“Ask Dr. HKSH” - Radiotherapy for Prostate Cancer

Dr. POON Ming Chun, Darren

Specialist in Clinical Oncology

Q1. At which stage of prostate cancer is radiotherapy recommended?

Prostate cancer can be classified as early-stage or metastatic. Traditionally, radiotherapy has been mainly used for early-stage or non-metastatic cases. However, recent research has found that, even when cancer cells have already metastasised, we can still treat the primary tumour in the prostate with radiotherapy. It may even be used for the management of some oligometastatic cases.

Q2. Is there only one type of radiotherapy?

Radiotherapy refers to the use of external radiation beams to target and kill an internal tumour while sparing the surrounding healthy organs to minimise any side effects or long-term complications. In fact, there are many different types of radiotherapy. The ultimate goal is to deliver a high dose of radiation to and destroy the tumour with high precision. Many new radiotherapy techniques can achieve treatment precision, such as MRI-guided radiotherapy, proton therapy, and CyberKnife. Doctors will select the appropriate type of precision radiotherapy based on individual conditions.

Q3. How many sessions of radiotherapy does a patient usually need? How long does each session take?

For prostate cancer, radiotherapy used to take 30 to 40 sessions with the “lower dose, more fractions” approach. With advances in technology and research, it is now feasible to deliver higher doses per fraction with the “higher dose, fewer fractions” approach. For example, stereotactic body radiotherapy needs only five sessions to treat prostate cancer.

In practice, patients are exposed to radiation for only 15 to 20 minutes during treatment. Healthcare professionals will carry out specific preparations before treatment, such as various checks to verify the patient’s position, whether the target organs are within the planned target area, and to confirm the tumour’s presence in the planned treatment region. Imaging such as MRI or CT scans may be used for verification before treatment begins. Therefore, the entire treatment session usually takes about 30 minutes to one hour.

Q4. What side effects do prostate cancer patients usually experience during radiotherapy?

Side effects can generally be divided into early immediate side effects and late side effects. Immediate side effects occur during radiotherapy, such as frequent urination, nocturia, and a burning sensation during urination. To facilitate treatment, doctors will advise patients to keep their bowels clean. During radiotherapy, patients may experience increased bowel sensitivity and more frequent bowel movements. Skin reactions are less common in prostate radiotherapy. All these treatment side effects will often resolve following completion of prostate radiotherapy.

Thanks to advances in radiotherapy technology, late side effects are generally less common nowadays. Even when they occur, they mainly affect the surrounding organs, such as causing proctitis and rectal bleeding as a result of rectal damage, or cystitis and blood in urine due to bladder damage. Another possible late side effect is sexual dysfunction, which affects one’s sexual performance. It may also affect urination, resulting in incontinence or urine leakage. In general, these late side effects are becoming less likely with technological advances. Some of them are less common with radiotherapy. For example, urinary incontinence and sexual dysfunction are less likely to occur after radiotherapy compared with surgery.

Q5. Can patients receive radiotherapy again when cancer recurs?

Doctors will first assess the location of recurrence. If the recurrence is only confined to the original prostate area, new techniques such as proton therapy or creating a space between the prostate and the rectum with hyaluronic acid may be adopted for another course of radiotherapy to the recurrent site. Multiple studies and clinical experiences have shown that these approaches are effective in managing the recurrence of prostate cancer.