In looking at the Luminal A and Luminal B breast cancer sub-types, we’ve summarised excerpts from a variety of expert sources into which we’ve included links for you to follow for deeper insights.
Luminal A and Luminal B types:
- The luminal types are estrogen receptor (ER)–positive.
- The gene expression patterns of these cancers are similar to normal cells that line the breast ducts and glands (the inside of a duct or gland is called its lumen).
- Luminal A cancers are low grade, tend to grow fairly slowly, and have the best prognosis.
- Luminal B cancers generally grow somewhat faster than luminal A cancers and their outlook is not as good.
Luminal A — the least aggressive and most common subtype — accounts for 42% to 59% of all breast cancers, according to background information in the study.
Luminal B typically occurs in younger women and accounts for about 10% of all breast cancers.
Current research suggests that luminal A and luminal B cancers are two completely different diseases, and work is being performed to better distinguish between these two disease types so as to deliver more effective therapy to individual patients.
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- These cancers grow slowly.
- When cancers turn up on screening mammograms, they are most often Luminal A.
- They have a cure rate of more than 90% and generally can be treated with limited surgery and radiation.
- Chemotherapy is usually not necessary.
- Compared to Luminal A, these cancers are more likely to grow aggressively
- Can spread into blood vessels and the lymph system.
- Not as aggressive as Basal and HER2-positive cancers.
- Luminal B cancers can be challenging to remove completely, so a second surgery is sometimes necessary to achieve clear surgical margins around the tumor with no cancer cells.
- Luminal A breast cancer cells can remain in a single location without spreading into the lymph system or blood stream.
- Because Luminal A breast cancers are so slow-growing and unlikely to spread, there is a risk of overtreatment.
- Luminal A breast cancers can generally be cured without chemotherapy, using limited surgery alone or in combination with radiation therapy.
- Left untreated, there is a possibility that Luminal A cancers can develop into Luminal B cancers.
- Unlike Luminal A cancers, which are situated in a specific site, Luminal B cancers can manifest in multiple sites within a particular region of the breast, with normal breast tissue existing in between.
- In these instances, mammography often underestimates the size of primary cancers and fails to detect secondary cancers.
- Magnetic resonance imaging (MRI) can help to more accurately measure and detect Luminal B cancers.
- Treatments for Luminal B breast cancers can include limited surgery, mastectomy, radiation therapy and chemotherapy.
- Recommended treatment options available to each woman will vary based on a range of personal factors regarding her disease and her risk factors.
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