Radiation therapy (RT) is a common and effective treatment option for prostate cancer, utilizing high-energy rays or particles to target and destroy cancer cells. It is often recommended for patients with localized or advanced prostate cancer, either as a standalone treatment or in combination with other therapies.

The goal is to eradicate cancer cells while minimizing damage to surrounding healthy tissues. Modern advancements, such as image-guided and intensity-modulated radiation therapy, have significantly improved precision, reducing side effects and enhancing treatment outcomes.

What is radiation therapy for prostate cancer?

RT for prostate cancer is a treatment that uses high-energy radiation to destroy cancer cells in the prostate gland. It can be delivered externally (from outside the body) or internally (through radioactive seeds placed in the prostate). This therapy is used to treat localized prostate cancer or shrink tumors before or after other treatments.

Indications of RT for prostate cancer

Radiation therapy is a versatile treatment option for prostate cancer and is used in various clinical scenarios, including:

• Localized Prostate Cancer: As a primary treatment for early-stage prostate cancer to destroy cancer cells within the prostate gland. Suitable for patients who are not candidates for surgery or prefer a non-surgical approach.
• Locally Advanced Prostate Cancer: To treat cancer that has extended beyond the prostate but has not spread to distant sites. Often combined with hormone therapy to enhance effectiveness.
• Post-Surgical Treatment (Adjuvant Therapy): Recommended after prostatectomy when there are high-risk features, such as positive surgical margins or seminal vesicle invasion, to eliminate residual cancer cells.
• Salvage Therapy: Used after surgery in cases of rising PSA levels, indicating a recurrence of cancer.
• Advanced or Metastatic Prostate Cancer: For palliative purposes, to relieve symptoms like pain from bone metastases or urinary obstruction caused by advanced cancer.
• Recurrent Prostate Cancer: Applied to target localized recurrence following initial treatment, depending on patient health and previous therapy.

How to do RT for prostate cancer

Radiation therapy for prostate cancer is a carefully planned and executed treatment process that aims to target and destroy cancer cells in the prostate. There are different types of radiation therapy, with external beam radiation therapy (EBRT) and brachytherapy being the most common. Below is a step-by-step guide for each type:

• External Beam Radiation Therapy (EBRT): EBRT uses high-energy rays (like X-rays) directed at the prostate from outside the body. It’s a non-invasive procedure performed on an outpatient basis.
• Brachytherapy (Internal Radiation Therapy): Brachytherapy involves placing radioactive seeds directly into the prostate, allowing the radiation to be delivered from within the body. It’s typically used for early-stage prostate cancer.

Antiandrogene therapy combined with radiation therapy

Antiandrogen therapy (AAT) involves the use of medications that block the action of androgens (male hormones such as testosterone), which can promote the growth of prostate cancer cells. Antiandrogen therapy is often used in combination with radiation therapy for the treatment of prostate cancer, particularly in cases where the cancer is locally advanced or has a higher risk of recurrence. This combination approach can help improve treatment outcomes by targeting the hormonal pathways that contribute to prostate cancer growth.

Benefits of Combining Antiandrogens and Radiation Therapy

• Increased Effectiveness: The combination of antiandrogens and radiation therapy has been shown to improve the overall effectiveness of treatment, leading to better tumor control and a higher chance of long-term remission.
• Improved Survival Rates: Studies have demonstrated that adding antiandrogen therapy to radiation therapy can help improve overall survival, especially in patients with high-risk prostate cancer.
• Reduced Risk of Recurrence: By depriving prostate cancer cells of testosterone and enhancing the effects of radiation, this combined approach may reduce the likelihood of cancer returning after treatment.
• Targeted Approach: It allows for a more targeted treatment strategy that addresses both local (radiation) and systemic (antiandrogen therapy) factors of the disease.

Indications of AAT and RT combination

The combination of antiandrogen therapy and radiation is commonly recommended in the following scenarios:

• Locally advanced prostate cancer: When cancer has spread beyond the prostate but is still confined to nearby areas (such as the seminal vesicles or lymph nodes).
• High-risk prostate cancer: For patients with high PSA levels, Gleason scores, or a large tumor burden.
• Post-surgery adjuvant therapy: For patients who have had prostate surgery but are at high risk for cancer recurrence, adding radiation and antiandrogens can help reduce the chances of relapse.
• Inoperable prostate cancer: For patients who are not candidates for surgery but require aggressive treatment to control the cancer.

How to use AAT together with RT for prostate cancer

The combination of antiandrogen therapy and radiation therapy is a commonly used approach in the management of locally advanced or high-risk prostate cancer. This combined therapy can improve the effectiveness of treatment, reduce the risk of cancer recurrence, and enhance overall survival. Here’s how antiandrogen therapy is typically used in conjunction with radiation therapy:

• Neoadjuvant Therapy (Before Radiation): In some cases, antiandrogen therapy is used before radiation therapy, a strategy known as neoadjuvant therapy. The goal is to shrink the prostate tumor and make it more susceptible to radiation.. Antiandrogen therapy is typically started 2-3 months prior to radiation therapy. The exact duration may vary based on the patient’s risk and the specific type of prostate cancer.
• Concurrent Therapy (During Radiation): In certain situations, antiandrogen therapy is given concurrently with radiation therapy. This approach is typically used when patients have more advanced disease or higher risks of recurrence. Antiandrogen therapy is typically continued throughout the course of radiation therapy, which usually lasts about 7-8 weeks.
• Adjuvant Therapy (After Radiation): In some cases, antiandrogen therapy is used after radiation therapy, especially for patients who are at higher risk of recurrence. This approach is called adjuvant therapy.

Monitoring and Follow-Up

During and after the combination of antiandrogen and radiation therapy, patients require close monitoring to assess the effectiveness of the treatment and manage any potential side effects.

• PSA testing: PSA (prostate-specific antigen) levels are regularly measured to monitor for signs of recurrence.
• Imaging: Imaging may be done periodically to evaluate the size of the prostate and check for any signs of metastasis or recurrence.
• Side effect management: Doctors monitor and manage side effects, adjusting medication as necessary.

Side effects of AA and RT

Both antiandrogen therapy and radiation therapy have side effects. Some side effects of combining these therapies include:

• Hot flashes
• Decreased libido
• Erectile dysfunction
• Fatigue
• Urinary symptoms (frequent urination, discomfort)
• Bowel issues (diarrhea, rectal discomfort)

Complications of RT

While radiation therapy is an effective treatment for prostate cancer, it carries potential side effects and complications, which can vary in severity and duration depending on the patient, the dose, and the type of radiation used. These complications can be grouped into acute (short-term) and chronic (long-term) effects.

1. Acute Complications (Occur during or shortly after treatment)

Urinary Symptoms

• Frequency and Urgency: Increased need to urinate or difficulty holding urine.
• Dysuria: Burning or pain during urination.
• Hematuria: Blood in the urine, though usually mild and temporary.

Gastrointestinal Symptoms

• Diarrhea: Increased frequency or loose stools.
• Rectal Irritation (Proctitis): Discomfort, rectal bleeding, or mucus discharge.
• Abdominal Cramps: Due to inflammation of the bowel lining.

Fatigue

• Generalized tiredness is common during the course of radiation therapy.

Skin Reactions (with external beam radiation therapy)

• Mild redness, dryness, or peeling of the skin near the treatment area.

2. Chronic Complications (May occur months or years after treatment)

Urinary Complications

• Radiation-Induced Cystitis: Chronic inflammation of the bladder causing blood in the urine or discomfort.
• Urinary Incontinence: Difficulty controlling urination.
• Urethral Stricture: Narrowing of the urethra, potentially leading to obstructive symptoms.

Gastrointestinal Complications

• Chronic Proctitis: Persistent rectal bleeding, discomfort, or diarrhea.
• Fistula Formation: Rare but serious complication involving an abnormal connection between the rectum and other structures.

Sexual Dysfunction

• Erectile Dysfunction (ED): Radiation may damage nerves and blood vessels needed for erections, with effects worsening over time.
• Reduced Libido or Infertility: Often linked to hormonal changes or damage to reproductive structures.

Secondary Cancer Risks

• A small increased risk of developing secondary cancers in the pelvic region due to radiation exposure.

Summary

Radiotherapy for Prostate Cancer is a treatment that uses high-energy radiation to target and kill cancer cells in the prostate. It is commonly used to treat localized prostate cancer, either alone or in combination with other therapies like antiandrogens or hormone therapy.

Radiotherapy can be delivered through two main methods: external beam radiation, and brachytherapy. It is typically used for patients with localized or locally advanced prostate cancer, and can be given neoadjuvantly (before surgery), concurrently (with other treatments), or adjuvantly (after other treatments). The treatment aims to reduce the tumor size, improve survival rates, and manage symptoms, but may cause side effects like fatigue, urinary, and bowel issues.

Prof. Dr. Emin ÖZBEK

Urologist

Istanbul- TURKIYE