Study Notes on Mammography and Breast Cancer

MAMMOGRAPHY

Breast Cancer Statistics and Overview

  • Breast Cancer

    • 2nd most common cancer among women.

    • Accounts for 15.2% of all new cancers detected.

    • Accounts for 6.9% of cancer deaths.

    • According to the American Cancer Society (ACS), 1 in 8 women will develop breast cancer in her lifetime.

  • Men can also develop breast cancer, challenging the common perception that it is solely a female disease.

  • While various risk factors for breast cancer have been identified (e.g., genetics, lifestyle), specific causes remain largely unknown.

  • The best defense against breast cancer includes early detection and treatment.

Early Detection of Breast Cancer

  • Importance of early detection emphasized through:

    • Mammography: A primary screening tool.

    • Clinical Breast Examination: A method performed by healthcare providers to assess breast health.

    • MRI: Utilized in high-risk cases, such as women with a strong family history of breast cancer.

    • Treatment and recovery outcomes demonstrate higher success rates with early detection.

Mammography Details

  • Applicable for identifying lesions as small as 2 mm or 0.2 cm (equivalent to the size of the pointed end of a crayon).

  • It may take approximately 2-4 years for a lesion to grow sufficiently large to be detected during clinical breast examinations.

  • Once a lesion reaches 2 cm, it is often indicative that metastasis has occurred, reducing the expected lifespan of the patient diagnosed with metastasis to about 2 years.

Mammography Imaging Requirements

  • Optimal Imaging: Requires high contrast between structures to provide clear images.

    • The images must be high-resolution and free of artifacts.

    • Procedure performed by a qualified mammographer to ensure accuracy and reliability.

Mammography Quality Standards Act (MQSA)

  • The MQSA was enacted in 1994 in response to poor quality mammography services available at that time.

  • Major tenets include:

    • Facilities performing mammograms must be approved by an accredited body (commonly the Joint Commission).

    • Facilities must obtain certification by the Department of Health and Human Services (DHHS).

    • Facilities are required to undergo on-site inspections by state agencies representing the DHHS.

    • The Act includes a comprehensive Quality Assurance program to maintain standards.

Breast Anatomy and Measurements

  • Key Measurements:

    • Mediolateral Diameter: Measures width of the breast from side to side.

    • Craniocaudad Diameter: Measures vertical height from top to bottom.

Structure of the Breast

  • Comprehensive anatomical overview includes:

    • Nipple: Central point for lactiferous ducts exit.

    • Areola: Pigmented area surrounding the nipple.

    • Inframammary Fold: Junction between the lower part of the breast and the anterior chest wall.

    • Axillary Tail: Band of breast tissue extending towards the axilla (armpit).

    • Pectoralis Major Muscle: Underlying structure (bony thorax) that supports breast tissue.

    • Adipose Tissue: Surrounds glandular tissue within the breast.

    • Lobular Structure: Divided into 15-20 lobules that resemble spokes of a wheel, also containing alveoli and ducts.

Breast Localization Systems

  • Quadrant System: Used to refer to breast areas for imaging and evaluation.

    • Includes upper outer quadrant (UOP), upper inner quadrant (UIQ), lower outer quadrant (LOQ), and lower inner quadrant (LIQ).

  • Clock System: Describes localization by correlating breast surfaces with clock face positions.

    • Example: 12 o'clock corresponds with the superior aspect of the breast.

Breast Tissue Classifications

  • Fibroglandular: Typically seen in women aged 15-30 or during pregnancy/lactation. Characterized by high radiographic density with minimal fat.

  • Fibrofatty: Common in women aged 30-50, identified as having an average radiographic density (50% fibrous, 50% fatty).

  • Fatty: Typically observed in women over 50 and postmenopausal individuals, showing minimal radiographic density, also present in children and men.

  • Densities can range from less than 25% (Fatty) to over 75% (Extremely Dense).

Mammography Equipment

  • A dedicated mammography unit is necessary to accurately capture breast images.

  • Characteristics of mammography units include:

    • Unique tube designs facilitating the visualization of minute breast anatomy.

    • Inclusion of a compression device which smooths and evens out breast thickness while applying 15-30 pounds of consistent pressure for optimal imaging.

    • Compression is gradually administered allowing patient adjustment to minimize discomfort.

Reasons for Compression Use

  1. Decrease breast tissue thickness to make it uniform.

  2. Position breast structures closer to the image receptor.

  3. Decrease the required radiographic dose while maintaining image quality.

  4. Minimize motion and enhance image sharpness.

  5. Improve contrast by optimizing exposure factors.

  6. Separate overlapping breast structures in the images.

Mammography Techniques

  • Techniques can involve magnification to enlarge small areas of interest seen on initial scans, achieved through increasing the object-to-image distance (OID).

Patient Dose in Mammography

  • The overarching goal is the production of high-quality images while minimizing unnecessary radiation exposure to the breast tissue.

  • Key factors influencing the patient dose include:

    • Equipment used.

    • Technique factors applied.

    • Size and density of breast tissue.

  • Recommended maximum skin dose is between 800-900 mrads for mammograms featuring 4 cm thickness.

Patient Preparation and History for Mammography

  • Prior to the procedure, a thorough explanation of the process is given to the patient.

  • The patient must:

    • Remove jewelry and any powders or deodorants.

    • Provide a comprehensive medical history including:

    • Number of pregnancies and live births.

    • Family history of cancer.

    • Use of medications or birth control pills.

    • Previous breast surgeries, mammograms, or reasons for current imaging request (screening or diagnostic).

Imaging Techniques Used in Mammography

  • Film/screen technique: Utilizes imaging cassettes containing an intensifying screen in conjunction with x-ray film.

  • Digital mammography: Replaces traditional systems with an image detector linked to a computer that allows for advanced image processing and manipulation, though it has slight drawbacks such as increased dose and modest loss of spatial resolution.

  • Other Imaging Modalities: Can include ultrasound, MRI, computer-assisted detection systems, contrast-enhanced radiography, PET mammography, and nuclear medicine.

Mammographic Positioning Techniques

  • Cranio-Caudal (CC) Position: Focusing on top-to-bottom imaging – radiographic beam enters from the top and exits underneath.

  • Mediolateral (MLO) Position: Radiographic beam enters the medial side of the breast and exits the lateral side; the image receptor is positioned later and tilted at a 45-degree angle.

Special Procedures in Mammography

  • Biopsy techniques include:

    • Fine Needle Aspiration (FNA)

    • Core Biopsy

    • Surgical Resection Biopsy

  • Challenges faced in mammography include not only technical aspects but also the need to reassure patients about procedures and potential outcomes.

Pathology of Breast Cancer

  • Carcinoma classifications include:

    • Noninvasive: Confined to glandular tissues without lymphatic access; includes ductal and lobular carcinoma in situ.

    • Invasive (e.g., infiltrating ductal carcinoma): accounts for 80% of breast cancer cases.

  • Other benign conditions include:

    • Cysts: Fluid-filled sacs.

    • Fibroadenoma: Solid lumps of fibrous and glandular tissue; benign.

    • Fibrocystic Changes: Involve fibrous and cystic alterations in the breast ducts.

    • Intraductal Papilloma: Growth within the duct that may produce nipple discharge.

    • Paget's Disease of the Nipple: Presents as crusty or scaly nipple areas and may be linked with lumps within the breast.

Key Imaging Notes

  • Differentiation between fatty and dense breast tissue is critical:

    • Fatty breast tissues allow for easier cancer detection whereas dense breast tissues may conceal lesions, thereby complicating the diagnostic process.

Recommendations for Patient Dose

  • The ACR recommends a repeat rate of less than 5% to mitigate patient dose exposure during mammography visits.

Types of Mammograms

  • Screening Mammograms: For individuals without prior breast issues, aimed purely at early detection.

  • Diagnostic Mammograms: Targeted towards individuals with prior identified abnormalities, often involving additional imaging for clarity.