Credit: Penn Medicine
Three studies presented at ASTRO to further define benefits of proton therapy
October 20, 2015
by Gus Iversen, Editor in Chief
Clinical trials undertaken at the Roberts Proton Therapy Center at Penn Medicine are shedding new light on the value of proton therapy over conventional radiation for treatment of various cancers. Dr. James Metz, chair of the department of Radiation Oncology, pointed out that the facility's contributions to defining the value of proton therapy is no coincidence.
"When the Roberts Proton Therapy Center opened in late 2009, we called for an increase in capacity for harder-to-treat cancers, and to open new clinical trials that help pinpoint the best uses of the technology," he said in a statement accompanying the institution's presentations at the 57th American Society for Radiation Oncology (ASTRO) meeting.
"These studies are prime examples of that mission, providing the field with more data to help establish the effectiveness and clinical benefits of proton therapy in more cancers," he continued.
Metz was a researcher on the first study outlined, along with presenter Dr. Pamela J. Boimel, a resident in the department of Radiation Oncology, and co-author Dr. John P. Plastaras, an associate professor of Radiation Oncology. They looked at 15 patients whose pancreatic cancers had returned. Such local recurrences take place in nearly 25 percent of these cases, following treatments like chemotherapy, surgery and radiation, and are frequently fatal, according to the researchers.
The researchers found that patients survived, on average, 15 months after reirradiation with proton therapy, and only 28.5 percent of patients did not survive an entire year. This is a significant finding in comparison to treatment with stereotactic body radiation therapy (SBRT), with which patients only survive an average of six to eight months.
The most commonly used treatment for patients such as these, with unresectable recurrent pancreatic cancer, is chemotherapy alone, said the researchers. In those cases, patients typically do not live longer than nine months after treatment.
"Our data suggests that pursuing proton reirradiation may benefit these patients who have no other good treatment choices, and does so with minimal side effects," said Plastaras. "While these results are promising, larger, follow-up studies are needed to establish which people with recurrent pancreatic cancer stand to benefit most from this therapy."
Other researchers from Penn Medicine provided the first clinical report of proton therapy versus intensity modulated radiation therapy (IMRT) in the post-operative setting for late-stage, non-small cell lung cancer.
Typically, these cases are treated with radiation after surgery to remove a tumor, but the toxicity of that treatment has been shown to sometimes outweigh the benefits. Authors, Dr. Jill Remick, a resident in the department of Radiation Oncology, Dr. Charles Simone, an assistant professor of Radiation Oncology, and Dr. Abigail Berman, an instructor in the department of Radiation Oncology, showed that proton therapy is well tolerated by patients while maintaining the positive clinical outcomes of IMRT.
Out of 34 patients, 17 underwent IMRT while 17 underwent proton therapy. One year overall survival and local recurrence-free survival rates were "excellent" in both groups, 85.7 and 94.1 percent for proton and IMRT, respectively. In each group, two study participants had side effects (radiation pneumonitis and esophagitis) but in the proton group the side effects were reportedly less severe.
"Proton therapy appears to be well-tolerated, while maintaining the positive clinical outcomes witnessed with IMRT," the authors reported in a statement.
Finally a team from Penn Medicine presented results from a prospective clinical of proton therapy for chordoma and chondrosarcoma, two rare and hard to treat bone cancers. Normally, those cases are treated with surgery followed by conventional radiation, but that treatment can fail.
Dr. Brian Baumann, a resident in the department of Radiation Oncology, and Dr. Michelle Alonso-Basanta, an assistant professor of Radiation Oncology, studied 20 patients with non-metastatic chordoma and chondrosarcoma who underwent proton therapy between 2010 and 2014. They found that all of the patients were alive at last follow up in February of this year. Local recurrence-free survival, distant metastases-free survival, and disease-free survival at two years were 92 percent, 95 percent, and 87 percent respectively.
"When the Roberts Proton Therapy Center opened in late 2009, we called for an increase in capacity for harder-to-treat cancers, and to open new clinical trials that help pinpoint the best uses of the technology," he said in a statement accompanying the institution's presentations at the 57th American Society for Radiation Oncology (ASTRO) meeting.
"These studies are prime examples of that mission, providing the field with more data to help establish the effectiveness and clinical benefits of proton therapy in more cancers," he continued.
Metz was a researcher on the first study outlined, along with presenter Dr. Pamela J. Boimel, a resident in the department of Radiation Oncology, and co-author Dr. John P. Plastaras, an associate professor of Radiation Oncology. They looked at 15 patients whose pancreatic cancers had returned. Such local recurrences take place in nearly 25 percent of these cases, following treatments like chemotherapy, surgery and radiation, and are frequently fatal, according to the researchers.
The researchers found that patients survived, on average, 15 months after reirradiation with proton therapy, and only 28.5 percent of patients did not survive an entire year. This is a significant finding in comparison to treatment with stereotactic body radiation therapy (SBRT), with which patients only survive an average of six to eight months.
The most commonly used treatment for patients such as these, with unresectable recurrent pancreatic cancer, is chemotherapy alone, said the researchers. In those cases, patients typically do not live longer than nine months after treatment.
"Our data suggests that pursuing proton reirradiation may benefit these patients who have no other good treatment choices, and does so with minimal side effects," said Plastaras. "While these results are promising, larger, follow-up studies are needed to establish which people with recurrent pancreatic cancer stand to benefit most from this therapy."
Other researchers from Penn Medicine provided the first clinical report of proton therapy versus intensity modulated radiation therapy (IMRT) in the post-operative setting for late-stage, non-small cell lung cancer.
Typically, these cases are treated with radiation after surgery to remove a tumor, but the toxicity of that treatment has been shown to sometimes outweigh the benefits. Authors, Dr. Jill Remick, a resident in the department of Radiation Oncology, Dr. Charles Simone, an assistant professor of Radiation Oncology, and Dr. Abigail Berman, an instructor in the department of Radiation Oncology, showed that proton therapy is well tolerated by patients while maintaining the positive clinical outcomes of IMRT.
Out of 34 patients, 17 underwent IMRT while 17 underwent proton therapy. One year overall survival and local recurrence-free survival rates were "excellent" in both groups, 85.7 and 94.1 percent for proton and IMRT, respectively. In each group, two study participants had side effects (radiation pneumonitis and esophagitis) but in the proton group the side effects were reportedly less severe.
"Proton therapy appears to be well-tolerated, while maintaining the positive clinical outcomes witnessed with IMRT," the authors reported in a statement.
Finally a team from Penn Medicine presented results from a prospective clinical of proton therapy for chordoma and chondrosarcoma, two rare and hard to treat bone cancers. Normally, those cases are treated with surgery followed by conventional radiation, but that treatment can fail.
Dr. Brian Baumann, a resident in the department of Radiation Oncology, and Dr. Michelle Alonso-Basanta, an assistant professor of Radiation Oncology, studied 20 patients with non-metastatic chordoma and chondrosarcoma who underwent proton therapy between 2010 and 2014. They found that all of the patients were alive at last follow up in February of this year. Local recurrence-free survival, distant metastases-free survival, and disease-free survival at two years were 92 percent, 95 percent, and 87 percent respectively.