External Beam Radiation Therapy

The therapy which I am going to discuss in this post is the most common one, which is external beam radiation therapy. The reason for the frequent use of this therapy as it uses a machine outside the patient’s body to perform the treatment. LINAC (Linear Accelerator) is the most common machine used in this therapy. 

How does it work?

Photon beams of radiation light are guided on the place of the tumor and destroying the cancerous cells and through this stops them to spread and develop. These photon beams are constitutes of x-rays that is of a bit low energy level or either it can be of gamma rays that is highest energy level.

The radiation oncologist, who uses this treatment for cancer and mesothelioma, is a well- trained physician. It can take up to several weeks to complete the course of treatment. Patient receives this treatment at the hospital or clinic, but does not need to stay overnight.

How does it work for Mesothelioma?

External beam radiation therapy is used in treating the most common types of mesothelioma that are pleural mesothelioma (which affects the lungs) and peritoneal mesothelioma (which affects the abdominal cavity). But, surgery is the primary treatment for it; it means, a patient will undergo the surgical process and then opt for the secondary treatment that is radiation therapy. The radiation treatment is done to eradicate and damage the remaining cancerous cells, which were left behind after the surgical process.  

When pleurectomy/decortications surgery (P/D) is done on pleural mesothelioma patient, administrating radiation is really hard as there is much risk of damaging of lungs not only this there may be chances of inflammation of lungs (pneumonitis).

If a patient undergoes extrapleural pneumonectomy surgery (EPP) there is a great chance of lengthens survival rates. In this surgical process, the affected lung is removed and the radiation can be easily delivered to the cavity without damaging the healthy lung. But, there is still possibility of inflammation of lungs. 

Image Guided Radiation Therapy

Image-Guided Radiation Therapy, also called IGRT, is another specialized radiation treatment, which is very precise when targeting the tumor by delivering the radiation beam on the affected area without harming the tissues and organs that surrounds the tumor. The image-guided radiation therapy (IGRT) is done by the radiation oncologist by using a very precise imaging system or equipment and LINAC (Linear accelerator) to deliver the radiation onto the tumor. This imaging system is really helpful as it let the radiation oncologists to observe the tumor before, during and after the treatment. In other words, one can see the every step of the treatment.

When starting the therapy session for mesothelioma cancer, first the patient is lay on the treatment table so that marks can be made on the treatment area, which are in position with the path of the radiation beam. Then, the images are being taken, first for the preliminary stage when the therapy is being started for the patient. With the use of computer software these images are then compared and analyzed throughout the therapy sessions. All these comparisons are being made just to ensure whether the adjustments need to be made to the position of patient and also for the path of radiation beams. Sometimes adjustments are needed then; we have to take new set of images, which are then compared with the old set to make sure the tumor is being targeted really precisely. 

What are the equipments used in taking images?

Magnetic Resonance Imaging

 

Magnetic Resonance Imaging or MRI is a kind of imaging process that uses a radio waves and magnetic field to create three dimensional images. These images came very handy if we want to view from variety of angles.

Computed Tomography (CT Scan)

 

CT scan or CAT scan makes use of multiple images, which are then combined by the computer to show the cross-sectional and three dimensional views of the tumor.

Ultrasound

 

Transducer is a small device, which is being passed all along the area, which is to be tested. Sound waves are being produced by this device through bouncing off the tissues that produce echoes.

Positron Emission Tomography

 

In Positron Emission Tomography or PET scan, a very small quantity of a radioactive material is given to the patient either via breathing in, injection or orally. Eventually, this radioactive material collected in the affected area and can be acknowledged as a bright spot on the scan. 

This therapy can offer better understanding of the movement of tumor before, during and after the treatment in the near future, which I truly believe.

Proton Therapy

What is proton therapy? Why should we go for it?

In the course of their treatment, Mesothelioma patients often receive radiation therapy, although most of the time the delivery is imprecise. Because of this imprecision, radiation can easily damage the healthy tissues or cells. Right now, the therapy that I want to discuss is the Proton therapy. The most beneficial thing about this therapy is that it beams highly energized protons straight where the growth of cancer is. That is why is considered to be one of the most specialized types of radiation particle therapy. Protons hardly ever go outside the area of treatment, as it can travel through some centimeters of the affected tissue. Thus, it reduces the risk of damaging the healthy tissues surrounds the affected area like in pericardial mesothelioma it is heart and in pleural mesothelioma there are lungs.

Who are eligible for this therapy?

If the cancer in patient is metastasized (the cancer is spread out all through the body), in general this therapy is not given to him as this is a very location specific treatment. It is more appropriate for the patient in their advance stage of cancer to go for chemotherapy that will be more responsive than other ways of treatment. Therefore, a patient at his early stage of mesothelioma cancer can go for proton therapy, which can play an effective role at this point. Other requirement is the patient should not weigh more than 360 pounds as it is impossible for the equipment to accommodate heavy person. The patient should stay near the treatment facility so he/she can easily commute to it on a daily basis.

Proton therapy is delivered noninvasively so it is a type of mesothelioma treatment, which is treated externally. Protons are delivered to the tumor through moving or steady beam, this technique is said to be as pencil beam scanning proton therapy. Through pencil beam scanning proton therapy, the oncologists delivered the beam at the affected area without damaging healthy tissues, vital organs or the areas, which is already being treated or radiated. Furthermore, the intensity of protons can easily adjust by the radiation therapists or oncologists so that the protons cannot penetrate into the area, which is beneath the tumor. Because of this, the radiation will remain in the area of the tumor.  The patient received proton therapy in cycles of up to 7-8 weeks. The time duration of the mesothelioma cancer treatment depends upon the dose of radiations. Like if the higher doses of radiation are delivered, then there will be shorter cycles of treatment whereas if the low doses are given, then there will be longer cycles. Before starting the proton therapy, the patient will undergo a simulation session (generally a week earlier the actual treatment), so that he/she can be prepared for the treatment.

Now, there must be a question come up in your mind… How is it done?

Patients are lay on a device, which prevents them to move throughout the proton therapy session. After that the radiation therapists position the radiation beam, on the markings made on the body that is required to treat during simulation sessions. Furthermore, radiation therapist also administrates the dose of radiation from the control room. Generally, it is a 30-90 minutes session and during the treatment the patient can communicate with the radiation therapist through a two-way intercom. Don’t worry the procedure is completely painless and the great thing about this that after the sessions the patient is not considered to be radioactive.

As already have been told about proton therapy that the healthy tissues are not affected by the radiation. Just 20% surrounding tissues has an effect of the radiation, but this is too weak to cause a considerable side-effects.

Let me, share a study that when pleural mesothelioma patients undergo proton therapy session, it exhibited lower post-treatment radiation in the regions like heart, kidneys, spinal cord healthy or non- cancerous lung and liver as compared to the levels of radiation in the organs of the patients, who are treated with other type of radiation treatments. 

Luckily now the mesothelioma is detected much earlier. So, many patients are qualifying for this one of the most sophisticated treatment. In 2005, 20 mesothelioma patients from Sweden are qualified for the proton therapy. In United States, it has been used since 1990 in clinical cancer treatments. In 2009 survey, there are 38 facilities of proton therapy available worldwide, including the University of Florida Proton Therapy Institute and the Proton Therapy and Treatment Center at Loma Linda University.

If you want to go through this treatment the very first eligibility is that the mesothelioma cancer should be detected at early stage or stage 1, then you can qualified for this treatment!

Three-Dimensional Radiation Treatment

Three-Dimensional Conformal Radiation Treatment (3D-CRT) is another type of internal radiation therapy. The need to prefer an internal radiation therapy over traditional external beam radiotherapy is necessary as the new methods of internal radiation makes it easier to target more precisely the tumor without damaging the other areas or healthy organs. Whereas in external beam radiotherapy, the oncologists has to go through numerous Computed Tomography scans (CT), nuclear imaging scans (NMRI) and Magnetic resonance imaging (MRI) and the worst thing about this type is that it can cause damage to the healthy organs as it is not precise enough as compared to any internal radiation therapy. One of these internal radiation therapies is 3D-CRT (Three-Dimensional Conformal Radiation Treatment).

Firstly, MRI, PET Scans and CT Scans of a patient is gathered, which are actually two-dimensional images, then they are put in concave-shaped or dome-shaped rotating projector. This projector is plugged into a computer, which creates projections of the images as three-dimensional holograms. Now the interesting thing about this that it doesn’t create pictorial images like we used to see in any other tests, but these light images  show characteristics like shape, location and size of the cancer tumor and also the organs which are affected.

Now to create a customized radiation beam oncologists use these tools:

Multi-leaf collimator

It is fixed to the head of the radiation machine. This either blocks or allows the radiation from penetrating the target. It will create the initial size and shape of the doorway through which radiation beams will be emitted.

Custom-fabricated

It is made by lead, which is used to prevent the flow of light. They are set around the doorway to further conform radiation beams according to the shape of the tumor.

Are there any risks?

This question must arise in your mind, and the answer is yes there are some side-effects associated with 3D-CRT.

Esophagitis

Inflammation in esophagus (it is a tube for food that runs from throat to stomach). Around two weeks after beginning of the treatment you will observe this symptom, but generally it disappears more or less 2-3 weeks after the treatment is ended.

Mucositis

Inflammation of oral mucosa (membrane of gums, throat and mouth). You will observe symptoms like thick saliva, dry mouth, sores and difficulty in swallowing and chewing. This symptom will disappear within few weeks after the end of the treatment.

Pneumonitis (Radiation)

Inflammation of the lungs. You will observe this symptom around two weeks at the beginning of the treatment. It is accompanied by the symptoms like breathlessness due to exertion, fever and dry cough. These symptoms are not permanent, but it will scar the lungs permanently.

Brachytherapy

What is Brachytherapy?

Brachytherapy is a kind of radiation therapy. The harmful radiation is administered through a small object put inside the tumor; due to this it minimizes the damage of healthy tissue. Thus, this tumor has more narrow focus on the growth of tumor.

I want to tell you one very significant thing about Brachytherapy that it does not use any external radiation like other traditional radiation therapies. Due to this Brachytherapy may also be called internal radiation therapy and the other traditional radiation therapies are referred to as EBRT (External Beam Radiation Therapy).

In treating Mesothelioma or Lung cancer, brachytherapy is not used as a standard treatment! Although still the researchers are testing this way of treatment in clinical trials and from early studies it shows very promising and positive results to increase the life expectancy and minimize the harshness of the disease symptoms!  

When we look for effectiveness of brachytherapy, it plays a vital role in treating lung cancer. But the researchers found out more positive results in treating both cancers that are mesothelioma and lung cancer, when a patient goes through a treatment called permanent brachytherapy. In permanent brachytherapy a radioactive material is put inside the tumor and after few months of span it loses its radioactivity.

Want More Information about Brachytherapy?

By now we already know that brachytherapy is administered by placing a radioactive material, which is called implant. This radioactive material is may be in the form of seed (size of a grain of rice) or a wire.

The implant may be put during the surgery; this technique is called IORT (Intraoperative Radiation Therapy). Other than that, it can be injected into the cancer tissue via hollow tube. When this type of administration is used, a patient will receive general or local anesthesia and then doctors usually take the help of imaging scans like ultrasound and CT scan. As soon as the implant is placed inside the tumor, it attacks the cancer tissue in radius of 1cm. It can easily target the tumor inside, but accuracy is necessary.

Usually brachytherapy is implemented in the combination with other treatments. Moreover, IORT is always administered in conjunction with surgery.

The brachytherapy treatment can also used together with the traditional radiation treatment to attack the growth of tumor in various ways. Brachytherapy can be used as a curative treatment to get rid of mesothelioma cancer, but it largely depends upon the each patient’s condition and treatment. Not only this it can also used as palliative treatment to minimize the harsh symptoms of the disease like breathlessness and coughing, etc.

What are the side-effects of brachytherapy?

When comparing with external beam radiation therapy the side-effects of brachytherapy are quite minimal. Tenderness at the location of insertion is the most common side-effect that goes away within few months. Temporary swelling at the location of the treatment may also occur. While in EBRT, patient may experience nausea, irritation in skin and fatigue.

Now let me discuss the types of Brachytherapy!

Types of Brachytherapy

There are mainly two types of brachytherapy, which are low-dose rate brachytherapy and high-dose rate brachytherapy. Mesothelioma patients are usually treated with permanent brachytherapy; it is a kind of low-dose rate brachytherapy. In permanent brachytherapy it attacks the tumor with the radiation for several months.

The treatment can go up to several weeks depending upon which type of brachytherapy is used. Brachytherapy treatment time is much shorter than EBRT; EBRT takes about 2-10 weeks of treatment time.

Low- Dose Rate Brachytherapy

Low dose of radiation is given in LDR (Low-Dose Rate) for quite a long period of time. Radioactive material is placed for a week in the site. These radiations are very unsafe for the people in close proximity; therefore the patients that are receiving this treatment will be in hospital for the whole duration of the treatment. Moreover, these patients are not allowed to meet any guest and they are kept in private rooms. The good thing about LDR treatment is that it is not painful and uncomfortable.

High-Dose Rate Brachytherapy

High dose of radiation is given for not more than 20 minutes in HDR (High-Dose Rate). In HDR treatment, the patient may undergoes this treatment once or twice a day for a number of weeks. The patient can leave the hospital as soon as the doctor inserts the implant through hollow tube in the place. Like LDR, this treatment is also not painful and uncomfortable.

Study results of Brachytherapy

Only few tests of brachytherapy are being carried out for mesothelioma patients with varying results.

In 2005, 123 cases of pleural mesothelioma were treated with brachytherapy. Then, these patients went through pleurectomy/decortication. The conclusion of these tests was that with or without brachytherapy is not that much effective to stop the growth of mesothelioma tumor.

Brachytherapy is still expected to be one of most promising treatment of mesothelioma regardless of this study. The tests are still going on to prove its effectiveness on mesothelioma and we hope that it will come out as expected!