Mammogram Reports: Section 2.c.

CONTENTS:

2.8 Quality Control and Radiology Reporting
2.8.1 The Mammography Report and Clinical Decision-Making
i. A Negative Mammography Report
ii. A Positive Mammography Report or an Abnormal Mammogram
2.8.2 The Breast Imaging Reporting and Data System (BI-RADS)
2.8.3 The Structure of the Mammography Report
2.8.4 Double Reading of Mammograms
2.8.5 Computer Aided Detection (CAD)

What did the bra say to the hat? You go on a head and I’ll give these two a lift.

2.9 Breast Magnetic Resonance Imaging (MRI)
2.9.1 Breast MRI in Screening
2.9.2 Specific Roles for Breast MRI
2.9.3 MRI-Guided Breast Biopsy
2.10 Abnormal Mammogram: I. The ‘Spiculated’ Soft Tissue Mass
2.11 Abnormal Mammogram: II. Breast Micro-Calcifications
2.11.1 Clustered micro-calcifications
2.11.2 Linear, branching micro-calcifications
2.11.3 ‘Benign’ breast calcifications
2.12 Abnormal Mammogram: III Intra-Mammary Lymph Nodes

Forward to 2D on biopsies. Back to 2B on mammography.

2.8 Quality Control and Radiology Reporting

Analysis and reporting of breast images iare done by a medically qualified and specialist trained Radiologist or a physician trained in Nuclear Medicine. For Radiologists who specialize in breast screening, there are a number of reporting guidelines and standards that are implemented to ensure patient safety and reassurance.

Like quality control then?

Yes, Exactly that.

My definition of quality means always doing it right, even when no one is looking.

2.8.1 The Mammography Report and Clinical Decision-Making

For patients, the most important aspect of the mammography report is whether it is positive or negative.

For the patient’s clinician, the details of a positive report will begin a well-tested clinical diagnostic pathway that will lead to the best management for each individual patient.

When life gives you lemons, bite them and make a funny face.

i. A Negative Mammography Report:

A negative mammogram should not prevent any further intervention if there is clinical suspicion for malignancy.

The false-negative rate of screening mammography has been reported between 10 % to 30 %, with a false-negative rate being highest in women with markedly dense breast tissue.

How can you tell then if the breasts are dense or rather clever?

Oh Moose! You’re too cute.

Breasts are considered dense if they have a lot of fibrous or glandular tissue but not much fatty tissue.

Up to 15 % of cancers detected on clinical breast examination are not visible even on diagnostic mammography.

The addition of ultrasound decreases the false negative rate, but still does not exclude the presence of breast cancer.

The final disposition of a palpable abnormality rests with the clinician in the presence of a negative imaging evaluation as the chance of malignancy ranges between 0 % and 3%.

Why would you be able to feel a breast lump but it not show up on mammogram?

Some women have lumps formed by normal breast tissue called ‘pseudo-lumps’ and breasts can get more lumpy with hormonal changes too.

This is why it is so important to know how your own breasts feel throughout the whole month, then you will notice any unusual lumps and bumps.

ii. A Positive Mammography Report or an Abnormal Mammogram:

All reports with BIRADS 0, 4 or 5 require further intervention. In most clinical centers, the clinician will be contacted and informed of the need for biopsy, and the clinician and the patient are contacted and informed of the need for further imaging.

A BI-RADS designation of 4c or 5 alerts the Pathologist that a malignant diagnosis is strongly suspected; this means that a further evaluation (and possible re-biopsy) is required if the biopsy is initially interpreted as ‘benign.’

2.8.2 The Breast Imaging Reporting and Data System (BI-RADS)

In 1987, the American College of Radiology developed a mammographic accreditation program. The Mammography Quality Standards Act (MQSA) was passed in 1992 by the U.S. Congress. The MQSA has established guidelines for implementing quality control for individual imaging centers. MQSA mandates that all U.S. imaging and screening facilities should be accredited by the American College of Radiology (Kivel, 2994).

The Breast Imaging Reporting and Data System (BI-RADS), was developed by the American College of Radiology to standardize the mammography report. BI-RADS was initially developed for use in mammography but has now been extended to include breast ultrasound and magnetic resonance imaging (MRI) interpretation.

Remember there are two words in life that will open doors for you. ‘Push’ and ‘Pull’.

The BI-RADS imaging manual consists of standardized language that describes the radiological findings and conclusions. One of the seven final assessments categories is used at the conclusion of each report. The final diagnostic assessment categories also indicate the relative likelihood for a normal, benign, or malignant diagnosis based solely on the imaging findings.

The FDA now mandates that all mammography reports include a final BI-RADS assessment category.

The use of BI-RADS results in standardized reporting helps guide decision making and also serves as a useful tool in collecting data and in auditing individual practices.

Figure 2.7 BI-RADS.

From: Breast Imaging Reporting and Data System
(BI-RADS) Atlas, 4^th ed, American College of Radiology,
Reston, VA 2003.

I have more detail on birads, here.

2.8.3 The Structure of the Mammography Report

The organization of the mammography report and the language used to describe abnormalities are based on the BI-RADS manual.

The mammography report contains the following elements:

Indication: The main indication for type of examination (screening versus diagnostic) is stated. Any previous examinations used for comparison are mentioned at the beginning of the report.

Breast density: All reports have a statement regarding the breast density. Radiologists now use the four categories described in the BI-RADS atlas; these are based on the proportion of glandular (radiodense) tissue compared to fatty (radiolucent) tissue.

The four main density categories are:

Predominantly fatty (0 to 25 % dense)
Scattered fibro-glandular densities (25 % to 50 % dense)
Heterogeneously dense (51 % to 75 % dense), and
Dense (greater than 75 %)

I don’t think I’d like the ‘predominantly fat’ result, it’s a bit rude.

No Moose, it’s ‘predominantly fatty and it’s referring to the breast tissue’.

…and that’s better, how?

Description of Abnormal Mammogram: The main body of the report includes the location and description of any abnormality using standard BI-RADS descriptors. The location of any lesion is given, with reference to a quadrant or ‘clock position,’ and the depth within the breast.

The breast is arbitrarily divided into anterior, middle and posterior depth.

Each breast is divided into four quadrants: upper-outer, upper-inner, lower-outer and lower-inner. The location can also be indicated using the breast as a clock with nipple in the center.

Well, that gives a whole new meaning to ‘keeping a breast of time’!

Summary: The mammography report concludes with a summary that gives most important findings and the final BIRADS assessment category.

2.8.4 Double Reading of Mammograms

Double reading of screening mammograms involves two Radiologists reviewing every screening mammogram, in order to increase the rate of breast cancer detection.

Double reading is standard practice in many European countries, including the U.K., but not in the United States.

The mammographic examination can be interpreted by the two radiologists either independently or interpreted together in consensus. If Radiologists differ in their interpretation of a mammogram, there are a variety of institutional protocols on how this is adjudicated. Patients may be called back for follow-up studies if either reader identifies an abnormality (highest reader recall).

It’s not a bad job, radiology, is it? Just sitting around discussing ‘Fifty Shades of Grey’.

Clever!

Several studies have demonstrated benefit for double reading, but no randomized controlled trials have not been performed to evaluate the impact of double reading on long-term outcomes.

Double reading increases radiologist time and therefore the cost per examination, and there may also be a delay before the final interpretation can be made.

Looks like there could be some interesting trials on the benefits of double reading.

Yes, and also on the pros and cons of Computer Aided Detection (CAD).

Hello, Radiology Students? Dissertations.

2.8.5 Computer Aided Detection (CAD)

Computer aided detection (CAD) refers to computer-based technology that is designed to recognize mammographic patterns and help radiologists identify suspicious areas (Chan et al., 1987).

CAD reading of digitalized or digital mammograms adds marks to areas of concern, which are most often calcifications, masses, or asymmetries. These marks are then for special attention in the review by a Radiologist.

CAD increases the detection of breast ductal carcinoma in situ (DCIS) as CAD software has increased sensitivity to detect micro-calcifications.

The US Food and Drug Administration (FDA) approved CAD in 1998 after several studies showed the usefulness of CAD in increasing cancer detection. Its use among Medicare patients has increased rapidly, from 3.6 % of mammographic breast examinations in 2001 to nearly 75 % of studies performed in 2008 (Rao et al., 2010).

CAD may improve the sensitivity of mammographic screening, but this may be offset by a higher recall rate and the potential for over diagnosis. CAD has not been proven to reduce mortality rates from breast cancer screening, and the costs associated with the equipment and increased recall rate with CAD may outweigh possible marginal benefits. No randomized trials have been performed to determine the effect of CAD reporting on breast cancer mortality.

2.9 Breast Magnetic Resonance Imaging (MRI)

MRI is not used in routine mammographic screening, but may be used to further assess an abnormality detected on screening or to get a better view of the breast.

What exactly is an MRI?

MRI scans use magnets and radio waves instead of x-rays to produce very detailed, cross-sectional images of the body.

Magnets, I find them very attractive, you know.

2.9.1 Breast MRI in Screening

Magnetic resonance imaging (MRI) has two roles, firstly in the assessment of dense breast tissue and secondly in tumor-staging, particularly if a multi-focal cancer is detected.

Breast MRI is not used as part of the initial screening process but may be helpful when a mammographic abnormality has been detected as part of the initial assessment.

2.9.2 Specific Roles for Breast MRI

A limitation of mammography is in the assessment of disease extent or borders due to overlying dense breast tissue.

Contrast-enhanced breast magnetic resonance imaging (MRI) can complement mammographic assessment and tumor staging.

The challenge for imaging in the staging of any breast cancer that is identified to be multi-focal is that most staging classifications (such as TNM) require that the largest tumor mass is assessed for T-staging. Other staging classification systems have shown that the total tumor volume, tumor surface area or aggregate measurements are a better indicator of prognosis (Coombs & Boyage, 2005).

Invasive breast cancers that are adjacent to or are invading the chest wall may not be completely visualized in mammographic projections. MRI may be necessary to assess tumor extension as if this is present, it that will determine surgical approach or therapy.

In patients with known breast cancer, MRI has increased sensitivity (DeMartini & Lehman, 2008).

Figure 2.8

Breast magnetic resonance imaging (MRI)
used here to image the extent of infiltrating
breast carcinoma shows tumor (white)
spreading along breast ducts. MRI has
high sensitivity but low specificity.

The tumor on that MRI is very clear to see, even for me.

Yes, that’s quite a large one which has spread along the breast ducts.

The following benefits for breast imaging using MRI have been given:

Improved selection of patients for breast conservation surgery;
Decreased number of surgical procedures needed to obtain clear margins;
The synchronous detection of contralateral cancers (DeMartini & Lehman, 2008).

What on earth is the synchronous detection of contralateral cancers?

Yes, I’m a bit baffled by that too.

It’s simply means finding another tumor in the opposite breast at the same time, on the MRI scan.

The use of MRI for a Breast Cancer Diagnosis

For women who are newly-diagnosed with breast cancer, MRI may be considered for the following patient groups (DiMartini & Lehman, 2008):

For patients with axillary nodal metastases but with a clinically unknown or ‘occult’ primary breast tumor.
For patients whose tumor is clinically more extensive than is appreciated by mammography, particularly in the setting of dense breasts.
For patients who have posterior tumor extension, pectoralis fascia or muscle involvement and who require assessment to determine the surgical approach or the use of neo-adjuvant therapy.
For women who have nipple involvement with Paget’s disease of the breast but who have a negative mammogram or physical examination.
In women who are being considered for neo-adjuvant systemic therapy as they have locally advanced breast cancer.
For women who are at high risk for contralateral breast disease (due to an inherited susceptibility or previous chest wall irradiation).

Pssst! I’m back. Did I miss anything? Just popped off to check my Facebook account

Please try and pay attention Jess, this stuff is really good.

When do you think Facebook will develop an ‘eye roll’ button? I’d use that a lot!

Studies regarding MRI and Outcome for Breast Cancer Patients

However, as yet there is no data from prospective randomized trials that demonstrate improved patient outcomes from the use of breast MRI to the evaluation of newly-diagnosed breast cancer.

A criticism of the use of breast MRI is its limited specificity. Breast MRI has been reported to increase the number of unnecessary breast biopsies and so may delay definitive diagnosis and treatment, and may increase the number of patients undergoing mastectomy.

In conclusion, at the present time, MRI is not recommended routinely as part of the evaluation of breast cancer for most women.

So thankful to Facebook, otherwise I would have to show 362 people a photo of the waffles I just ate for breakfast!

2.9.3 MRI-Guided Breast Biopsy

Patients with non-palpable, mammographically ‘occult’ breast lesions may have lesions that are detectable by MRI.

A proportion can be identified in on subsequent, targeted or ‘second-look ultrasound, but for the remaining lesions, targeting for biopsy requires MRI guidance.

MRI-guided interventions will not be available at all hospitals, and they can be more time-consuming and expensive than other biopsy methods.

But MRI does not allow real-time monitoring of needle biopsy. The MRI table brings the patient out of the machine for needle placement, then sends the patient back into the machine for imaging to verify needle placement at each step of the biopsy process. On average, an MRI biopsy can be expected to last from 30 minutes to an hour.

In most institutions, MRI-guided core needle biopsy (CNB) has been replaced by MRI-guided vacuum-assisted biopsy (VAB).

MRI-guided wire localization and surgical excision may be indicated if a suspicious lesion is not accessible to MRI-guided VAB or if the core biopsy results are discordant with the imaging findings.

2.10 Abnormal Mammogram: I. The ‘Spiculated’ Soft Tissue Mass

Two kinds of mammographic findings are suggestive of a breast cancer: soft tissue masses and micro-calcifications.

A description of a ‘spiculated soft tissue mass’ is the most specific mammographic feature of breast cancer with almost nearly 90% of these lesions representing invasive breast cancer (from Stomper, 2000).

In approximate terms, for all diagnosed breast cancers:

30% of non-calcified breast cancers appear as ‘spiculated masses’:
25 % appear as masses with an ‘irregular outline’;
25 % appear as round, oval or lobulated masses;
< 10 % appear as well-defined round, oval, or lobulated masses, and
5 % appear as areas of architectural distortion or dense tissue without a border or capsule.

The likelihood of malignancy of a well-defined solid mass seen on ultrasound with benign imaging features is between 0 and 7 %. In these cases, biopsy or short-term (three to six months) follow-up is considered appropriate management.

I don’t even know what the word ‘spiculated’ means.

Spiculated means that the surface is not smooth; it looks spiked, a bit like a star.

I think there’s a good image coming up, so just hold on.

Figure 2.9 The ‘spiculated’ soft tissue breast mass.

Breast screening mammograph shows a dense
tumor mass with an irregular, spiculated, stellate
edge and some spotty micro-calcification,
likely to be breast cancer.

The lump here has spicules, or thin elongated pieces of tissue sticking out from the edge. This is suggestive of cancer.

The BIRADS Classification System

There are many different types of tissues in the breast, fat, connective tissue and glands with the following BI-RADS classification:

Breast Density: BI-RADS type 1: The first classification of breast density is of almost entirely fat. Glandular tissue is less than 25%.

Breast Density: BI-RADS type 2: In type 2 breast density, there are scattered fibrous and glandular tissues, ranging from 25% to 50% of the breast.

Breast Density: BI-RADS type 3: The breast tissue in type 3 may be termed ‘heterogeneously dense‘, ranging from 51% to 75% of the breast tissue.

Breast Density: BI-RADS type 4: The highest category of breast density means that the breast contains more than 75% glandular and fibrous tissue. At this level, the sensitivity of the mammogram might be reduced.

2.11 Abnormal Mammogram: II. Micro-Calcification

There second general category of mammographic findings suggestive of a breast cancer is micro-calcification, of which there are two kinds, ‘clustered’ and ‘linear.’

The Le-Gal classifications system for micro-calcification originated in France in the early 1980s and is still used in parts of Europe.

The Le-Gal system uses five categories of micro-calcification:

Type 1: Virtually no risk for breast cancer.
Type 2: Usually benign and of the lobular type. Malignancy rate is thought to be between 15 to 22%.
Type 3: Dusty micro-calcification, too fine to be counted. Malignancy rate is around 40%.
Type 4: Punctate or granular micro-calcification with irregular contours, often with pleomorphism. Risk of breast cancer is around 60%.
Type 5: Vermicular (linear) micro-calcification with branching patterns. Risk of breast cancer is around 95%.

However, this evaluation of micro-calcification has been replaced in several countries by the use of the BI-RADS classification system.

I’ve decided! I’d like a job cleaning mirrors, it’s something I could really see myself doing.

Neither the BI-RADS nor the Le-Gal system is accurate and specific enough to forego biopsy or additional imaging for confirmation of the nature of the breast lesion.

2.11.1 Clustered Micro-Calcification

Clustered micro-calcification described on mammograms are calcium particles with a variety of sizes and shapes. This micro-calcification measures between 0.1 to 1 mm in diameter.

Micro-calcification is associated with necrotic cells. Necrotic cells are found in high-grade, in-situ ductal carcinoma (DCIS or ‘comedo-carcinoma’) and the mucin of mucin-secreting tumors.

Comedo-carcinoma, is that a ductal cancer?

Yes, Comedo-carcinoma is a type of early, ductal breast cancer. It tends to grows fast and has a higher risk of becoming invasive in the future.

Mammographic appearance alone cannot differentiate between purely intra-ductal in-situ (DCIS) and invasive ductal (IDC) breast cancers as there is no mammographic correlate of invasion.

10 % of cases of DCIS present as a soft tissue mass, without micro-calcification.
30% of invasive breast carcinomas are associated with micro-calcification, with or without a soft tissue mass.

Ductal Carcinoma In-Situ (DCIS)

Ductal carcinoma in-situ (DCIS) is a non-infiltrative cancer which is still confined to the breast duct. DCIS represents between 20% to 40% of all detected breast cancers. The rate at which DCIS progresses to invasive cancer is around 30% of all cases over a ten year period.

DCIS is almost always accompanied by micro-calcification, which underscores the importance of screening mammograms and micro-calficiation identification.

About 58% of screen-detected DCIS is of a high grade (less well-differentiated). Approximately 85% of DCIS is of either high or intermediate grade.

Less than half of low-grade DCIS show micro-calcification.

High-Grade DCIS

High-grade DCIS will very likely progress to grade 2 or 3 invasive ductal carcinoma within 3-10 years, if not successfully identified and treated.

A sentinel lymph node (SLN) biopsy is not usually performed with DCIS.

Figure 2.10 Micro-calcification.

A. The mammographic appearance of breast micro-calcification
with B. a photomicrograph of the histopathology of high-grade
ductal carcinoma in-situ (DCIS) also known as
‘comedo-carcinoma.’

The Van Nuys Prognostic Index

The Van Nuys Prognostic Index (VNPI): Treatment options for DCIS are sometimes evaluated using the Van Nuys Prognostic Index (VNPI). It assesses the risk of recurrence on a scale of 1 to 3 and considers diagnostic factors such as the tumor size, width of resection margins, presence of necrosis (dead cells and debris), and nuclear grade. A woman’s age is also taken into consideration (Asjoe et al., 2007).

I don’t really like the Prognostic prediction thing. I think belief in your own recovery is far more important.

I agree. Don’t get too bogged down in statistics, charts and tables, each case is totally individual.

Everybody should believe in something, I believe I’ll have another coffee.

2.11.2 Linear, Branching Micro-Calcifications

These are commonly associated with the non-invasive, ‘comedo’ ductal carcinoma in-situ (DCIS), with a higher predictive value for breast cancer than granular or non-linear, irregular calcification.

2.11.3 ‘Benign’ Breast Calcification

Calcification that is not suspicious for malignancy include skin and vascular calcification; large, coarse calcification; rim-like calcification; and smooth round or oval calcification.

Mammographic findings of breast masses and calcification can be stratified by suspicion for malignancy, as in the BI-RADS 4a, 4b, and 4c categories.

These categories are helpful in alerting the referring physicians, pathologists, and surgeons to the potential risk of malignancy, with ‘high risk’ micro-calcification more likely to indicate breast cancer and ‘low risk’ micro-calcification more likely to be benign.

Although mammography and other imaging techniques may provide categories for suspicion, a diagnosis of malignancy can only be made with a tissue diagnosis (histopathology) from the most relevant part of the breast.

So not all breast calcifications are malignant then?

Breast calcifications are spots of calcium salts, they are very small, extremely common and mostly benign.

2.12 Abnormal Mammograms

III. Intra-Mammary Lymph Nodes

Intra-mammary lymph nodes are common in normal breasts but are not usually enlarged or palpable.

Intra-mammary lymph nodes are detected in up to 30% of patients with breast cancer, and their mammographic appearances can be suggestive of lymph node involvement.

Definitive assessment of lymph node involvement by tumor can only be made histologically.

Recent studies have shown that involvement of intra-mammary lymph nodes in patients with breast cancer is associated with a poorer patient prognosis (Shen et al., 2004).

In breast cancer staging, ‘intraMLN’ is considered to be a Stage II disease, even if the axillary lymph nodes are uninvolved.

References:

Kivel, M. (1994). FDA’s mammography facility quality assurance program. Adm Radiol. 13(2), 43. (Retrieved October 28^th 2014): https://www.ncbi.nlm.nih.gov/pubmed?term=10132931

Chan, H.P., Doi, K., Galhotra, S., Vyborny, C.J., MacMahon, H., Jokich, P.M. (1987). Image feature analysis and computer-aided diagnosis in digital radiography. I. Automated detection of microcalcifications in mammography.

More references for this section are on this page.

Patient Information:

American Cancer Society Mammograms. Mammograms and Other Breast Imaging Tests: Understanding your mammogram report – BI-RADS categories (Retrieved January 28^th 2015) http://www.cancer.org/treatment/understandingyourdiagnosis/examsandtestdescriptions/mammogramsandotherbreastimagingprocedures/mammograms-and-other-breast-imaging-procedures-mammo-report

American Cancer Society Breast magnetic resonance imaging. (Retrieved January 31^st 2015): http://www.cancer.org/cancer/breastcancer/moreinformation/breastcancerearlydetection/breast-cancer-early-detection-a-c-s-recs-m-r-i

More patient information for this section is on this page.

Forward to 2D on biopsies. Back to 2B on mammography.