The treatment spectrum includes a wide range of uses in cancer therapy. In principle, the physical and biological properties of protons allow any tumor previously treated with x-ray radiation to be irradiated with protons.
This includes all tumors previously treated using linear accelerators (with and without intensity modulated radiotherapy, or IMRT) or related X-ray equipment (including Rapid Arc and Cyberknife).
Children are given priority for treatment with proton therapy because it can significantly reduce the incidence of secondary tumors later in the child’s life caused by therapeutic radiation. Furthermore, radiation damage to growing organs, such as growth plates and other vital organs can be prevented or reduced to a level where function is preserved (particularly in the brain, eyes, ears and the base of the skull). Please see more information for children treatment here.
Proton therapy is especially suitable for tumors where X-ray treatment is difficult or impossible due to the associated side effects. Such tumors include:
Tumors in the head/neck areas:
After X-ray therapy these patients suffer from a persistent dry mouth due to the almost unavoidable irradiation of saliva glands. This results in problems when speaking and eating and incurs follow-up treatment costs.These side effects can be minimized by proton therapy.
Tumors of the brain and base of skull:
With surrounding tissues and organs that are highly sensitive to radiation, such as the optic and auditory nerves, pituitary gland, brain stem and cranial nerves.
Malignant tumors of the eye have been treated with proton radiation for many years now because proton beams are the only form of radiation that can be stopped directly at the tumor. X-ray radiation penetrates deeper and would cause damage to the optic nerve and areas of the brain located behind the tumor.
Pulmonary and Liver Tumors:
For both pulmonary and liver tumors, the concomitant irradiation of healthy parts of the lung and neighboring organs can be kept to a minimal level. Moreover, comparative studies being conducted at the Loma Linda proton center in the USA seem to indicate that proton radiation for bronchial carcinomas (lung cancer) is even superior to surgery.
Tumors of the Abdomen and Pelvis:
Here as well, the adverse effects of proton therapy are reduced by 67% to 80% compared to X-ray therapy. This is crucial for patients’ quality of life and well-being.
The proton scanning used at the RPTC concentrates the radiation dose in an ideal manner within the target area, in the tumor. Compared to the X-ray method at the same tumor dose, proton scanning reduces the exposure of healthy tissue by 67% to 80%. When used as the sole treatment, proton scanning achieves the same favorable dose distribution as combined brachytherapy/X-ray irradiation.
The objectives are clear: we want to maximize the effective dose in the tumor while minimizing side effects and radiation exposure of healthy tissues, all while maintaining continence and erectile function.
Tumors and metastases in the area of the spinal column:
This is exactly where the spot-scanning technique used at the RPTC offers previously unimagined possibilities. This cutting-edge proton radiation method, in which a target area is scanned in a meandering course point by point, enables a sharply circumscribed dose modulation within a volume of radiation. For example, this technology allows the radiation dose to the spinal cord to be drastically reduced, even at the center of the radiation field, to the much-sought-after lower dose without reducing the actual tumor dose, enabling doctors to protect the spinal cord in the process.
Local recurrence and individual metastases:
In selected cases, proton therapy is the only way to effect partial or total removal of local recurrence and metastases of all localizations in the body to preserve organ function necessary for survival. For example, proton therapy is the most common option for metachronous multiple liver metastases (following carcinomas of the colon), which are not suitable for X-ray therapy because of the risk of liver damage.
The following cannot be irradiated:
- Mobile tumors (upper colon) and those where broad-spectrum radiation is not helpful (for example, the bone marrow) cannot be treated with radiation. This includes many types of leukemia.
- For the moment the postoperative irradiation of breast cancer
It is hoped internationally that the improved accuracy and improved protection of surrounding healthy tissue offered by proton radiotherapy can reduce side effects and late-term consequences that may include lung cancer (bronchial carcinoma) on the side of the treated breast as a long term consequence. There is also an increased frequency of coronary artery calcification and heart attacks in patients who have undergone radiation treatments for the left breast due to the asymmetrical position of the heart. Theoretically, this is possible – protons enable better targeting, but must be aimed better! To achieve this, both the patient and the breast to be irradiated must be maintained in precisely the same position for each and every radiation session. This is usually quite difficult in practice due to the high mobility of both the breast also itself and the skin over the whole chest area. This becomes even more problematic if the lymph nodes are also being irradiated toward the armpit area along with the former tumor bed. Our plan is to use surface profile comparisons to correct the positions three-dimensionally with the assistance of lasers so that they remain sufficiently identical from diagnostics to each and every single treatment session. In this manner, we hope to provide a gentler radiation also for our breast cancer patients.