Proton therapy differs significantly from traditional radiation therapy. Both techniques treat tumors by beaming radiation into the tumor site where it deposits radiation doses that destroy cancerous cells, but traditional radiation therapy also irradiates nearby healthy tissue as the beam enters and exits the tumor. as a result, can cause collateral damage.
This collateral radiation damage creates three problems:
- It has very undesirable side effects, such as prolonged nausea, long recovery times and, in some cases, loss of function in the irradiated tissue.
- It creates a risk of additional tumors at a later time.
- When the tumor is near sensitive organs, concern about collateral damage can restrict the physician from delivering dosages high enough to ensure tumor destruction.
Proton therapy helps significantly with all three problems. Protons are much heavier and scatter less as they enter the body compared to traditional radiation therapy, and protons can attain a much higher energy state (destructive power). Their penetration depth can be controlled with great precision. Proton beams have the unique property of delivering most of their destructive energy as they reach the target, so that appropriately high dosages can be delivered to precise points in the tumor without damage to healthy tissue beyond the tumor.
These unique properties of proton beams offer a significant clinical advantage when high dosages are needed to destroy a tumor, without harming critically important tissues outside the tumor. Examples include certain cancers of the eye, head and neck, brain, skull base, spine, prostate, and lungs, as well as colorectal and pediatric cancers and advanced breast cancer.
Proton therapy provides special clinical benefits to pediatric patients, who are more susceptible to radiation injury because their organs are growing rapidly. Proton therapy allows children’s cancers to be treated with less of the collateral damage that causes bodily dysfunctions, impaired cognitive performance, tissue atrophy and subsequent new tumors.
One of the most appreciated benefits of proton beam radiation — for patients of all ages — is that the more complete containment within the tumor reduces, or even eliminates, many of the harshest and most-feared side effects of radiation treatment. The usual post-radiation toxicity that causes nausea and related problems is greatly reduced, and prostate cancer patients have a significantly reduced incidence of impotence and incontinence. Patients experience much less discomfort, often continuing with normal and even recreational activities during their several weeks of proton therapy, which is administered daily for six to eight weeks.