Invasive lobular breast carcinoma – Diagnostics – Overview of Information and Clinical Research

Invasive lobular breast carcinoma is a type of breast cancer that starts in the milk-producing glands and grows in a unique pattern that can make it harder to detect than other breast cancers. Understanding how this cancer is diagnosed, and what tests are needed both for initial detection and for qualifying for clinical trials, helps patients and their families navigate the journey ahead with greater confidence.

Introduction: Who Should Seek Diagnostic Testing

Women who notice any changes in their breasts should seek medical evaluation promptly. Unlike many other breast cancers that form a firm lump, invasive lobular carcinoma often creates more subtle changes that are easy to overlook^[1]. This is because the cancer cells spread out in single file lines through the breast tissue rather than clustering together to form a mass.

You should contact your healthcare provider if you notice a change in the texture or appearance of your breast skin, such as dimpling or thickening. A new area of fullness or swelling in the breast warrants investigation, even if there is no distinct lump. Changes to the nipple, particularly if it turns inward when it previously pointed outward, should not be ignored. An area of thickening in part of the breast, or any unusual skin changes, are also reasons to schedule an appointment^[1].

Most healthcare professionals recommend that women begin considering routine breast cancer screening in their 40s. However, women with certain risk factors may need to start earlier. These risk factors include being age 55 or older, having had breast cancer previously, having a family history of breast or ovarian cancer, or having a condition called lobular carcinoma in situ, which means abnormal cells are present but have not yet become invasive^[3].

⚠️ Important

Invasive lobular carcinoma may not cause noticeable changes in your breasts for a long time because it grows slowly and may not form a lump. Since it can be present for years before it is detected on a screening mammogram or causes symptoms, regular screening becomes even more important for early detection^[3].

Women who have already been treated for invasive lobular carcinoma should maintain regular follow-up care. This type of breast cancer has an unusual characteristic: it can spread to other areas of the body many years after initial diagnosis and treatment. Some women develop metastatic invasive lobular carcinoma, meaning the cancer spreads to distant parts of the body, even 10 to 15 years after their original treatment^[3]. This makes ongoing monitoring essential.

Diagnostic Methods for Initial Detection

When you visit a breast clinic with concerns about possible breast cancer, the evaluation begins with a thorough clinical breast exam. During this exam, a healthcare professional looks at your breasts for anything unusual, including changes in the skin or nipple. The examiner then feels the breasts for lumps and checks along the collarbones and around the armpits for any swollen lymph nodes^[8].

This physical examination is particularly important for invasive lobular carcinoma because this cancer often does not create a firm lump. Instead, you and your healthcare provider may notice only a thickened area of breast tissue. The doctor or specialist nurse will also take your medical history, asking about any symptoms you have experienced and any risk factors you might have^[14].

Imaging Tests

A mammogram is typically the first imaging test used to look for breast cancer. This is an X-ray of the breast tissue that can detect abnormalities. However, invasive lobular carcinoma presents a unique challenge: it is less likely to be detected on a mammogram than other types of breast cancer^[8]. This happens because the cancer cells do not cluster together to form a dense mass that shows up clearly on X-rays. Instead, they spread in lines through the tissue, making them harder to distinguish from normal breast tissue.

If a screening mammogram finds something concerning, you might need another mammogram to look at the area more closely. This more detailed examination is called a diagnostic mammogram, and it is often used to look closely at both breasts^[8]. Despite the challenges, a mammogram remains a useful diagnostic tool and should not be skipped.

A breast ultrasound is another important imaging technique. It uses sound waves to create pictures of structures inside the body. A breast ultrasound may give your healthcare team more information about a breast lump or thickened area. For example, an ultrasound might show whether a lump is solid tissue or filled with fluid. If you are under 35 years old, you are more likely to have an ultrasound scan instead of a mammogram as your first test^[14].

Because invasive lobular carcinoma can be difficult to see on standard mammograms, many women benefit from additional imaging. A breast MRI scan uses magnetic fields, radio waves, and a computer to create detailed images of the breast tissue. MRI scans are particularly helpful for detecting invasive lobular carcinoma because they can show areas of abnormal tissue that might not appear on mammograms or ultrasounds^[8].

An MRI scan is especially useful if your cancer is found in more than one area within the breast, which happens more frequently with invasive lobular carcinoma than with other breast cancer types. This type of cancer is more likely to be multicentric, meaning there is more than one tumor in the breast, and bilateral, meaning cancer occurs in both breasts^[4]. Understanding the full extent of the cancer is critical for planning the best treatment approach.

Biopsy Procedures

To confirm whether cancer is present, a sample of tissue must be removed from the breast and examined under a microscope. This procedure is called a biopsy^[14]. A biopsy is the only way to definitively diagnose invasive lobular carcinoma and distinguish it from other types of breast changes or cancers.

There are different types of biopsies. During a core needle biopsy, a hollow needle is inserted into the breast to remove small cylinders of tissue from the suspicious area. This is one of the most common biopsy methods. The tissue samples are then sent to a laboratory where a specialist called a pathologist examines them under a microscope^[8].

Under the microscope, invasive lobular carcinoma cells have a characteristic appearance. They are typically arranged in a single-file linear pattern rather than forming tight clusters. The cells also lack a protein called E-cadherin, which normally helps cells stick together. This loss of cell-to-cell adhesion is what causes the cancer to grow in lines rather than masses^[15].

The pathologist’s report from your biopsy will provide critical information. It will confirm whether the cancer is invasive lobular carcinoma and provide details about its characteristics. The report typically includes information about the cancer’s grade, which describes how abnormal the cells look and how quickly they are likely to grow. It will also indicate the cancer’s hormone receptor status, meaning whether the cancer cells have receptors for estrogen and progesterone, and its HER2 status, which indicates whether the cancer cells make too much of a protein called HER2^[14].

⚠️ Important

Most invasive lobular carcinomas are hormone receptor-positive and HER2-negative. This means the cancer cells have receptors for estrogen or progesterone and do not make excess HER2 protein. This information is extremely important because it guides treatment decisions, particularly whether hormone therapy will be effective^[15].

Additional Diagnostic Tests

Once invasive lobular carcinoma has been confirmed, additional tests may be needed to determine whether the cancer has spread beyond the breast. These tests help doctors understand the stage of the cancer, which describes how large the tumor is and whether it has spread to nearby lymph nodes or to other parts of the body.

Your doctor may order blood tests to check your overall health and to look at certain markers that can indicate how the cancer might behave. Although there is no single blood test that can diagnose breast cancer, blood work provides important information about your general condition and can help identify any other health issues that might affect treatment planning^[8].

If there is concern that the cancer may have spread, you might need additional imaging tests. These can include a bone scan, which looks for cancer in the bones; a chest X-ray or CT scan, which examines the lungs and chest; or other scans depending on your symptoms and the characteristics of your cancer. Invasive lobular carcinoma has an unusual pattern of spread. While most breast cancers typically spread to the brain, bones, liver, and lungs, invasive lobular carcinoma may also spread to less common areas including the digestive system, reproductive organs, the lining of the brain and spinal cord, the lining of the abdomen, and tissues around the eye^[3].

Diagnostics for Clinical Trial Qualification

Clinical trials are research studies that test new ways to prevent, detect, diagnose, or treat diseases. For patients with invasive lobular carcinoma, participating in a clinical trial might provide access to new treatments that are not yet widely available. However, to qualify for a clinical trial, patients must meet specific criteria, and diagnostic tests play a crucial role in determining eligibility.

Before enrolling in a clinical trial, comprehensive diagnostic testing is required to confirm your exact diagnosis and understand all the characteristics of your cancer. The trial organizers need to know the precise type of breast cancer you have, its stage, its hormone receptor status, and its HER2 status. This information ensures that the trial treatment being tested is appropriate for your specific type of cancer^[14].

Most clinical trials require recent biopsy results confirming the diagnosis of invasive lobular carcinoma. The biopsy tissue may be tested again to verify the cancer’s molecular characteristics. Some trials focus specifically on cancers with certain features, such as hormone receptor-positive cancers or cancers that are HER2-negative. Your cancer must match these specific criteria for you to be eligible.

Imaging tests are typically required before enrollment in a clinical trial. These establish a baseline against which the effectiveness of the trial treatment can be measured. You will likely need recent mammograms, ultrasounds, or MRI scans. If the trial is for advanced or metastatic cancer, you may need CT scans, bone scans, or other imaging to document where the cancer has spread and how extensive it is.

Blood tests are standard requirements for clinical trial qualification. These tests check your blood cell counts, liver function, kidney function, and other important health markers. Clinical trials have strict safety requirements, and patients must be healthy enough to tolerate the experimental treatment. If your blood tests show that your liver or kidneys are not functioning well, you may not be eligible for certain trials.

Some clinical trials for invasive lobular carcinoma may require additional specialized testing. For example, trials testing new targeted therapies might require genetic testing of your tumor tissue to look for specific mutations. Trials testing immunotherapy treatments might require tests to see whether your cancer makes certain proteins that the immune system can recognize. These additional tests help researchers match patients with the treatments most likely to help them.

Throughout a clinical trial, participants undergo regular monitoring and repeat testing. This ongoing diagnostic work serves two purposes: it ensures patient safety by detecting any problems early, and it provides data about how well the treatment is working. Patients can expect to have imaging tests at regular intervals to see whether tumors are shrinking, stable, or growing. Blood tests are also repeated frequently to monitor side effects and overall health.

The frequency and type of follow-up testing during a clinical trial are typically more intensive than in standard care. While this requires more time and visits to the clinic, the close monitoring helps ensure that any problems are caught early and that researchers collect high-quality data about the treatment’s effectiveness and safety.

Prognosis and Survival Rate

Prognosis

The outlook for women with invasive lobular carcinoma depends on several factors. Generally, invasive lobular carcinoma tends to be low grade and grows slowly, meaning the cancer cells look more like normal cells under the microscope and the cancer spreads gradually over time^[15]. Most invasive lobular carcinomas are hormone receptor-positive and respond well to hormone therapy, which is a favorable characteristic.

However, invasive lobular carcinoma has some unique features that affect long-term prognosis. It is more likely than other breast cancers to be found in more than one area within the breast, and it more commonly affects both breasts. Approximately 20% of women with bilateral breast cancer at diagnosis have invasive lobular carcinoma^[4]. These characteristics can make treatment planning more complex.

One important consideration is that invasive lobular carcinoma can recur or spread to other parts of the body many years after initial treatment. Unlike some breast cancers that recur within the first few years, invasive lobular carcinoma has been known to spread to distant sites 10 to 15 years after diagnosis and treatment^[3]. This means that long-term follow-up care is essential, even many years after successful initial treatment.

When invasive lobular carcinoma does spread, it tends to go to a wider range of organs than other breast cancers. While it can spread to the typical sites such as bones, lungs, liver, and brain, it may also spread to less common locations including the digestive system, reproductive organs, the lining of the abdomen, and the tissues around the eyes^[3]. This unusual pattern of spread requires vigilance and careful monitoring over time.

Survival rate

Invasive lobular carcinoma accounts for approximately 10 to 15 percent of all invasive breast cancers, with an estimated 43,000 to 47,500 new cases diagnosed each year in the United States^[2]^[5]. Women with invasive lobular carcinoma are typically diagnosed at an older age, with 68% of all new lobular diagnoses occurring in women over the age of 60^[5].

The treatment for invasive lobular carcinoma is planned in the same way as for other breast cancers, based on factors such as stage, grade, and biomarker status rather than solely on the cancer being lobular type. Early diagnosis and treatment may cure invasive lobular carcinoma^[3]. Many women with this type of cancer become long-term survivors, particularly when the cancer is detected at an early stage.

At diagnosis, invasive lobular carcinoma tends to have a larger tumor size but a lower tumor grade compared to invasive ductal carcinoma^[9]. The fact that most cases are hormone receptor-positive is generally considered a favorable prognostic factor because it means the cancer is likely to respond to hormone therapy treatments. However, the tendency for late recurrence means that survival statistics need to account for outcomes over many years, not just the first five years after diagnosis.

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