What is Proton Therapy

A lot of curable cancer could achieve high curative and low complication rate when using proton beam therapy combining with surgical treatment or chemotherapy. As shown in the figure, the radiation dose was represented by different colors. Areas covered by blue color are low dose area, and areas covered by red color representing the high ones. In addition to irradiating cancer cells, proton beam therapy could avoid scattered radiation dose affecting the surrounding normal tissues. Therefore, the figure of proton beam therapy clearly shows the surrounding normal tissues receive scanty or no radiation dose. Aside from improving life quality during and after radiotherapy, using the proton beam therapy could also lower the risk of secondary cancer occurring in the previously normal tissues caused by radiotherapy.

Brain tumor

Lowering the radiation dose to normal brain tissues could further minimize the damage to brain tissue. This would reduce the impact on memory and endocrine function. Thereby, the quality of life is less affected after treatment.

  • Indication: (1) Resected tumor with positive margin    (2) Inoperable tumor with indication of radiosurgery, such as larger arteriovenous malformation, acoustic neuroma, pituitary adenoma and etc…

Head and neck cancer

When the proton beam therapy is utilized in treating the cancer in nasopharynx or oral cavity, radiation dose in oral cavity, hypopharynx and esophagus could be lowered or reduced to no dose. In this way, damage to the oral mucosa and throat was cut down, which could reduce the complication of pain, dry mouth, taste change and lowering the need of nasogastric tube insertion. For other head and neck cancer, the possibilities of dry mouth, mucositis, sore throat, hearing impairment, trismus, neck fibrosis and swallowing difficulties are lower in patient using proton beam therapy than ones using photon therapy, and therefore improving patients’ quality of life.

Esophageal cancer

Reducing the irradiation dose to the heart and lung could minimize the impact on cardiopulmonary function. It would therefore lower the complication rate of surgical treatment after concurrent chemotherapy and radiotherapy.

Lung cancer

Reducing the irradiation dose to the heart, normal lung and esophagus could minimize the impact on cardiopulmonary function and lung fibrosis. It also reduced the pain while swallowing. By using proton beam therapy, complications caused by conventional concurrent chemotherapy and radiotherapy, such as esophagitis, heart burning sensation, pneumonia, and shortness of breath are lowered.

Indication: Stage I to III

Contraindication: infiltrative tumor, multiple distant metastases (more than 3 sites)

Breast cancer

Common complications such as mild skin redness, swelling and eruption still occur in patients receiving proton beam therapy. The benefit of using proton beam therapy lies in reducing the radiation dose of heart, lung and contralateral breast. Using proton beam thereby reduce the risk of myocardial infarction, pulmonary function decline and secondary cancer in contralateral breast. Recent researches have shown that left breast cancer patients treated by conventional radiotherapy have higher risk of myocardial infarction as long-term complication. Therefore, the proton therapy could reduce the risk of myocardial infarction significantly.

  • Indication: (1) Internal or lower chest wall tumor    (2) Higher radiation dose of heart in conventional radiotherapy    (3) Bilateral reconstructed breast with permanent implantation    (4) Internal mammary lymph node metastasis    (5) Poor cardiopulmonary function    (6) Young age patient with intention to reduce lung and contralateral breast radiation dose
  • Contraindication: distant metastasis

Liver tumor

Proton beam therapy could achieve high radiation dose in liver tumor, and therefore reach a good local control. It also minimizes the influence of liver function and lower side effect in gastro-intestinal tract, such as nausea and vomiting. Patients who receive proton beam therapy would have lower rate of liver dysfunction, ascites and death.

  • Indication: (1) Patient that is inoperable or unwilling to receive surgical resection    (2) Tumor less than 5 cm: Tumor control rate is around 90~95%    (3) Tumor  from 5~10cm: Tumor control rate is around 85%    (4) Tumor larger than 10 cm: Tumor control rate is around 45%    (5) Tumor recurrence after previous surgical resection or failed to treat the tumor with radiofrequency ablation and trans-arterial chemo-embolization (6) Unable to control the lesion with surgical or other intervention    (7) Residual solitary tumor after small other small lesion being controlled.
  • Contraindication: (1) Infiltrative tumor    (2) Multiple large tumor    (3) Distant metastasis    (4) For tumor that is close to gastro-intestinal tract, further evaluation is needed

Pancreatic cancer

By using proton beam therapy, radiation dose to liver, kidney and gastro-intestinal tract could be lowered, and therefore the influences on organ function are reduced. The benefits of using proton beam therapy in pancreatic cancer result in the reduction of complication such as nausea, vomiting, poor appetite or body weight loss. The better quality of life helps those patients more tolerable to the concurrent chemotherapy, which is almost the standard treatment in most patients. The higher completion rate of the chemotherapy results in elevation in overall survival. This is especially important in cancers with very poor prognosis such as pancreatic cancer.

  • Indication: (1) Inoperable tumor without distant metastasis    (2)  High risk of recurrence after surgical treatment    (3) Concurrent chemo-radiotherapy to increase the possibility of complete resection before surgical treatment
  • Contraindication: (1) Extensive lymph node metastasis    (2) Distant metastasis

Gynecology tumor

Proton beam therapy would result in lower scattering radiation dose to small intestine, colon and ovary, which lower the complication of diarrhea. Endocrine function decline would also be less affected.

Pediatric tumor

Children are more sensitive to the effects of radiation because they are still in the process of body growing and development. Proton beam therapy could significantly reduce the moderate and low scattering dose, and therefore reduce the influence on children growth and development. Furthermore, it also reduces the risk of secondary tumor. Take pediatric brain tumor for example, the benefit of proton beam therapy is that normal tissues behind the tumor have no radiation dose at all. In this circumstances, risks of secondary tumor and mental and development disorder are lowered.

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