Medscape Medical News from the:
National Comprehensive Cancer Network (NCCN) 15th Annual Conference
Nick Mulcahy
March 12, 2010 (Hollywood, Florida) — In women with stage I/II breast cancer who have clinically negative axilla, "sentinel lymph node biopsy [SLNB] is now the standard of care" in staging these nodes, said Robert Carlson, MD, during the breast cancer guideline update here at the National Comprehensive Cancer Network (NCCN) 15th Annual Conference.
Not only is SNLB the standard of care, but full axillary lymph node dissection has been removed as an option for women with clinically negative axilla, noted Dr. Carlson, who is from the Stanford Comprehensive Cancer Center in Palo Alto, California.
The alterations represent the most significant new change in this year's NCCN breast cancer guideline, Dr. Carlson told reporters after making his presentation.
Randomized clinical trials indicate that there is a lower risk for morbidity associated with sentinel node mapping and excision than with level I/II axillary dissection, he said.
The change to the guideline also reflects current practice, suggested Dr. Carlson, who is also chair of NCCN's Breast Cancer Panel.
Between 1998 and 2005, SLNB in breast cancer increased to about 65% of all stage I/II cases, he said, adding that SLNB training is now standard in American surgery programs, and is widely available.
Only an "experienced sentinel lymph node team" should perform the SLNB, Dr. Carlson added. Otherwise, the NCCN's guideline calls for a patient to be referred to such a team, which would include a surgeon, a radiologist, a nuclear medicine physician, and a pathologist.
"In an experienced surgeon's hands, the sentinel lymph node is identified 95% of the time," Dr. Carlson told the NCCN audience. "The false-negative rate is less than 10%, and axillary recurrence is less than 1% if the sentinel lymph node is negative."
Lymph edema is about 7% with this approach, said Dr. Carlson. This compares favorably with the 10% to 20% rate of edema seen with axillary dissection.
SLNB has only been in practice for "about 10 years," and so not all surgeons know how to perform it. Thus, there might be limited access in some part of the United States, he told the audience while listing the "cons" associated with this new staging directive.
Dr. Carlson warned that some surgeons might feel forced to do SLNB, "despite lack of skill," because it is now the standard. "This could promote adoption by providers with limited opportunity to apply sentinel lymph node biopsy," he cautioned.
There was one other axillary lymph-node-related change to the breast cancer guideline.
A complete axillary dissection should not be performed in women with "apparent pure" ductal carcinoma in situ (DCIS), and thus an absence of invasive cancer or proven metastatic disease.
However, as Dr. Carlson noted, a small proportion of patients will be found to have invasive cancer at the time of their definitive surgical procedure.
"Therefore, the performance of a [sentinel lymph node] procedure may be considered if the patient with apparent pure DCIS is to be treated with mastectomy or with excision in an anatomic location compromising the performance of a future sentinel lymph node procedure," according to the guideline.
No Longer Silent About PET/CT
Previous NCCN breast cancer guidelines were "silent" about positron emission tomography (PET)/computed tomography (CT), said Dr. Carlson. But not any longer, because Dr. Carlson and his colleagues felt compelled to make a number of recommendations about the imaging technology in the current update.
"PET/CT is overused in breast cancer," opined Dr. Carlson, providing an overview of the recommendations for reporters.
PET/CT should not be used at all in early breast cancer, he said.
The use of PET or the combined PET/CT is not indicated in the staging of clinical stage I, II, or operable stage III breast cancer, according to a footnote added to the invasive breast cancer workup section.
The reasons for the exclusion include one of the "major problems" with PET/CT, said Dr. Carlson. "There is a remarkably high frequency of false positives" with the technology, he explained.
Dr. Carlson cited a breast cancer staging study from the University of Kansas as part of the evidence. Fifteen of the 83 women in the retrospective study had a "suspicious" FDG-PET/CT. Of those 15 women, 2 (13%) had confirmed metastatic disease, but the other 13 (87%) had false-positive scans.
Dr. Carlson also cited a set of studies that indicated that PET/CT was "not sensitive" in detecting nodal disease in early breast cancer. "The sensitivity is very poor," he said, referring to 5 studies in which the sensitivity of the technology was as low as 20% and no higher than 61% in research that used SLNB as the comparator, mostly.
However, PET/CT does have a role to play in locally advance disease.
It is cited as an "additional study" to bone scan and CT scan in the optional workup section of the guideline for locally advanced (stage III) disease.
"FDG-PET/CT is most helpful where standard staging studies are equivocal or suspicious, especially in locally advanced or metastatic disease" said Dr. Carlson, reading aloud the guideline. In various studies, the technology has identified distant metastases in 10% to 21% of patients, and might be able to identify extra-axial nodes, he said.
Even when PET or PET/CT scanning is encouraged in the case of metastatic disease with equivocal or suspicious standard staging results, the guideline is not enthusiastic. "Even in these situations, biopsy of equivocal or suspicious sites is more likely to provide useful information," it states.
"A positive result on a PET is just as likely to mislead you as help you," said Dr. Carlson, in reference to staging recurrent/metastatic disease when other results were equivocal/suspicious.
Joan S. McClure, MS, senior vice president of clinical information and publications for the NCCN, agreed with Dr. Carlson's summary assessment of PET/CT. "Overall, it's been used excessively," she told Medscape Oncology in an interview.
Dr. Carlson said that PET/CT has benefited from being a "new technology."
"Everybody likes to do the new thing," Dr. Carlson said. It is also simple to order, provides financial rewards for clinicians who order it, and is irrationally overvalued because of its "high price tag," he added.
Another Change for Genetic Counseling
Last year at NCCN, genetic counseling was highlighted after being added to the optional additional studies section for breast cancer patients who are found to be, with genetic testing, at high risk for hereditary breast cancer.
This year, the NCCN has bumped counseling up the ladder of importance.
Now, counseling is part of the general workup and has been added to all the workup sections, from DCIS onward. "We want to make sure people do it," explained Dr. Carlson.
National Comprehensive Cancer Network (NCCN) 15th Annual Conference. Presented March 11, 2010
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