Women in the U.S. have about a 12 percent chance of developing breast cancer within their lifetime, according to the American Cancer Society. The type of breast cancer they may be diagnosed with could be one of many forms.
The cancer is first labeled invasive or noninvasive, depending on if it has spread to other tissues. From there, the most common breast cancer diagnoses a woman can receive are lobular carcinoma or ductal carcinoma, which refers to exactly where the cancer started within the breast, according to Dr. Andrew Johnson, hematology and oncology physician at Longstreet Clinic.
Invasive vs. noninvasive
Invasive breast cancers spread to normal tissue. Noninvasive breast cancers present abnormal cells but do not appear to invade the surrounding tissue.
Johnson said invasive breast cancer is much more common and noted that 1 in 8 women in the U.S. will develop invasive breast cancer over the course of their life.
“If it is invasive breast cancer, then the next thing we look at is the size, whether or not there’s any lymph node involvement and then the hormone receptor status,” he said. “The reason that we look at the hormone receptor status, as well as something called the HER2 gene, is because that will define how we treat that particular kind of breast cancer.”
He said the HER2 gene is “involved in cell proliferation and growth.”
“If a breast cancer is expressing that gene, we know that those breast cancers are more aggressive, and we have drugs that can specifically target that gene and treat those breast cancers,” he said.
Ductal carcinomavs. lobular carcinoma
Ductal carcinoma, as the name suggests, begins within the ducts of a breast, which are the tubes that carry milk. Lobular carcinoma, on the other hand, begins in the glandular tissues of the breast where milk is produced. Ductal carcinoma is the most common type, lobular carcinoma the second most common.
“They’re not exactly the same and they have different patterns of spread, but especially for early stage breast cancer, which is the vast majority of breast cancers that we see, there’s not very many differences,” Johnson said.
The symptoms of these cancers are also the same, such as a lump in the breast or redness.
“Symptoms of breast cancer can include a palpable lump in the breast, so a lump that you can feel,” he said. “Occasionally it can be associated with pain but often times they’re not painful. It can be associated with skin changes if it’s close to the skin, including redness. Oftentimes it’s deeper and not associated with skin changes. If it’s close to the nipple, nipple inversion can be a presenting feature.”
Other breast cancers
There are numerous subtypes of breast cancer, but those are rare in comparison, Johnson said.
Inflammatory breast cancer
Johnson said most inflammatory breast cancers are still invasive ductal carcinomas.
“Inflammatory breast cancer represents 1 to 5 percent of all breast cancers diagnosed in the U.S,” he said. “Compared with other types of breast cancer, it tends to be diagnosed at a younger age. And it often presents with swelling and redness that affects a third or more of the breast.”
He said this specific subtype is more aggressive and has to be treated with chemotherapy, surgery and often radiation.
Breast sarcoma, known as a phyllodes tumor or cystosarcoma phyllodes, “can either be cancerous or noncancerous, meaning some of these are benign,” Johnson said. “They tend to occur in middle-age women or older.”
Adenoid Cystic Carcinoma
Adenoid cystic carcinoma represents less than 1 percent of breast cancer, Johnson said. “That one tends to be more slow-growing and often treated with surgery alone,” he said.
Medullary breast cancer
This type represents 2 to 5 percent of all breast cancer and tends to occur in younger women, Johnson said. It can be associated with the BRCA1 gene mutation and is usually treated similarly to other more common invasive cancers.
Mucinous breast cancer only appears as 1 out of every 100 breast cancers and is typically seen in older women.
“(It) tends to be slower growing,” he said. “(It’s) less likely to spread to lymph nodes, but treated the same way as other invasive breast cancers.”
Diagnosis and treatment
To determine if a patient has any type of breast cancer, Johnson said a mammography and biopsy are performed.
“Either a patient has gone through routine annual mammography or if something new has come up and they haven’t had mammography, they’ll undergo mammography and/or ultrasound,” he said. “And if something looks suspicious, then we’ll get a biopsy. And then that biopsy will let us know what’s going on.”
Johnson said the treatment is similar for ductal and lobular carcinoma.
“It really doesn’t change our treatment recommendations as much as one might think,” he said. “The staging and prognosis of both these breast cancers are similar. The treatment is similar, however, (it) varies based upon hormone receptor status and whether or not the HER2 gene is positive or amplified.”