Preliminary reports show promise of protons for treating head and neck cancers

Four months into treating patients with head and neck cancers using pencil beam scanning with protons, Alexander Lin, MD, is optimistic about the results he is seeing so far. Many cancers are in remission and patients aren’t experiencing the life-changing side effects so common among those treated with conventional radiation.

 

When it comes to sheer cancer-killing power, “protons and photons are equally efficient,” said Dr. Lin, clinical operations director at Penn Medicine’s Roberts Proton Therapy Center in Philadelphia, Pennsylvania. Penn Medicine is the branded name for the University of Pennsylvania Health System. There, head and neck cancer tumors typically are removed by surgery before follow-up treatment with radiation.

“Cancer cells treated with proton or non-proton radiation can’t tell the difference at all,” he added.

But the after-effects of these radiation therapies is another story. Conventional radiation treatment can be far more pernicious to everyday living — during treatment and years after, said Dr. Lin, because the area of radiation tends to be wider, harming more healthy tissue.

Dr. Lin recalled the radiation dose images he viewed of his first head and neck patient who was treated with protons. “We saw an immediate lessening of the radiation dose to the oral cavity in our computer scans,” he said. “This is at the front part of the tongue, where all the taste buds are.”

Seeing less radiation affecting the taste buds, Dr. Lin was optimistic that his patient wouldn’t experience the taste problems that are common to patients treated with Intensity Modulated Radiation Therapy. “Every week we’d ask about taste,” Dr. Lin said. “He had no taste abnormalities.”

Able to taste food normally, Dr. Lin’s patient could hold his weight better during treatment and ensure optimal proton precision. “If people lose a large amount of weight during radiation treatments, the radiation precision can be compromised,” he added. “And protons are very sensitive to changes in the patient’s anatomy.

 

 

If the body changes slightly, it could be the difference between protons going where you want them or going where you don’t want them.”

Head and neck cancer patients treated with conventional radiation also may develop mouth sores, dry mouth and an inability to generate saliva, Dr. Lin said. Such treatment side effects are no mere inconveniences; they often have significant impacts on a patient’s quality of life, during and long after completion of therapy.

“If there is no saliva to help break down food, you can imagine the weight one would lose,” Dr. Lin said. “Dry mouth can affect quality of life, too.” And with an increasing percentage of conventional radiation patients, dry mouth is long lasting, affecting their ability to speak, he added. “Ameliorating these acute side effects tends to improve long-term outcomes,” he said.Optimally, direct comparisons of patient outcomes from those treated with protons as opposed to photons are needed to definitively conclude that protons are superior to photons for treating head and neck cancers, Dr. Lin noted; however he believes that in a few years, he and his collaborators at the University of Pennsylvania will be able to report such outcomes to confirm the clinical benefits of protons.

 

 

When treating certain head and neck cancers, unintended radiation exposure to the teeth, jaw and tongue, and its potential side effects may be reduced using protons (top), as compared to intensity modulated radiation therapy (bottom).

  • (Images courtesy of Dr. Alexander Lin, Roberts Proton Therapy Center.)

Study shows proton therapy cuts risk of secondary tumors nearly in half compared to photon radiation

A study published in the International Journal of Radiation OncologyBiology • Physics has shown that proton therapy reduces the risk of a patient developing a second tumor by nearly half as compared with conventional radiation (photon) therapy.

The impetus for doing the study was to see if the improved dose distribution achievable with protons as compared with photons would translate into a reduced rate for second cancers. Previous math modeling studies showed that protons decreased the risk of second tumors; however, there was no clinical data to date. Additionally, critics of proton therapy have speculated that passive scattering — currently the most common technique used to deliver protons — was generating an unacceptable amount of neutrons, which may negate any perceived benefit and possibly even increase the second tumor risk.

“We wanted to look at this issue and settle it,” said Torunn I. Yock, M.D., chief of Pediatric Radiation Oncology at Massachusetts General Hospital, associate professor at Harvard Medical School, and one of the study authors. “That’s why we embarked on this study.”

 

Study specifics

The study, titled “Incidence of Second Malignancies Among Patients Treated With Proton Versus Photon Radiation,” compared the frequency of second cancers in 558 patients treated with proton radiation using the passive scattering technique to 558 patients treated with photon radiation from the population-based Surveillance, Epidemiology, and End Results (SEER) registry. Patients were matched by age at radiation treatment, sex, year of treatment, histology (or type of cancer), and cancer site.

Funded by the National Cancer Institute, SEER is a coordinated system of cancer registries strategically located across the United States. Proton patients cited in the study were treated from 1973 to 2001 at the Harvard Cyclotron in Cambridge, Massachusetts. Harvard offers the largest proton patient database in the world with long-term follow-up. During the study period, nearly all patients treated at the Harvard Cyclotron received some photon radiation (typically 20 percent of their treatment) in addition to proton radiation.

Medium length of follow-up was 6.7 years and 6.0 years in the proton and photon groups, respectively. Median age at treatment was 59 years in each group. Second malignancies occurred in 29 proton patients (5.2 percent) and 42 photon patients (7.5 percent).

After adjusting for sex, age at treatment, primary cancer site and year of diagnosis, proton therapy appeared to be associated with a decreased risk of developing a second tumor.

“When you use the passive scattering technique, you end up generating neutrons, and we don’t know what neutrons do,” said Dr. Yock. “But in the radiation world, we assign them a high quality factor for safety reasons. We err on the side of overestimating the detrimental effects of radiation in order to keep exposure limits to workers within limits that are believed to be safe.”

In many cases, the quality factor assigned to neutrons is 20 times that of photons (the more typical x-ray radiation). The same quality factors were used to estimate for carcinogenesis risk (the risk of developing cancer), although there is a near complete lack of data that inform doctors of what that risk is. In short, the study suggests that the carcinogenesis risk from the tiny amount of neutrons generated in passively scattered proton techniques does not completely negate the second tumor benefits of protons compared with photons.

 

Passive scattering vs. pencil beam scanning

Passive scattering entails placing a solid brass disk, with an aperture matching the shape of the tumor cut into it, near to the patient to help the proton beam find its target. The proton beam is directed through the aperture at the tumor. Some of the protons hit the brass, which then releases a small amount of neutrons that can be absorbed by the patient. In addition, there is neutron production from protons interacting with tissues that are also absorbed by the body, but this amount of neutron radiation is even smaller.

Pencil beam scanning, a more advanced technology that is available at some proton therapy centers, eliminates the need for brass apertures because the proton beam is so narrow in diameter. Therefore, it dramatically reduces the production of external neutron dose.

“We are still working on refining the technology for pencil beam scanning,” said Dr. Yock. “Once that happens, I think it will be better in many circumstances than passively scattered beams. We’re just not there yet.” With a beam spot of 3 millimeters — about the diameter of a headphone jack — “most pencil beams are still too large to do the finest of tumor targeting,” she said.

Dr. Yock said a major takeaway from the study was that fears that protons might increase the rates of secondary cancers due to neutron scatter were not realized and that, in fact, the clinical data seem to support that protons do indeed reduce the risk of a second tumor. “I think that’s very reassuring,” she said.

 

 

Torunn I. Yock, M.D., is chief of Pediatric Radiation Oncology at Massachusetts General Hospital and  associate professor at Harvard Medical School in Boston, Massachusetts.

 

WEB REVIEW – “Proton Therapy in Prague was the number one choice for me“

Benedek is a 39 year old from Belgium. At the end of 2013, Benedek underwent chemotherapy in order to treat a spinal cord tumour. Unfortunately this was not very effective and so he had to decide upon subsequent treatments. His Czech wife discovered the Proton Centre in Prague.

 

“Together with my doctors, we came to the conclusion that proton therapy was the only reasonable treatment since the tumour is located near my spinal cord. An unwanted dose of radiation could have paralysed me“. Benedek’s decision to go to Prague was clear. “Since there are no proton facilities in Belgium, and very few in Europe, I did not have many locations to choose from. Besides, through my wife I have really good connections in Prague, as well as due to my professional background – I know the city pretty well”.

The treatment process consisted of 20 days of radiation sessions and it all went very smoothly. The side effects were extremely minimal, according to Benedek: “Only my oesophagus was slightly irradiated causing mild discomfort when swallowing. Definitely nothing like the unpleasant side effects I have heard from patients undergoing conventional radiotherapy”.

 

 

Discussions with his health care provider in Belgium took a bit of effort. “Covering the cost of treatment abroad is clearly not an everyday case for them but in the end my public and private health insurance providers did cover the cost. I suppose that in the future the new European legislation concerning cross border treatments will make this process easier”, Benedek added.

“During my fight with cancer (Chondrosarcoma) this treatment is the first one to deliver results”.

Proton Therapy Center Czech  in Prague uses the very best tool to deliver proton therapy known as as ‘pencil beam scanning’ in all of its treatment rooms. Both the Czech team were extremely pleased to be able to assist a citizen from Belgium and wish Benedek all the best, as well as to those who may follow.

 

For more information, contact: jana.kulhankova@ptc.cz or visit the PTC website www.ptc.cz

WEB REVIEW – Father-to-be vows to battle brain tumor

Kerry and Mark Kelso are preparing for the birth of their first child. It should be the happiest time of their lives, but they are also facing an uncertain future as Mark has been diagnosed with a brain tumor.

Mark first realized there was something wrong when he started to suffer from double vision and headaches last year. The couple were just celebrating Kerry’s first pregnancy when they were given the devastating diagnosis. Only 14 adults a year are diagnosed with this type of tumor, but fortunately, it is not cancerous.

Mark has vowed to stay strong for his unborn baby as he prepares for treatment. He is set to undergo surgery to remove his tumor, which is the size of a golf ball right behind his eye, but he will also need to fly abroad for special pioneering treatment funded by the NHS to remove the rest of the tumor.

The couple are currently fundraising for Brain Tumour Research. They are hoping to raise hundreds of pounds to support the charity, which was launched in 2008, and aims to raise at least £7 million a year to create seven Brain Tumour Research Centres of Excellence across the UK.

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WEB REVIEW – Battling breast cancer with protons

A 71-year-old Califorian is the first breast cancer patient to receive treatment with proton therapy at the recently opened Scripps Proton Therapy Center, which is one of the 15 operational proton centers in the USA.

Anastasia C. Berkheimer chose to have proton radiation because of its precision compared to traditional X-rays. A report published in 2013 in the New England Journal of Medicine found that women who received X-ray treatments to their left breast developed a higher risk for heart disease, which was directly linked to the dose and volume of heart that was irradiated during treatment.

Having a heart condition, Anastasia wanted to protect both her heart and lungs, located just beneath the tumor. Proton therapy precisely directs the beam at the tumor, allowing to efficiently spare surrounding tissues : “Proton therapy is so precise, they could kill the cancer without damaging my heart or affecting my active lifestyle”, she said.

 

Anastasia battled breast cancer two years prior to receiving her treatment. She had travelled to Los Angeles for more than three months of X-ray radiation therapy, where she suffered from severe bouts of nausea, rashes and fatigue. To her great relief, Anastasia did not have any similar side effects either during or after her two week course of proton therapy.

 

 

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WEB REVIEW – 9-year-old fighting brain cancer

Cameron Rowell is taking on his biggest opponent yet, brain cancer. The 9-year-old who plays football, baseball and basketball was diagnosed with an ependymoma on February 28. The symptoms started a couple weeks after he was hit in the head with a baseball.

Glenn and Elicia Rowell worried their son’s pain and overall lethargy had to do with the injury. At the hospital, they were preparing for a concussion or even bleeding in his brain, but never cancer.

Three days later, Cameron underwent emergency surgery to remove the mass. He has adjusted better than anyone expected. The day before surgery, he told his parents he was ready. “He’s like the strongest, stronger than us, probably,” Elicia said.

 

 

He will start proton radiation therapy on Monday. Doctors are optimistic. For the next phase of treatment, the family must lease an apartment in Jacksonville for six weeks. Glenn and Elicia plan to take turns staying with Cameron and their three other sons. Radiation is scheduled to end a few days before Cameron’s 10th birthday. Everyone hopes for the same present: a clean bill of health.

 

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Proton beams are big guns against HPV-related oropharyngeal cancers

Radiation oncologists are using protons against a growing number of oropharyngeal cancers caused by the human papilloma virus (HPV).

“We’re seeing a decrease in smoking-related head and neck cancers and an increase in HPV-related oropharyngeal cancers,” said Alexander Lin, MD, clinical operations director at Penn Medicine’s Roberts Proton Therapy Center in Philadelphia, Pennsylvania. Penn Medicine is the branded name for the University of Pennsylvania Health System.

Dr. Lin’s observation echoed a national report published last year in The Journal of the National Cancer Institute. Accumulating data also suggest that HPV-associated oropharyngeal cancers will surpass HPV-associated cervical cancers by 2020.

“This is where protons have the potential to improve cancer outcomes,” Dr. Lin said. “We expect otherwise healthy men and women in their 40s and 50s with HPV cancers will have up to a 90 percent chance of being cured and will be able to live a good quality of life, cancer-free, for many years.”

At the University of Pennsylvania Health System, the approach to treatment of advanced HPV-associated oropharyngeal cancers is a combined effort of initial surgery followed by radiation.

“Penn has one of the preeminent head and neck surgery departments in the world,” Dr. Lin said. “They have pioneered a technique using a robotic, transoral approach (TransOral Robotic Surgery-TORS), that allows for a much less invasive surgery compared to traditional approaches. This equates to better functional outcomes for patients, less time needed for recovery, and the ability to offer surgery to patients who otherwise would not have been candidates with traditional approaches.”

Radiation therapy is often used after surgery to further improve the odds of long-term cure. Chemotherapy may also be used as a follow-up treatment to surgery.

“We currently use proton therapy for patients who have undergone surgery for tonsil or base of tongue cancers,” Dr. Lin said, “and are currently developing techniques that will allow us to offer proton therapy to patients with other types of head and neck cancer, and those who are not able to undergo surgery.”