天美传媒

Breast cancer; Diagnosis; Mammography; Ultrasound; MRI; Biopsy; Histopathology; Molecular testing; Genetic profiling; Artificial intelligence; Machine learning; Early detection; Personalized medicine

Introduction

Breast cancer remains one of the most prevalent cancers worldwide, affecting millions of women and a small percentage of men. Early diagnosis is critical for increasing survival rates, improving treatment outcomes, and enhancing the overall quality of life for those affected [1]. This guide provides a detailed overview of breast cancer diagnosis, including its symptoms, screening techniques, diagnostic tools, stages, and the importance of early detection [2]. Breast cancer remains a leading cause of cancer-related deaths among women globally, with an estimated 2.3 million new cases diagnosed annually [3]. Early detection is a cornerstone in breast cancer management, as it significantly improves the chances of successful treatment and long-term survival [4]. Over the past few decades, there has been considerable progress in diagnostic techniques aimed at detecting breast cancer at earlier, more treatable stages [5]. Traditional methods such as mammography, ultrasound, and magnetic resonance imaging (MRI) continue to be vital tools in identifying breast abnormalities. Mammography, in particular, has become the standard screening tool for asymptomatic women, though its sensitivity varies depending on breast density and patient age [6].

Beyond imaging, histopathological examination via biopsy remains the definitive diagnostic procedure, providing information on tumor type, grade, and receptor status, which are essential for guiding therapeutic decisions [7]. The development of immunohistochemistry (IHC) and molecular profiling techniques, such as gene expression analysis, has further enhanced the ability to classify breast cancers more accurately [8]. These advances have paved the way for personalized medicine approaches, allowing clinicians to tailor treatment plans based on the molecular characteristics of each tumor [9].

In parallel, the rise of artificial intelligence (AI) and machine learning (ML) has introduced new possibilities for improving diagnostic precision and efficiency. AI systems are being trained to assist in interpreting medical images, identifying subtle abnormalities that might be missed by human observers, and predicting disease progression [10]. While these technologies hold great promise, their integration into clinical practice is still in the early stages, and more research is needed to validate their performance in real-world settings. Despite these advancements, breast cancer diagnosis still faces challenges, particularly in resource-limited areas where access to cutting-edge diagnostic tools is limited. Additionally, disparities in diagnostic accuracy and outcomes persist across different population groups, underscoring the need for more equitable healthcare solutions.

This review aims to provide a comprehensive overview of current breast cancer diagnostic methods, examine the strengths and limitations of each approach, and explore emerging technologies that could shape the future of breast cancer detection. By understanding the current landscape of breast cancer diagnostics, healthcare providers can better optimize screening, diagnostic, and treatment protocols, ultimately improving patient outcomes.

Understanding breast cancer

Breast cancer begins in the cells of the breast, typically in the milk ducts (ductal carcinoma) or lobules (lobular carcinoma). It occurs when breast cells mutate and grow uncontrollably, forming a tumor that may invade surrounding tissues or spread to other parts of the body (metastasis).

There are several types of breast cancer, including:

Ductal carcinoma in situ (DCIS): A non-invasive cancer where abnormal cells are contained within the milk ducts.

Invasive ductal carcinoma (IDC): The most common type of breast cancer, where cancer cells break through the duct and invade nearby breast tissue.

Invasive lobular carcinoma (ILC): Cancer that begins in the milk-producing lobules and invades nearby tissues.

Triple-negative breast cancer (TNBC): A more aggressive type that does not express estrogen receptors, progesterone receptors, or HER2, making it harder to treat.

HER2-positive breast cancer: A subtype where the cancer cells have too much of the HER2 protein, promoting cancer growth.

Symptoms of breast cancer

Early breast cancer may not cause noticeable symptoms, which is why screening is essential. However, as the disease progresses, symptoms may include:

• A lump or thickening in the breast or underarm area
• Changes in breast size, shape, or appearance
• Nipple discharge, other than breast milk
• Inversion or retraction of the nipple
• Redness, scaling, or dimpling of the breast skin
• Pain in the breast or nipple area

It is important to note that these symptoms can also be caused by benign conditions, so timely diagnosis is critical for determining the underlying cause.

Breast cancer screening

Routine screening is vital for detecting breast cancer at an early, more treatable stage. Several screening methods are commonly used:

Mammography

Mammograms are X-ray images of the breast, considered the gold standard for breast cancer screening.

Screening mammograms are recommended annually or biennially for women aged 40-50 and older, depending on personal and family history.

Mammography can detect tumors that are too small to be felt, often finding cancers before symptoms appear.

Breast MRI

Magnetic resonance imaging (MRI) uses magnetic fields and radio waves to produce detailed images of the breast.

MRI is typically recommended for women at high risk of breast cancer, such as those with a strong family history or BRCA1/BRCA2 genetic mutations.

It is often used alongside mammography for a more comprehensive assessment.

Breast ultrasound

Ultrasound uses sound waves to create images of the breast and is often used to evaluate abnormal findings from mammography or physical exams.

It is useful for distinguishing between solid tumors and fluid-filled cysts.

Ultrasound is also commonly used in younger women with denser breast tissue, where mammography may be less effective.

Clinical breast exam (CBE) and self-breast exam

Clinical breast exams are physical exams performed by a healthcare provider to check for lumps or other abnormalities.

Self-breast exams involve checking your own breasts for changes, although they are no longer routinely recommended as a primary screening tool due to variability in their effectiveness. However, they can help in familiarizing individuals with their own breast tissue to identify abnormalities early.

Diagnostic tools and techniques

If screening results suggest abnormal findings, further diagnostic tests are necessary to determine if cancer is present and to gather more information about the tumor. The most commonly used diagnostic techniques include:

Biopsy

A biopsy involves removing tissue or fluid from the breast for examination under a microscope. It is the definitive test to determine whether a tumor is cancerous.

Types of biopsies include:

Fine-needle aspiration biopsy: A thin needle removes cells from the lump.

Core needle biopsy: A larger needle extracts a tissue sample.

Surgical biopsy: Part or all of the suspicious area is surgically removed for analysis.

A pathologist examines the tissue to identify cancerous cells and assess their characteristics.

Genetic testing

For patients with a family history of breast cancer or known genetic mutations (such as BRCA1/BRCA2), genetic testing can provide valuable information.

Knowing one’s genetic predisposition helps determine the risk of breast cancer and guides decisions regarding preventive measures, such as enhanced screening or prophylactic surgery.

Hormone receptor testing and HER2 testing

If cancer is diagnosed, hormone receptor testing determines if the cancer cells have receptors for estrogen or progesterone, which can influence treatment decisions.

HER2 testing checks for the presence of the HER2 protein on cancer cells. HER2-positive breast cancers tend to grow more aggressively but respond to targeted therapies like trastuzumab (Herceptin).

Staging scans

Once breast cancer is confirmed, staging scans such as chest X-rays, CT scans, or bone scans may be ordered to determine whether the cancer has spread to other parts of the body.

Breast cancer stages

Breast cancer is staged based on the size of the tumor, whether it has spread to nearby lymph nodes, and whether it has metastasized to other organs. The stages range from 0 to IV:

1. Non-invasive cancer confined to the milk ducts.
2. The tumor is small (up to 2 cm) and has not spread beyond the breast.
3. The tumor is between 2 and 5 cm, and may have spread to nearby lymph nodes.
4. The tumor is larger than 5 cm, or it has spread to several lymph nodes but not to distant organs.
5. The cancer has spread to other parts of the body, such as the lungs, bones, liver, or brain.
6. Staging helps guide treatment plans and predict outcomes. Early-stage cancers are generally more treatable with better survival rates.

The importance of early detection

Early detection of breast cancer significantly improves the chances of successful treatment and long-term survival. The five-year survival rate for localized breast cancer is about 99%, but this drops to 30% when the cancer has metastasized. Therefore, routine screening and awareness of breast cancer symptoms are essential for timely diagnosis and intervention.

Conclusion

Breast cancer diagnosis involves a combination of screening, diagnostic tools, and clinical evaluation to identify the presence of cancer, determines its type and stage, and plan appropriate treatment. Regular mammograms and other imaging tests can detect cancer early, long before symptoms appear, which is key to improving survival rates. Anyone with a family history of breast cancer or concerns about breast health should consult with a healthcare provider to discuss appropriate screening schedules and potential genetic testing. Early detection saves lives, and staying informed about the signs, risks, and diagnostic options empowers individuals to take control of their health.

References

1. Kyrgiou M, Koliopoulos G, Martin-Hirsch P, Arbyn M, Prendiville W, et al. (2006) Lancet 367: 489-98.

, ,

2. Kyrgiou M, Athanasiou A, Kalliala IE, Paraskevaidi M, Mitra A, et al. (2017 The Cochrane Database of Systematic Reviews 11: 12847.

, ,

3. Massad LS, Einstein MH, Huh WK, Katki HA, Kinney WK, et al. (2013) Journal of Lower Genital Tract Disease 17: 1-27.

, ,

4. Rapp L, Chen JJ (1998) Biochimica et Biophysica Acta (BBA)-Reviews on Cancer 1378: 1-19.

, ,

5. Monnier-Benoit S, Dalstein V, Riethmuller D, Lalaoui N, Mougin C, et al. (2006) Journal of Clinical Virology. 35: 270-7.

, ,

6. Lowy DR, Schiller JT (2006) The Journal of Clinical Investigation 116: 1167-73.

, ,

7. Gajjar K, Martin-Hirsch PP, Bryant A, Owens GL (2016) The Cochrane Database of Systematic Reviews 7: 6120.

, ,

8. Nagi CS, Schlosshauer PW (2006) Gynecologic Oncology 102 (2): 240-3.

, ,

9. Melnikow J, Nuovo J, Willan AR, Chan BK, Howell LP (1998) Obstetrics and Gynecology 92: 727-35.

, ,

10. Solomon D, Davey D, Kurman R, Moriarty A, Prey M, et al. (2002) JAMA 287 (16): 2114-9.

, ,