PDT is a treatment for certain types of cancer, Skin, neck and head.
I have just watched a news item, which says that what makes this type of treatment work is the fact that the drugs are used in connection with LIGHT.
On the clip, it shows two tubes inserted into – in this case, the patients arm and the tubes are lit up as the drugs go in. I must admit this is the first time I have heard of this. The treatment definitely works and the thing that appears to make a difference is the addition of light.
Light workers would not be surprised at this. Why isn’t more notice taken when we talk of our methods of treatment? Long ago, we said the smallest particle, way past the atom in fact, is made of light.
I strongly feel that our (Light workers) history should be fully revealed because, like it or not, scientists and doctors are validating what we, and Spirit have been saying for many decades now. Why can’t we cut out the middleman, go straight to what we (Light workers) know so that scientists and doctors can get a heads up where they should be looking. It sounds so simple doesn’t it?
Why on earth cant we speed this all up for the benefit of mankind?
Below I have copied from the site: http://www.cancer.gov/cancertopics/factsheet/Therapy/photodynamic
- What is photodynamic therapy?
Photodynamic therapy (PDT) is a treatment that uses a drug, called a photosensitizer or photosensitizing agent, and a particular type of light. When photosensitizers are exposed to a specific wavelength of light, they produce a form of oxygen that kills nearby cells (1, 2, 3).
Each photosensitizer is activated by light of a specific wavelength (3, 4). This wavelength determines how far the light can travel into the body (3, 5). Thus, doctors use specific photosensitizers and wavelengths of light to treat different areas of the body with PDT.
- How is PDT used to treat cancer?
In the first step of PDT for cancer treatment, a photosensitizing agent is injected into the bloodstream. The agent is absorbed by cells all over the body but stays in cancer cells longer than it does in normal cells. Approximately 24 to 72 hours after injection (1), when most of the agent has left normal cells but remains in cancer cells, the tumor is exposed to light. The photosensitizer in the tumor absorbs the light and produces an active form of oxygen that destroys nearby cancer cells (1, 2, 3).
In addition to directly killing cancer cells, PDT appears to shrink or destroy tumors in two other ways (1, 2, 3, 4). The photosensitizer can damage blood vessels in the tumor, thereby preventing the cancer from receiving necessary nutrients. In addition, PDT may activate the immune system to attack the tumor cells.
The light used for PDT can come from a laser or other sources of light (2, 5). Laser light can be directed through fiber optic cables (thin fibers that transmit light) to deliver light to areas inside the body (2). For example, a fiber optic cable can be inserted through an endoscope (a thin, lighted tube used to look at tissues inside the body) into the lungs or esophagus to treat cancer in these organs. Other light sources include light-emitting diodes (LEDs), which may be used for surface tumors, such as skin cancer (5).
- What types of cancer are currently treated with PDT?
To date, the U.S. Food and Drug Administration (FDA) has approved the photosensitizing agent called porfimer sodium, or Photofrin®, for use in PDT to treat or relieve the symptoms of esophageal cancer and non-small cell lung cancer. Porfimer sodium is approved to relieve symptoms of esophageal cancer when the cancer obstructs the esophagus or when the cancer cannot be satisfactorily treated with laser therapy alone. Porfimer sodium is used to treat non-small cell lung cancer in patients for whom the usual treatments are not appropriate, and to relieve symptoms in patients with non-small cell lung cancer that obstructs the airways. In 2003, the FDA approved porfimer sodium for the treatment of precancerous lesions in patients with Barrett esophagus (a condition that can lead to esophageal cancer).
- What are the limitations of PDT?
The light needed to activate most photosensitizers cannot pass through more than about one-third of an inch of tissue (1 centimeter). For this reason, PDT is usually used to treat tumors on or just under the skin or on the lining of internal organs or cavities (3). PDT is also less effective in treating large tumors, because the light cannot pass far into these tumors (2, 3, 6). PDT is a local treatment and generally cannot be used to treat cancer that has spread (metastasized) (6).
- Does PDT have any complications or side effects?
Porfimer sodium makes the skin and eyes sensitive to light for approximately 6 weeks after treatment (1, 3, 6). Thus, patients are advised to avoid direct sunlight and bright indoor light for at least 6 weeks.
Photosensitizers tend to build up in tumors and the activating light is focused on the tumor. As a result, damage to healthy tissue is minimal. However, PDT can cause burns, swelling, pain, and scarring in nearby healthy tissue (3). Other side effects of PDT are related to the area that is treated. They can include coughing, trouble swallowing, stomach pain, painful breathing, or shortness of breath; these side effects are usually temporary.
- What does the future hold for PDT?
Researchers continue to study ways to improve the effectiveness of PDT and expand it to other cancers. Clinical trials (research studies) are under way to evaluate the use of PDT for cancers of the brain, skin, prostate, cervix, and peritoneal cavity (the space in the abdomen that contains the intestines, stomach, and liver). Other research is focused on the development of photosensitizers that are more powerful (1), more specifically target cancer cells (1, 3, 5), and are activated by light that can penetrate tissue and treat deep or large tumors (2). Researchers are also investigating ways to improve equipment (1) and the delivery of the activating light (5).
- Dolmans DEJGJ, Fukumura D, Jain RK. Photodynamic therapy for cancer. Nature Reviews Cancer 2003; 3(5):380–387.
- Wilson BC. Photodynamic therapy for cancer: Principles. Canadian Journal of Gastroenterology 2002; 16(6):393–396.
- Vrouenraets MB, Visser GWM, Snow GB, van Dongen GAMS. Basic principles, applications in oncology and improved selectivity of photodynamic therapy. Anticancer Research 2003; 23:505–522.
- Dougherty TJ, Gomer CJ, Henderson BW, et al. Photodynamic therapy. Journal of the National Cancer Institute 1998; 90(12):889–905.
- Dickson EFG, Goyan RL, Pottier RH. New directions in photodynamic therapy. Cellular and Molecular Biology 2003; 48(8):939–954.
- Capella MAM, Capella LS. A light in multidrug resistance: Photodynamic treatment of multidrug-resistant tumors. Journal of Biomedical Science 2003; 10:361–366.
I also looked at this site.
Photodynamic therapy (PDT)
This information is about photodynamic therapy (PDT). PDT is a treatment for some cancers, and for some conditions that may develop into a cancer.
On this page
- How PDT works
- When it is used
- How PDT is given
- Possible side effects
- Skin cancer and Bowen’s disease
- Cancers of the head and neck
- Cancers in other parts of the body
How PDT works Back to top
PDT uses laser, or other light sources, combined with a light-sensitive drug (sometimes called a photosensitising agent) to destroy cancer cells. For cancers of the skin, the drug is usually applied as a cream.
A photosensitising agent is a drug that makes cells more sensitive to light. Once in the body, the drug is attracted to cancer cells. It does not do anything until it is exposed to a particular type of light. When the light is directed at the area of the cancer, the drug is activated and the cancer cells are destroyed. Some healthy, normal cells in the body will also be affected by PDT, but these cells will usually heal after the treatment.
When it is used Back to top
PDT can be used to treat some cancers, or conditions that may develop into a cancer if not treated (precancerous). It is used when the affected area or the cancer is on or near the lining of internal organs. This is usually with cancers or conditions that affect:
- the bile duct and gall bladder
- the gullet (oesophagus)
- the head and neck
- the lung
- the mouth
- the gullet
- the skin (but not melanoma).
Researchers are trying to identify the types of cancer for which PDT is most effective. Research trials| are looking at new photosensitising agents, new laser and non-laser light treatments and ways of reducing the side effects.
Some research studies have used PDT to treat precancerous changes in the cells affecting the vulva (vulval intraepithelial neoplasia or VIN| ), the vagina and the anus.
In cancers that are being treated at an early stage, the aim of treatment may be to try to cure the cancer.
The aim of PDT for advanced cancer is usually to reduce symptoms by shrinking the cancer.
Your doctor can advise you about whether PDT is an appropriate treatment in your situation and if there are any suitable research trials.
How PDT is given Back to top
The treatment is normally in two stages.
Stage 1 A light-sensitive drug is given. For cancers of the skin, the drug is usually applied to the skin as a cream.
For cancers that are inside the body, the drug may be given as a drink or more usually as an injection into a vein (intravenously). The way that the drug is given will depend on which one is best for your treatment.
There is a delay between the drug being given, or the cream being applied, and the next stage of treatment. This allows time for the drug to concentrate in the cancer cells. The length of time you need to wait for treatment after having the drug can vary from hours to days.
There are several drugs that can be used as the photosensitising agent. The most common are 5-aminolevulinic acid (ALA), temoporfin (Foscan®) and porfimer sodium (Photofrin®). The drug used will depend on the type of cancer that you have and which is best for your situation. Your doctor or nurse will explain which drug will be used and how it will be given.
Stage 2 The second stage of treatment involves shining light directly onto the cancer. A laser delivers energy in the form of light in a very precise way. Special non-laser lamps may also be used in some situations. For skin cancers , the light is shone directly onto the skin. For internal cancers, a flexible tube (an endoscope) may need to be passed into your body to deliver the light to the tumour.
Sometimes, depending on where the cancer is, a scan or ultrasound may be used to help direct the laser light to the tumour.
Possible side effects Back to top
As with all kinds of treatment, the experience of PDT can vary from person to person. How the treatment is given and the side effects that it may cause vary
- the area of the body affected by the cancer
- the type of photosensitising drug given
- the amount of time between giving the drug and applying the light
- the amount of skin sensitivity to light following treatment.
When PDT is used to treat skin cancer, the side effects are different to when PDT is used for a cancer elsewhere in the body. We have divided the following information into three sections; people being treated with PDT for skin cancers, head and neck cancers and cancers in other parts of the body.
Skin cancer and Bowen’s disease Back to top
PDT can be used instead of surgery to treat basal cell skin cancers and Bowen’s disease (a precancerous skin condition). It’s also used to treat areas of raised, rough skin that are sensitive to the sun (known as actinic keratoses), which have a small risk of developing into skin cancer.
A photosensitising cream which makes the cancer cells more sensitive to light will be applied to the area of your skin that is affected. There are different creams which can be used.
Before they apply the cream your nurse or doctor will remove any crusting from the skin.
The area is then covered with a dressing to protect it and you’ll have to wait for about 3-6 hours (to allow time for the cream to work) before you have your treatment. The length of time you wait varies depending on the skin condition being treated.
When you come back for treatment you’ll be asked to sit or lie down in a comfortable position. A strong light is then shone directly onto your affected skin. This can take 8-45 minutes depending on the particular procedure you’re having.
The treatment is often repeated a week later.
Possible side effects
Sensitivity to light The treated area of skin will be sensitive to daylight and bright,indoor lighting. This effect will probably last for 24-36 hours. You will need to keep the treated area of skin covered during this time. After that you can wash, bathe or shower as usual, but you will still need to treat your skin gently and avoid rubbing the area until it has healed.
Pain You might feel a bit of discomfort (like a burning sensation) when you’re having the treatment. A cooling fan and/or a water spray can sometimes be used to relieve this. Taking some painkillers before the treatment also helps. Occasionally some people have a local anaesthetic to numb the area before treatment.
You may be given some steroid cream to apply at home if your skin is still sore.
Healing - a scab will form on the treated area The scab usually falls off after about three weeks. As PDT heals quickly without scarring, the appearance after treatment is usually very good.
Cancers of the head and neck Back to top
In early-stage cancer of the head and neck PDT may be used to try to cure the cancer and is usually given as part of research trials. PDT can sometimes be used to shrink an advanced cancer to reduce symptoms.
The photosensitising drug is given as an injection through a small tube (cannula) inserted into a vein. This takes a few minutes and then the tube is removed.
You will have to wait up to about four days before the light treatment is given. The length of time varies depending upon the particular photosensitising drug you’ve been given. Generally, only one treatment is given, although it is possible to have a second treatment a few weeks after the first.
Possible side effects
Sensitivity to light Although the photosensitising drugs are mostly taken up by the cancer cells and are concentrated there, they can also make your ordinary skin cells, or your eyes, highly sensitive to light. People who have had PDT are advised to protect themselves from exposure to sunlight and bright indoor lighting. The duration of sensitivity to light (photosensitivity) varies depending on which drug is used.
The drug temoporfin (Foscan®) is commonly used to treat head and neck cancers and will make you sensitive to direct sunlight for at least a month.
It’s advisable to avoid going outside during the day while your skin is photosensitive. However, you do not need to stay in total darkness during this time. To begin with you’ll need to stay in a darkened room, but you can gradually build up the amount of light over two weeks.
If you need to go out, use clothing to cover your skin: for example, wear a brimmed hat, scarf, long-sleeved shirt or blouse and trousers, gloves and dark glasses. Using sunscreens will not give you any additional protection.
You can go out uncovered very early in the morning or after sunset, and you can use low-level artificial light indoors (maximum 60W bulb).
In the first few days it’s possible to get ‘sunburn’ even on a dull winter day. You won’t notice that you are getting burnt while you are out in the sun. As with sunburn, the damage to your skin can take a few hours to show up.
You can even get burnt through glass if the light is strong. Remember to draw your curtains during the day if the sun is bright. Bright artificial lights can also cause a skin reaction, so spot lamps are best avoided.
It is important to be aware of unexpected sources of light – for instance, warming your hands over a fire could result in being burnt. It is a good idea not to use a computer during this time and not to watch the television from less than about 2 metres (6 feet) away. You may be given a light meter to use at home, to check that the light intensity is at a safe level.
Avoid having your eyes checked while you’re sensitive to light as the area at the back of your eye (retina) will be more vulnerable to light than usual. You shouldn’t have light shone into your eyes at this time.
Towards the end of the period of photosensitivity, a small area of skin can be exposed to brighter light for five minutes and the reaction assessed 24 hours later. Your doctors will advise you on how to do this.
After this time, you can gradually increase the amount of light you’re exposed to and most people are able to go outside as usual after about three weeks. Your doctor or specialist nurse can let you know for exactly how long you will need to protect your skin.
Pain Treatment with PDT can cause pain| in the tumour area. Your specialist nurse can explain how this may affect you and make sure you have the right kind of painkillers to take.
The amount of pain will vary according to where your tumour is and which light-sensitising drug has been used.
Some people may only need simple painkillers such as aspirin or paracetamol. Others may need a stronger drug such as morphine. Let your doctor know if you have any pain. They can prescribe painkillers or give you a stronger painkiller if the one you’re taking isn’t controlling your pain.
Swelling Some photosensitising drugs can cause swelling in the treated area. This varies from one person to another. If you’ve had treatment in your mouth or throat, the swelling may make it difficult for you to swallow. It’s important to let your nurse or doctor know if swallowing becomes difficult.
Feeling sick (nausea) Some people may feel sick| , but this can be controlled with mild anti-sickness tablets.
Healing PDT causes much less scarring than surgery. However, the time taken for PDT-treated areas to heal can vary a lot. It may be several weeks, depending on the area treated and how deeply the light has penetrated into the body tissues.
Cancers in other parts of the body Back to top
PDT is used to treat precancerous conditions which we’ve mentioned earlier and occasionally some early cancers. It is also used to treat the symptoms of advanced cancer.
PDT as a treatment is often given in trials to find out more about how helpful it is for different cancers.
Early cancers PDT can sometimes be used to treat some small early lung cancers (non-small cell) in people who can’t have surgery.
PDT may also be used to treat early bladder cancer (only in the lining of the bladder) but this is still experimental and only available in a research trial.
Another trial is giving PDT along with other treatments to people who have just been diagnosed with a brain tumour. Again, this is still an experimental treatment.
Advanced cancers PDT can be used to relieve the symptoms of advanced cancer. It’s main use is to shrink the cancer. This can help when the cancer is causing a blockage. It can be used to relieve breathlessness in people with lung cancer and difficulty in swallowing in people with cancer of the gullet (oesophagus).
PDT can also be used to treat the symptoms of advanced bile duct, pancreas or gall bladder cancer. It’s usually given at the same time as another treatment (a stent) to relieve a blockage that’s causing a build-up of bile. This can help to relieve jaundice (yellowing of the skin and eyes).
A trial is trying to find out if having PDT and a stent is better than a stent on its own. Another trial is looking at PDT as a treatment to try to shrink cancer of the pancreas that cannot be operated on.
PDT may sometimes be used to treat brain tumours that have come back after treatment. This is still experimental and is only given in a research trial.
Possible side effects
Many of the side effects will be similar to those described in our section on PDT for head and neck cancers.
The period of sensitivity to light varies in length, ranging from one or two days to several months. This depends on which photosensitising drug is used. You can read more about sensitivity to light in our section on head and neck cancers. Your doctor or nurse will tell you how long you’ll need to protect your skin for.
Some people may have pain| or discomfort, or feel sick| . These side effects can be controlled with painkillers and anti-sickness drugs. Other side effects will depend upon the part of the body that is treated. Let your doctor or nurse know about any side effects that you have.
Cancer and pre-cancer of the gullet (oesophagus) Swelling and inflammation can occur around the treatment area. this may make you feel sick, and cause chest pain. You may find swallowing difficult for a few days.
Cancer of the lung PDT may cause swelling and inflammation in the lung which may cause some chest pain, a cough and breathlessness| .
You may produce more sputum and rarely it may be blood-stained. Occasionally there may be a build-up of fluid in the lining of the lung. this is known as pleural effusion| and it can be drained if needed.
Cancer of the bile duct or gall bladder Possible side effects may include infection, tummy (abdominal) pain or bleeding.
Cancer of the pancreas Possible side effects include tummy (abdominal) pain and diarrhoea| .
Cancer of the prostate Possible side effects include temporary mild incontinence of urine and difficulty passing urine. PDT for cancer of the prostate is still experimental.
Cancer of the bladder (early) PDT may cause some irritation of the bladder (cystitis). Its use in early bladder cancer is still being studied in trials.
Brain tumours Possible side effects may include swelling and increased pressure in the brain. PDT as a treatment for brain tumours is still being studied in trials.
References Back to top
This section has been compiled using information from a number of reliable sources including:
- Souhami and Tobias. Cancer and its Management . 5th edition. 2005.Oxford Blackwell Scientific Publications.