Invasive lobular carcinoma (ILC), also known as infiltrating lobular carcinoma or lobular breast cancer, is cancer in the milk-producing glands. People with ILC are unlikely to feel the tell-tale lumps. ILC grows and spreads differently from other breast cancers like invasive ductal carcinoma (IDC), or cancer of the milk ducts.
When cancer spreads, it’s called metastatic. In ILC, the cancer starts in the breast lobules, and move to the surrounding breast tissue. It can also travel to lymph nodes and other organs in the body. If the cancer doesn’t spread beyond the lobules, your doctor will diagnose it as early stage lobular breast cancer.
More than 180,000 women in the United States each year will received an invasive breast cancer diagnosis. ILC makes up about 10 percent of them.
ILC develops differently from more common types of breast cancer. It’s less likely to have obvious lumps, and in the early stages there could be no signs or symptoms. But as the cancer grows, you may notice your breasts:
- thickening or hardening in a certain area
- swelling or feeling full in a certain area
- changing in texture or skin appearance, such as dimpling
- developing a newly inverted nipple
- changing in size or shape
Other signs may include:
- breast pain
- nipple pain
- discharge other than breast milk
- a lump around the underarm area
These are usually the first signs of breast cancer, including ILC. See your doctor if you notice these signs or symptoms.
The cause of ILC is unclear. But this type of cancer starts when the cells in your milk-producing glands form a mutation in their DNA that normally controls cell growth and death. The cancer cells start dividing and spreading out like branches, which is why you are unlikely to feel a lump.
According to the Mayo Clinic, the chances of getting ILC increases:
- as a female
- at an older age, more than other types of breast cancer
- in women on hormone replacement therapy (HRT), typically after menopause
- with inherited cancer genes
Lobular carcinoma in situ (LCIS)
Your risk of developing ILC may increase if you’ve had an LCIS diagnosis. LCIS is when atypical or abnormal cells are found but these cells are confined to the lobules and have not invaded surrounding breast tissue.
LCIS isn’t cancer and is considered an uncommon condition.
Your doctors will use several different imaging tests to help diagnose lobular breast cancer. These tests include:
- breast biopsy
ILC has a few subtypes, which are based on the appearance of the cells under the microscope. In the classic type of ILC, the cells line up in a single file.
Other less common types include the following:
- solid: grow in large sheets
- alveolar: grow in groups of 20 or more cells
- tubulolobular: some cells are single-file formation and some form tube-like structures
- pleomorphic: larger than classic ILC with nuclei that look different from each other
- signet ring cell: cells are filled with mucus
Mammograms have false-negative rates from 8 to 19 percent for lobular cancer. This is because, in an X-ray, lobular cancer looks similar to normal tissue.
ILC also spreads through the breast tissue differently from IDC. Well-formed tumors and calcium deposits aren’t as common, making it hard for a radiologist to distinguish ILC from normal breast tissue on mammogram. It’s also more likely to develop in more than one area of the breast or in both breasts. If it’s seen on mammogram, it may appear smaller than it actually is.
Breast staging is when your doctor determines how advanced the cancer is or how far it has spread from the breast. Staging is based on the size of the tumor, how many lymph nodes have been affected, and if the cancer has spread to other parts of the body. There are four stages of ILC, from 1 to 4.
Like IDC, if ILC spreads, it tends to show up in the:
- lymph nodes
Unlike IDC, ILC is more likely to spread to unusual places like the stomach and intestines, abdomen lining, and reproductive organs.
To determine if the cancer cells have spread, your doctor may test your lymph nodes, blood, and liver function.
Your best treatment option will depend on your cancer stage, age, and your general health. Treating ILC usually involves surgery and additional therapy.
Choosing your surgeon carefully is especially important because of ILC’s unusual growth pattern. Less aggressive surgeries like lumpectomy have similar results to aggressive treatments like a mastectomy, according to the National Cancer Data Base.
A lumpectomy may be a good option if only a small portion of the breast has cancer (in this surgery, the surgeon only removes the cancer tissue). If more breast tissue is involved, then your doctor may recommend a mastectomy (complete breast removal). Other options include removing lymph nodes near your breast, called sentinel lymph node biopsy, and armpit, called axillary lymph node dissection.
You may need additional treatment, such as radiation, hormonal therapy, or chemotherapy, to reduce the risk of the cancer growing back after surgery.
Complementary and alternative treatments
While complementary and alternative medicine (CAM) treatments aren’t known to cure breast cancer, they can help relieve some of the symptoms and side effects of cancer and its treatments. For example, people taking hormone therapy for breast cancer can experience hot flashes, or sudden, intense warmness, and sweating.
You may find relief through:
- vitamin supplements
- relaxation exercises
Always talk to your doctor before trying a new medication or supplement. They may interact with your current treatment and cause unintended side effects.
Hormone therapy (HT) may be recommended if your cancer cells are sensitive to hormones like estrogen and progesterone. This is usually the case in lobular breast cancer. HT can block your body’s hormones from signaling the cancer cells to grow.
Early diagnosis and treatment increases your chance of living a long and healthy life. Advances in treatment are helping people with cancer live longer, healthier lives. The long-term outlook of ILC depends on multiple factors, such as:
- the stage of cancer
- grade and subtype
- surgical margins, or how close the cancer cells are to the tissue removed from the breast
- your age
- your overall health
- how well you respond to treatment
Another factor that affects outcome in ILC is whether or not estrogen, progesterone, or HER2 (human epidermal growth factor receptor 2) receptors are found on the surface of the cancer cells.
Survival rates for ILC are similar to survival rates of IDC. One study showed that five years after the diagnosis, 85.6 percent of people with ILC were still living — compared to 84.1 percent of those with IDC.
But these rates don’t take into account the different stages of cancer and other factors that affect prognosis. For example, the five-year survival rate is close to 100 percent for a stage 1 diagnosis. At stage 4, or if the cancer is metastatic, the five-year survival rate is 22 percent.
Lobular carcinoma, like other breast cancers, can develop in otherwise healthy individuals. You can reduce your risk by:
- drinking alcohol in moderation, if at all
- doing self-exams
- getting annual checkups including mammograms
- maintaining a healthy weight
- eating a balanced diet and exercising regularly
If you are considering HRT, discuss the risks and benefits of this therapy with your doctor. HRT may raise the risk of lobular carcinoma and other types of breast cancer. If you do choose to take HRT, you should take the lowest effective dose for the shortest possible time.
There is an increased risk of developing invasive breast cancer if you are diagnosed with LCIS. You can take medications like tamoxifen to lower your risk. Your doctor may also suggest a mastectomy if you have a family history of breast cancer.
Getting a breast cancer diagnosis of any type can be overwhelming. Learning about breast cancer and the treatment options may help you feel more at ease as you move through your journey. Places you can turn to for support if you’re diagnosed with lobular breast cancer include:
- your healthcare team
- friends and family
- online communities
- local support groups
The breast cancer community is a visible and vocal one. Local support groups may be helpful in connecting with others who are going through similar experiences.