Definitive independent statistics- Prostate proton beam prostate cancer therapy. Outcomes with Proton therapy method.
The following tables, 3 and 4, as presented, compare the acute and long-term complications of localised prostate cancer treatment with proton beam prostate cancer therapy, conventional X-rays and radical surgical removal of the prostate.
Table 3. Acute complications associated with the treatment of prostate cancer.
|Acute Toxicity||Protons||Conventional Radio Therapy, photons.||Prostatectomy|
|Grade 2 GU toxicity(frequency, nocturia, dysuria)||0%||28%||N/A|
|Grade 2 toxicity(diarrhea, rect/abdon pain)||0%||35%||N/A|
|Either Gu or GI morbidity||0%||53%||N/A|
|Hospitalisation||none||none||5 to 7 days|
|Absence from work||none||none||4 to 6 weeks|
|Pulmonary embolism or DVT||0%||0%||2.6%|
|Myocardial infarction or arrhythmia’s||0%||0%||1.4%|
|Surgical rectal injury||N/A||N/A||1.5%|
Table 4. Long term complications associated with the treatment of prostate cancer.
|Chronic Toxicity||Protons||Conventional radio therapy (photons)||Prostatectomy|
|Incontinence requiring a pad||<1%||1.5%||32%|
|Bladder neck contracture||0%||3%||8%|
|Grade 3 GU toxicity. Severe frequency q 1hr, dysuria||0.3%||2%||36%|
|Grade 3 GI toxicity. Rectal bleeding erquiring transfusion, severe pain,(>70gy)||0%||7%||N/A|
Lung cancer is globally the most common malignancy in both men and women, with a very high mortality rate. At some point during their illness, many patients are treated with conventional radiation therapy. A substantial number of these patients have poor lung function in general, mainly due to years of tobacco abuse. It is therefore important that whatever is left of functioning lung tissue be preserved.
X-ray radiation treatment has a destructive effect on healthy lung tissue. Proton beam therapy does not have this effect, as it is more precise when targeting the tumour, and enters and leaves the body at a much lower dosage.
Because of the minimal damage to healthy tissue, a higher, more beneficial radiation dose can be delivered.
Head and neck cancers.
The treatment of head and neck cancers with X-ray radiation therapy poses considerable risks of serious side effects to patients. These side effects include blindness, xerostomia, which is a chronically dry mouth resulting from a lack of, or a total absence of saliva flow, and also dysphagia, which is a condition that often affects the oesophagus, making it very difficult to swallow.
Some patients suffering the side effect of an inability to swallow, have to periodically make use of a gastrostomy feeding tube to obtain necessary nutrients.
Proton treatment for these devastating cancers negates practically all of the side effects.
Table showing comparison of side effects – proton therapy vs X-ray radiation treatments.
|Side Effect||Protons =200||Conventional radiotherapy(photons) N=501|
|Bilindness (maxillary sinus tumours)||2%||15%|
|Xerostomia (dry mouth)||< 5% (with protons)|
|Dysphagia (no swallowing)||12%||100%. 80% will require liquid nutrition|
|PEG (gastrotomy) nutrition||0%||30%|
Proton beam therapy treatment for paediatric patients greatly reduces the acute and long term complications arising from X-ray radiation. Children, who are not yet fully grown, run the risk of stunted growth, second malignancies later in life and possible cardiac and pulmonary toxicities.
There is also documented research of the damage done by conventional radiation to the healthy tissue of the brains of young children, in relation to the dose administered.
Protons deliver radiation to the tumour site with minimal damage to the surrounding tissue.
Table showing complications associated with cranial spinal irradiation in children.
|Side Effect||Protons||Conventional Radiotherapy Photons|
|Restrictive lung disease||0%||60%|
|Reduced exercise capacity||0%||75%|
|Growth abnormality – vertebral body receiving significant dose||20%||100%|
|IQ drop of 6 points at 6yrs||1.6%||28.5%|
|Risk of IQ score < 90||15%||25%|
Recurrence of cancer tumours.
Some patients may suffer a local recurrence of cancer in a site which has previously been irradiated. Because of damage already done to surrounding tissue by X-ray radiation treatment, irradiation cannot be done in the same area more than once.
However, because proton therapy largely spares normal tissue, proton treatment can be offered to such patients. This will of benefit to upping the cure rate of certain cancers.
This table shows the comparative PSA levels after proton treatment.
|PSA Level||Proton Therapy||X-ray Radiaition||Rad. Prostatectomy|
|4 to 10||89%||69%||83%|
|10 to 20||72%||62%||56%|
Proton Beam Therapy can treat a cancer in any part of the body, with markedly lower risks of damage to surrounding tissue.
Research is also underway for the proton treatment benefits of benign conditions such as Parkinson’s disease, malformation of veins or arteries, as well as severe rheumatic conditions.
There is some data available in the US re the treatment of macular degeneration. Of the current treatments on offer, X-ray radiation is offered to radiate the abnormal growth of blood vessels behind the eye. This has not been a major success due to the damage radiation can cause to the rest of the eye.
Studies have now shown that protons can obviate this problem with a single, precise dose, higher than that of conventional radiation, because of the greatly reduced risk normal tissue damage.
n beam therapy
kills the cancer cells without collateral damage often caused by traditional radiation.
Skin burns. Second cancers. Sterility.
The potential side effects in the use of conventional radiation therapy are quite frightening. It’s a potent weapon against cancer, physicians say, especially with today’s technical advances, and it’s less damaging to healthy tissues than it was 10 years ago. But an accumulating pile of studies are drawing attention to an older radiation treatment that pounds cancer with far more energy at the tumour’s exact location than conventional radiation and saves normal tissues from extensive injury. It’s called proton beam therapy, and medical experts call it the next generation of radiation therapy.
Despite its modern precision, proton beam therapy has actually been around since the 1950s, when physicists began to understand the compelling differences between proton beams and intense Xray beams, called photons, used in conventional therapy. Those differences let doctors control the depth of proton beams more precisely and deliver more cancer-killing radiation to tumours—a particularly appealing effect for discrete tumours of the eye and for treating children, who are most vulnerable to the damaging side effects of radiation. Proton beam therapy is also used to treat prostate, brain, lung, oesophageal and head and neck cancers, among others.
“I don’t love military analogies, but it really is like having a smart bomb. You can avoid collateral damage,” says Dr. James Cox, Oncologist MD,
Physics and Cancer
Protons are minute particles with a positive charge, accelerated to great speed by equipment once familiar only to research physicists. Because protons have mass, they work on impact with the tumour and don’t travel all the way through the body.
Conventional X-rays are a form of electromagnetic radiation with short wavelengths. Without charge or mass, X-rays irradiate cells continually as they pass through the body, delivering injury both at the surface of the body at the point where they enter, as well as healthy tissues behind the cancer.
“Protons are different. Their dose is deposited with a burst of energy where you want it—precisely in the tumour,” “The location is determined by the energy of the proton beam.” Doctors are able to determine precisely where they want to deliver the bulk of the cancer-busting potency of protons. By accelerating protons to different speeds, they can target a tumour just under the surface of the skin, or one deep inside a body cavity. Some call this the “depth charge effect,” because it’s akin to dropping a bomb into the water, and determining the precise depth at which it detonates.
Although side effects are still possible, they are considerably less intense than with conventional radiation and are far less likely to be long-term. More common symptoms include skin irritation (which clears up quickly after treatment) and hair loss in the direct path of radiation, and fatigue if a very large area of the body is treated. Proton beam therapy can sometimes also be used in combination with other cancer treatments that carry their own side effects.
Today, cancer patients can receive proton beam therapy at a limited number of facilities worldwide.
The American Food and Drug Administration approved proton beam therapy as a cancer treatment in 1988, and most medical insurers in the USA cover proton beam treatment for specific cancers. So why all the fuss now?
Jerry Slater, MD, chair of the radiation department at Loma Linda proton facility, says the current excitement is a by product of better imaging techniques that are finally accurate enough to let physicians take advantage of the precision of proton beam therapy.
“You could have done proton therapy in the ’50s if you had advanced scanning techniques such as PET (positron emission tomography) and MRI (magnetic resonance imaging
Those images let doctors understand the three dimensional structure of a tumour, which is necessary for guiding proton beams to exactly the right place. “It’s also just such a high-tech thing.
There was a perception you couldn’t do something this complicated in a hospital. We believed it could be done, and showed it.”
Long-term clinical studies are finally being published that demonstrate the effectiveness of proton beam therapy. Studies have shown doctors can use proton beams to control ocular melanomas while letting many patients retain vision; to control acoustic neuromas while avoiding nerve injury; and improve survival rates from chordomas and chondrosarcomas of the skull base, among many other results.
For the more frequently occurring cancers, such as prostate cancer, studies indicate proton beam therapy offers the same or higher tumour control than X-ray radiation. Dr. Kubes, head of radiation oncology at the proton facility in Prague explains it this way – “If you use a better form of treatment it’s inevitable that you will obtain better outcomes, and that’s what we’re seeing here in Prague with our patients.”
13 years ago, when Bob Marckini’s doctor called to tell him he had prostate cancer, Loma Linda was the only medical center in the United States offering proton beam therapy.
Marckini, 57, had just watched his brother go through surgery for prostate cancer. “I was scared to death,” Marckini says of seeing his brother in the recovery room after surgery. “He was the patriarch of our family. Strong, healthy and athletic. I watched him go through his slow recovery.”
Bob Marckini chose proton beam therapy to treat his prostate cancer because of its effectiveness and it’s far lower risk of side effects.
With his own prostate cancer diagnosis, Marckini (an enquiring engineer) dug into medical literature and sought advice from doctors and prostate cancer patients who had undergone a variety of radiation therapies, including conventional X-ray therapy, intensity-modulated radiation therapy and brachytherapy. Although each therapy seemed to have an equal chance of getting rid of the cancer, proton beam therapy was non-invasive and by far promised the fewest side effects. For instance, more than 60 percent of prostate cancer patients suffer impotence after conventional radiation compared with less than 30 percent after proton beam therapy. After 10 weeks of research, Marckini traveled from his home for proton beam treatment.
The power of proton therapy relies on its precision. Another factor to consider is that the risk of side effects often limits the oncologist’s ability to deliver a strong radiation doses using conventional X-ray radiation – the risk of dangerous side effects would simply be too high. On the other hand, with the accuracy of proton beam therapy, this means that a more powerful dose can be delivered at one time, which can mean fewer treatments, and the potential for higher cure rates.
Paediatric patients’ developmental stage makes them particularly vulnerable to the side effects of radiation, so researchers are excited about the possibilities of proton beam therapy in children.
Dr. Cox says proton beam therapy is especially promising for children. Pediatric patients’ developmental stage makes them particularly vulnerable to the side effects of radiation, including later cancers induced by treatment, so researchers are excited about the possibilities of proton beam therapy in children. The technique has shown tremendous success in paediatric head and neck cancers, in particular, increasing tumour control and survival.
Over the past decade, key improvements to conventional X-ray therapy, specifically three dimensional conformal X-rays and intensity modulated radiation therapy, have increased dose delivery to tumours and lessened side effects. The same things are happening now with protons. Proton technology has also evolved, and now proton facilities world-wide are beginning to use ‘pencil-beam’ scanning nozzles. This means an even greater level of accuracy and safety. The proton therapy facility in Prague uses the most advanced pencil-beam scanning technology in the world, produced by Belgian company ‘Ion Beam Applications’ (IBA), the world’s most experienced proton therapy manufacturer.
‘Pencil-beam scanning’ unleashes the full-potential of proton beam technology, enabling what is now known as ‘Intensity-Modulated Proton Therapy’ or IMPT.
IMPT in Prague results in greater accuracy, safety, and even less side effects than older forms of proton therapy technology.