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The merging of cutting-edge accelerator technology with state-of-the-art cancer therapy could result in a method to tackle tumors resistant to current cancer treatments.
CERN, operators of the Large Hadron Collider (LHC) particle accelerator, have teamed up with Lausanne University Hospital (CHUV) to develop the conceptual design for a radiotherapy facility used for the treatment of cancer. The technique is based on new accelerator technology and the FLASH radiotherapy method.
FLASH is a cutting-edge cancer treatment that delivers a highly targeted blast of electrons to tumors. It is capable of reaching deep inside a patient’s body, causing less damage to healthy tissues. CERN will provide a technology capable of accelerating electrons to high energies over a short distance. The methodology could have significant benefits for cancers currently difficult or even near-impossible to treat.
The new collaboration between CHUV and CERN builds upon a study that concluded this month, conducted by the former. Researchers investigated the effectiveness of FLASH radiotherapy in the treatment of skin cancer.
FLASH radiotherapy involves administering a high dose of radiation almost instantaneously — over milliseconds rather than minutes. This results in the tumor being damaged in the same way as in traditional radiotherapy, but with healthy tissue less exposed to damage. This means a reduction in negative side effects from the treatment.
At a joint press conference held by CERN and CHUV, professor Jean Bourhis, Head of the UNIL-CHUV radio-oncology service, explains that with the FLASH effect, healthy tissues receive only 1/3 of the standard dose of radiation, while the tumor they surround receives the full dose.
Bourhis points out that the reduced delivery to healthy surrounding tissues has another benefit besides reducing adverse side effects. It means that tumors can be exposed to higher doses of radiation. Therefore, it is possible that larger, more resistant tumors can be tackled by FLASH therapy.
Bourhis’ colleague, Professor George Coukos, Head of the UNIL-CHUV oncology department, points out that this also means that while Flash could be used to treat any solid tumor, it could be particularly useful in pancreatic cancer and brain tumor treatments.
The advantages of FLASH therapy were first demonstrated by researchers at CHUV in 2018 when testing showed the complete disappearance of a resistant skin cancer tumor with few adverse side effects. Bourhis explains that this was a first for FLASH treatment on humans and significantly accelerated the clinical transition of FLASH therapy.
The key requirement of FLASH therapy is the ability to accelerate electrons to high velocities, and therefore high energies, over a short distance. This requires using a compact linear accelerator — and as powerful as the LHC is, it is not suitable for the job, being a circular accelerator and over 16 miles in diameter. This is where CERN’s proposed Compact Linear Collider (CLIC) accelerator technology comes in.
CLIC: Energising Electrons for FLASH Therapy
CLIC is an accelerator proposed as an addition to CERN’s accelerator complex — a succession of machines that accelerate particles to increasingly higher energies. It is designed to collide electrons and positrons (antielectrons) head-on at several teraelectronvolts (TeV).
This makes it the perfect machine to accelerate electrons to the energies required in FLASH therapy. Once accelerated to energies of several TeV, the electrons treat tumors of a depth of up to 15 to 20 cm.
The small size of CLIC also means that the electrons can be accelerated to these energies over a short distance and in a brief period. Walter Wuensch, project leader at CERN, explains at the joint press conference that these elements make the CLIC accelerator almost the perfect match for FLASH therapy. Wuensch describes the collaboration between CERN and CHUV as the next stage for accelerator technology.
Coukos agrees, pointing out that getting advancements in particle physics from the lab to the bedside has been a challenge in the past due to the lack of a suitable infrastructure. The CERN and CHUV collaboration is now looking for professional partners and investment to develop this infrastructure further. They will launch an appeal by 31st December 2020 to obtain finance for the development and implementation of the clinical transfer of the FLASH therapy.
Dr. Manuela Cirilli, Medical Applications section leader at CERN’s Knowledge Transfer group, points to the combination of CLIC and FLASH therapy as the perfect synergy between medical innovation and the knowledge achieved at CERN. She adds that the project is the ideal opportunity to demonstrate the benefits particle physics can have in everyday life.
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Early Days for CLIC and FLASH Therapies
The collaboration between CERN and CHUV is very much in its early stages. The team assembled at the joint press conference point to an aggressive development period that should see the technology ready to implement in 2-3 years.
The next step is more clinical trials, which should give CHUV a better idea of the cancers FLASH is most effective at tackling, what patients will receive the most benefit from the methodology, and what other cancer treatment modalities FLASH can be combined with.
Though the treatment will initially only be available at CHUV, ultimately, the conservative size of the CLIC accelerator means the technology required for FLASH therapy is only slightly larger than that needed for traditional radiotherapy. That means it could be deployed in almost any hospital.
With regards to the cost of treatment, Wuensch points out that while the cost of FLASH is greater than that of traditional radiotherapy, the highly directed nature of the therapy hopefully means that patients will have to endure much fewer treatments , which balances the overall cost and makes FLASH competitive with other forms of cancer therapy.
References and Further Reading
CERN/CHUV Press Conference (15th September 2020).
The Compact Linear Collider, CERN, [https://home.cern/science/accelerators/compact-linear-collider]
IntraOp and Lausanne University Hospital Announce Collaboration in FLASH, CHUV, , [https://www.chuv.ch/fileadmin/sites/chuv/documents/chuv-communiques-radiotherapie-flash-en-200618.pdf]