Prostate Cancer

Prostate cancer

The prostate is a part of the male reproductive organ that helps make and store seminal fluid. In adult men, a typical prostate is about three centimetres long and weighs about twenty grams. It is located in the pelvis, under the urinary bladder and in front of the rectum. The prostate surrounds part of the urethra, the tube that carries urine from the bladder during urination and semen during ejaculation. Because of its location, prostate diseases often affect urination, ejaculation, and rarely defecation. The prostate contains many small glands which make about twenty percent of the fluid constituting semen. In prostate cancer, the cells of these prostate glands mutate into cancer cells. The prostate glands require male hormones, known as androgens, to work properly. Androgens include testosterone, which is made in the testes.

The cancer cells may metastasize (spread) from the prostate to other parts of the body, particularly the bones and lymph nodes. Prostate cancer may cause pain, difficulty in urinating, problems during sexual intercourse, or erectile dysfunction. Other symptoms can potentially develop during later stages of the disease.

Management

Treatment for prostate cancer may involve active surveillance (monitoring for tumor progress or symptoms), surgery (i.e. radical prostatectomy), radiation therapy including brachytherapy (prostate brachytherapy) and external beam radiation therapy, High-intensity focused ultrasound (HIFU), chemotherapy, chemotherapeutic drugs (Docetaxel / Mitoxantrone), cryosurgery, hormonal therapy, or some combination.

Which option is best depends on the stage of the disease, the Gleason score, and the PSA level. Other important factors are the man’s age, his general health, and his feelings about potential treatments and their possible side-effects. Because all treatments can have significant side-effects, such as erectile dysfunction and urinary incontinence, treatment discussions often focus on balancing the goals of therapy with the risks of lifestyle alterations. Prostate cancer patients are strongly recommended to work closely with their Oncologist and urologist and use a combination of the treatment options when managing their prostate cancer.

The selection of treatment options may be a complex decision involving many factors. For example, radical prostatectomy after primary radiation failure is a very technically challenging surgery and may not be an option. This may enter into the treatment decision.

If the cancer has spread beyond the prostate, treatment options significantly change. Treatment by watchful waiting / active surveillance, HIFU, external beam radiation therapy, brachytherapy, cryosurgery, and surgery are, in general, offered to men whose cancer remains within the prostate. Hormonal therapy and chemotherapy are often reserved for disease that has spread beyond the prostate. However, there are exceptions: radiation therapy may be used for some advanced tumors, and hormonal therapy is used for some early stage tumors. Cryotherapy (the process of freezing the tumor), hormonal therapy, and chemotherapy may also be offered if initial treatment fails and the cancer progresses.

External Beam Radiotherapy

Megavoltage X-rays are produced by linear accelerators (“linacs”) operating at voltages in excess of 1000 kV (1 MV) range. Beams with the voltage range of 6-16 MV are used to treat patients because radiation oncologists find that they penetrate well to deep sites within the body.

For instance, in one particular technique of prostate radiotherapy, a patient will usually be treated with 4 radiation beams of 10 MV X-rays. While the beams will point into the patient from different angles, all the beams will be pointed towards one point or centre in the prostate. In this way the linac can rotate around the patient who does not need to move. In fact, patient motion is a source of positioning error which a radiation therapist tries to eliminate.

By crossing multiple beams, the radiation dose delivered internally in the prostate is much higher (~70-74 Gy) than the radiation dose delivered on the entry and exit tracks of each individual beam (~40 Gy). This lower dose outside the prostate rarely leads to side effects or any detectable change.

In general, you will be invited to attend the Beatson West of Scotland Cancer Centre for initial Gold seeds clinic. This will involve inserting 3 gold markers into your prostate under ultrasound guidance. It is a very straightforward procedure that usually last around 10 minutes and is done as an outpatient procedure.

10-14 days later you will have a planning CT scan to help plan your radiotherapy accurately. Accuracy of treatment is significantly enhanced by the gold seeds within the prostate. This will involve another visit to the Beatson West of Scotland Cancer Centre. It will require around 2 weeks to generate your final radiotherapy plans by then you will be ready to start your treatment.

Radiotherapy treatment is delivered on a daily basis for 37 – 40 days excluding the weekends. Each treatment will last for about 15 minutes on an outpatient basis. For more information about radiotherapy to the prostate gland and side effects, please click here.

Brachytherapy

This is a form of prostate radiotherapy using radioactive seeds in the form of Iodine 131. Brachytherapy is usually considered for patients with early stage and relatively low risk prostate cancer. Click here for more information.

Radical Prostatectomy

Surgery is one of the treatment options for prostate cancer. Each patient will be assessed carefully and the treatment options will be discussed with you. Based on your fitness, general health, other medical conditions and the extent of prostate cancer, the treatment decision will be discussed carefully with you outlining the advantages and disadvantages of each option.

For more information on surgical treatment of prostate cancer, click here.

Other treatment options and new drugs

Recent advances in imaging have led to the development of new techniques for treatment of prostate cancer that have recurred following initial therapy. This includes Cryotherapy as well as HIFU. These are treatment options that may be considered particularly in patients who have cancer recurrence within the prostate after being treated with radiotherapy. For more information, click here.

Active Surveillance

Active surveillance means that your doctors will keep a close eye on you to see if the cancer is growing significantly. You will usually have blood tests every 2-3 months to monitor your PSA levels and frequent digital rectal examinations, and will be asked if you have developed any new symptoms. You may also have prostate biopsies every few years.

If these regular tests show that the cancer is starting to grow your doctors will then recommend treatment intended to cure the cancer, such as surgery or radiotherapy. If your cancer is not growing or developing, it is safe to continue with active surveillance. For more information, click here.

Hormonal therapy

Hormonal therapy uses medications or surgery to block prostate cancer cells from getting dihydrotestosterone (DHT), a hormone produced in the prostate and required for the growth and spread of most prostate cancer cells. Blocking DHT often causes prostate cancer to stop growing and even shrink. However, hormonal therapy rarely cures prostate cancer because cancers that initially respond to hormonal therapy typically become resistant after one to two years. Hormonal therapy is, therefore, usually used when cancer has spread from the prostate. It may also be given to certain men undergoing radiation therapy or surgery to help prevent return of their cancer.

There are several forms of hormonal therapy:

  • GnRH agonists such as leuprolide and goserelin acetate suppress Testosterone production through the process of down regulation after an initial stimulation effect which can cause initial tumor flare.
  • Antiandrogens are medications such as bicalutamide, flutamide and cyproterone acetate that directly block the actions of testosterone and DHT within prostate cancer cells.
  • Orchidectomy, also called “castration,” is surgery to remove the testicles. Because the testicles make most of the body’s testosterone, after orchidectomy testosterone levels drop. Now the prostate not only lacks the testosterone stimulus to produce DHT but also does not have enough testosterone to transform into DHT.

Chemotherapy for prostate cancer

Chemotherapy is mainly used to treat advanced prostate cancer that is no longer being controlled by hormonal therapy| (hormone-refractory prostate cancer). It is used in this situation to try to shrink and control the cancer and relieve symptoms, with the aim of prolonging a good quality of life. The chemotherapy drugs are usually given by injection into a vein (intravenously). Docetaxel is the most commonly used chemotherapy in prostate cancer. It is usually given on outpatient basis once every 3 weeks. The intention is to give you a total of 10 cycles. This treatment has been shown to be effective in controlling the disease and improving on symptoms. The Oncology nursing team at Ross Hall will contact you to arrange a visit to the chemotherapy unit and introduce the team to you and confirm the time of treatment that suites you. For more detailed information on Docetaxel (Taxotere) chemotherapy, click here.

New chemotherapy and hormone therapy:

There are number of other treatment options that are available, some of which are very new and have just been approved recently including Cabazitaxel which is a chemotherapeutic agent which is currently used if prostate cancer progress after first line chemotherapy. On the other hand, the new drug Abiraterone, is a form of hormonal therapy which has been recently evaluated in a clinical trial with encouraging results. This is currently available within a special access program.

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