Luminal B breast cancer: a mismatched group of baddies

We learn about luminal B breast cancer, the cancer that is the most common male breast cancer.


The baddie we are talking about this time is more than a one but rather a ‘onesie’. In other words, it can fit any size and shape. So, if you’re old like me, you remember The Dirty Dozen or Con Air; or more recently the Death Eaters in the Harry Potter movies, or those in Crimes of Grindelwald. So many different magical baddies.

Mismatched group of baddies

Luminal B breast cancer is a mismatched group of baddies that have variable oestrogen and progesterone positivity; and a Ki-67 above 15%. 

This means this baddie has takkies on that can be anything from cool trendy sneakers to serious track shoes. Note, I didn’t mention Usain Bolt as breast cancers are long-distance creatures not sprinters.

Luminal B is about lumping a whole group of cancers together. So, I’m talking about all the other prisoners in the jail. Hence the baddie analogies above. Gee-wiz! What pressure for a treating oncology team!

How do you treat the B and E specialist, or differentiate the embezzler from the murderer when they are locked up? Diagnosing a breast cancer is like having the opportunity to analyse a breast cancer while in jail.

No ‘ist’ at all

So, to recap: let’s remember we are no longer sizeist; ageist; racist, or any ‘ist’! Breast cancer happens to anyone at any age. In fact, most male breast cancers are luminal B.

So, what do we know? We have caught the luminal B breast cancer, locked up in the breast. How was it diagnosed? You felt a mass, you were worried your breast had undergone a change, you went for a mammogram (under duress or as part of screening), and now we have a psychopath to analyse.

When you diagnose a breast cancer by core needle biopsy under radiology guidance (not surgical), one should start with the minimum of a mammogram and ultrasound. A breast MRI (the helicopter birds-eye view) is nice to have as well. T&Cs apply. 

This is a reminder – no surgical biopsies to make the diagnosis; no rushing into emergency surgery, particularly taking off a breast (mastectomy) one or both. Breast cancer doesn’t spread to the other breast. There is no emergency. Rather a detailed attack strategy should be sought via a large multi-disciplinary team prior to starting with treatment.

What is after imprisonment?

Once the luminal B breast cancer is diagnosed (imprisoned), it’s stratified into two groups: spread to the glands (lymph nodes) or not. The best way to check the glands is with a breast ultrasound. If the ultrasound shows no spread, a sentinel lymph node biopsy is the way to confirm this.

Spread to the glands

If the cancer is in the glands, we need to start with primary chemo. Now I have yet to know a single person who lines up outside the door of an oncology suite saying, “I want chemotherapy.” But remember that oncology is the umbrella under which all cancer treatment sits, and chemotherapy helps to attack cancer cells that have spread from the breast.

Let’s digress here for a moment and go back to the age where Alexandra Fleming found penicillin. 

I’m sure every suspected bug was then treated with penicillin…and not that successfully either. Imagine having consumption (TB) and being placed on penicillin, or the plague and being placed on penicillin. Well you would die as penicillin doesn’t work in this setting. This is how oncology was many moons ago. Not now though. So, different cancers require different oncology drugs to achieve successful cancer kill-rates; and oncology treatment is personalised and not ‘penicillin/red drip for all’.

Personalised oncology

Because luminal B breast cancers are such a diverse group, the oncology treatment can be varied. For example, you have an infection and need an antibiotic. The choice is varied as to what to have, as is the way it can be administered.

The term ‘personalised oncology’ is very important today. The team looks at the behaviour of the cancer (considering the Ki-67; the degree of oestrogen (ER) and progesterone (PR) sensitivity; the size of the cancer at presentation and the number of involved lymph nodes. Furthermore, the biological age of the patient as well as medical problems are also considered. 

Remember that in this scenario (cancer in the glands), most people will require radiation after oncology treatment and surgery. Surgery only involves taking the cancer out after the initial oncology treatment, and doesn’t require the original size of the cancer to be excised.

No spread to glands

If luminal B cancer is not in the glands at initial presentation; our unit confirms this with a sentinel lymph node biopsy. Once confirmed that the first gland the cancer drains to is negative, the next step is to remove the cancer. The type of surgery is your choice – either a mastectomy or breast-conserving surgery with immediate reconstruction – made after a discussion with your oncology and reconstructive surgeons.

Post-surgery, the cancer is re-analysed: the size and again the dress code (ER; PR; Ki-67; grade) is considered. Many of these tumours that haven’t spread to the glands should be sent for genetic profiling (read What revs your motor?). If the profiling score is low, these tumours are deemed not to need chemotherapy.

Endocrine therapy

A big T&C for all luminal B breast cancers is the need for endocrine treatment. Endocrine therapy today is for a minimum of five years. It’s the cancer contraceptive pill for preventing cancers from coming back.

It’s always of concern to me, how compliant people are with blood pressure medicine but not cancer endocrine medicine. Before you rush to read the package insert of the side effects, let me paint a cautionary tale.

The biggest side effect of not taking the medicine is cancer returning elsewhere with devastating effects. Cutting out a cancer doesn’t prevent it from returning. The cancer often leaves small cells that spread, hide and nest in obscure places, such as the bone marrow, lungs, liver and brain. 

Endocrine treatment is the most effective way of ensuring a constant security force to prevent these cells from waking. There are different cancer endocrine medicines on the market, and most side effects can be managed, or medicines can be changed.

Discussing the side effects with a member of your treating team is far safer than listening to Gossip Central (aunty, neighbour, friend etc.), or accessing Voldemort by googling medicine side effects. Remember, as different as each person is, so is the cancer and your body’s response to medicine. 

So, before you decide that you can’t manage the medicine, consider the same way a diabetic patient needs to take insulin to survive; how antiretroviral drugs have ensured people can live with HIV for many years, and how blood pressure medicine prevents strokes and heart attacks. Endocrine medicine is the most significant way of preventing hormone-sensitive breast cancers from returning. Furthermore, it’s a critical component in ensuring luminal A and B cancers don’t return or spread.

Final thought

Today the luminal B cancer family ensures that we don’t take a one-size-fits-all treatment option. This diverse family allows oncology physicians and surgeons to offer a wide variety of oncology treatment options. They also ensure that you, the patient, are central in the management decisions of your treatment. 

I look forward one day to us using genetic profiling upfront (i.e. before any treatment by profiling the core needle biopsy) in the treatment decisions for this cancer. Thus, further ensuring we reach our goal of a 100% cancer kill-rate.[/vc_column_text][/vc_column][/vc_row]

Prof Carol-Ann Benn heads up internationally accredited, multi-disciplinary breast cancer centres at Helen Joseph Hospital and Netcare Milpark Hospital. She lectures at Wits University and, in 2002, established The Breast Health Foundation.

MEET OUR EXPERT – Prof Carol-Ann Benn

Prof Carol-Ann Benn heads up breast cancer centres at Helen Joseph Hospital and Netcare Milpark Hospital. She lectures at Wits University and, in 2002, established Breast Health Foundation.


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