Risk stratifying of prostate cancer

Dr Sithembile Ngidi educates us on the risk stratifying system of prostate cancer.

Once a patient has been diagnosed and the tumour biological behaviour (personality) has been identified, treatment modalities are chosen, based on what risk profile the cancer falls into. 

Parameters, such as prostate-specific antigen (PSA) level, Gleason score and T-staging, determine the risk profile. Other factors considered are patient choice, lifestyle, medical co-morbidities, risks and benefits, and life expectancy.

I tell my patients to think of the risk profiles as dogs. Low-risk being your small friendly dogs, like a Chihuahua, which further divides into very low-risk and low-risk. This is the type of dog you put a bow on and carry around. This cancer is well-behaved. In very low-risk, its sleeping and you have time. So, you can simply watch and monitor closely over time. Low-risk in a younger or healthy man, you can be proactive with a single form of treatment. 

Then intermediate-risk is like a Jack Russell; it’s still small but can be quite feisty and you need a more active approach. Here you need to take control of the cancer, so it doesn’t turn on you and become aggressive and dangerous.

High-risk is your Rottweiler or Doberman. An aggressive approach is needed so these cancers can be stopped in their tracks or they can cause great damage.

Metastatic cancer is when the cancer has spread to other organs of the body.This is the Pitbull. A beast that has gone rampant. Here symptom control, like pain management, and actively slowing the disease with systemic treatment and quality of life becomes the goal. A multi-disciplinary team approach is imperative.   

Risk profiles

1. Low-risk 

• PSA level: less than 10.
• Gleason score: of 6.
• T-staging: T1 staging. 
• Low-risk or very low-risk subgroup.

Low-risk treatment

Only one treatment modality is needed. The treating doctors will choose one of three options:

Watchful waiting – You carefully continue to monitor the patient with a PSA level test, digital rectal exam, and imaging every year. This is only chosen if the patient is compliant in coming for check-ups every year, and for elderly men.

Brachytherapy – a form of radiotherapy where sealed radiation pellets are placed inside the prostate. This can be high-dose (temporary) or low-dose (permanently). The downtime is low, with the patient discharged the next day, up and about, with minimal side effects. There are certain criteria that your oncologist will review to ensure that this is a suitable treatment choice.

Prostatectomy – surgical removal of the whole prostate. 

Before brachytherapy came to the forefront, this was the widely-chosen treatment. There are side effects, such as erectile dysfunction, nerve damage, incontinence, and long-recovery process. 

The survival rate at five years for low-risk is excellent at 100%.

2. Intermediate-risk

• PSA level: between 10 – 20.
• Gleason score: of 7.
• T-staging: T1 and T2 staging.
• Favourable or unfavourable subgroup. 

Intermediate-risk treatment

Two treatment modalities are needed to tame this cancer. The chosen plan is a discussion between oncologist and patient on what best suits the patient and his disease profile. Five-year survival is nearly 100%. 

The two modalities can either be:

• Brachytherapy, and hormone treatment for six months. 
• Prostatectomy, and hormone treatment for six months.
• External beam radiation of the prostate for seven weeks, and hormone treatment for six months.

What is hormone treatment?

Also known as androgen deprivation therapy, the aim is to reduce testosterone/androgens levels in the body. These androgens are food for prostate cancer and drive the cancerous process. We can achieve castration in two ways: surgically removing the testes, or chemically with drugs. 

There are two types of hormone treatment that work on the brain to stop the release of hormones: luteinizing hormone-releasing hormone (LHRH) agonists and antagonists, and anti-androgens which work peripherally.

The antagonists drug is given monthly while the agonists are given monthly or three-monthly. These can come in the form of pellets or fluid that are injected under the skin. There are cons of using hormone therapy, such as hot flushes, low libido, weight gain and irritation. 

Choice of drug is dependent on patient factors, such as other medical conditions, side effects, choice and ease/compliance to treatment and follow-up. 

Anti-androgens are oral tablets that work on the testes and prostate decreasing the testosterone level. Depending on their risk profile, patients will be given six-month treatment (intermediate-risk), or it could be for two to three years (high-risk), or for the rest of the patient’s life (metastatic).

3. High-risk 

• PSA level: over 20.
• Gleason score: over 7 (8-10).
• T-staging: T3 and T4.

High-risk treatment

Multiple treatment modalities are needed here, irrespective of whether the cancer has or hasn’t spread outside the prostate gland. The combinations and sequencing of treatment chosen are dependent on local and regional spread of the cancer and patient profile and choice.

The modalities are surgery, brachytherapy, external beam radiation, and hormone therapy (two to three years). Provided that all treatment is adhered to, the survival rates is quite favourable.

Metastatic disease

Treatment is based on patient presentation, severity of symptoms and sites of metastatic spread, patient co-morbidities and choice. 

Hormonal therapy is the mainstay and is lifelong, or changed when patients develop resistance to castration. Other treatment choices are chemotherapy; biological immunotherapy; or palliative radiotherapy to relive symptoms.

MEET OUR EXPERT  – Dr Sithembile Ngidi

Dr Sithembile Ngidi is a clinical and radiation oncologist in Johannesburg. She is passionate about prostate cancer. She is also an honorary lecture at the University of Kwa-Zulu Natal and provides teaching support to registers in radiation oncology at Charlotte Maxeke Johannesburg Academic Hospital.