Proton therapy for cancer lowers risk of side effects

by Julia Evangelou Strait, Washington University School of Medicine

Proton therapy results in fewer side effects than traditional X-ray radiation therapy for many cancer patients, according to a new study led by Washington University School of Medicine in St. Louis and the Perelman School of Medicine at University of Pennsylvania. Even with reduced side effects, proton therapy resulted in cure rates similar to those of X-ray radiation therapy.

Proton therapy for cancer lowers risk of side effects
A new study led by Brian Baumann, M.D., of Washington University School of Medicine in St. Louis, found that proton therapy (bottom) is associated with fewer severe side effects than conventional X-ray radiation therapy (top) for many cancer patients. Credit: Brian Baumann/Mike Worful

The study is the first major side-by-side comparison of side effects related to proton therapy and X-ray radiation therapy. It included almost 1,500 patients receiving combined chemotherapy and radiation therapy for lung, brain, head and neck, gastrointestinal and gynecologic cancers that had not yet spread to other parts of the body. Such patients receive both radiation and chemotherapy, a treatment regimen that often cures nonmetastatic cancer. But it also causes severe side effects—such as difficulty swallowing, nausea and diarrhea—that reduce quality of life and can, in some cases, require hospitalization.

After controlling for differences between the groups, such as age and additional medical problems, the researchers found that patients receiving proton therapy experienced a two-thirds reduction in the relative risk of severe side effects within 90 days of treatment, compared with patients receiving X-ray radiation therapy. Forty-five of 391 patients receiving proton therapy experienced a severe side effect in the 90-day time frame (11.5 percent). In the X-ray radiation therapy group, 301 of 1,092 patients experienced a severe side effect in the same period (27.6 percent). Patient data on side effects were gathered as the trial was ongoing, rather than after the fact.

“Proton therapy was associated with a substantial reduction in the rates of severe acute side effects—those that cause unplanned hospitalizations or trips to the emergency room—compared with conventional photon, or X-ray, radiation for patients treated with concurrent radiation and chemotherapy,” said Baumann, an assistant professor of radiation oncology at Washington University and an adjunct assistant professor of radiation oncology at Penn. “The opportunity to reduce the risk of severe side effects for patients and thereby improve their quality of life is very exciting to me. While there have been other studies suggesting that proton therapy may have fewer side effects, we were somewhat surprised by the large magnitude of the benefit.”

The researchers focused their study on what are called grade 3 adverse events, which are severe enough to require hospitalization. These can include pain, difficulty swallowing that might result in weight loss, difficulty breathing, and nausea and diarrhea severe enough to cause dehydration.

The researchers also found no differences between the two groups in survival, suggesting that proton therapy was just as effective in treating the cancer even as it caused fewer side effects. Overall survival at one year for the proton therapy group was 83 percent of patients versus 81 percent for the X-ray radiation therapy group. This difference was not statistically significant.

This study is the first large review of data across several cancer types to show a reduced side-effect profile for proton therapy compared with X-ray radiation therapy for patients receiving combined chemotherapy and radiation. Both types of radiation therapy are approved by the Food and Drug Administration for cancer treatment. Protons are relatively heavy, positively charged particles that hit their target and stop. X-ray beams consist of photons, which are much smaller particles that have almost no mass, allowing them to travel all the way through the body, passing through healthy tissue on the way out.

https://medicalxpress.com/news/2019-05-proton-therapy-cancer-lowers-side.html

Please follow us:
error

Montefiore Study May Help Establish Patient Criteria for Proton Therapy

N. Patrik Brodin, PhD

Data supporting the efficacy of proton therapy are robust for pediatric cancers, brain and base-of-skull tumors, and complex-shaped tumors near critical structures (…)

Proton therapy has emerged as an attractive option for patients with head and neck cancer. This is due to proton therapy beam technology, which precisely destroys cancers with an unmatched ability to stop at precise locations within the body.

Protons also have significantly fewer adverse effects (AEs) and toxicities than most other cancer therapies, because of the protons’ unique ability to sculpt radiation doses according to the shapes and sizes of tumors. This is particularly important for head and neck cancers, which frequently are close to or impeding on vocal cords, air passageways, swallowing muscles, salivary glands, and the oral mucosa. The opportunity to preserve healthy tissue is considerable.

AEs estimated to be significantly less prominent include swallowing difficulties, inflammation of the esophagus, and reduced saliva production. For people suffering from head and neck cancer and their families, the ability to avoid these types of complications makes an overwhelmingly important difference in QoL.

Younger patients, non-smokers, and patients with HPV p16- positive tumors will most likely benefit from proton therapy (…)

The highest expense in cancer therapy involves the regrowth of cancer—large sums are required to prolong survival and maintain QoL. By increasing cure rates and improving patients’ QoL, we can increase cost-effectiveness.

It is important for healthcare providers not only to educate our patients and their families about each treatment’s ability to destroy cancers, but also to manage expectations about different treatments and what life may look like “post cancer.”

Proton therapy is one of the most modern therapies available, and its ability to minimize AEs such as trouble swallowing, reduced ability to eat, dental problems, and difficulty digesting food can’t be understated for some of our patients (…) By increasing cure rates and improving patients’ Quality of Life, we can increase cost-effectiveness.

https://www.onclive.com/publications/oncology-live/2019/vol-20-no-11/montefiore-study-may-help-establish-patient-criteria-for-proton-therapy

Please follow us:
error

Dosimetric studies show that proton therapy can reduce the low/intermediate radiation dose to uninvolved tissue in children with low-grade glioma (LGG).

Outcomes Following Proton Therapy for Pediatric Low-Grade Glioma Indelicato, Daniel J. et al. International Journal of Radiation Oncology • Biology • Physics , Volume 104 , Issue 1 , 149 – 156.

Low-grade gliomas (LGGs) are the most common brain tumors in children, with approximately 800 cases diagnosed each year in the United States. Management of these tumors depends on several elements, including host factors (eg, patient age and comorbidities) and disease characteristics (eg, tumor location and histologic subtype). With a long-term survival rate that exceeds 90%, therapy selection involves careful consideration of minimizing late toxicity from surgery, chemotherapy, and irradiation. Treatment side effects can be permanent or life threatening and include neurocognitive impairment, neurologic deficits, neurovascular compromise, neuroendocrine deficiency, and second malignancies.

Surgery, radiation therapy, and chemotherapy may be used as solitary therapies or in combination, offering different therapeutic ratios depending on the setting. As a result, establishing the ideal treatment choice and sequencing has historically been an area of controversy, presenting challenges that are further complicated by the emergence of molecular targets.

Several studies have attempted to mitigate the impact of late radiation toxicity through selective radiation avoidance, systematic reduction in the size of target volumes, and the use of advanced radiation techniques. Of these radiation techniques, proton therapy is particularly promising because it allows for reductions in the low and intermediate radiation dose to normal tissue outside of the target volume. Accordingly, LGGs in children are considered a “Group 1” indication for proton therapy according to the United States American Society for Radiation Oncology Model Policy, and they have become the third most common pediatric brain tumor type treated with proton therapy worldwide.

Compared with modern photon series, proton therapy reduces the radiation dose to developing brain tissue, diminishing acute toxicities without compromising disease control.

https://www.redjournal.org/article/S0360-3016(19)30162-2/pdf

Please follow us:
error

What is the best therapeutic approach to a pediatric patient with a deep-seated brain Arteriovenous Malformations ?

Meling TRPatet G

Proton Therapy offers promising results with a more accurate radiation that avoids the surrounding tissue

Although brain arteriovenous malformations (bAVMs) account for a very small proportion of cerebral pathologies in the pediatric population, they are the cause of roughly 50% of spontaneous intracranial hemorrhages. Pediatric bAVMs tend to rupture more frequently and seem to have higher recurrence rates than bAVMs in adults. Thus, the management of pediatric bAVMs is particularly challenging. In general, the treatment options are conservative treatment, microsurgery, endovascular therapy (EVT), gamma knife radiosurgery (GKRS), proton-beam stereotactic radiosurgery (PSRS), or a combination of the above. In order to identify the best approach to deep-seated pediatric bAVMs, we performed a systematic review, according to the PRISMA guidelines. None of the options seem to offer a clear advantage over the others when used alone. Microsurgery provides the highest obliteration rate, but has higher incidence of neurological complications. EVT may play a role when used as adjuvant therapy, but as a stand-alone therapy, the efficacy is low and the long-term side effects of radiation from the multiple sessions required in deep-seated pediatric bAVMs are still unknown. GKRS has a low risk of complication, but the obliteration rates still leave much to be desired. Finally, PSRS offers promising results with a more accurate radiation that avoids the surrounding tissue, but data is limited due to its recent introduction. Overall, a multi-modal approach, or even an active surveillance, might be the most suitable when facing deep-seated bAVM, considering the difficulty of their management and the high risk of complications in the pediatric population.

Neurosurg Rev. 2019 Jun;42(2):409-416. https://www.ncbi.nlm.nih.gov/pubmed/30980204

Please follow us:
error

Advances in Neuro-oncology

Proton Therapy for Children and Adults

Proton therapy has grown in prominence in recent years as another radiotherapy technique that spares healthy tissue. Unlike photons, which travel all the way through a target and come out the other side, protons can be programmed to stop inside the target, delivering the entire dose to a tumor.

Proton therapy particularly offers attractive benefits for pediatric cancer patients, as they are susceptible to more long-term effects of radiation. Gondi and colleagues at Northwestern presented another study at the 2018 American Society for Radiation Oncology (ASTRO) meeting comparing neurocognitive effects of proton versus photon therapy in 125 children with brain tumors. The median age at diagnosis was 7 years old, and the median time from treatment to last assessment was four years. According to Gondi, the children treated with proton therapy scored higher post-treatment in full-scale IQ, processing speed and parent-reported practical functions.

Proton therapy also offers opportunities for treating adults with brain tumors, particularly gliomas, one of the most common types of primary brain tumors. In particular, Gondi is interested in low-grade gliomas, a slow-growing tumor that can develop earlier in life. “The average age of someone with a low-grade glioma is actually 37 — that’s the prime of these young adult lives. Their cognitive function is so important. So we’re using proton therapy to try to treat that tumor, avoid as much unnecessary radiation dose to normal brain tissue, and see if we can’t help preserve that cognitive function,” he said.

“It’s about that survivorship and how we can optimize that survivorship,” he added.

https://www.itnonline.com/article/advances-neuro-oncology

Please follow us:
error