Keen to the targeted cancer-killing power of protons with little radiation exposure to nearby vital organs, radiation oncologists at the Roberts Proton Therapy Center in Philadelphia are the first in the world to use proton beams to treat locally recurrent pancreatic cancer.
As of March 2010, three relapsed pancreatic cancer patients had been treated with a combination of protons and chemotherapy under a protocol devised by James Metz, M.D., and his team at the center, which is part of the Abramson Cancer Center at the University of Pennsylvania Health System (UPenn).
Up until UPenn’s application of protons for localized recurrent pancreatic cancer cases, the therapeutic options and likelihood of success were distressingly limited for patients, says Metz, who is Vice Chair of the Clinical Division and Associate Professor of Radiation Oncology. “Most patients with recurrent tumors go on to hospice and get no treatment at all,” he says.
Newly diagnosed pancreatic cancers are typically treated with a combination of surgery, chemotherapy and conventional radiation therapy when localized. “The challenge is that the pancreas sits amid a number of critical organs, like the spinal cord, both kidneys, the bowel and the liver, which can experience significant damage when you push the limits of photon treatments,” Metz says. Those limits, he adds, deter the use of conventional radiation on relapsed localized cancers.
“Because of the nature of protons, we can defy the mantra, ‘once you get radiation you can’t get it again,’” Metz says. “With protons, we now have the ability to treat the cancer, minimizing re-exposure of nearby critical organs to radiation.”
Metz and his team first used their protocol to treat a middle-aged woman from a Philadelphia suburb who had experienced her second relapse of an adenocarcinoma of the pancreas.
“She really had no other option,” Metz recalls. “She was first diagnosed four years ago and was treated with surgery, radiation and chemotherapy. She had a local recurrence a year later and received chemotherapy, and responded well. But last summer, the cancer started growing back. She called me and I said, ‘Get in here and let’s look at this.’”
After completing the six-week protocol, the patient has been in remission for more than six months and is doing well clinically, he says.
Metz emphasizes that the three patients treated thus far “have no evidence of disease spread to other parts of the body. These are local recurrences only.” Patients with recurrent pancreatic cancer and evidence of metastatic disease are not appropriate for this treatment, he says.
UPenn’s combination protocol of protons and chemotherapy is also being used for locally recurrent cancers of the esophagus and rectum, Metz adds.
