Superior Intellectual Outcomes After Proton Radiotherapy Compared With Photon Radiotherapy for Pediatric Medulloblastoma

Proton Radiotherapy Preserves Intellectual Function in Children suffering from Medulloblastoma – New study shows that children treated with Proton Therapy have superior intellectual outcomes, compared to children treated with conventional photon/x-ray radiotherapy.

Radiotherapy is essential for treating children’s brain tumours – however conventional radiotherapy treatment increases the risk of permanent cognitive impairment. Memory problems, learning problems, global IQ decline, and other serious cognitive impairments can occur. A new study published in the Journal of Clinical Oncology on the 27th November 2019 has demonstrated the superiority of proton therapy over traditional x-ray/photon radiotherapy in treating paediatric Medulloblastoma.

Medulloblastoma is an invasive, rapidly growing form of tumour, and the most commonly occurring type of brain cancer in children. This study showed that the use of proton therapy in treating these cancers (instead of conventional photon/x-ray radiotherapy) resulted in significantly improved long-term intelligence outcomes in children.

This study provides the strongest evidence to date that proton therapy preserves the intellectual function of children with medulloblastoma – as opposed to traditional x-ray radiation which can cause damage and result in a lower quality of life for children following treatment. The authors of the study concluded:

“Even in the context of CSI (craniospinal irradiation), patients treated with PRT (Proton RadioTherapy) exhibited stable intellectual outcomes in most domains and experienced significantly better long-term outcomes in global IQ, perceptual reasoning, and working memory compared with patients treated with XRT (conventional x-ray radiotherapy).”

These results expand on previous research suggesting an intellect-sparing benefit of proton therapy in the treatment of paediatric brain tumors, reported Lisa S. Kahalley, PhD, of Texas Children’s Hospital (TCH) in Houston, and colleagues in the Journal of Clinical Oncology.

“It’s getting very difficult to argue that there isn’t a very strong clinical benefit associated with proton, so now it really becomes an access issue. We have to think really hard about ways to improve access to families that aren’t located near proton centres.”

The Proton Therapy Center in Prague has considerable experience treating children’s brain tumours with protons, and has treated many children suffering from medulloblastoma – including British child Ashya King, who received proton therapy at the Prague Proton Therapy Center after an international manhunt in 2014. Ashya’s story received widespread public attention, and his successful proton therapy treatment in Prague resulted in him having less risk of cognitive problems following treatment.

Extreme hypofractionated proton radiotherapy for prostate cancer using pencil beam scanning: Dosimetry, acute toxicity and preliminary results

Prague Proton Therapy Medical Team Publishes their Latest Results, Using Proton Therapy to Treat Prostate Cancer.

Several treatment options exist for managing prostate cancer in men. Surgery and conventional radiotherapy have been shown to be equally effective at treating prostate cancer, however conventional treatments such as these can result in side effects that can reduce overall quality of life. Proton therapy is equally effective at treating prostate cancer, however causes less side effects, thereby preserving the quality of life of patients during and after treatment.

Proton therapy has been used to treat prostate cancer for over 25 years. Doctors at the Proton Therapy Center (PTC) in Prague have been treating prostate cancer with proton therapy since opening their facility in 2012. The Prague Proton Therapy Center uses the most advanced form of proton therapy available known as ‘Intensity-Modulated Proton Therapy’ (IMPT) – otherwise known as ‘Pencil-Beam Scanning’ (PBS). This highly accurate form of proton therapy allows high doses of cancer-killing proton radiation to be delivered to the tumour, while sparing healthy surrounding tissue from harm.

The PTC medical team have published their latest treatment findings, using IMPT proton therapy to treat prostate cancer. Their success in treating prostate cancer with proton therapy was published in the Journal of Medical Imaging and Radiation Oncology (the Official Journal of The Royal Australian and New Zealand College of Radiologists).

This study follows the progress of 200 prostate cancer patients that received an advanced and accelerated proton treatment program. The results show that this treatment is extremely effective at treating and removing prostate cancer. The research also shows that proton therapy for prostate cancer results in extremely low side effects. The PTC medical team was able to successfully remove the prostate cancer with almost no side effects using an accelerated, 2 week treatment schedule.

Side effects to the bladder and bowel are commonly reported among patients undergoing conventional radiotherapy for prostate cancer. The Radiation Therapy Oncology Group (RTOG) rates side effects on a ‘grading’ scale from 0 (none) to 4 (severe). Patients examined during the PTC study experienced an extremely low degree of bladder side effects, or in many cases, no side effects at all (grade 0). Only 22.5% of patients experienced grade 2 side effects. The majority of these grade 2 side effects completely disappeared following treatment. Patients undergoing treatment experienced absolutely no severe (i.e. no grade 3 or 4) bladder-related side effects.

In addition to low bladder-related side effects, patients undergoing proton therapy in Prague experienced virtually no bowel side effects. 20% of patients experienced mild, short-term bowel-related side effects that disappeared following treatment. Importantly, 80% of patients experienced no bowel-related side effects during or after treatment. Excitingly, no patients experienced severe (grade 3 or 4) side effects!

To read more about their latest results using proton therapy for prostate cancer, click here.

Comparative Effectiveness of Proton vs Photon Therapy as Part of Concurrent Chemoradiotherapy for Locally Advanced Cancer

Doctors at the University of Pennsylvania in Philadelphia published retrospective, nonrandomised comparative effectiveness study that compares proton versus photon therapy for concurrent chemoradiotherapy of locally advanced cancer.

The authors compared adverse events associated with unplanned hospitalisations among 1,483 adult patients with nonmetastatic, locally advanced cancers treated with concurrent chemoradiotherapy and proton therapy (391 patients) or photon therapy (1092 patients). The results were published in August 2019 in JAMA Oncology. This study found that proton therapy significantly reduced severe adverse events in adults with locally advanced cancers without affecting outcomes when compared with photon therapy.

Concurrent chemoradiotherapy can be associated with substantial toxicity, including
oral mucositis, oesophagitis, nausea, vomiting, signifiant weight loss, and radiation-induced lung injury that can result in unplanned hospitalisations, emergency department visits,
treatment interruptions that can diminish the effectiveness of treatment, and decreased patient performance status.

Proton therapy as part of concurrent chemoradiotherapy may be able to reduce treatment toxicity, but limited data have been so far available comparing results of proton chemoradiotherapy with chemoradiotherapy delivered with photon therapy, and proton therapy remains unproven in this setting. This comparative effectiveness cohort study focused therefore on the rate of severe 90-day adverse events associated with unplanned hospitalisations.

The study comes to a result that compared with photon therapy, proton therapy was associated with a nearly two-thirds reduction in 90-day severe adverse events associated with unplanned hospitalisations. Proton therapy was also associated with significantly lower risk of a decline in Eastern Cooperative Oncology Group (ECOG) performance status and significantly less risk of adverse events causing impairment in patients’ instrumental activities of daily living.

Proton therapy was also shown to be equally effective at treating the cancer – disease-free and overall survival outcomes were similar between the two groups, which included patients with head and neck, lung, brain, oesophagus/gastric tract, rectum, and pancreas cancers.

Before this study, data on the toxicity differences between proton vs photon chemo-radiotherapy have been limited, with relatively small patient numbers, although most studies have found a toxicity advantage and/or dosimetric advantage in favour of proton chemoradiotherapy.

This study mentions 3 important implications for future research:

  • First, proton therapy’s lower observed toxicity raises the possibility that the higher up-front cost of proton therapy may be offset by cost savings from reduced hospitalisations  and enhanced productivity from patients and caregivers.
  • Second, the lower observed toxicity of proton therapy offers an opportunity to explore clinical trials combining proton therapy with intensified systemic therapy and/or dose-escalated radiotherapy, which may, in turn, improve survival outcomes.
  • Third, proton therapy may allow also older, sicker patients with more comorbidities to receive the most effective combined-modality treatments.