Breast Cancer Screening Information for Radiologists

Healthcare Professionals - Radiologist

Breast Surgeons and Oncologist Ob/Gyn or Primary Care Provider
Radiologist Pathologists
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    • 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 physiciansidentify 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.

NAF Cytology Enables Early Detection of Cancerous Growth at the Pre-Invasive Stage

    • 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.
  • Clinical Data Supporting HALO
    • HALO has been FDA cleared for the collection of nipple aspirate fluid for cytological evaluation for the determination and/or differentiation of normal versus pre-malignant versus malignant cells.
    • Wrensch and Petrakis published their seminal work in 1992 and found that women with atypia in NAF were 4.9x relative risk of developing breast cancer compared to women who did not produce NAF.  They manually collected NAF from 2,706 women who were then followed for an average of 12.7 years.   They found that age makes a difference and the greatest relative risk was in women 25 to 54.1
    • Three other studies found similar relative risks (RR) for women with atypia discovered through biopsy or FNA:
      • DuPont & Page (JCNI 1985) found 5.3x RR with biopsy-proven atypia in 3,303 women followed for an average of 17 years.2
      • Fabian (JCNI 2000) found 5x RR with atypia discovered by FNA in 480 women followed for 4 years.3
      • Hartmann (NEJM 2005) found 4.2x RR with biopsy-proven atypia in 9,087 women followed an average of 15 years.  Women under 45 had a 6.99x RR.4

Cytologic Assessment-Clinically Validated

    • Two other recent studies looked at risk associated with the presence of epithelial cells in NAF regardless of whether the cells were normal or atypical.
      • Buehring (Epidemiology 2006) found 1.92x RR in 972 women followed for 25 years.5
      • Baltzell (Biomed Central 2008) found a 1.9x RR in 946 women followed for 20.7 years.6
    • Our HALO clinical study (Proctor  BMC Women’s Health 2005) proved that results from NAF collected via HALO are stratified equivalently to NAF collected manually (i.e. we have the same percentage of non-yielders, acellular samples, atypia, etc.).7
  • Differences between Nipple Aspiration and Ductal Lavage
    • Ductal Lavage (DL) uses small catheters inserted inside the ducts to flush with saline and collect ductal epithelial cells, a complicated and poorly tolerated procedure. DL’s FDA approval limits its use women already known to be at high risk. Therefore, the 50 to 70 percent of women who display no risk factors – the very group risk assessment seeks to help – are excluded from this procedure. DL was forced into more of a diagnostic role than cytology is capable of playing.  Cytology is a proven risk stratifier but is a poor diagnostic for breast cancer.
    • DL requires a specialized training program to perform the procedure, as well as a laboratory certificate program to evaluate and report results. Unlike DL, cytological interpretation of HALO samples doesn’t require precise differentiation between grades of atypia.  HALO cytology is a simple binary evaluation for the presence or absence of atypia. Since HALO results are used only for risk stratification rather than pathologic diagnosis, the subtle differences in degree of atypia are much less important.
  • Atypia’s Role in Choosing Imaging Modality
    • Atypia alone doesn’t tell us which imaging modality is most appropriate for a particular patient, but it is a very influential factor given that it confers 4 to 5x relative risk for developing breast cancer.  These women need a comprehensive risk assessment, usually by a breast specialist.  If a woman has atypia but no other significant risk factors, she might be upgraded to a diagnostic mammogram or ultrasound, and simply be monitored more frequently.  However, atypia plus nearly any other significant risk factor will elevate a woman above a 20 to 25% lifetime risk, at which point the American Cancer Society Guidelines suggest MRI. 
    • Some Radiologists feel pressured to find abnormalities with imaging if the patient has atypia. But it’s important to remember that NAF abnormalities are at the cellular level; suspicious findings on follow up imaging are a possibility but should not be expected.
  • Care Path for Women with Atypia
    • Women at very high risk are typically referred for enhanced imaging, will be counseled on risk reduction options including lifestyle changes and chemoprevention, and will undergo increased surveillance. Biopsies or surgical options should not be pursued unless follow up diagnostics reveal suspicious findings.
  • 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.

  • Helpful Links


1  Wrensch MR, Petrakis NL, et al. Breast cancer incidence in women with abnormal cytology in nipple aspirates of breast fluid.  Am J Epidemiol 1992;135(2):130-41.
2  Dupont WD, Page DL.  Risk factors for breast cancer in women with proliferative breast disease.  NEJM 1985;312(3):146-151
3  Fabian CJ, Kimler BF.  Short-term breast cancer prediction by random periareolar fine-needle aspiration cytology and the Gail Risk Model.  JNCI 2000; 92(15):1217-1227
4  Hartmann LC,  Sellers TA,  Frost  MA, et al.  Benign Breast Disease and the Risk of Breast Cancer. NEJM 2005;353(3):229-237  
5  Buehring GC, et al. Presence of epithelial cells in nipple aspirate fluid is associated with subsequent breast cancer: a 25-year prospective study. Breast CA Res & Treat 2006; 98:63-70
6  Baltzell KA, et al. Epithelial cells in nipple aspirate fluid and subsequent breast cancer
risk: A historic prospective study.
 BMC Cancer 2008, 8:75 doi:10.1186/1471-2407-8-75
7  Proctor KAS, Rowe LR, Bentz JS.  Cytologic features of nipple aspirate fluid using an automated non-invasive collection device:  a prospective observational study.  BMC Women’s Health 2005;5:10.


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