Papillary breast cancer is an uncommon type of invasive breast cancer. It’s generally slow-growing and responds well to treatment.

In this article, we’ll discuss the features of papillary breast cancer, who gets it, and what you can expect from treatment.

Papillary breast cancer is rare, making up only 0.5 to 1 percent of all breast cancers. Like many breast cancers, it starts in the milk ducts. However, it tends to contain both invasive cells and noninvasive cells (in situ).

Under a microscope, a papillary breast tumor appears to have small, finger-like growths called papules. Borders are typically well-defined. It’s a distinctive look that sets it apart from other breast cancers.

Lymph node involvement is less likely with papillary breast cancer than it is with other types of breast cancer. Papillary breast cancer tends to be:

  • small
  • estrogen receptor-positive, progesterone receptor-positive, or both
  • HER2-negative

A retrospective study published in 2021 analyzed 44 cases of invasive papillary breast cancer. Of those, 72.7 percent were estrogen receptor-positive and progesterone receptor-positive, while only 13.6 percent were HER2-positive.

The symptoms of papillary breast cancer are the same as symptoms of other types of breast cancer. These may include:

  • a lump, thickening, or swelling on the breast or underarm
  • any change in breast size or shape
  • discharge from the nipple
  • nipple pulling inward
  • puckering or dimpling of the skin
  • redness or flaking of the skin
  • pain

Cancer occurs when there are errors in DNA. As abnormal breast cells grow and divide, they create more cells with errors. Eventually, these cells start to grow out of control and form a tumor. What causes a person to develop papillary breast cancer isn’t known.

Papillary breast cancer is most common in postmenopausal people assigned female at birth. However, people assigned male at birth and younger females can get it, too.

Research suggests that papillary breast cancer is typically diagnosed in people ages 63 to 67. It’s not always the case, but some may have a preexisting papilloma (a type of noncancerous tumor).

According to the American Cancer Society, having one papilloma does not raise the risk of breast cancer unless it has other changes such as atypical hyperplasia. Having several papillomas may slightly increase the risk of breast cancer.

Factors that put you at risk

Factors that put you at high risk of breast cancer are:

  • strong family history of breast cancer
  • inherited genetic changes such as BRCA1 and BRCA2 mutations

Other risk factors for breast cancer include:

  • menstruation before age 12
  • menopause after age 55
  • taking hormonal therapy or certain oral contraceptives
  • sedentary (inactive) lifestyle
  • having overweight and obesity after menopause
  • drinking alcohol

Papillary breast cancer is diagnosed the same way as other breast cancers. This may include a:

If a diagnosis can’t be made based on a clinical exam and imaging tests, you’ll need a breast biopsy. This is the only way to rule out or confirm cancer.

In this procedure, the doctor uses a needle to remove samples of the suspicious tissue. The samples then go to a laboratory, where a pathologist uses a microscope to look for cancer cells.

The pathology report will state whether the sample is benign (noncancerous) or malignant (cancerous). If cancer is found, it will also provide information such as:

Tumor grade describes how the cells look and behave. Grade 1 means the cells look and behave similar to normal breast cells. Grade 3 means the cells look very different from normal cells and are growing aggressively. Papillary breast cancer is often grade 2.

Papillary tumors can be benign or malignant. This makes the diagnosis challenging. When performing a needle biopsy, the doctor can get several samples from the tumor. These samples may not contain invasive cancer cells.

However, papillary breast cancer can have both invasive and noninvasive cells. Other parts of the tumor may indeed contain invasive cancer cells. According to Johns Hopkins Medicine, this is why surgery to remove a papilloma is usually recommended, even if it’s thought to be benign.

Papillary breast cancer is an invasive breast cancer.

Intraductal papillomas are not cancerous. They’re benign tumors that grow in the milk ducts, usually close to the nipple. These tumors are made of gland tissue, fibrous tissue, and blood vessels. If you have a single tumor like this, it’s called a solitary intraductal papilloma.

Sometimes, a group of benign papillomas grow in small ducts farther away from the nipple. In this case, they’re called multiple papillomas.

Papillomatosis in a condition in which you have tiny, less distinct areas of cell growth within the ducts.

Treatment for papillary breast cancer depends on the specific features of the cancer. These are the:

  • estrogen and progesterone receptor status
  • HER2 status
  • tumor size
  • tumor grade

Surgery

In most cases, you’ll need surgery to remove the tumor. Breast-conserving surgery, also known as lumpectomy, is when the surgeon removes the tumor, plus a small margin of healthy tissue around it. A mastectomy is when the entire breast is removed.

You also have the option of reconstructive surgery.

Radiation therapy

Radiation therapy usually follows breast-conserving surgery and may also follow mastectomy. This can help destroy any remaining cancer cells. Radiation therapy can be directed toward the site of the tumor, the chest wall, or the lymph nodes.

Chemotherapy

Chemotherapy drugs are used to destroy cancer cells anywhere in the body. This may be recommended if there’s a chance the cancer has spread beyond the primary tumor. This can help lower the chances that the cancer will reach distant sites or recur.

Hormone therapy

If your tumor is estrogen or progesterone receptor-positive, it means the cancer is using hormones as fuel. Hormone therapies are drugs that help block or stop the effects of these hormones. Hormone therapy is not an option when the tumor is estrogen and progesterone receptor-negative.

Targeted therapies

Targeted therapies are drugs that target a specific feature of cancer. Some breast cancers use a protein called HER2 to fuel growth. Most papillary breast cancers are HER2-negative. If your breast cancer tested HER2-positive, your treatment plan may include anti-HER2 therapy.

This type of cancer generally responds well to treatment, and the outlook is good.

According to the National Cancer Institute, the 5-year relative survival rates for breast cancer are:

  • localized: 99 percent
  • regional spread: 85.8 percent
  • distant spread: 29 percent

This data is based on females diagnosed from 2011 to 2017.

Papillary breast cancer rarely metastasizes (spreads to other parts of the body) and has a better overall survival and prognosis than other breast cancers. Your individual outlook depends on many factors, such as:

  • stage at diagnosis
  • tumor grade
  • age and overall health
  • estrogen and progesterone receptor status
  • HER2 status

Your oncologist can discuss how your risk factors and treatment options may affect your outlook.