Nasopharyngeal Cancer Successfully Treated with Pencil-Beam Proton Radiotherapy at the Prague Proton Therapy Center. An Effective Treatment with Less Side Effects.

The Prague Proton Therapy Center Medical Team have released their latest results in treating Nasopharyngeal Cancer with Pencil Beam Proton Radiotherapy, entitled ‘Proton pencil‑beam scanning radiotherapy in the treatment of nasopharyngeal cancer: dosimetric parameters and 2‑year results‘. The article was published in the European Archives of Oto-Rhino-Laryngology and Head & Neck in June 2020.

Radiotherapy plays a crucial role in the treatment of nasopharyngeal cancer. Due to the high curability of nasopharyngeal cancer, the focus is now upon preserving quality of life, particularly in view of this high curability, and the long life spans ahead for patients suffering with these particular forms of cancer. Conventional x-ray/photon radiotherapy for nasopharyngeal cancer can cause side effects such as mucositis, dysphagia, skin reactions, weight loss, xerostomia, hearing loss, necrosis of temporal lobes, cranial nerve injury, optical tract impairment, and pain. Modern conventional techniques can reduce these side effects, however hospital admission is still required during radiotherapy or chemoradiation in 42% of cases. Patients with nasopharyngeal cancer are particularly suitable candidates for the healthy-tissue-sparing benefits of proton therapy, due to the high number of sensitive and critical body structures within immediate vicinity of the malignant spread.

40 patients with Nasopharyngeal Cancer were treated at the Prague Proton Therapy Center between 2013 and 2018 using Proton Therapy Pencil-Beam Scanning technology. The purpose of the study according to the authors is to ‘present the feasibility of Pencil-Beam Scanning proton radiotherapy in the treatment of Nasopharyngeal Cancer, dosimetric parameters, early treatment outcomes, as well as acute and late side-effect profiles.’ The median age of the 40 patients treated was 47. The majority of patients treated had locally advanced tumours, and pencil-beam proton therapy was used to treat the primary tumour and the bilateral neck lymph-node areas. 85% of patients received concomitant chemotherapy. The two year overall survival was 80%. Disease-free survival was 75%, and local control was 84%. Acute toxicity was generally mild despite large target volumes and concurrent application of chemotherapy.

Computer tomography (CT) was utilised for treatment planning and image registrations with planning magnetic resonance and positron emission tomography (PET) with fluorodeoxyglucose scans were performed prior to contouring. The contouring of targets and organs at risk was performed using advanced particle therapy (Elektra AB).

Treatment plans were developed with a full optimisation approach and all patients were treated with a three-field arrangement, chosen to maximise reduction of radiation to healthy tissues. All patients were treated using daily image guidance with position corrections performed via a robotic treatment couch. CT check-ups were conducted once weekly. Check-ups were based on image fusion with the planning CT. New plans were prepared when dose distribution changed due to tumor regression changes in cavity contents or changes in patient contours, and were made on an individual basis.

The median follow-up time was 24 months and all patients were treated without interruption. The two-year overall survival, disease-free survival, and locoregional control were 80%, 75%, and 84% respectively. Acute toxicity was evaluated at the last follow-up visit using the Radiation Therapy Oncology Group (RTOG) scale, and was generally mild. Skin toxicity and dysphagia were reported as the most frequent acute side effects. The insertion of a PEG was necessary in four patients. Late toxicity was extremely low across this patient group.

The 2-year overall survival of patients treated in this study was 80% and is comparable to published data for  nasopharyngeal cancer. The doses used in this patient group were similar to those used for conventional (photon) radiotherapy; therefore overall survival is expected to be similar. Importantly, 65% of the patients treated were referred to the Prague Proton Center with highly advanced tumours that excluded the use of conventional IMRT radiotherapy. This patient group was therefore burdened with a sample selection bias of highly advanced cases. With this sample bias of patients with highly advanced cancer in mind, the results are considered very promising.

In comparison to published late toxicity for conventional photon chemoradiotherapy with respect to xerostomia, hearing impairment, temporal lobe necrosis, auditory/salivary gland/skin/mucositis/oesophagus disturbances, the late toxicity profile in the PTC patient group is so far mild.

This study supports the results of previous research studies demonstrating the effectiveness of proton therapy in treating nasopharyngeal cancer. Patients with nasopharyngeal cancer appear to be suitable candidates for proton radiotherapy, mainly due to the reduction of acute and late side effects. With respect to the published literature, this study is the largest patient population treated with pencil-beam scanning proton radiotherapy to date.

In conclusion, pencil-beam scanning proton therapy for nasopharyngeal cancer patients is feasible with mild acute toxicity. Treatment plan dosimetry is positive and the treatment outcome is promising despite the high number of patients with extremely advanced disease states. The authors conclude that ‘Proton therapy should be considered in young patients or patients with advanced disease close to critical organs at risk of serious toxicity’. To find out if Pencil-Beam Proton Therapy in Prague is appropriate for you or a loved one, please do not hesitate to contact us.

Viktoria’s Germinoma Cancer Journey

Hello world 😊

My name is Viktoria.

I am from Bulgaria and I am 7 years old.

Six months ago I bumped into a world in which there is no difference in age, sex, race or nationality. Into this world we are all equal and each day we are fighting because it is not just a battle but it is a war.

This fight is like a solo sport but so many people help me, some of them I have never had the chance to meet and say thank you.

You are one of them and I want to thank you with all my heart for doing this for me!

P.S. My mam always says that people have good hearts and I believe in that too because of you!

Viktoria Todorova

The Benefits Of Proton Therapy For Childhood Cancers Clearly Acknowledged By Medical Professionals

In a February 2020 study published in the Journal of Paediatric Oncology, the role of proton therapy in treating paediatric cancer was examined across a wide variety of cancer types. This study highlighted that with improved management of the disease, survival rates continue to improve across childhood cancer types. Reducing treatment-related long-term side effects and reducing the risk of secondary treatment-related cancers thus have become a major focus.

The use of proton radiation as medical therapy was first proposed in the 1940s, with the first treatment occurring in 1958. Since then, proton radiotherapy has undergone dramatic changes and has been increasingly sought after in childhood cancer patients with potentially-curable malignant cancers. Real gains in endocrine outcomes, neurocognitive outcomes, quality of life, and other metrics have been reported. For instance through the use of proton therapy, the radiation dose to normal healthy tissues is estimated at 60% lower than with conventional radiotherapy. Additionally, the benefits of proton radiotherapy are now being widely accepted by insurance companies and other health service providers. A survey conducted across 54 proton centres in 11 countries in 2016 estimated that between 2,000 and 2,500 child patients were treated with proton therapy in 2016, a number that has doubled since 2012.

This article highlighted the superiority of proton therapy at treating essentially every form of childhood cancer – from central nervous system cancers such as Medulloblastoma, Ependymoma, Atypical teratoid/rhabdoid tumours, Craniopharyngioma, and CNS germ cell tumours, to non-central nervous system cancers such as Rhabdomyosarcomas, Ewing’s sarcoma, Base of skull chondrosarcoma and chordoma, Hodgkin’s lymphoma, Neuroblastoma, Retinoblastoma, and Osteosarcoma.

Childhood cancers are simply better treated with protons, resulting in less impact on quality of life outcomes, developmental delays, memory impairment, clinically significant endocrinopathy, hearing difficulties, and intelligence quotient (IQ) declines. Additionally, the use of proton therapy was shown to reduce the risk of secondary cancers.

The clinical data now shows that proton radiotherapy is as effective in controlling cancer as conventional radiotherapy, and there is now increasing evidence that the toxicities of proton treatment are also lower. While randomised trials are simply ‘not possible, feasible, or even ethical’ in the United States, other methods of studying patients are being adopted through important registry work both in the United States and abroad.

Further study is essential to continue to improve outcomes in this ‘most deserving’ paediatric population. To find out if proton therapy is appropriate for you or a loved one, please contact Proton Therapy UK and the oncologists at the Prague Proton Therapy Center.

Sources:

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Goitein M, Cox JD. Should randomized clinical trials be required for proton radiotherapy? J Clin Oncol 2008;26(2):175–6.

Greenberger BA, Yock TI. The role of proton therapy in paediatric malignancies: Recent advances and future directions. Semin Oncol. 2020 Feb 21. pii: S0093-7754(20)30002-6.

Gross JP, Powell S, Zelko F, et al. Improved neuropsychological outcomes following proton therapy relative to x-ray therapy for paediatric brain tumour patients. Neuro Oncol 2019.

Kahalley LS, Ris MD, Grosshans DR, et al. Comparing intelligence quotient change after treatment with proton versus photon radiation therapy for paediatric brain tumours. J Clin Oncol 2016;34(10):1043–9.

Kahalley LS, Peterson R, Ris MD, et al. Superior intellectual outcomes after proton radiotherapy compared with photon radiotherapy for paediatric medulloblastoma. J Clin Oncol 2019 JCO.19.01706.

Langen K, Zhu M. Concepts of PTV and robustness in passively scattered and pencil beam scanning proton therapy. Semin Radiat Oncol 2018;28(3):248–55.

Noone AM, Howlader N, Krapcho M, Miller D, Brest A, Yu M, Ruhl J, Tatalovich Z, Mariotto A, Lewis DR, Chen HS, Feuer EJ, Cronin KA, editors. SEER Cancer Statistics Review, 1975-2015, Bethesda, MD: National Cancer Institute; 2018.