In February 2014, San Diego County’s first proton treatment center opened its doors for patient care. Carl Rossi, M.D., medical director of the Scripps Proton Therapy Center, offers a glimpse into how this advanced treatment can benefit cancer patients.
Q: What makes proton therapy different from other current forms of radiation?A: Proton therapy is the most precise form of radiation treatment available today. Conventional X-ray treatment beams penetrate well beyond the tumor, but protons can be controlled to conform precisely to the shape of the tumor and to release most of their energy within the tumor. Protons stop where the tumor stops.
Q: How do patients benefit from this precision?A: The accuracy of protons enables doctors to treat tumors with a substantially lower total radiation dose to healthy tissue, compared to the latest X-ray therapy. The beam stops at the tumor, which helps preserve normal tissue. By minimizing harm to healthy tissue, patients tolerate their treatments better and are less likely to have problems in the long run related to their treatment.
Q: What’s the harm in low-dose radiation from X-rays?A: At some level, you will always create damage by irradiating healthy tissue. As we get better at curing cancer and people are living longer after treatment, there is cause for concern about long-term side effects. For example, a 2013 report in the New England Journal of Medicine analyzed the records of thousands of breast cancer patients who received X-ray treatments to their left breast. The report found these women developed a higher risk for heart disease, which was directly related to the volume of the heart that was irradiated during treatment.
Q: What types of cancer can proton therapy treat effectively?A: Proton therapy is best suited for solid tumors that are 1) localized (i.e., have not spread); 2) situated near sensitive normal tissue; and 3) require high doses of radiation. Specific tumor sites well-suited for proton therapy include breast, lung, prostate, spine, head, neck, brain, gastrointestinal tract and central nervous system, among others. Proton is also recognized as the preferred form of radiation therapy for many pediatric cancers. Because children’s bodies are still growing, they are extremely sensitive to the harmful effects of radiation.
Q: Is proton therapy supported by research?A: Yes, there is a wealth of scientific research studies published in peer-reviewed medical journals that have demonstrated the safety and effectiveness of proton therapy. These studies have examined a broad range of tumor sites and have shown a reduced rate of secondary cancers and treatment-related side effects in proton patients, compared to X-ray patients.
Q: What is proton treatment like for patients?A: During therapy, patients feel no physical sensation from the proton beam and hear very little noise. Delivery of the proton beam to the patient lasts (on average) only about a minute per treatment field. Time spent in the treatment room is usually about 15 to 25 minutes, for precise patient positioning and equipment adjustments. Afterward, patients are free to go about their daily activities. (Pediatric patients may receive their treatments under anesthesia.)
Treatments are typically delivered five days a week for four to eight weeks.
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