Breast Cancer and Estrogen in Grand Rapids, Michigan

Many Different Types of Breast Cancer

Breast cancer is not a single disease. There are many different types, and around 70% are sensitive to the female sex hormone estrogen. These cancers have special proteins on their cells called estrogen receptors. When estrogen binds to these receptors, it can promote cancer cell growth and spread. These are called estrogen receptor–positive (ER-positive) breast cancers.

When breast cancer is diagnosed in Grand Rapids, pathology labs at local hospitals such as Corewell Health (formerly Spectrum Health), Trinity Health Grand Rapids, Metro Health – University of Michigan Health, and Mercy Health routinely test tumor samples to see if they have these hormone receptors. This helps your care team decide which treatments are most likely to work.

Hormone (Endocrine) Therapy as a Treatment

How Estrogen Is Produced Before and After Menopause

  • Before menopause:
    The ovaries are the main source of the hormones estrogen and progesterone.

  • After menopause:
    The ovaries stop making most hormones. Instead, estrogen is produced in body fat, including fat in the breast tissue. This is especially important in areas like West Michigan, where weight gain can be more common in winter months due to reduced outdoor activity.

How Hormone Therapy Works

Hormone (endocrine) therapy for breast cancer works by:

  • Lowering the amount of estrogen in the body, and/or
  • Blocking estrogen from attaching to breast cancer cells

Depending on your age and menopausal status, hormone therapy may be used to:

  • Stop estrogen production in the ovaries (for premenopausal women)
  • Reduce estrogen production in fat cells (for postmenopausal women)
  • Prevent estrogen from interacting with tumor cells

Hormone therapy can:

  • Reduce the chance that breast cancer will come back
  • Reduce the chance it will spread to other parts of the body

Breast cancer is rare in women under age 25, but the risk increases with age. It is most common in postmenopausal women, and most of those cancers are hormone receptor–positive.

Aromatase and Estrogen Production in the Breast

What Is Aromatase?

As women age, fat cells in the breast make increasing amounts of an enzyme called aromatase. Aromatase converts other hormones into estrogen.

  • With age, estrogen levels within the breast tissue increase
  • This locally produced estrogen can contribute to the development and growth of breast cancer, especially in postmenopausal women

Once an ER-positive tumor is established, it can further increase local estrogen levels to help itself grow. Immune cells in the breast tissue may also boost estrogen production around the tumor.

Obesity, Estrogen, and Breast Cancer Risk

Studies show a strong link between obesity and higher estrogen levels, especially after menopause. Research has found that:

  • Obesity can double the risk of breast cancer in older women
  • This is likely because women with more body fat have more cells that produce estrogen

In Grand Rapids and across Michigan—where cold winters, less sunlight, and indoor living can contribute to weight gain—maintaining a healthy weight is an important part of breast cancer risk reduction.

Treatment Options for ER-Positive Breast Cancer in Grand Rapids

Treatment for ER-positive breast cancer typically involves a combination of therapies. Depending on the stage and type of cancer, your care plan in Grand Rapids may include:

  • Surgery

    • Lumpectomy – removal of the tumor and some surrounding breast tissue
    • Mastectomy – removal of the entire breast

  • Radiation therapy (radiotherapy)
    Precisely targeted x-rays to destroy cancer cells, often after lumpectomy.

  • Chemotherapy
    Medications that circulate through the body to destroy cancer cells.

  • Hormone (endocrine) therapy
    Medications that block or lower estrogen to prevent it from helping cancer cells grow.

These treatments are available through major cancer centers in Grand Rapids, including Lemmen-Holton Cancer Pavilion (Corewell Health), Trinity Health Lacks Cancer Center, and other specialty clinics in the metro area.

Types of Hormone (Endocrine) Therapies

Hormone therapies can be used:

  • Before or after breast surgery
  • After chemotherapy or radiotherapy
  • Instead of surgery (when surgery is not possible due to other health issues)
  • If breast cancer has spread (metastatic disease) or has returned

1. Ovarian Suppression Therapy

Ovarian suppression is used for premenopausal women with ER-positive breast cancer. It works by stopping the ovaries from making estrogen.

It can be done by:

  • Surgical removal of the ovaries (oophorectomy/ablation)

    • Permanent decrease in estrogen production
    • Done as a one-time procedure

  • Medications called gonadotropin-releasing hormone (GnRH) agonists

    • Temporarily “switch off” the ovaries
    • Estrogen production usually returns after treatment stops

Ovarian suppression may be combined with other hormone therapies to improve outcomes in younger women in Grand Rapids who have ER-positive tumors.

2. Anti-Estrogen (Selective Estrogen Receptor Modulator) Therapy

Anti-estrogen medications block estrogen receptors on breast cancer cells so estrogen cannot attach and stimulate growth.

The most commonly used medication is:

  • Tamoxifen
    • Often taken for 5–10 years after surgery
    • Reduces the risk of breast cancer recurrence
    • Lowers the risk of cancer developing in the other breast

Possible Side Effects of Tamoxifen

Side effects vary, but may include:

  • Hot flashes
  • Trouble sleeping
  • Vaginal dryness or discharge
  • Irregular periods (in premenopausal women)
  • Low mood or emotional changes
  • Weight gain
  • Decreased libido (sex drive)
  • Hair thinning
  • Skin changes

For most women, especially those treated at comprehensive cancer centers in Grand Rapids, the benefits of tamoxifen outweigh the risks, but your oncology team will discuss your personal situation in detail.

3. Aromatase Inhibitor (AI) Therapy

Aromatase inhibitors (AIs) are mainly used in postmenopausal women. They block the aromatase enzyme, reducing estrogen production in fat tissue, including the breast.

Common AIs include:

  • Anastrozole
  • Exemestane
  • (Also letrozole, though not mentioned in the original text, is widely used in practice)

By blocking aromatase, these medications:

  • Lower estrogen levels in the breast
  • Help reduce the risk of cancer coming back
  • Are often used instead of, or after, tamoxifen

Studies show that AIs can provide more benefit with fewer serious side effects than tamoxifen for many postmenopausal women.

Newer therapies, such as fulvestrant, work by causing the breakdown (degradation) of the estrogen receptor itself.

Possible Side Effects of Aromatase Inhibitors

Potential side effects include:

  • Hot flashes
  • Joint stiffness or joint pain
  • Bone thinning or osteoporosis

Because the body still needs some estrogen for healthy bones and cardiovascular health, AIs are generally used only in postmenopausal women, and bone health is monitored closely. This is especially important in Michigan, where vitamin D deficiency can be more common due to limited winter sunlight, which may further affect bone health.

Researchers are working on newer medications that selectively block estrogen production only in the breast, aiming to protect other tissues.

Breast Cancer and Hormone Replacement Therapy (HRT)

Menopause can cause uncomfortable symptoms, including:

  • Hot flashes
  • Night sweats
  • Vaginal dryness
  • Sleep problems
  • Mood changes

Hormone replacement therapy (HRT) can ease these symptoms by boosting estrogen and sometimes progesterone levels. HRT may also:

  • Reduce the risk of osteoporosis
  • Help protect heart health in some women

However, because some breast cancers depend on estrogen, long-term HRT can affect breast cancer risk:

  • Using HRT for more than five years is associated with a small (about 30%) increased risk of breast cancer
  • Using HRT for a shorter time (around two years) appears to carry no significant increase in risk compared with women who have never used HRT

For many women in early post-menopause, the benefits of short-term HRT may outweigh the risks, but this decision should always be made with a healthcare provider who understands your personal and family cancer history.

In Grand Rapids, talk with your primary care provider, gynecologist, or menopause specialist about whether HRT is appropriate for you, especially if you have a history of breast cancer or a strong family history.

Local Support and Resources in Grand Rapids, MI

Living with breast cancer or managing breast cancer risk can feel overwhelming, but there are many local resources in the Grand Rapids area:

  • Your GP / Primary Care Provider
    First point of contact for screening, referrals, and ongoing care.

  • Oncology and Breast Centers

    • Corewell Health (Spectrum Health) breast and cancer programs
    • Trinity Health Grand Rapids – Lacks Cancer Center
    • Metro Health – University of Michigan Health cancer services
    • Mercy Health cancer care programs

  • Kent County Health Department
    Offers information on cancer screening, women’s health, and local support programs.

  • Grand Rapids Public Health and Community Clinics
    May provide low-cost or sliding-scale mammograms and follow-up services for eligible patients.

  • Local and National Cancer Support Organizations

    • Support groups and survivorship programs at Lemmen-Holton Cancer Pavilion and Lacks Cancer Center
    • Online and in-person breast cancer support groups throughout West Michigan
    • National organizations (e.g., American Cancer Society) with resources specific to Michigan residents

If transportation, insurance, or financial concerns are a barrier, social workers and patient navigators at Grand Rapids hospitals can help connect you with transportation assistance, financial counseling, and community support services.

Key Points to Remember

  • Around 70% of breast cancers are estrogen receptor–positive (ER-positive).
  • If a tumor is ER-positive, hormone (endocrine) therapy may be used to lower estrogen levels or block its action.
  • Breast cancer risk increases with age and is most common in postmenopausal women.
  • Ovarian suppression can be an effective treatment for ER-positive tumors in women of childbearing age.
  • Tamoxifen is the most commonly used anti-estrogen medication and is often prescribed after surgery to lower the risk of recurrence or spread.
  • Aromatase inhibitors are usually used in postmenopausal women and can be more effective than tamoxifen in some cases.
  • Long-term HRT slightly increases breast cancer risk; short-term use in early menopause may be safe for many women but should be carefully discussed with a doctor.

For personalized advice, breast cancer screening, or treatment options in Grand Rapids, consult your local healthcare provider or breast cancer specialist. Early detection and tailored treatment significantly improve outcomes.