Proton Therapy for Prostate Cancer: Overview & Success Rate

Prostate cancer remains one of the most prevalent cancers among men worldwide, prompting continuous advancements in both diagnostic and therapeutic treatment options. Among the emerging innovations in prostate cancer treatment, proton therapy has garnered significant attention for its precision and potential to minimize collateral tissue damage. 

Unlike conventional photon-based radiation therapy, proton therapy utilizes charged particles that deliver high-dose radiation directly to the tumor with sub-millimeter accuracy. This advanced treatment offers a potentially safer and more targeted approach to managing localized prostate cancer. 

This article explores the principles of proton therapy, its success rate, cost for the patient and more so you can gain a comprehensive understanding of proton therapy for prostate cancer.

“Proton therapy is a highly effective and advanced treatment option for prostate cancer that uses radiation to target and destroy cancer cells within the prostate.”

What is Proton Therapy for Prostate Cancer?

 

Since its development, proton therapy has emerged as a promising alternative to traditional prostate cancer treatment methods¹. While the advantages of proton therapy remain well documented, its use in prostate cancer treatment remains controversial due to the high cost to patients and has caused members of the scientific community to question its value.

Like other radiation treatments, proton therapy for prostate cancer delivers a high dose of radiation directly to the cancerous lesion within the prostate. Unlike X-rays, protons deposit most of their energy at a specific depth and then stop radiation to avoid damaging surrounding tissue.

Proton therapy is used for treating localized prostate cancer to reduce radiation exposure to the bladder and rectal regions while minimizing long-term side effects like erectile dysfunction and urinary incontinence (although they are still risks). It remains a viable alternative for patients who may not be ideal candidates for surgery or conventional radiation. 

Proton Therapy Success Rate

The success rate of proton therapy is first measured by the levels of prostate-specific antigens (PSA) in the blood through a standard PSA blood test. With proton therapy, PSA levels are expected to decline over the following several years. However, an increase in PSA levels in patients could indicate that prostate cancer has returned.

Measuring the success rate of proton therapy is often difficult, since most conventional statistics only measure the survival rate after a given period. Nonetheless, the UF Health Proton Therapy Institute monitors patients after their initial proton therapy and found that 99 percent of patients remained cancer-free after five years with low-to-intermediate prostate cancer, with 76 percent of patients cancer-free with high-risk cancer². Subsequent studies by UF Health also showed high survival rates after five years.

Traditional prostate cancer treatments and focal therapy procedures show similarly high success rates compared to proton therapy. Researchers at UCLA found that cryotherapy (freezing of prostate cancer cells) was effective at treating clinically-significant prostate cancer, noting that 80 percent of patients had no signs of recurring prostate cancer at six and 18 months after treatment³.

Proton Therapy Drawbacks

 

While proton therapy can be an effective and non-invasive treatment option for prostate cancer, there are inherent drawbacks and limitations to the procedure.

The first and most controversial drawback to proton therapy is the cost. As we’ll discuss, the cost of proton therapy is more expensive than conventional radiation therapy and other traditional treatment methods. Additionally, proton therapy is not widely available and only select clinics and medical centers offer the treatment.

Also, proton therapy is comparable in long-term outcomes to other prostate cancer treatment options. Survival and recurrence rates are similar, particularly in low-to-intermediate risk prostate cancer patients. 

“Proton therapy is similar in long-term outcomes when compared to other effective prostate cancer treatment options and may not be ideal for all patients.”

Proton Therapy Side Effects

As with any cancer treatment, side effects are a major concern for patients. While some treatments, like radical prostatectomy (removal of the prostate), are highly effective at eliminating cancer, the side effects reduce quality of life in patients. Let’s talk about proton therapy side effects in more detail for a better understanding of how the treatment affects patients. 

Short-Term Side Effects

Short-term side effects of proton therapy are often mild to moderate in severity, and include urinary symptoms like burning or discomfort as well as increased frequency and urgency to urinate. Additionally, bowel changes like loose stools, increased gas, and blood in stools are common side effects.

Other side effects include fatigue, hair loss and skin redness around the treatment site, and general soreness.

Long-Term Side Effects

Urinary problems are most common in the short-term, but issues may persist chronically in some cases. In addition to the urinary problems mentioned above, the narrowing of the urethra and long-term irritative symptoms occur, but less frequently⁴. 

Another long-term side effect possible with proton therapy for prostate cancer is sexual dysfunction issues like erectile dysfunction and ejaculatory changes, as well as bowel issues like rectal bleeding and chronic changes in bowel habits. 

Cost of Proton Therapy for Prostate Cancer

 

The cost of proton therapy remains a high concern and is a major drawback. The cost is often too high for many patients, and the procedure isn’t widely available.

While the cost of proton therapy varies among treatment centers and may depend on insurance coverage, the procedure is generally much more expensive than other treatments that offer similar benefits. Because of this, many insurance companies consider proton therapy costs to be excessive and won’t provide full coverage⁵. 

Although the cost of proton therapy varies, the Oklahoma Proton Center cites targeted proton therapy procedures cost between $25,000 and $100,000 for a single course of treatment⁶. 

“Although the cost of proton therapy varies, some targeted proton therapy procedures cost between $25,000 and $100,000 for a single course of treatment. ”

Final Thoughts

Proton therapy remains an effective, but controversial, treatment option for prostate cancer. While statistics show a high success rate, many physicians and researchers doubt the value of the procedure when considering the cost and availability of alternative treatment options that provide the same success rate.

Ask your urologist about KOELIS, or find a certified provider in our network with our KOELIS Locator.

References

1 – Bryant CM, Henderson RH, Nichols RC, Mendenhall WM, Hoppe BS, Vargas CE, Daniels TB, Choo CR, Parikh RR, Giap H, Slater JD, Vapiwala N, Barrett W, Nanda A, Mishra MV, Choi S, Liao JJ, Mendenhall NP; Genitourinary Subcommittee of the Particle Therapy Co-Operative Group. Consensus Statement on Proton Therapy for Prostate Cancer. Int J Part Ther. 2021 Apr 12;8(2):1-16. doi: 10.14338/IJPT-20-00031.1. PMID: 34722807; PMCID: PMC8489490.

2 – Survival rates for prostate cancer treated with proton therapy. UF Health Proton Therapy Institute. Bradlee Robert and Christina L. Mershell. 2023. https://www.floridaproton.org/blog-spot/survival-rates-prostate-cancer

3 – UCLA Researchers find cryotherapy as an effective treatment for men with intermediate-risk prostate cancer. UCLA Health. 2020. https://www.uclahealth.org/news/release/ucla-researchers-find-cryotherapy-as-an-effective-treatment-for-men-with-intermediate-risk-prostate-cancer

4 – Moltzahn F, Dal Pra A, Furrer M, Thalmann G, Spahn M. Urethral strictures after radiation therapy for prostate cancer. Investig Clin Urol. 2016 Sep;57(5):309-15. doi: 10.4111/icu.2016.57.5.309. Epub 2016 Sep 7. PMID: 27617311; PMCID: PMC5017559.

5 – Proton Therapy for Prostate Cancer. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/prostate-cancer/proton-therapy-for-prostate-cancer

6 – Proton Therapy- What about the Cost? Oklahoma Proton Center. 2022. https://www.okcproton.com/proton-therapy-what-about-the-cost/