When most people think about breast cancer, they imagine a lump that can be felt during a self-exam or detected on a mammogram. However, not all breast cancers behave the same way. Lobular breast cancer, also known as invasive lobular carcinoma (ILC), often grows differently than other types of breast cancers, making it more challenging to detect and diagnose.

As the second most common type of invasive breast cancer, lobular breast cancer accounts for approximately 10% to 15% of breast cancer diagnoses in the United States. It begins in the lobules of the breast and can spread into surrounding breast tissue and beyond if left untreated.

We spoke with CU Medicine breast surgical oncologist Lauren Gamble, MD, who is a founder and co-chair for the Lobular Breast Cancer Initiative at CU Anschutz Cancer Center and sees patients at both CU Medicine Breast Surgical Oncology – Highlands Ranch Pavilion 1 and the Diane O’Connor Thompson Breast Center located at Anschutz Outpatient Pavilion.

What is Lobular Breast Cancer?

Lobular breast cancer develops in the breast's lobules. "Invasive" means the cancer cells have moved beyond the lobules into surrounding breast tissue and may spread through the lymphatic system or bloodstream.

Unlike the more common invasive ductal carcinoma, which often forms a distinct lump, lobular breast cancer tends to grow in single-file patterns throughout the breast tissue. This growth pattern can make the cancer harder to feel during a breast exam and more difficult to identify on imaging studies.

“The difference with lobular breast cancer is that it invades the breast tissue in a single-file line, making it harder to notice,” said Dr. Gamble. “The key difference in this cancer from ductal is that it doesn’t have E-cadherin protein, which is a protective protein that keeps breast tissue together. When that protein is missing, the cells can more freely move around and spread.”

Symptoms of Lobular Breast Cancer

Lobular breast cancer may not cause noticeable symptoms in its earliest stages. When symptoms do occur, they can be subtle and may include:

• Thickening or fullness in part of the breast
• Changes in breast size or shape
• Breast swelling
• Skin dimpling or puckering
• Nipple changes, including inversion
• Persistent breast pain or discomfort
• A firm area that feels different from surrounding tissue

Because lobular tumors often do not form a distinct mass, many patients are diagnosed with larger and more advanced tumors after routine screening or additional imaging studies.

Why is Lobular Breast Cancer Harder to Detect?

One of the defining characteristics of lobular breast cancer is the way it grows. Rather than forming a bulky, concentrated tumor, the cancer cells often spread through breast along tissue planes in a linear pattern. This can make mammograms less effective at detecting some cases compared with other breast cancer types.

“Oftentimes women don’t receive the diagnosis until it’s much larger and causing more symptoms,” said Dr. Gamble.

As a result, physicians may recommend additional imaging, such as breast MRI or ultrasound, to better evaluate suspicious findings or assess the full extent of disease.

How is Lobular Breast Cancer Diagnosed?

Diagnosing lobular breast cancer typically involves several steps, including:

• Clinical breast examination
• Screening or diagnostic mammography
• Breast ultrasound
• Breast MRI when appropriate
• Image-guided biopsy to confirm the diagnosis

After diagnosis, additional testing helps determine the cancer's stage and biologic characteristics, including hormone receptor and HER2 status. Most lobular breast cancers are hormone receptor-positive, meaning they use estrogen or progesterone to grow.

Treatment Options for Lobular Breast Cancer

Treatment for lobular breast cancer is highly individualized. A patient's care plan depends on factors such as tumor size, stage, hormone receptor status and overall health.

Treatment options may include:

Surgery - Surgery is often the first step in treatment and may include lumpectomy or mastectomy. Lymph nodes may also be evaluated to determine whether the cancer has spread.

Radiation therapy - Radiation therapy may be recommended after surgery to reduce the risk of recurrence.

Chemotherapy and targeted therapies - Some patients may benefit from chemotherapy, targeted therapies or other advanced treatment approaches depending on the biology and stage of their cancer.

“We are still learning about this cancer and know that some treatments are more effective than others,” said Dr. Gamble. “That’s why it’s so important to see an oncologist with ILC experience.”

Specialized Lobular Breast Cancer Care at CU Medicine

Patients diagnosed with lobular breast cancer often have unique questions and concerns. Because this cancer behaves differently from other breast cancer subtypes, specialized expertise can play an important role in treatment planning.

The Lobular Breast Cancer Initiative is dedicated to providing comprehensive, patient-centered care for individuals diagnosed with lobular breast cancer. The initiative brings together specialists with expertise in diagnosis, treatment and ongoing management of this unique breast cancer.

“Our program has assembled a group of specialists focused on this one type of cancer to better understand and treat patients diagnosed with ILC,” said Dr. Gamble.

Through the multidisciplinary approach, patients have access to advanced imaging, surgical expertise, personalized treatment recommendations and coordinated care throughout their cancer journey.

The clinic's goal is to ensure that every patient receives care tailored to their specific diagnosis while benefiting from the latest research and advances in breast cancer treatment.

When to Talk with a Breast Cancer Specialist

Any new breast change should be evaluated by a healthcare provider, even if it doesn't feel like a traditional lump. Changes in breast texture, persistent swelling, skin changes or unusual breast discomfort may warrant further evaluation.

While a lobular breast cancer diagnosis can feel overwhelming, advances in screening, imaging and treatment continue to improve outcomes. Early evaluation and access to specialized care can help patients make informed decisions and confidently move forward with treatment.

For patients seeking expert breast cancer care, the specialists at CU Medicine Breast Surgical Oncology – Highlands Ranch Pavilion 1 provide comprehensive evaluation and treatment, including dedicated lobular breast cancer services.

Learn more about Dr. Lauren Gamble and CU Medicine Breast Surgical Oncology – Highlands Ranch Pavilion 1 by calling 720-516-2122.