Primary Care Guide to Managing a Breast Mass: Step-by-Step Workup

Janet Rose Osuch, MD, Vence L. Bonham, JD, Laura L. Morris, MD

Mammography and Other Radiologic Procedures: Appropriate Use and Interpretation

Routine mammography is generally not recommended in women younger than 30 years of age unless dictated by family history ( Table II ). This is because mammography is less likely to demonstrate occult lesions in young women, who tend to have dense breast tissue; further, radiation-exposure risks are higher in this age group than in older women.^[22] Consequently, the benefits of mammography do not outweigh the risks in younger women unless the mass is clinically suspicious.

A mammogram should be performed in any woman older than age 30 in whom a palpable breast lump or thickening has been found. Although a mammogram cannot be used to distinguish whether a mass is cystic or solid, it is helpful in evaluating the breast tissue in the uninvolved portions of the breast and in the other breast.

Mammography can also help in characterizing the mass -- if it can be seen on the film. However, the false-negative rate of mammography ranges between 10% and 22%.^[23,24,25] This rate can be as high as 30% to 35% in younger women^[25] and is one of the most common clinical pitfalls cited by women who file a malpractice suit against a physician for failure to diagnose breast cancer. A false-negative result is usually due to dense breast tissue (Fig. 8).^[1]

(Enlarge Image)

Mammogram demonstrating small infiltrating ductal carcinoma (note arrow). Film would have been interpreted as normal had density representing carcinoma been located nearer nipple, where breast tissue is dense. Reprinted with permission from Breast Imaging: A Guide for Clinicians, Slide Lecture Program: Slide 19, American College of Radiology Task Force on Breast Cancer.^[27]

Dense breast tissue can be seen in premenopausal women, in postmenopausal women on HRT, and in some postmenopausal women who are not on HRT. For this reason, any palpable abnormality needs further workup, despite a normal mammogram.

After pregnancy, screening mammography is not recommended until a woman resumes menses. Diagnostic mammography can be done in lactating women, but the risk of a false negative may be higher than in women not lactating because of increased tissue density. However, the data do not definitely support this clinical recommendation. We, along with many others, question the clinical usefulness of this approach, except for women who have breast pain in luteal phase of their cycle. Cornelia Baines and her team^[26] reported that mammograms taken during the luteal phase were twice as likely to be read as false-negative as were those taken during the follicular phase of the menstrual cycle (days 1 to 14).

Mammograms can be used to identify mass lesions, asymmetries, and microcalcifications. Radiologists often use the BI-RADS system developed by the American College of Radiology^[27] to categorize mammograms, in addition to a narrative description of the characteristics of the image. The BI-RADS system assigns a mammogram to one of 5 categories:

Category I = Normal.

Category II = Benign-appearing abnormality.

Category III = Probably benign/possibly malignant.

Category IV = Suspicious for malignancy.

Category V = Malignant until proven otherwise.

If a mammogram is abnormal, it is critically important for the radiologist to be able to compare current findings with previous films. In addition, the radiologist often recommends additional mammographic views and/or ultrasound to further characterize the abnormality.

Cone compression is used to compress breast tissue selectively over the area where the mammographic abnormality is identified. This can differentiate superimposed breast tissue from a true abnormality. In palpable masses containing microcalcifications, magnification views may further characterize the lesion(s).

To distinguish cystic from solid masses, high-frequency ultrasound performed with a linear array transducer may be useful. A cyst appears round or oval with smooth walls and a dark or anechoic center (Fig. 9). In contrast, a solid mass will be echoic, that is, reflect the ultrasound waves. An ultrasound examination, however, may fail to visualize a palpable abnormality. As is the case with mammography, radiologists depend on tissue contrast to interpret films. If a lesion is isodense with surrounding tissue, it is not imaged by ultrasound, and a false-negative reading results. Therefore, any palpable abnormality warrants further evaluation, even with a normal ultrasound.

(Enlarge Image)

Breast cyst demonstrated by mammography and ultrasound. Generally, mammogram does not characterize whether mass is cystic or solid. By ultrasound, cyst appears round or oval with smooth walls and dark or anechoic center. Reprinted with permission from Love N: Primary Care Considerations in Breast Diagnosis, Slide Lecture Program: Slide 41, Copyright © 1992, American Cancer Society, Tampa, Florida Division, Inc.^[6]

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Cite this: Primary Care Guide to Managing a Breast Mass: Step-by-Step Workup - Medscape - Sep 01, 1999.

Abstract and Introduction
Epidemiology: Who Is at Risk for Breast Cancer?
What Is the Proportion of Benign Versus Malignant Breast Masses at Each Age?
The Workup: What to Ask When Taking the History
Clinical Breast Examination: Impact of Normal Breast Changes
Mammography and Other Radiologic Procedures: Appropriate Use and Interpretation
Cystic or Solid? The Role of FNA and FNAB
Management of an Unconfirmed Patient-Perceived Mass
Management of a Palpable Breast Mass
Management of a Palpable Cyst
Management of a Palpable Solid Mass
Triple Diagnosis for Management of the Solid Breast Mass
A Technique for Clinical Breast Examination
References
Sidebar: Risk Factor Interpretation

Table 1. Systematic Approach to Breast Mass Workup
Location
Ask the woman to point to the area of concern with 1 finger. Document this area on the physical examination record pictorially with an "X."
Method of Discovery
Establish how familiar the woman is with her own breast examination. How often does the woman perform breast self-examination (BSE)? Did she discover the lump during BSE or by accident? Was the lump found when the patient was in the supine position, standing in the shower, or in a different position? The evaluation may be very different if a patient rarely performs BSE and is not sure that a mass is present compared with a patient who performs BSE regularly and feels a difference on her examination compared with baseline.
Size
How big is the lump currently? Liken the size to familiar items, such as a pea, a grape, or a walnut.
Duration
When was the lump first found? Has it changed since first date of discovery?
Hormonal Influences
What is the woman's ovulatory status? When was her last menstrual period? Is she premenopausal? If so, does the mass change depend on the phase of her ovulatory cycle? Is she on hormone replacement therapy? If so, what are the drug names and dosages?
Tenderness
Is the mass tender? If the patient is premenopausal, does the tenderness change with the ovulatory cycle?

Table 2. Screening Guidelines for Women in Different Risk Categories
Risk Category	Lifetime Risk (%)	Clinical Breast Examination Schedule	Mammogram Schedule
No risk factors	11-12	Annual after age 30	1-2 years after age 40-49 Annual at and after age 50
Weak family history (2 or fewer second-degree or more distant relatives with postmenopausal breast cancer)	15-20	Annual after age 30	Annual after age 40
Strong family history (any first-degree relative with breast cancer, 3 or more relatives with breast cancer, or any second-degree relative with breast cancer before age 40)	Greater than 20	Annual after age 25; Twice yearly after age 30	Annual after age 35 or 5 years younger than youngest affected relative, whichever comes first
Carrier of known breast cancer susceptibility gene	20-85	Twice yearly after age 25	Annual after age 25
Identifiable breast cancer syndrome	20-85	Twice yearly after age 25	Annual after age 25
Very strong family history (2 or more first-degree relatives with breast or ovarian cancer, 1 or more first-degree relatives with breast cancer before age 40, or any first-degree relative with premenopausal breast)	20-85	Twice yearly after age 25	Annual after age 25
Atypical hyperplasia with a negative family history	15-20	Annual after diagnosis	Annual after diagnosis
Atypical hyperplasia with a positive family history	Greater than 20	Twice yearly	Annual after diagnosis
Lobular carcinoma in situ	20-30	Twice yearly	Annual after diagnosis

Table 2. Screening Guidelines for Women in Different Risk Categories
Risk Category	Lifetime Risk (%)	Clinical Breast Examination Schedule	Mammogram Schedule
No risk factors	11-12	Annual after age 30	1-2 years after age 40-49 Annual at and after age 50
Weak family history (2 or fewer second-degree or more distant relatives with postmenopausal breast cancer)	15-20	Annual after age 30	Annual after age 40
Strong family history (any first-degree relative with breast cancer, 3 or more relatives with breast cancer, or any second-degree relative with breast cancer before age 40)	Greater than 20	Annual after age 25; Twice yearly after age 30	Annual after age 35 or 5 years younger than youngest affected relative, whichever comes first
Carrier of known breast cancer susceptibility gene	20-85	Twice yearly after age 25	Annual after age 25
Identifiable breast cancer syndrome	20-85	Twice yearly after age 25	Annual after age 25
Very strong family history (2 or more first-degree relatives with breast or ovarian cancer, 1 or more first-degree relatives with breast cancer before age 40, or any first-degree relative with premenopausal breast)	20-85	Twice yearly after age 25	Annual after age 25
Atypical hyperplasia with a negative family history	15-20	Annual after diagnosis	Annual after diagnosis
Atypical hyperplasia with a positive family history	Greater than 20	Twice yearly	Annual after diagnosis
Lobular carcinoma in situ	20-30	Twice yearly	Annual after diagnosis

Sidebar: Risk Factor Interpretation

A risk factor represents an association and does not necessarily infer a cause-and-effect relationship. Its presence does not guarantee the development of a disease, nor does its absence confer absolute protection. However, risk factors are important to consider when assessing an individual woman. The 4 terms most important to consider are odds ratio, relative risk, confidence interval, and absolute risk.

The odds ratio is a risk calculation based on retrospective studies, representing expression of the chance of having a disease in a population with a given characteristic, as compared with a population without the characteristic.

When studied prospectively, the odds ratio is expressed as relative risk.^[1] In other words, relative risk (RR) is a ratio of an outcome disease in a group exposed to a risk compared with the outcome in a group not exposed to a risk.
For both odds ratio and RR, an expression of 1.0 represents the baseline risk of disease in the population without the characteristic.
Any number less than 1.0 in the study group represents a lack of association, whereas any number over 1.0 represents an association of the trait with the disease.

The statistical expression of significance for odds ratio or RR is the confidence interval.
If a range of numbers overlaps 1.0, the trait in question has not achieved significance.

An RR of 2.0 means that a person who possesses the characteristic is twice as likely to get the disease over a given number of years as is someone without the characteristic. This also can be expressed as conferring a 100% increase in risk: A patient with an RR of 2.0 is 100% more likely to get the disease than someone without the characteristic, who has an RR of 1.0.

A 100% increase in risk can be very startling, but what does this number really mean? To answer this question, consider the following example in a population of 500 people age 50 to 60 studied over 10 years:

Variable X	Cases Breast Cancer	Relative Risk and Confidence Intervals *
Absent	20	1.0
Present	40	2.0 (1.14-1.54)

* Of the people with variable X, 40 of a total population of 500 developed breast cancer (RR of 2.0) compared with people without variable X, in which 20 of a total population of 500 developed the disease (RR = 1.0). This illustrates the reality of an expression of "a 100% increase in risk" for the clinician. Notice in this example that the confidence interval is above 1.0 and is relatively narrow, adding validity to the interpretation.

Absolute risk (AR) is the actual number of people, exposed and unexposed to the risk, who acquired the disease.
AR represents the chance of developing a disease over a given time interval. For breast cancer, the best known statistic is the 12.5% (or 1 in 8) risk over a lifetime.

Vogel VG: Assessing women's potential risk of developing breast cancer. Oncology 10:1451-1458, 1996.

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Primary Care Guide to Managing a Breast Mass: Step-by-Step Workup

Mammography and Other Radiologic Procedures: Appropriate Use and Interpretation

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References

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Authors and Disclosures

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Sidebar: Risk Factor Interpretation

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