Healthcare Professionals - Pathologists
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Click here to download the HALO NAF Cytology Laboratory Training Program (pdf file).
- Putting HALO into context
- HALO is a risk assessment tool, not a diagnostic, and there is an important distinction between the two. HALO is not intended to screen for the presence or absence of breast cancer as a diagnostic would; it is a tool to help find women who are at high risk for developing breast cancer in the future. HALO is an adjunct to, not a replacement for routine mammograms and breast exams.
- HALO is an innovative office-based system that helps primary care doctors assess their patients’ risk of developing breast cancer. It is a 5-minute, noninvasive method of collecting Nipple Aspirate Fluid (NAF) to be cytologically evaluated for atypia, which confers a 4 to 5X relative risk of developing breast cancer. Atypia will be found in only 1% of an asymptomatic, normal risk population. These few high risk women are typically referred to breast specialists for a complete risk assessment and any necessary follow up care.
- Why wait for a lump?
- Today between 50 and 70% of women who develop breast cancer have no warning signs prior to being diagnosed. HALO is an innovative but simple tool to help primary care physicians identify high risk women from an asymptomatic, normal risk population. These are women who otherwise go unnoticed unless or until they develop a lesion several years down the road. We believe that knowing who is at high risk and getting them into the hands of specialists in the precancerous stage has the potential to impact deaths from breast cancer significantly.
- Who should be tested with HALO?
- HALO is recommended for all non-lactating women 25 and older as part of an annual checkup. It is most useful in asymptomatic premenopausal women, many of whom are too young for effective mammograms or breast exams. Studies have shown that Nipple Aspirate Fluid (NAF) production tends to decrease after 55, so the test becomes less valuable as a woman ages. Fortunately, mammograms become more effective with age.
- Controversies in terminology
- Why do we call it a Breast Pap Test?
- We realize this raises concerns among some specialists, but there are more parallels between HALO and the cervical Pap than there are differences. Both concepts were discovered by Dr. Papanicolaou back in the 1950s, both look for precancerous changes in the epithelial lining of the cervix or breast ducts, and both assess risk of future cancer. We admit that there is no scientific evidence yet of the progression of breast ductal epithelium from normal to abnormal to malignant, but this is generally believed to be true. This same cervical progression was only proven after adoption of the cervical Pap.
- There is an important difference in the sampling between the two tests. The cervical Pap is a direct scraping of the target tissue, whereas HALO depends on exfoliation of cells from a vastly branching ductal system. Thus with HALO we act on the positives and draw limited conclusions (i.e. “normal risk”) from the negatives.
- Why do we call HALO a Screening test?
- We are screening for women at high risk for developing breast cancer rather than screening for the disease itself, just like a cholesterol screen looks for people at risk for cardiovascular disease.
- HALO Specimen Collection, Transport and Processing
- NAF specimens are collected will a custom, non-cell binding swab which is placed in non-gyn Liquid Based Cytology (LBC) fixative, such as Cytolyt® or CytoRich® Red. Use of gyn fixatives, such as PreservCyt ®, will not adversely affect the specimen, but its use is restricted (by FDA) to gyn applications.
- The custom swab has a polystyrene handle and a polyurethane foam tip. It should be vigorously swirled in the fixative and discarded before processing.
- Typical specimens are only 10 to 50 microliters with very scant cellularity so a concentration step is required to optimize slide cellularity.
- Following concentration, the specimens are processed following FNA processing instructions.
- Evaluating Slides
- Cytological assessment of epithelial changes, whether cervical or NAF, is inexact with some inevitable shades of grey. However, HALO specimens with cytological findings of acellular, normal epithelium or hyperplasia are considered “normal” and typically do not result in further clinical action. Findings of atypia, suspicious cells or malignant cells are considered “abnormal” and are not as challenging to differentiate. Only findings of abnormal cells are associated with significant increase in breast cancer risk, which simplifies the interpretation process. NAF is a protein rich material, and is usually hypocellular in normal, asymptomatic patients. Types of cells found in NAF might include: macrophages (foam cells), squamous cells (nipple contaminate), ductal epithelial cells, and occasionally blood and inflammatory cells.
- Sample adequacy statements are not necessary since recent guidelines from the College of American Pathologists (Crothers BA et al – APLM in press) state that adequacy statements aren’t required for many non-gynecological cytology specimens as many of these specimens are normally hypocellular. Many women do not produce fluid, and are labeled “non-yielders.” Those who do produce NAF commonly have an acellular specimen. This is a normal result indicating the woman’s risk is only slightly higher than someone who does not produce fluid. Neither of these situations should be considered “inadequate” or “non-diagnostic”.
- Click here to see annotated slide examples.
- Reporting results
- Since HALO is used for risk assessment rather than pathologic diagnosis, using general reporting categories to indicate benign, atypical, or suspicious can quickly and unambiguously communicate results. The following table describes reporting categories used for NAF results.
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