Prostate Cancer, Cancer, Theranostics, Prostate Cancer Treatment, Nuclear Medicine

What Is Prostate Cancer?

Prostate cancer is one of the most common cancers in men. Statistically, it is known that 1 out of every ten men will be diagnosed with this disease.

In the United States, the diagnosis is usually in the initial stages, but it does not represent all cases, especially in Latin America, whose diagnosis is late. That is, cancer has metastasised to other organs and tissues.

The most affected population is the one between 65 years of age and older (representing 60% of cases), according to epidemiological data from the American Cancer Society (ACS).

The prostate is a small gland located below the urinary bladder and surrounding the urethra (pelvic cavity). This gland is regulated by the testosterone hormone and is responsible for producing seminal fluid or semen.

Cancer occurs when abnormal growth occurs in the prostate gland, and in many cases, it usually spreads to the surrounding tissues.

What Are the Different Types of Prostate Cancer?

The prostate cancer with the highest incidence of cases is called Adenocarcinoma, which develops from glandular cells (they produce the prostate fluid that binds to semen).

Although it is not the only type, there are others whose percentage of appearance is minimal. Among them, we have:

  • Small cell carcinomas
  • Neuroendocrine tumours (other than small cell carcinomas)
  • Transitional cell carcinomas
  • Sarcomas

Prostate cancer can also be classified according to its growth:

  • Aggressive or fast-growing: The tumour grows rapidly and usually spreads to neighbouring organs quickly.
  • Non-aggressive or slow-growing: the tumour does not grow, or its growth is very slow.

What Causes Prostate Cancer?

Doctors and scientists still do not know the causes that trigger prostate cancer. It is known that family history (a family member with cancer), exposure to radiation, or certain chemical compounds can influence the development of this pathology.

Other risk factors that have already been mentioned are advanced age, obesity, race, especially African ethnicity, which are risk factors for developing.

Age is undoubtedly a relevant factor since it occurs more frequently in men over 65 years of age and with a 14: 1 ratio in men between 60 and 69 years of age.

What Are the Symptoms of Prostate Cancer?

The symptoms of prostate cancer are not always perceptible by the subject since many can go years without knowing that they have such a disease. This event occurs commonly in those patients with slow-growing prostate cancer.

In general, the men who develop symptoms are those whose cancer has advanced in extension and/or size. Among these symptoms, we have:

  • Urinary problems: the frequent desire to urinate, slow urination stream, blood in the urine (hematuria).
  • Sexual issues: sexual dysfunction (impotence), bleeding after ejaculation.
  • Pelvic, back, or chest pain due to the spread of cancer to bone tissue, affecting these areas.
  • Numbness or loss of sensation in the legs and bladder due to the spread of cancer to the spinal cord.

The first symptoms to appear are urinary symptoms. However, some of these symptoms are associated with other pathologies such as benign prostatic hyperplasia and prostatitis.

It is important to note that if some of these symptoms occur – especially hematuria – a specialist doctor should be consulted immediately. Early diagnosis is the key to a speedy recovery.

How Is Prostate Cancer Diagnosed?

The diagnosis of prostate cancer is usually according to the individual’s preference, given that it does not generate symptoms in most cases, and its diagnosis is advantageous.

Sometimes, specific antigen tests produce a false positive, which leads to unnecessary treatments. Routine annual exams and a preventive check-up in the population at risk described above are keys to a more accurate diagnosis.

The doctor will perform a physical examination, and it will review your medical history in detail, emphasising the family history, but may also perform one of the following tests:

Lab tests

Digital rectal exam: The doctor will insert a gloved finger into your rectum to evaluate the presence of lumps, lumps, or an out-of-normal growth of the prostate.

Prostate-Specific Antigen (PSA) Test: This is a test that detects your blood levels.

Biopsy

Prostate biopsy: 

The specialist will extract a small sample of the prostate gland. This test is linked to a Gleason scale. When the score is less than 6, it means it does not have signs of cancer, and if the value is equal to or greater than 7, it may be a sign of cancer.

The PSA tests and biopsy are evaluated by a specialist doctor, who will determine the state and severity of the disease.

Imaging tests

Magnetic resonance (MRI): 

It creates a detailed image of the soft tissues, especially a very clear image of the prostate and neighbouring tissues. It is useful to determine the incision point in case of surgery.

Computed tomography: 

Although it is not a study of choice, it is used in cases where metastases to bone or surrounding organs are suspected – such as screening after chemotherapy or radiotherapy – to see the size of the prostate and determine if the treatment is being effective.

Bone scan: 

Generally speaking – if the prostate cancer has spread – it does so towards the bone tissue, and this scan allows detection of possible areas of metastasis. To corroborate this diagnosis, resonance and/or tomography should be used.

PET/CT:

This is advanced hybrid imaging that utilises radiotracers to detect specific metabolic pathways or cells. In respect to prostate cancer, a ligand called prostate-specific membrane antigen (PSMA) is typically used to detect prostate cancer cells. This form of imaging can be considered the current gold standard of prostate cancer staging.  

What Are the Treatment Options Available for Prostate Cancer?

Your doctor will recommend the best therapeutic options, according to your age and stage of the disease. In some cases, it begins with active surveillance in the absence of symptoms.

In case of preexisting symptoms, the therapeutic alternatives for the treatment of prostate cancer are the following:

1) Radiation

Radiation therapy is one of the therapeutic options used to treat prostate cancer. The most common type is the external beam of radiation, which goes to specific points on the body.

Its primary purpose is to reduce the size of the tumour and cancer cells, which is why half of the patients receive this type of treatment. Its use can be before or after a surgical intervention or in combination with other therapies.

Each radiotherapy session lasts from 10-30 minutes on average, and its frequency being approximately five a week for ten weeks. This may vary depending on the size of the cancer and the specialist’s criteria.

Here are some of the possible side effects of radiation therapy:

  • Involvement of healthy cells that will eventually recover
  • Burning, dry, itchy, and peeling skin condition
  • Diarrhoea
  • Earache
  • Dry mouth
  • Mouth ulcers
  • Throat pain
  • Nausea
  • Difficult to swallow
  • Difficult to urinate, pain, and urinary urgency
  • Sexual dysfunction
  • Joint problems
  • Oedema of the tissues or lymphedema (accumulation of fluids in the lymph nodes)

Most of these effects disappear after two months. In case of persistence, consult your doctor.

2) Chemotherapy

It is a chemical pharmacotherapy procedure whose purpose is to destroy rapidly growing cells, prevent their spread to other regions. In other words, to prevent metastasis, reduce the size of the tumour and reduce the symptoms caused by cancer. Chemotherapy is usually combined with radiation therapy, surgery, or other treatments.

One of the disadvantages of this type of treatment is that other rapidly growing cells can be affected, such as blood cells, skin, hair, and epithelial lining.

Although chemotherapy is beneficial, it generates the following side effects:

  • Presence of bruising and excessive bleeding
  • Diarrhoea
  • Dry mouth
  • Mouth ulcers
  • Fatigue
  • Fever
  • Hair loss
  • Loss of appetite
  • Nausea and vomiting
  • Weight loss
  • Pain from nerve damage
  • Infections
  • Anaemia
  • Constipation
  • Neuropathy
  • Lymphedema
  • Memory and concentration problems
  • Skin and nail changes
  • Insomnia
  • Sexual changes, such as impotence and low sexual desire
  • Fertility changes

These effects are reversed at the end of the treatment, although in some cases, you may see some organ involvement (heart, kidneys, lungs, reproductive organs, and nerves).

3) Targeted Therapy

It is a cancer treatment that uses drugs to destroy cancer cells, causing minor damage to normal cells. Each targeted therapy works differently but has the same goal, which is to destroy cancer. 

Among the most widely used drugs, we have rucaparib (rubraca) and olaparib (Lynparza), which treat metastatic castration-resistant prostate cancer. These help repair cellular DNA damage. The medic will be the one who determines if this type of treatment is necessary.

Targeted therapy has the following side effects:

  • Nausea and vomiting
  • Diarrhoea or constipation
  • Tiredness
  • Loss of appetite
  • Low red blood cell count (anaemia)
  • Skin lesions
  • Abnormalities in blood tests for the liver
  • Low platelet count
  • Cough and shortness of breath
  • Rare cases of blood clots in the legs and lungs

4) Immunotherapy

Immunotherapy is nothing more than a treatment that stimulates the immune system of men with prostate cancer to attack cancer cells. The vaccine is called Sipuleucel-T (Provenge).

This vaccine treats patients with advanced cancer who do not respond to hormone therapy and have little or few symptoms. It is created specifically for each man from his white blood cells in combination with proteins.

The vaccine does not cure cancer, but it does increase survival rates. Once again, it will be the doctor, the one person who determines if you are a suitable candidate for this treatment.

The side effects of immunotherapy are as follows:

  • Fever
  • Shaking chills
  • Tiredness
  • Headache, back, and joint pain
  • Nausea
  • In some cases, breathing problems and hypertension

5) Surgery

Known as radical or partial prostatectomy, where the entire prostate gland (radical) or only a segment of it (partial) is removed. The prostatectomy for both cases can be open, which generates a larger scar at the level of the lower abdomen or of the laparoscopic type, which would be through small incisions.

General or regional (spinal) anaesthesia is usually used, which numbs the lower body.

Patients often choose laparoscopic surgery or robot-assisted prostatectomy since recovery is faster and has fewer side effects. Other types of surgery are laser and endoscopic, and – in both – a probe is inserted through the opening of the penis.

Transurethral Resection of the Prostate and Transurethral Incision of the Prostate (TUIP) is another procedure to cut enlarged prostate segments, which are removed through the bladder.

These are some side effects of the different types of surgery:

  • Blood in the urine
  • Urinary irritation
  • Difficulty holding urine
  • Urinary tract infections
  • Inflammation of the prostate
  • Reaction to anaesthesia
  • Infection of the surgical site
  • Impotence or erectile dysfunction, transient, rarely permanent (only if the nerves are injured)
  • Transient sexual dysfunction, that is, difficulty obtaining orgasms
  • Lymphedema in the leg or genital area

6) Theranostics

In relation to this type of treatment, we will mention two options aimed at prostate cancer:

  1. Radio-223 (Xofigo) Therapy: This drug works like targeted radiation therapy, used when cancer has spread to the bone and helps prevent symptoms of the disease.
  2. Prostate-Specific Membrane Antigen (PSMA) Therapy with Lutetium-177: Like all theranostics therapies, it is a nuclear medicine radionuclide treatment. This allows for very specific and targeted radiation therapy.

These are some side effects of the theranostic treatment of radio-223 therapy (Xofigo):

  • Decrease in red, white blood cells and platelets
  • Patients with low-grade myelosuppression are the most common.
  • Nausea and vomiting
  • Diarrhoea
  • General weakness

Side effects of prostate-specific membrane antigen (PSMA) therapy with lutetium-177:

  • Decrease in red, white blood cells and platelets (transitory event)
  • Nausea and fatigue
  • 10-20% of patients experience decreased salivation

Who Will Benefit From Treatment With Radium-223 (Xofigo) Therapy?

 

It is a targeted radioactive therapy that is ideal for patients with metastatic castration-resistant prostate cancer (mCRCP) that has metastasised to bone and generates symptoms in the patient without visceral metastases and biochemical progression.

Who Will Benefit From Treatment With Lutetium-177 Prostate-Specific Membrane Antigen (PSMA) Therapy?

Lutetium-177 PSMA therapy (“Lu177 PSMA therapy”) is a treatment for those individuals who cannot tolerate chemotherapy, have bone marrow involvement, or have mCRPC.

This therapy has shown a significant improvement in these types of patients, thanks to the fact that it acts as a radiation therapy directed at cancer cells.

What Are Some Questions I Should Be Asking My Doctor When Considering Treatment Options for Prostate Cancer?

  1. How far has the prostate cancer spread? Do I have metastases?
  2. Is my prostate cancer fast-growing?
  3. What is my best treatment option?
  4. Can I be left with sexual impotence?
  5. What is my real life expectancy after treatment?
  6. Would a prostatectomy be the best option to avoid metastasis?
  7. Do you know of any trials with less invasive alternative treatments?