Hard-to-treat cancers respond to proton therapy

When 30-year-old Olga Alarcon Cruz learned she had invasive breast cancer, she was terrified. A mother of two, Cruz pondered her treatment options, seeking one with fewer side effects than chemotherapy and less drastic than a mastectomy.

She explored the possibility of proton therapy, which uses a powerful machine to target radiation in the form of protons to the exact location of the tumor with a pencil-like beam. Now, after 36 treatments ending in November, her breast cancer is gone, and she will follow up with a year of immunotherapy, a treatment that boosts the body’s immune system to fight cancer.

“It was a commitment to go back for treatment every day, but I really had no side effects,” said Cruz, of Miami.

Over the past three years, Miami Cancer Institute at Baptist Health South Florida has used proton therapy on more than 500 patients for a variety of hard-to-treat cancers. Because the 200,000-pound machine allows doctors to target high doses of radiation at the tumor with precision, patients with tumors in the brain, head and neck, spine, breast, lung, esophagus, pancreas, liver, prostate, anal canal and chest are seeing better results and fewer side effects than other cancer treatment options, according to doctors at the facility.

“The main difference between proton therapy and X-ray therapy (traditional radiation) is that protons will stop exactly where we want them to stop so there is no dose that will go through the other side of the tumor,” explains Dr. Michael Chuong, director of Clinical Research & Education at Miami Cancer Institute.

Each week, the oncologists at Miami Cancer Institute, the only South Florida hospital using the treatment, meet to determine which patients will benefit most from proton therapy, limited by the hours in a day patients can access the three multimillion-dollar machines the center has purchased.

The machines direct a proton beam into an area less than a millimeter in diameter to treat tumors that are inoperable, close to critical parts of the body or in difficult locations such as behind the eye or in the anal canal. Small pencil beams of protons are delivered one layer at a time until the entire tumor is treated.

Traditional X-rays penetrate healthy tissue and organs on their way in and out of the body, but protons can target the tumor without that damage. Proton therapy also creates less chance of a recurrence of cancer from excessive radiation exposure.