Proton Therapy and Prostate Cancer
Prostate cancer is the second most deadly form of cancer for men; however, if prostate cancer is detected early it can have a survival rate of approximately 99%. Thousands of men have used Proton Therapy as a part of their treatment and have successfully gone into remission. Overall, research is showing some key benefits of proton therapy compared to traditional radiation therapy.
Benefits of Proton Therapy
Traditional radiation therapy uses photon beams to irradiate tumors. Photons deposit their energy throughout the body, including before and after the tumor. This can cause damage to the healthy cells surrounding the target tumor. Additionally, the prostate is located in deeper tissue, thus normal tissues that are in line with the beam in front of the target must be irradiated at a higher dose than the tumor itself. To compensate for this high dosage, multiple photon beams of lower dosage converge together on the target; however, this significantly reduces the number of beam angles that can be used for treatment.
Proton therapy utilizes protons to damage the tumor. Protons are heavy particles, so they deposit their energy in the body instead of going through the body like photons. Additionally, protons have a special property called the Bragg Peak. This property allows all of the Proton’s energy to be distributed in one location and avoids most of the extra-target radiation that is inherent to photons. This means that proton therapy has minimal impact on tissues surrounding the prostate, such as the rectum and bladder.
Other benefits include:
- Precision – a proton beam can be less than a millimeter wide to target the tumor with greater accuracy.
- Non-invasive – treatment is painless and requires little to no downtime
- Therapy achieved with 2 beams -compared to 8 beams for conventional radiation therapy
- Pencil beam scanning – allows for the protons to deposit their energy in the tumor layer by layer, allowing the beam to perfectly fit the tumor
- Quicker treatment time – no apertures or shaping devices are needed
- Higher dosage of treatments without damaging healthy tissues
- Minimal risk of impotency
- Fewer side effects
Research Results
Proton therapy can reduce sessions of treatment because it can deliver higher doses safer than traditional radiation treatments. Researchers from the University of Pennsylvania and Roborts Proton Therapy Center examined data on prostate cancer patients treated with 28 doses of proton therapy instead of the standard 44 and found that the rates of cancer control at four years were the same in both groups.
In a study comparing the risk of secondary malignancy of proton therapy and conventional therapy, researchers at the Harvard cyclotron laboratory found that only 6.4% of proton therapy patients had secondary malignancies compared to 12.8% of photon patients.
Overall, studies have shown favorable results for proton therapy. The control of cancer was equivalent to traditional methods but with much lower toxicity rates. Currently, there is a current phase III trial open that will help clarify the full benefits of proton therapy.
Further Resources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4080851/
https://protons.com/proton-treatments/prostate-cancer