Prostrate Cancer

What is Prostate Cancer?

Prostate cancer is a type of cancer that occurs in males. In fact, it is the third most common cancer in Singaporean men1.

The prostate gland is a small gland located below the bladder near the base of the penis. It produces white-coloured fluid that mixes with sperm to form semen.

prostate cancer
Image from American Cancer Society

 

Prostate cancer occurs when there is an abnormal growth of prostate gland cells. Almost all prostate cancers are adenocarcinomas (cancers that start from cells that line glands, which in this case is the prostate gland).

 

What are the Risk Factors of Prostate Cancer?

1. Age

The biggest risk factor for prostate cancer is increasing age. Prostate cancer usually occurs after the age of 50 and is most common in those over 70 years of age.

Only 4.3% of prostate cancer cases were diagnosed in patients aged <55, while 24.6% of cases were diagnosed in the age group of 55-64, and 71.1% of cases were diagnosed amongst those >641.

2. Genetic Predisposition

A small proportion of prostate cancers are due to genetic predisposition. Patients who carry germline mutations in their DNA-repair genes are more likely to develop prostate cancer, regardless of whether they have a family history of prostate cancer. These mutations are built into the genes, and hence can be passed down to children.

4.6% of patients with localised prostate cancer have these genetic mutations, while 11.8% of patients with metastatic prostate cancer have the mutations.2 Localised prostate cancer means the cancer is confined to the prostate gland, whilst metastatic cancer means that the cancer has spread beyond the prostate gland.

Those with a positive family history for prostate cancer are at higher chance of contracting cancer. Having a first-degree relative (such as a father or brother) with prostate cancer increases a man’s risk of having prostate cancer in the future.

Preventing Prostate Cancer

Can changing my diet help with prostate cancer?

A diet high in lycopene (tomato-based) or cruciferous vegetables (broccoli and cauliflower) is linked to a less lethal form of prostate cancer. This can be helpful as some prostate cancers can be slow-growing and do not cause issues. On the other hand, other types of supplements such as Vitamin E and Selenium, have not been shown to help cancer.

What are the Signs & Symptoms of Prostate Cancer?

  • normal prostate

    Most men with early-stage prostate cancer will typically not show any symptoms of the cancer.
  • Increased urinary frequencyurgencynocturia (the feeling of wanting to urinate at night) and hesitancy (involuntary delay in starting urination) are commonly observed, but these symptoms are not specific to cancer. They also occur with benign prostate enlargement; therefore, seek a doctor’s opinion if you are experiencing such symptoms.
  • Haematuria (blood in urine) is an uncommon presentation of prostate cancer.
  • Bone pain may be the presenting symptom in men whose prostate cancer has spread to other parts of the body.
  • Due to the absence of symptoms most of the time, a large proportion of patients are only diagnosed with prostate cancer after further investigations following an abnormal PSA testProstate-specific antigen (PSA) is a protein made by prostate cells, that can be found in your blood.
 
 
 

Prostate Cancer Screening Tests:

There are two main screening tests used to test for prostate cancer. The first is a PSA test, and the second is a digital rectal exam.

1. PSA Screening Test

Since abnormal PSA levels could indicate the presence of prostate cancer, PSA tests might be used as a preliminary screening test for prostate cancer. This test is sometimes included in comprehensive health or cancer screening packages for males.

What is a PSA Screening Test?

A PSA test is a blood test that measures the amount of PSA in your blood.

What are the possible reasons for abnormal PSA levels apart from prostate cancer?

While abnormal PSA levels can indicate cancer, PSA levels can also be elevated because of

  1. Rigorous exercise
  2. Sex
  3. Other prostate conditions, such as benign prostatic hyperplasia (BPH) or prostatitis.

On the other hand, PSA levels can also be suppressed by other factors such as taking certain medications.

Should I do a PSA test?

Due to the limitations of the test, PSA screening for prostate cancer is a very controversial area. There is a variation in the recommendation for PSA screening from major bodies such as the American Cancer Society, United States Preventive Services Task force (USPTF) and United Kingdom National Screening Committee.

The benefits to screening need to be weighed against the potential for:

  1. Over-diagnosis – For example, raised PSA levels does not mean cancer is present, and even if cancer were present, a significant number of prostate cancers are slow-growing and do not result in symptoms or illness, which may mean that treatment may not be necessary. Thus, such scenarios can cause stress and anxiety with no benefit to the patient.
  2. Complications related to subsequent investigations and treatment – Further testing or treatment may lead to issues such as pain, bleeding and infection.

Based on the 2018 USPTF recommendation, PSA testing can be considered for average-risk (no family history) males aged between 55 to 69, who have a life expectancy in excess of 10 years after discussion with a physician on the pros and cons of the screening.

The decision to screen is considered individually for each patient, especially for higher-risk (positive family history) males.

2. Digital Rectal Exam

If the prostate gland has cancer, it can result in abnormal bumps or hard areas on the prostate gland. Thus, such abnormalities might indicate the presence of prostate cancer.

Digital Rectal Examination
Image from National Cancer Institute

What is a Digital Rectal Examination (DRE)?

A Digital Rectal Examination (DRE) is a simple screening test to check for prostate cancer. During this test, the doctor inserts a gloved finger into the rectum to feel the prostate. This allows them to judge if the prostate has abnormal bumps or hardness.

Do I have cancer if my test results are abnormal?

PSA test and Digital Rectal Exam do not conclusively diagnose prostate cancer. Having abnormal test results does not mean you have cancer. The physician might recommend a prostate biopsy to diagnose cancer.

Prostate Cancer Diagnosis and Staging:

How do I confirm if I have prostate cancer?

It is advisable to first confirm the presence of raised PSA levels through a repeat PSA test. If the results are abnormal, the doctor may recommend a prostate biopsy to confirm if the presence of cancer.

What is a prostate biopsy?

Prostate biopsy is a diagnostic test for prostate cancer. The biopsy allows the doctor to remove a small amount of prostate cells that are suspected to be cancerous. The sample of cells will be analysed under the microscope to determine if they are cancerous.

Prostate biopsy is generally safe with a small risk of infection and rarely inflammation of the prostate or urinary retention.

How is the biopsy done?

It is usually performed via an ultrasound-guided procedure through the rectum (also known as a TRUS biopsy).

It is less commonly done through the perineum. Occasionally, MRI-directed prostate biopsy is used in patients who have rising PSA but prior negative prostate biopsy.

Are there any additional tests I might have to do?

An MRI scan of the prostate gland may provide information on high risk features such as spread of cancer to regional lymph nodes or extension of prostate cancer beyond the prostatic capsule. A bone scan and CT scan may be done to exclude distant metastasis (when cancer is spread to other parts of the body). The physician may discuss your suitability for sensitive novel imaging techniques such as PSMA-based PET and whole-body MRI on a case-by-case basis.

Prostate Cancer Treatment at The Cancer Centre, Singapore

While prostate cancer is the sixth most common cause of death among Singaporean men who have cancer, not all men with prostate cancer die of this condition. The treatment and the outcomes will depend on the extent (staging) of cancer at the point of diagnosis.

What are the treatment options for Prostate cancer?

The treatment options for prostate cancer depend on the patient’s age and general health, PSA level, Gleason score (a grade of how aggressive prostate cancer cells look), and the stage of the cancer.

Localised (confined to the prostate) prostate cancer is treated with either active surveillance, surgery, or radiotherapy. Your doctor will select treatment options for you based on a risk stratification scale that is determined by looking at your:
• Gleason score
• PSA level
• local extent
• percentage of prostate biopsy cores that are positive for cancer

Metastatic (spread beyond the prostate) prostate cancer is treated with androgen-deprivation therapy (ADT) and/or chemotherapy and novel antiandrogen.

 

1. Active Surveillance

Who is suitable for Active Surveillance?

Patients with small, low Gleason score prostate cancers which are at low risk of progressing or spreading.

What is Active Surveillance?

Active Surveillance is not a “treatment”. Instead, the physician will monitor the prostate cancer via regular PSA blood tests, digital rectal exams, as well as prostate biopsies.

The goal of surveillance is to avoid treatment-related complications in men who are at low risk of prostate cancer progression. That is because prostate cancer can be slow-growing, and might not cause medical problems.

Thus, no medical treatment will be administered unless there is signs or risk of progression of cancer. Curative-intent (Intent to cure) treatment will be delivered if there is clinical progression.

2. Surgery (Prostatectomy)

What is Surgery for prostate cancer?

Radical prostatectomy (removal of the prostate gland) can be performed either via a minimally invasive surgery (robotic or laparoscopic/key-hole) or an open surgery. All prostate tissue is removed during surgery, and the experience of the surgeon is important for the best surgical outcome.

Potential complications of surgery include urinary incontinence and erectile dysfunction.

How is surgery done?

Laparoscopic/key-hole surgery is done through a small incision (cut). Then, a camera or scope is inserted in the incision. It allows the surgeon to see and remove prostate gland tissues. Robotic surgery includes the use of robotic arms to help the surgeon make more precise movements.

On the other hand, an open surgery is traditionally done with a long incision across the abdomen. As the cut is large, this type of surgery has a longer recovery time and more bleeding and pain compared to robotic or laparoscopic surgery.

3. Radiotherapy

What is Radiotherapy for prostate cancer?

Radiotherapy uses radiation to kill cancer cells. There are two types of radiotherapy that can be used in treatment:

  • External beam radiotherapy (EBRT) utilises an external source of radiation to treat the prostate gland and a margin of adjacent normal tissue.
    brt

    Image from Cancer Research UK

  • Brachytherapy directly implants a radioactive source within the prostate to treat the cancer, thus providing the highest dose of radiation over a very limited distance.
    brachytherapy

    Image from Prostate Cancer Foundation of Australia

  • Potential Complications
    • Early complications (within a day to a week) include inflammation of rectum, urinary frequency, urgency and dysuria which typically resolves
    • Late complications (after a few months to a year) can include urinary incontinence, erectile dysfunction and narrowing of the urethra.

The Treatment of Metastatic Prostate Cancer

Metastatic prostate cancer typically involves the bones. The cornerstone of treatment is androgen-deprivation therapy (ADT), either in the form of surgical castration or medical castration using gonadotrophin-releasing hormone agonist or antagonist. By depriving prostate cancer cells of testosterone stimulation, the majority of the cancerous cells will regress. In some situations, novel antiandrogen or chemotherapy may be added to ADT right at the start of treatment, if the patients have metastatic disease at presentation.

If the cancer progresses after ADT, other treatment options include the use of novel antiandrogen, chemotherapy, bone targeting alpha-emitting radioisotope or PSMA radioligand.

There is still ongoing research in terms of:

  • Identifying biomarkers for treatment selection to assist doctors in selecting the most appropriate treatment
  • Use of active agents in earlier setting, and
  • Planning the optimal sequence of treatment types used.

The physician will work closely with the patient to determine the ideal treatment plan that suits the patient’s needs.

Được thành lập vào năm 2005, Tập đoàn Y tế Singapore (SMG) là một tổ chức chăm sóc sức khỏe với mạng lưới các nhà cung cấp chuyên khoa tư nhân trên bốn trụ cột đã được thiết lập - Thẩm mỹ, Chẩn đoán hình ảnh & Sàng lọc, Ung thư và Sức khỏe Phụ nữ và Trẻ em. Tại Singapore, SMG có hơn 40 phòng khám có vị trí chiến lược ở trung tâm Singapore và các khu trung tâm. Ngoài Singapore, SMG cũng đã có mặt tại Indonesia, Việt Nam và Úc. Tìm hiểu về chính sách bảo mật của chúng tôi tại đây.

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