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Applicability of Proton Therapy Treatments

Applicability of Proton Therapy Treatments
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Proton Therapy can make a difference in a large variety of cancers.

Because of the physical and biological properties of Protons, all tumors which have been traditionally treated with X-rays can be  irradiated with protons. These are therefore all tumors that were  previously using linear accelerators (with and without intensity modulated radiotherapy – IMRT) or related equipment with X-rays (this includes Rapid Arc and CyberKnife).

Video -link: Conditions treated by Proton Therapy

  • Children  

Children have priority in the indications for proton therapy because the frequency of radiation-induced second cancers can be reduced. Radiation damage to growing organs, such as growth plates and other functional organs can be avoided or reduced to the extent that their functions are retained (especially in the brain, eyes, ears and skull base region). For more information on the treatment of children, see ..

Proton beam therapy of pediatric patients

 

Source: ProCure Training and Development Center

Tumors that are particularly suitable for Proton Therapy are tumors that are hardly treatable due to the high side effects with X-rays.

These include e.g.:
  • Tumors of the head and neck 
These patients suffer from an X-ray therapy induced dry mouth due to hard-to-avoid irradiation of the salivary glands. The malfunction of the salivary glands causes discomfort when speaking, eating and adds treatment costs. Treatment with protons reduces such side effects by providing much more prcise control of the irradiated region.
  • Brain and skull base tumors 
Treatment with Protons helps to protect healthy tissue and organs in the area, such as visual and auditory nerves, pituitary gland, brain stem and cranial nerves. For more information on the treatment of brain and skull base tumours, see .. Link: Proton beam therapy for brain and skull base tumours

Proton beam therapy for brain tumour compared to other radiation techniques.

Source: Tarbell, Yock, Loeffler MGH-FBPTC, HMS

Proton beam therapy for skull base tumour compared to other radiation techniques.

Source: ProCure Training and Development Center.

  • Tumors of the eye
Malignant tumors of the eye have been the domain of the proton irradiation for many years, because only the proton beam can be directly targeted at the tumor without causing damage to the eyes. The more extensive X-ray radiation would lead to damage to the optic nerve and underlying brain regions.
  • Lung and liver tumors 
In lung tumors, Proton Therapy can minimise the damage to the healthy parts of the lung and adjacent organs – as well as in liver tumors. In addition, a comparative study at the Loma Linda proton center in the U.S., suggests that the proton irradiation is also effective with bronchial carcinoma (lung cancer) surgery itself.  For more information on the treatment of liver tumours, see .. Link: Proton Beam Therapy for Liver cancer

Proton beam therapy of non small cell lung cancer compared to other radiation techniques.

Source: ProCure Training and Development Center.

Adapted from Chang JY, et al. Int J Radiat Oncol Biol Phys. 2006:65(4):1087-1096.
Gy=standard measure of absorbed radiation; CGE=cobalt gray equivalent.

  • Tumours of abdomen and pelvis 
Here, too, the side effects of X-ray therapy can be reduced to 1/5 to 1/3. For quality of life and well-being of patients, this is of crucial value. For more information on the treatment of pancreatic tumours, see .. 
  • Prostate cancer 
Proton scanning concentrates the radiation dose ideally to the target areas in the tumor. For the same dose, the impact on healthy tissue is reduced to 1/3 to 1/5 of the X-ray method. Thus this allows the proton scanning to achieve the favorable dose distribution of a combined brachytherapy / X-ray irradiation. The objective is clear: the highest effective dose to the tumor with the lowest damage doses and side effects in healthy tissue: preservation of continence and potency. Surgery or radiation? – Certainly a difficult decision for you. That is why we have set detailed information for you here.
For more information on the quality of life after proton therapy of prostata cancer, see .. Link : Erectile function, incontinence, and other quality of life outcomes following proton therapy for prostate cancer in men 60 years old and younger.

Proton beam therapy for prostate cancer compared to other radiation techniques.

Source: ProCure Training and Development Center

Compared with IMRT/X-rays, proton therapy delivers:

  • 35% less radiation to the bladder
  • 59% less radiation to the rectum

Adapted from Vargas C, et al. Int J Radiat Oncol Biol Phys. 2008;70(3):744-751.
Gy=Gray, the standard measure of absorbed radiation; CGE=Cobalt Gray Equivalent

  • Tumors and metastases in the spine 
This is where the technique of spot scanning  offers  unprecedented opportunities. Because only this modern method of proton radiation therapy, in which a target area is scanned point by point, allows a sharply circumscribed dose modulation within an irradiation volume. This technique can, for example, reduce the radiation dose to the spinal cord in the middle of the radiation field without sacrificing the tumor dose. The spinal cord can be spared.

Proton beam therapy for tumor next to spine compared to other radiation techniques.

Source: ProCure Training and Development Center.

  • Local recurrence and individual metastases 
In selected cases, for local recurrences and metastases, Proton Therapy can remove all localizations in the body and maintain vital organ functions. FOR EXAMPLE the most common metachronous multiple liver metastases (following carcinomas of the colon) are not accessible to X-ray therapy because of the risk of liver damage. For more information on the treatment of liver metastases, see: liver metastases 

  • Rectal and Anal Cancers 

Clinical data is limited regarding the efficacy of proton irradiation in rectal and anal cancers. For more than 30 years, the standard of care for this cancer has been radiation therapy to the primary site and draining the lymphatics delivered concurrently with aggressive chemotherapy. While this is a successful regimen, the risk of significant toxicity is high.

A small comparative treatment-planning study of proton and X-ray radiation therapy indicated that proton therapy, used either as the sole modality or as a boost to X-rays, has potential advantages over conventional X-rays used alone in the treatment of inoperable patients with a large rectal cancer. The proton therapy treatment plan is more effective in sparing the small bowel, the bladder, and the femoral heads. Higher doses are possible with proton therapy and may allow for downstaging and potentially curative resection in patients with locally advanced disease. ( Isaacson U, Montelius A, Jung B, and Glimelius B. Comparative treatment planning between proton and X-ray therapy in locally advanced rectal cancer. Radiother Oncol. 1996;41(3):263-272. ; Meyer JJ, Czito BG, Willett CG. Particle radiation therapy for gastrointestinal malignancies. Gastrointest Cancer Res. 2007;1(suppl 2):S50-59.)

  •  Not suitable tumors are
Mobile tumors such as those of the upper colon and those in which a large-scale radiation – for example on the bone marrow – is not helpful. The latter includes various leukemias.

For the time being, postoperative breast irradiation is still not suitable.
There is hope that with better accuracy and protection of the  surrounding tissue proton radiation will be able to reduce the side effects and late sequelae such as the occurrence of lung cancer (lung cancer) or a higher incidence of coronary atherosclerosis and myocardial infarction in the left breast irradiation. Theoretically, this is possible due to the better accuracy of irradiation with protons. For this to work, not only the patient but also the breast itself must be positioned exactly the same for each exposure. Such a precise bearing is so far very difficult due to the high mobility of not only the breast but also the skin of the entire chest area. We are currently working on a storage concept that corrects the irradiation using lasers for surface profile comparisons to store three-dimensional shapes to ensure that each individual exposure sessions remains sufficiently identical to the original location, in order to enable even breast cancer patients a gentle irradiation of the breast.


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