How Radiotherapy May Allow Men with Prostate Cancer to Skip Prostate Removal Surgery

While some low-grade or early stages of prostate cancer may not require immediate treatment, this cancer is commonly treated by having the prostate gland surgically removed. What if there is a way to avoid surgery and keep the prostate gland while treating the cancer? Thanks to advances in radiotherapy, it is now indeed a possibility.

WORDS ASSOCIATE PROFESSOR DR AMINUDIN RAHMAN MOHD MYDIN

FEATURED EXPERT ASSOCIATE PROFESSOR DR AMINUDIN RAHMAN MOHD MYDIN Consultant Clinical Oncologist KPJ Damansara Specialist Hospital

QUICK FACTS ABOUT PROSTATE CANCER

• The prostate is a gland located below the bladder and in front of the rectum. It produces fluids that, combined with sperm cells and other fluids, make up semen.
• Prostate cancer usually shows no symptoms.
• Because of this, the Malaysia National Cancer Registry 2012-2016 noted an increased number of men seeking medical help only when their cancer has advanced to stages 3 and 4, when surgery is often necessary.
• The prostate-specific antigen (PSA) test can be used to detect prostate cancer. Talk to your doctor if you would benefit from taking this test.

Aside from surgery, common treatments include:

• Hormone therapy
• Use of heat or cold to destroy cancer cells (ablative therapies)
• Chemotherapy
• Immunotherapy
• Radiotherapy

We’ll be talking more about radiotherapy in this article.

WHAT IS RADIOTHERAPY?

• Radiotherapy uses high doses of radiation to destroy cancer cells and shrink tumours. Depending on the type and stage of cancers, it can be the sole treatment or given alongside other cancer treatments.
• Radiotherapy is also frequently used to eliminate any remaining cancer cells in a certain area of the body after a tumour-removal surgery.

Types of Radiotherapy

• External beam radiation therapy is what many people think of when it comes to radiotherapy. A machine aims the radiation beam to the cancer site.
• Brachytherapy, or internal radiation therapy, places a soldi liquid source of radiation inside the patient’s body.

Stereotactic body radiation therapy (SBRT), an external beam radiation therapy, will be the focus of our article.

HOW HIGHLY PRECISE STEREOTACTIC BODY RADIATION THERAPY (SBRT) WORKS

Stereotactic body radiation therapy (SBRT) is a radiotherapy treatment that administers substantial daily radiation doses to the prostate gland.

• Compared to traditional radiotherapy, the patient requires fewer sessions of treatment.
• Typically, one needs about 5 sessions (plus one session for planning) compared to the average of 45 sessions in traditional radiotherapy.

SBRT Sessions

Session 1: Planning 

• The radiologist will ‘map’ out the tumour in the patient’s body.
  • This is to determine where the radiation should be targeted at, the dosage, and other details in order to optimize delivery of radiation and minimizing damage to surrounding healthy tissues.
  • Imaging techniques such as magnetic resonance imaging (MRI) and prostate specific membrane antigen positron emission tomography (PSMA-PET) are useful for this procedure.
• For CT-guided SBRT, implanted markers, called fiducials, are placed into the prostate for the radiologist to detect these markers and accurately hone in on the prostate during each treatment session.
• MRI-guided SBRT allow the radiologist to forgo the need for markers.

Preparations before each subsequent session

• Before each session, the patient will be asked to come in with a full bladder and empty rectum.
• Instructions will be provided by the radiologist in advance on how to do this.

During each of these sessions

• Each session typically lasts about 45 minutes. It is usually painless.

Side Effects?

• There are usually no immediate side effects.
• Patient may experience fatigue after the final session and/or urge to urinate more frequently during or after SBRT.

BENEFITS OF SBRT

• Not a surgery (non-invasive), so no risk of bleeding and other surgery-related issues.
• Shown by research to be as safe and effective as traditional radiotherapy.
• Shorter and fewer treatments mean more convenience for the patient.
• Fewer sessions also mean lower rates of toxicity compared to traditional radiotherapy.
• If effective on the patient, forgoes need for surgical prostate removal.

WHAT DOES RESEARCH SAY ABOUT SBRT?

High Survival Rate

• The randomized controlled trial Prostate Testing for Cancer and Treatment (ProTecT) established that survival from clinically localized prostate cancer remains very high over a median of 15 years (96% to 97%), irrespective of treatment allocation.

Potential to be a Curative Treatment Option from Prostate Cancer That Has Spread to a Few Sites Outside the Prostate

• Oligometastatic prostate cancer refers to prostate cancer that has spread to only a few sites outside the prostate.
• For these patients, SBRT has the potential to be a curative treatment option.
• Additionally, SBRT can effectively eliminate small pockets of cancer cells that have spread outside the prostate (micrometastases) when combined with systemic therapies such as hormone therapy and chemotherapy.

SBRT Versus Surgery for Localized Prostate Cancer

• The phase-3 randomized controlled trial PACE-A reported that patients receiving SBRT had better urinary continence and less sexual bother compared with those who underwent surgery.
• However, SBRT patients also reported more bowel symptoms than surgery patients.

References:

1. Giona, S. (2021). The epidemiology of prostate cancer. In: Bott, S.R.J. & Ng, K.L. (Eds.), Prostate cancer [Internet]. Exon Publications. https://www.ncbi.nlm.nih.gov/books/NBK571326/
2. Wang, L., Lu, B., He, M., Wang, Y., Wang, Z., & Du, L. (2022). Prostate cancer incidence and mortality: Global status and temporal trends in 89 countries from 2000 to 2019. Frontiers in Public Health, 10, 811044. https://doi.org/10.3389/fpubh.2022.811044
3. Hamdy, F. C., Donovan, J. L., Lane, J. A., Metcalfe, C., Davis, M., Turner, E. L., Martin, R. M., Young, G. J., Walsh, E. I., Bryant, R. J., Bollina, P., Doble, A., Doherty, A., Gillatt, D., Gnanapragasam, V., Hughes, O., Kockelbergh, R., Kynaston, H., Paul, A., Paez, E., … ProtecT Study Group (2023). Fifteen-year outcomes after monitoring, surgery, or radiotherapy for prostate cancer. The New England Journal of Medicine, 388(17), 1547–1558. https://doi.org/10.1056/NEJMoa2214122
4. Van As, N. J., Tree, A., Ostler, P. J., Van Der Voet, H., Ford, D., Tolan, S., Wells, P., Mahmood, R., Winkler, M., Chan, A., Thompson, A., Ogden, C., Brown, S., Pugh, J., Burnett, S. M., Griffin, C., Patel, J., Naismith, O., & Hall, E. (2023). PACE-A: An international phase 3 randomised controlled trial (RCT) comparing stereotactic body radiotherapy (SBRT) to surgery for localised prostate cancer (LPCa)—Primary endpoint analysis. Journal of Clinical Oncology, 41(6_suppl), 298. https://doi.org/10.1200/jco.2023.41.6_suppl.298