Breast Cancer and Uterine Cancer: What Is the Relationship?

Breast cancer and uterine cancer may not seem associated with each other, but there is an increased risk for one if you have had the other. This is due to shared risk factors like hormone levels and several lifestyle factors, as well as treatments for one cancer increasing the risk of the other.

While risk can increase, it’s important to remember that having one type of cancer does not necessarily mean you will develop the other type.

Read on to learn more about breast cancer and uterine cancer, and the relationship between them.

Connection Between Breast Cancer and Uterine Cancer

People treated for breast cancer with the drug Nolvadex (tamoxifen) have a higher risk of later developing uterine cancer. Extended exposure to estrogen and certain lifestyle factors, like obesity and diet, are also linked to both cancers.

Having one cancer does not necessarily mean you will develop the other. However, your risk of developing the other cancer is increased. Talk with your healthcare provider about your risk and how you will be monitored for any subsequent cancers.

Risks

It is not very common for a person to have both breast cancer and uterine cancer at the same time. It is more likely that you would develop one cancer sometime after being treated for the other cancer.

If you are treated with tamoxifen for breast cancer, your uterine cancer risk increases. The risk is dose-dependent, which means it increases with the amount of time you are on it and the dosage you use. The increased relative risk of developing uterine cancer after taking tamoxifen for breast cancer is about 2 to 3 times that of the general population.

A 2022 study exploring breast cancer after uterine cancer found that the increase in breast cancer risk after uterine cancer was highest in the first three years after the uterine cancer diagnosis, and the median time to develop secondary breast cancer was 6.4 years. Older women had a shorter time between the two diagnoses than younger women did.

Treatment and Management of Breast Cancer With Uterine Cancer

As mentioned, it’s not common to have both cancers at the same time. It is more likely for a person to develop the second cancer after being treated for the first cancer.

Treatment for breast cancer depends on the stage of the cancer, a person’s general health, and any medical factors, personal preferences, and characteristics of the cancer like hormone status or any proteins or tumor markers.

Treatment usually consists of more than one modality and can include:

• Surgery: Removal of the tumor and tissues to which it may spread
• Radiation: Use of high-energy particles to destroy a tumor
• Chemotherapy: Medications that target rapidly dividing cells
• Targeted therapy: Therapies that directly target cancer cells or signaling pathways that contribute to the growth of cancer cells
• Immunotherapy: Treatment that uses the immune system or products of the immune system
• Hormone therapy: Treatment that blocks the production of hormones or the effects of hormones that can contribute to the growth of cancer cells

Treatment for uterine cancer depends on the type (uterine sarcoma, which is very rare, or endometrial cancer) and stage of the cancer, a person’s age and general health, personal preferences, and characteristics of the cancer.

It can consist of one or more types of treatment, including:

• Surgery
• Radiation
• Chemotherapy
• Targeted therapy
• Immunotherapy
• Hormone therapy

Your healthcare team will review all of your treatment options. By talking through each option, along with the risks, benefits, and side effects, you will be able to make an informed decision about your care.

Prevention

There is no definitive way to prevent subsequent breast or uterine cancer after having the other type of cancer. However, there are things you can do that can help reduce your risk. Your healthcare team will discuss your individual risk for subsequent cancers. It also helps to practice preventive measures.

Lifestyle Modifications

Several factors are linked to both breast and ovarian cancer and can be managed by making lifestyle changes.

Obesity, a high-fat diet, and lack of exercise have been linked to increased risk of both breast and uterine cancer. A high-fat diet is linked to both cancers and can lead to obesity. Obesity can impact estrogen levels, which is also linked to both kinds of cancer.

Eating a healthy diet, maintaining a healthy weight, and getting adequate physical activity are good for overall health and can help reduce your cancer risk.

Cancer Screening

If you’ve had breast or uterine cancer, talk with your healthcare team about what this means for subsequent cancers and what your cancer screening will look like.

If you have been treated for breast cancer, especially with tamoxifen, your healthcare provider will monitor you for endometrial hyperplasia (thickening of the uterine lining) or cancer.

If you are premenopausal, routine gynecologic care is sufficient. If you are postmenopausal and are having any bloody vaginal discharge, spotting, or bleeding, this should be investigated immediately.

If you first had uterine cancer, your risk for breast cancer is elevated, particularly in the first three years after your first cancer diagnosis. Talk with your healthcare provider about what this means for your breast cancer screening, based on your age, family history, and ethnicity.

Summary

If you have had breast or uterine cancer, your risk of developing the other cancer is increased. Your risk can vary, depending on the kind of treatment you have had, your age and medical and family history, and the characteristics of your cancer. Your healthcare provider can discuss this in detail with you.

While you cannot eliminate your risk of developing a second cancer, you can take steps to help keep yourself as healthy as possible and minimize risk factors. Being aware of the increased risk can also help you stay vigilant about any symptoms that might develop.

Staying on top of regular screenings and follow-up appointments can also help keep you healthy and detect any issues as early as possible.

A Word From Verywell

Surviving cancer can be challenging, especially emotionally. Knowing you have an increased risk of developing another cancer can be doubly concerning.

Having an increased risk for cancer is stressful. Talk with your treatment team about resources like a support group at your treatment center or hospital, or ask for a referral for a local therapist who specializes in working with people living with cancer or chronic illness.