By Alice Goodman
January 25, 2016
The ability to classify breast cancer according to biologic subtype has enabled researchers to dig deeper and determine which therapies benefit specific subgroups. Encouraging evidence from an analysis of a Danish trial presented at the 2015 San Antonio Breast Cancer Symposium suggests that patients with luminal type A breast cancer can safely forgo chemotherapy.1
“A large body of evidence suggests that luminal type A breast cancer has the best prognosis of all breast cancer subtypes. It has been difficult to do randomized trials without offering women with breast cancer adjuvant chemotherapy, because we know it helps them. We need prospective randomized trials to establish that these low-risk women do not need chemotherapy,” explained lead investigator Torsten O. Nielsen, MD, PhD, Professor in the Department of Pathology and Laboratory Medicine at the University of British Columbia, Vancouver, Canada.
Dr. Nielsen and colleagues performed a test of interactions between chemotherapy benefit and breast cancer subtypes based on women treated in a phase III randomized trial of chemotherapy vs no chemotherapy. “This is the best way to test whether intrinsic breast cancer subtype predicts the value of chemotherapy,” he said.
The investigators used tissue samples from the Danish Breast Cancer Cooperative Group 77B (DBCG77B) trial of 1,146 premenopausal women with node-positive, high-risk breast cancer with any hormone receptor or HER2 status. High-risk features included tumors of 5 cm or greater or node-positive status; hormone receptor and HER2 status were not ascertained because in 1977, when the trial was started, this was not standard of care.
In the DBCG77B study, all women received standard treatment (for 1977): mastectomy plus axillary node dissection plus radiation. They were then randomly assigned to one of two no-chemotherapy arms (receiving levamisole [Ergamisol] or no agent), or one of two chemotherapy arms (receiving single-agent cyclophosphamide or combination therapy with CMF [cyclophosphamide, methotrexate, and fluorouracil]). Both cyclophosphamide and CMF improved 10-year disease-free survival and 25-year disease-free survival.
For the present study, an interaction test was conducted between luminal A status and chemotherapy for the trial’s primary endpoint of 10-year disease-free survival. “This was a formal prospective-retrospective study,” Dr. Nielsen noted.
The main finding was that luminal A patients had similar 10-year disease-free survival with and without chemotherapy regardless of whether they were node-positive and not on hormonal therapy, whereas non–luminal A patients were 50% more likely to survive disease-free at 10 years if they were treated with chemotherapy. The interaction between chemotherapy and luminal A/non–luminal A subtypes was significant (P < .05).
Dr. Nielsen acknowledged several caveats about this trial. The immunohistochemistry method has limited analytic validity as a clinical test, and this was a tissue microarray study on blocks recollected for gene-profiling analysis. Moreover, this was an older trial, in which patients did not receive modern treatments such as endocrine therapy, anthracyclines, or taxanes.
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Nonetheless, he told The ASCO Post, “This study extends the body of evidence showing that women with low-molecular-risk breast cancers do not benefit from aggressive therapy.” That being said, larger prospective studies are needed to change practice in this regard. ■
Disclosure: Dr. Nielsen has disclosed royalties and receipt of intellectual property rights and consulting fees from NanoString Technologies as well as ownership interest in Bioclassifer LLC.
1. Nielsen TO, Jensen MB, Gao D, et al: High-risk premenopausal luminal A breast cancer patients derive no benefit from adjuvant chemotherapy: Results from the DBCG77B randomized trial. 2015 San Antonio Breast Cancer Symposium. Abstract S1-08. Presented December 9, 2015.
— Update: 12-03-2023 — cohaitungchi.com found an additional article What Is Luminal A Breast Cancer? from the website www.verywellhealth.com for the keyword luminal a breast cancer treatment.
Breast cancer is one of the most common cancers for women, with approximately 1.3 million new cases diagnosed worldwide each year. Breast cancer can be divided into two overarching categories: Invasive (meaning it has spread) or non-invasive (localized). Luminal A is one of the four types of invasive breast cancer.
Learn more about luminal A breast cancer, its symptoms, causes, diagnosis, treatment, and more.
Types of Breast Cancer
Breast cancer is generally considered non-invasive or invasive. Non-invasive breast cancer is localized or contained within breast’s milk ducts or lobules. Invasive breast cancer means cancer has spread or metastasized outside of these areas.
Non-Invasive Breast Cancer
Types of non-invasive breast cancer fall into one of these two broad categories:
- Ductal carcinoma in situ (DCIS): DICS is non-invasive cancer within the lining of the milk ducts in the breast tissue.
- Lobular carcinoma in situ (LCIS): LCIS is not considered cancerous but is a risk factor for breast cancer. LCIS means there are abnormal cells in the lobes of the breast.
Invasive Breast Cancer
Most breast cancers are considered invasive, meaning the abnormal cancer cells have grown outside the initial point of origin and are now growing in the surrounding breast tissue. Invasive breast cancers tend to fall into four main categories, based on hormone receptor (HR) sensitivity and human epidermal growth factor receptor 2 (HER2) sensitivity (a protein on the outside of breast cells that instructs them to grow).
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The four main categories of invasive breast cancer include:
- Luminal A (HR+/HER2-): Luminal A is the most common type of breast cancer. It tends to grow slowly and is less aggressive than other types. Luminal A is considered to have a favorable prognosis because it is hormone receptor sensitive and is HER2-negative.
- Luminal B (HR+/HER2+): Luminal B is hormone receptor sensitive, but the cancerous tumors associated with Luminal B tend to be a higher grade (more abnormal) than Luminal A. Additionally, Luminal B is HER2-positive, so outcomes tend to be poorer.
- Basal-like (HR-/HER2-): Sometimes referred to as triple-negative breast cancer, basal-like breast cancer tend to have poorer outcomes due to lags in treatment advances. In addition, basal-like breast cancer tends to occur more frequently in Black women, pre-menopausal women, and women with a BRCA1 gene mutation.
- HER2-enriched (HR-/HER2+): Despite significantly improved outcomes due to treatment advances, HER2-enriched breast cancers are among the most challenging types of breast cancer to treat.
Breast Cancer Symptoms
Depending on the breast tissue density, it can be difficult to notice symptoms of breast cancer early on. Performing monthly self-breast examinations can assist with the early detection of breast cancer by identifying subtle changes associated with it, such as:
- Nipple or breast changes, such as unexplained size or shape changes, skin dimpling, or newly identified asymmetry of the breast
- Changes in skin texture or enlargement of the breast skin pores, sometimes described as feeling or looking like an orange peel or a lump not present before
- Nipple discharge in the absence of breastfeeding, which could appear clear, milk-like, or bloody
- Newly identified tenderness in a specific area of the breast, or the nipple
Most of the time, there is no known cause of breast cancer, also known as idiopathic. Cancer grows due to damaged DNA in a cell; environment, genetics, or a combination of environment and genetics can result in breast cancer. However, some inherent risk factors for breast cancer cannot be changed or avoided. These include:
- Sex (assigned at birth): Breast cancer occurs in women at a rate 100 times that of men.
- Age: Breast cancer is more prevalent in women over age 55.
- Race: Breast cancer is more prevalent in White women than in any other race.
- Family history: A family history of breast cancer increases breast cancer risk, particularly if there is a known genetic mutation in the BRCA1 or BRCA2 genes.
- Menstrual and reproductive factors: Menstruation onset before the age of 12, menopause after age 55, giving birth to a first child at an older maternal age, or never having given birth are risk factors for breast cancer.
Other risk factors that can be controlled or changed to minimize the risk of developing breast cancer include:
Read more What Is Luminal A Breast Cancer?
- Unhealthy or unbalanced diet
- Alcohol use
- Radiation therapy to the chest
- Menopausal hormone therapy
A breast cancer diagnosis is primarily made through mammography. Other technologies used in addition to mammography include breast ultrasound, breast magnetic resonance imaging (MRI), and molecular breast imaging.
Additional testing that may be done following mammography findings include:
- Breast biopsy
- Genetic testing of blood samples
Treatment options should be discussed with your healthcare provider and may depend on preferences, risks, stage of cancer, and tumor size, among other factors. Breast cancer treatment often includes:
- Hormone therapy
- Radiation therapy
- Targeted medication therapy
Studies have shown that luminal A breast cancer responds best to hormone therapy. Luminal A breast cancer tends not to respond to chemotherapy or radiation therapy as well as it does to hormone therapy.
Many factors affect a breast cancer prognosis, including:
- Type of breast cancer (such as the presence of hormone receptors or HER2)
- Invasive versus non-invasive breast cancer
- Stage of breast cancer
- Risk factors
It is essential to have discussions with your healthcare provider about how different factors might impact your breast cancer diagnosis.
Luminal A breast cancer has a 75% to 80% response rate with hormone therapy and has a 90% or higher 10-year survival rate.
Unfortunately, invasive breast cancer affects approximately 1 in 8 women and kills 1 in 39 women. Receiving a breast cancer diagnosis is often overwhelming, but there are many organizations available to help with support and resources.
For example, the American Cancer Society can assist with transportation to treatment and other cancer-related needs or places to stay if treatment options are far from home and provide a helpline available 24/7 to answer questions.
Breast cancer affects many women worldwide. Luminal A is one of the most common forms of invasive breast cancer. Understanding your risk factors and early detection and diagnosis is essential for long-term outcomes.
Many breast cancer treatment options exist, but luminal A breast cancers respond best to hormone therapy. The prognosis for luminal A breast cancer is good, with high survival rates. If you need help after a breast cancer diagnosis, many organizations are available to assist with resources and support.
A Word From Verywell
Being told you have breast cancer can be frightening and overwhelming. Understanding what type of breast cancer you have, available treatment options, and where or who you can turn to for support is important in taking an active role in your recovery. Remember that you are not alone and that luminal A breast cancer survival rates are high.