recurrence and survival in patients with breast cancer is if cancer has spread to the axillary lymph nodes.
Dr. Alyssa Cubbison at The Ohio State University Wexner Medical Center specialises in breast imaging. She puts forward an algorithm she helped create that uses preoperative ultrasound imaging of the axilla when facing suspected breast cancer.
Read the original research: 10.1016/j.clinimag.2022.04.011
Image source: Adobe Stock Images / lordn
Hello and welcome to Research Pod. Thank you for listening and joining us today.
In today’s episode we will be discussing the research of Dr. Alyssa Cubbison at The Ohio State University Wexner Medical Center involving the staging of breast cancer. Breast cancer is the most commonly diagnosed cancer worldwide and a leading cause of morbidity and mortality from breast cancer. It affects over 2 million women each year. The most important predictor of both recurrence and survival in patients with breast cancer is if cancer has spread to the axillary lymph nodes. Ultrasound is a non-invasive tool used by radiologists to assess for suspicious lymph nodes that would require a biopsy. The utility of this practice has been called into question as surgical literature suggests it may not ultimately affect management in some instances.
Dr. Cubbison , a radiologist that specialises in breast imaging, puts forward a standardized algorithm she helped create during her time at Prentice Women’s Hospital of Northwestern Medical Center that directed the use of preoperative ultrasound imaging of the axilla in the setting of suspected breast cancer.
The evaluation of axillary lymph nodes remains a fundamental component of breast cancer management as it affects staging and overall prognosis. Historically, if metastatic breast cancer was found in the axillary lymph nodes preoperatively via ultrasound-guided needle biopsy, this would lead to a complete surgical removal of all axillary lymph nodes.
The surgery of removing all of the axillary lymph nodes is called axillary lymph node dissection (ALND). A procedure was subsequently developed called a sentinel lymph node biopsy (or, SLNB), in which the sentinel lymph node, ie the first lymph node that drains a particular lymph node basin, was marked with a radioisotope and would then undergo surgical excision. If metastatic disease was not found within the sentinel lymph node, it was safely assumed there was no metastatic disease elsewhere in the axilla.
This assumption is made with the acknowledgement that metastasis drains in a consistent pattern throughout lymphatic channels. After large scale trials showed no statistical difference in survival or disease recurrence, SLNB largely replaced ALND as the initial management for surgical staging of the axilla.
Initially, if metastatic disease was found on SLNB or preoperatively on ultrasound-guided percutaneous biopsy, this would lead to ALND. This practice changed, however, following the results of the monumental American College of Surgeons Oncology Group Z-11 (Zee Eleven} trial in 2011. The Z-11 trial was a prospective, randomized, multicenter trial that included women with early stage breast cancer, specifically cancers less than 5 cm, and two or less positive nodes on SLNB. The patients were randomized to either undergo ALND or no further axillary surgery. Results demonstrated no statistical difference in survival or local breast cancer recurrence between the two groups.
This trial demonstrated that not all axillary metastatic disease required ALND, obviating the need for a separate, invasive surgery with significant comorbidities. Notably, patients excluded from the evaluation were those with plans for a mastectomy or chemotherapy prior to surgery, if lymph nodes were palpable prior to surgery, or if three or more lymph nodes were positive in surgery.
Previously, the use of axillary ultrasound with preoperative biopsy could allow patients with metastasis to directly proceed to ALND and avoid sentinel lymph node surgery. However, results of the Z0011 trial challenge the utility of ultrasound biopsy, as surgeons may omit ALND for minimal nodal disease. So even if axillary lymph node metastasis was proven via ultrasound biopsy preoperatively, these patients may still be eligible for SLNB and therefore, the procedure would not have been necessary. Radiology and surgical practices are still evolving in light of this revolutionary trial, and it was these evolving concepts that prompted Dr Cubbison and her colleagues pursuit to standardize their approach of when to perform axillary ultrasound and/or ultrasound core needle biopsy.
This research article summarizes the department’s standardized approach and algorithm for utilizing axillary ultrasound in the setting of a mass at high suspicion for malignancy. The standardization was intended to provide more effective and consistent care for both patients and referring clinicians. By outlining their division’s approach to axillary imaging, Dr Cubbisons team hoped to facilitate transparency and reflect the practices of a large, multi-disciplinary breast cancer center in this transitional state of axillary imaging.
The breast surgery division at the Northwestern Medical Center academic women’s hospital, which includes four breast surgeons, were queried individually regarding their axillary surgical practices as well as their preference towards pre-operative axillary imaging.
The query involved a one-on-one discussion with each surgeon in order to create a thorough, open dialogue on this complex topic. Once a surgical consensus opinion was reached, a discussion followed among the 11 breast radiologists at the institution in an intradepartmental meeting that led to the finalization of the teams algorithm.
All four surgeons were in keeping with the national trend towards practicing Z0011 management, and agreed SLNB would still be performed in the setting of a normal axillary US to exclude metastasis, in most instances. Three out of the four agreed that metastasis on core needle biopsy would not prevent performance of SLNB, as long as they otherwise met Z0011 criteria.
The creation of the Northwestern teams algorithm was based on the consensus of surgical practice. The algorithm stated that the performance of axillary ultrasound in the setting of a suspicious breast mass should be deferred at the initial presentation unless there is palpable lymph nodes; suspicious axillary lymph nodes demonstrated on mammography; or if the breast mass is over 5 cm. The reason ultrasound would be used for palpable lymph nodes or if breast mass is over 5 cm is because they would be excluded from Z0011 management in those instances.
If ineligible to meet Z0011 criteria, any metastasis proven preoperatively via an ultrasound-guided biopsy, would be directed to ALND, and potentially spare patients a separate surgery. Although lymph nodes seen on mammography does not preclude Z0011 management, it is best radiologic practice to ultrasound lymph nodes in this instance. The algorithm also stated that ultrasound-guided biopsies of suspicious lymph nodes would not be performed without prior surgical consultation. This is to prevent a potentially unnecessary procedure which may not only be costly and uncomfortable to the patient, but could potentially interfere with the axillary clinical exam due to post biopsy changes.
To put this algorithm and its impact in context, Dr Cubbison explains :
This approach helps standardize an evolving practice that is inline with up to date literature in order to provide the most effective, consistent care for our patients.
In summary, with Z0011 surgical practices in mind, performance of axillary ultrasound in the setting of a suspicious breast mass is now deferred at Northwestern Medical Centre until after surgical consultation unless there is palpable axillary lymphadenopathy, a suspicious lymph node on mammography, or a tumor that is at least over 5 cm in size.
Through open discussion with breast surgery colleagues, the team have developed a practical approach to the utilization of axillary ultrasound in the setting of a suspicious breast mass using an evidence and experience-based approach, and encourage colleagues to communicate with their clinical team regarding axillary imaging preferences for the most effective patient care.
That’s all for this episode. Please feel free to reach out to Alyssa via twitter or email, with contact link available in the show notes for this episode
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