Ultrasound of Axillary Nodes Predicts Breast Cancer Status
Ed Susman · Oncology Times · 2015
SAN ANTONIO—The use of axillary ultrasound examination to detect extensive lymph node involvement appears to be warranted, researchers suggested here at the San Antonio Breast Cancer Symposium. “We advise the use of axillary ultrasound imaging to more specifically identify breast cancer patients with a high risk for extensive nodal involvement for whom a more aggressive treatment of the axilla might still be beneficial,” said Nicole Verheuvel, MD, a surgical resident at Maxima Medical Center in the Netherlands, “In Holland, everyone, irrespective of palpability of lymph nodes, will get axillary ultrasound—and that group includes patients diagnosed with invasive cancer as well as women who are found to have ductal carcinoma in situ.” She explained that the procedure is that if positive findings are shown on mammography or in clinical examination, women then go to their radiologist for the ultrasound of the breast and the radiologist also performs an ultrasound test of the axilla. If the radiologist sees ultrasound evidence of an enlarged lymph node, the next step is a fine needle biopsy. If the biopsy proves negative, a sentinel node procedure is performed, and if the biopsy is positive, the doctor can perform an immediate dissection of the axilla. The new findings, though, mean that the procedure may eliminate the need for a separate procedure of sentinel node biopsy. Verheuvel noted that there are differences in the guidelines between the European/Dutch treatment algorithms and those in the United States: “In America, as I understand it, you do the axillary ultrasound if you have palpable lymph nodes or suspicion of enlarged lymph nodes,” she said. Study Details In the study, the researchers identified 1,281 patients with invasive breast cancer. Of that group, 431 were lymph node positive after axillary dissection was performed. In 302 cases with enough clinical information to be included in the study, the researchers found that in 177 women, one to two positive lymph nodes were discovered. In the other 125 women, three or more positive lymph nodes were identified. The definition in the study for extensive lymph node involvement is the finding of three or more positive nodes. Verheuvel said that when compared with sentinel node biopsy as the reference level, use of ultrasound was more than five times more likely to identify extensive nodal involvement. “Axillary staging by ultrasound is the more important factor predicting extensive nodal involvement,” she reported. Tumor size was also significantly associated with extensive nodal involvement, she said. Lymphovascular invasion was also associated with extensive nodal involvement. “There is still some discussion about whether ultrasound is advisable in this setting, but if the patient has enlarged nodes you can omit a sentinel node operation and improve aesthetics because a biopsy would be enough. For those patients, it is one surgical procedure less.” The researchers initiated the retrospective study to try to understand the best procedures for staging axillary lymph nodes in patients with invasive breast cancer. The aim was to assess how well ultrasound-guided lymph node biopsy would compare with sentinel node biopsy in determining extensive nodal involvement. “Various prediction models have been developed to predict the risk of not having additional axillary metastases in patients with a positive sentinel node, thereby disregarding patients with a positive ultrasound,” she said. “However, it is important to identify all patients with extensive nodal involvement in whom an axillary lymph node dissection cannot be omitted.” All patients diagnosed with invasive breast cancer in the period between January 2006 and December 2011 at the breast center of the Máxima Medical Center were included for analysis. To be eligible for inclusion patients had to have proven invasive breast cancer; proven lymph node metastases; and a complete lymph node dissection. Excluded were patients found to have distant metastases at diagnosis; ipsilateral recurrent breast cancer; clinical Stage 2-3 breast cancer; inconclusive biopsy after an ultrasound guided procedure; or neoadjuvant systemic therapy. “This study has identified clinically important factors predicting extensive nodal involvement in patients with a positive lymph node biopsy by either a sentinel lymph node procedure or an ultrasound guided lymph node biopsy,” Verheuvel reported. “Hence, the role of axillary staging by ultrasound should be redefined since it might play an important role in selecting patients with extensive nodal involvement who, in our opinion, may still benefit from axillary treatment.” In their analysis, the researchers identified several factors that were statistically significant or trended toward significance in a univariate analysis: The ability to palpate lesions; The type of surgery—i.e., mastectomy or breast-conserving therapy; The tumor grade at initial analysis; and Molecular subtypes of the breast cancer. However, all these factors failed to maintain that significance when the multivariate analyses were performed, Verheuvel reported. ‘Help Streamline Care, Help Reduce Anxiety’ Asked her opinion for this article, Stephanie Bernik, MD, Chief of Surgical Oncology at Lenox Hill Hospital in New York, said: “Many women already get an ultrasound of the axilla before surgery, but some do not. If an ultrasound done before surgery would help to reduce the number of trips to the operating room and help define who should go straight to an axillary dissection, its use should become more uniform. “This would help streamline care for the breast cancer patient and help reduce anxiety.” She noted that over the last few years, surgeons have moved away from performing a completion axillary lymph node dissection in women undergoing breast conservation even when the sentinel lymph nodes have metastatic disease. This is because the axilla will be treated with both chemotherapy and radiation therapy. “However, women who have clinically positive lymph nodes before surgery are still encouraged to undergo an axillary lymph node dissection, despite the increased risk of lymphedema,” she said. “The definition of what constitutes a clinically positive lymph node has not been clearly defined. Often, a lymph node seen on ultrasound that turns out to have disease is thought to be ‘clinically positive.’ It would therefore be recommended that these women undergo a completion dissection.”