Photodynamic Therapy Of The Cervix: Pros And Cons, Stages

2024 Author: Josephine Shorter | [email protected]. Last modified: 2024-01-07 17:49

Photodynamic therapy of the cervix

Photodynamic therapy is one of the newest methods of cancer treatment. Its essence boils down to the selective accumulation of a photosensitizer by a tumor after intravenous or local administration. Subsequently, the cancer is irradiated with a light source (laser or non-laser). As a result, a reaction with the release of singlet oxygen occurs in the affected tissues. This leads to the death of cancer cells.

The beneficial differences between photodynamic treatment and standard procedures for getting rid of cancerous tumors are reduced to the following factors:

• During the treatment, the patient's immunity does not suffer.
• The patient does not develop toxic reactions.
• There are no local and systemic complications.
• The treatment can be repeated several times.
• Hospitalization of the patient is not always required.

Content:

• What is photodynamic therapy?
• Stages of photodynamic therapy
• The use of photodynamic therapy for the treatment of cancer patients
• Benefits of photodynamic treatment
• Cons of photodynamic therapy
• Indications for therapy
• Contraindications to PDT treatment
• What drugs are used for treatment?
• The names of drugs used for PDT
• Photofrin application in practice
• Undesirable effects after photodynamic treatment
• How to make rehabilitation easier after treatment
• Reviews of photodynamic treatment
• On the prospects of using PDT

What is photodynamic therapy?

The method has the abbreviated name PDT and comes down to the effect on the cancer tumor with photosensitizers (a group of drugs) and a light source. The drug can be applied directly to the skin, or injected into the body through the veins. After a short time, it is absorbed in the tissues, and then a light beam is directed to the affected area.

The tumor, after exposure to photodynamic therapy, should be deprived of nutrition. For this purpose, it will be necessary to remove the blood vessels.

Stages of photodynamic therapy

Photodynamic therapy is carried out in several sequential stages:

• The sensitizing solution is administered through a vein.
• The drug accumulates in the affected tissues. This process can take several days.
• A laser beam is applied to the tumor, destroying it. If the neoplasm lies in deep tissues, then special LED tubes are used for irradiation. This leads to a toxicological reaction and the tumor dies. At the same time, healthy tissues surrounding the unhealthy area are not negatively affected.
• Pathological cells disintegrate, and mutated tissues are restored. This stage takes about 30 days.

The use of photodynamic therapy for the treatment of cancer patients

This type of treatment improves the quality of life of cancer patients. Although photodynamic exposure does not cause significant harm to health, it still has not found widespread use in many countries.

In the capital of Russia, this type of treatment began to be used back in 1998. At the moment, the procedure can be completed in five offices in Moscow. About 2,000 cancer patients received treatment.

The method of contact photodynamic therapy was created and is successfully used in the Oncological Dispensary at number one. In this case, the penetration depth of the laser beam is 2 cm.

Benefits of photodynamic treatment

Photodynamic treatment is a method for combating cancer and precancerous conditions.

Doctors try to actively use PDT when detecting oncology in the early stages of development, as this provides many advantages:

• Only cancer cells are destroyed.
• All patients tolerate this type of therapy well, regardless of their age.
• The tissues surrounding the tumor are minimally affected.
• In the treatment of skin oncology, a positive result can be achieved, which is equal to 100%.
• The impact of PDT on the cervix does not negatively affect a woman's subsequent ability to bear children.
• There is no need to admit the patient to the hospital for treatment.
• If the need arises, then photodynamic therapy can be performed several times.
• The method has no systemic effect on the body.
• During the procedure, no anesthesia is required, since it is absolutely painless.
• In the complex treatment of oncological diseases, photodynamic therapy can be implemented as an independent technique.

It has been found that photodynamic therapy has a destructive effect not only on cancer cells, but also on the human papillomavirus. In parallel, there is an antibacterial and antifungal effect, the body's immune defense increases. Such a large number of PDT advantages makes this method of treatment quite popular.

Cons of photodynamic therapy

In addition to the positive aspects, photodynamic therapy has several disadvantages, including:

• The method has a limited scope. With its help, it is possible to affect only those cancer cells to which the light beam can access.
• After the administration of photosensitizing drugs, increased sensitivity to light persists for a certain period of time.

However, PDT allows you to get rid of cancerous tumors, so the disadvantages of the method can be considered insignificant.

Indications for therapy

Photodynamic therapy is effective for treating the following diseases:

• Various cancers and precancer.
• Vitiligo, psoriasis, systemic lupus erythematosus and other dermatological diseases.
• Diseases of the organs of vision.
• Treatment of trophic ulcers and other wounds that do not regenerate for a long time.

Contraindications to PDT treatment

The list of contraindications for photodynamic therapy is rather small:

• Liver disease.
• Kidney disease.
• Decompensated diseases of the heart and blood vessels.
• Hypersensitivity reaction to the components of administered drugs.
• Hematological diseases.
• Pregnancy.
• Lactation.

The method is used for the treatment of oncological diseases only on strict medical grounds.

What drugs are used for treatment?

To implement the PDT method, drugs from two groups are applicable:

• First generation sensitizers. They are made on the basis of porphyrins (Photohem, Photofrin-1 and Photofrin-2, as well as others). These drugs have a number of disadvantages, including: poor selectivity of accumulation in tumor tissues, the inability to penetrate to a depth of more than 1 cm. The use of first-generation drugs provokes the development of a photosensitization reaction, which continues for several weeks.
• Photosensitizers belonging to the second generation (Photolon, Photosens-aluminum-sulfophthalocyanine). They were developed to circumvent the negative effects that occur with first generation drugs. These include phthalocyanines, synthetic porphyrins that absorb light in the 670-700 nm range. However, the period of cutaneous phototoxicity of these drugs remains rather long (from six months to 9 months). Chlorines and chlorin-like sensitizers are also second-generation drugs. They are able to absorb the light wave in tissues at a greater depth.
• Third generation sensitizers. One of the few representatives of this group is Bacteriochlorophyllide-serine. During experiments on animals, this drug has shown excellent results in the treatment of melanoma and other oncological tumors.

The main characteristics of drugs used in PDT:

• The drugs should accumulate exclusively in cancerous tumors, but not affect intact cells.
• The drugs should be of low toxicity.
• The drugs must be rapidly excreted from the body.
• Drugs should not accumulate in the dermis.
• The drugs must have luminescent properties.
• The drugs must be stable during storage and introduction into the body.
• The preparations should have an intense absorption maximum of 660-900 nm.

Other characteristics of photosensitizers:

• Fluorescence;
• High light absorption coefficient;
• Photoresistance to radiation used to treat cancer.

The names of drugs used for PDT

Photophrin is one popular drug used in photodynamic therapy. Its activation occurs after exposure to red light.

With the help of Photofrin, the following diseases are treated:

• Lungs' cancer.
• Larynx cancer. Photodynamic therapy is prescribed in cases where the neoplasm reaches an impressive size and its removal with a laser is impossible.
• Barrett's esophagus. Photofrin is prescribed for prophylactic purposes in order to prevent the development of oncology.

The drug that is used to treat senile keratosis is called Aminolevulinic acid. The acid becomes active after being exposed to the blue color. It is allowed to apply the drug exclusively on the head and face.

In Russia, a domestic drug for photodynamic therapy called Photogem was developed, which has passed all the necessary clinical trials and has been approved for use since 1996.

Modern medicine also has other drugs for photodynamic therapy, however, they are used much less often.

Photofrin application in practice

The drug is injected into the body through a vein. After ingestion, it is distributed throughout the body, without penetrating exclusively into cancerous growths. However, healthy tissues will get rid of Photofrin on their own after a few days. On the other hand, the substance will remain in cancer cells.

However, without exposure of the tumor to a ray of light of a certain wavelength, nothing will happen to it. The destruction process is activated only after the treatment procedure is carried out completely.

When it is necessary to get rid of lung cancer, they are irradiated with a bronchoscope. Since the laser has low power, it does not cause any damage to the lung tissue.

In general, the procedure can take 5-45 minutes. Its duration directly depends on where exactly the tumor is located and what size it is. After a few days, the body will independently get rid of the destroyed tissues. When the need arises, the treatment procedure is repeated.

Contraindications to treatment with Photofrin:

• Too narrow channel separating the esophagus from the bronchi.
• The presence of a neoplasm that affects large blood vessels.
• Stomach ulcer.
• Dilated veins of the stomach.
• Individual intolerance to the components of the drug.

Undesirable effects after photodynamic treatment

More often than other side effects from the therapy, patients experience increased sensitivity to sunlight, swelling at the site of exposure and the appearance of minor pain.

The increased photosensitivity is explained by the fact that the drug is not excreted from the body immediately, but over time. Depending on the individual characteristics of the patient, this side effect can persist for several months. When exposed to sunlight and bright light on unprotected areas of the dermis, blisters will appear on it. Moreover, this reaction happens almost instantly.

As for the duration of the preservation of the increased photosensitivity reaction, this fact depends on which drug was used for treatment. When using 1st generation sensitizers, it lasts about 30 days, for 2nd generation sensitizers - up to six months, and for chlorins - no more than a few days.

To avoid negative reactions, you need to reliably protect your skin and eyes. However, this does not mean that a person should remain locked in a dark room for several months. After all, daylight helps to remove the medicine from the body. The photosensitivity reaction will gradually decrease, but this will not happen earlier than 30 days after the treatment.

When the procedure was performed in the area of the larynx, then its swelling can lead to problems with swallowing. If the effect has been made on the lung tissue, then breathing difficulties are often observed. These symptoms cannot be ignored, they must be reported to the treating doctor.

Other side effects are:

• Headaches, vomiting or nausea, hiccups. They appear after photodynamic treatment on the esophagus.
• Bronchitis, pneumonia and shortness of breath are side effects of lung cancer treatments.

If a person has any unusual symptoms, then the doctor must be the first to know about them.

How to make rehabilitation easier after treatment

To reduce or completely avoid side effects from photodynamic therapy, the following recommendations allow:

• All incandescent lamps in the home should be protected by lampshades or dark shades.
• The curtains must be kept closed after returning from the hospital.
• To protect yourself while returning home from a medical facility, you must wear a wide-brimmed hat and dark glasses. Clothes should have long sleeves and legs should not be exposed.
• Within a month after the treatment, you need to stop going outside during the daytime. If this is not possible, then even if the sky is covered with clouds, the skin must be carefully protected.
• Direct light should be avoided.
• Do not use a hair dryer to dry your hair. The fact is that even getting a jet of hot air on the skin can provoke unwanted side effects.

Compliance with these rules will minimize the risks of developing adverse events after the treatment.

Reviews of photodynamic treatment

Generally, patients respond positively to this therapeutic method. PDT does not injure the skin, does not leave scars and scars, and the effectiveness of the treatment is very high.

All patients indicate that they did not experience pain during treatment. However, a hypersensitivity reaction to light is observed in every patient. This causes corresponding difficulties in maintaining the usual way of life.

As for negative reviews, almost all of them come from people who were negligent in their medical recommendations and did not follow them. You should pre-tune in the fact that when treating a tumor of the larynx, it may be difficult to swallow food and breathe. However, after a while they self-destruct.

Professor S. D. Nikonov, practicing in Novosibirsk, has developed a new method of treatment using PDT. He practices it for diseases of the brain, as well as for carcinomatous pleurisy. The doctor has published a lot of scientific papers on the effectiveness of the technique he uses.

You can also go through the PDT procedure at the Krasnodar Oncological Dispensary at number one. The hospital has the most modern equipment, which guarantees high-quality therapy.

Thanks to the development of modern medicine, oncology is no longer a death sentence for humans. If you identify the disease at an early stage, then you can successfully get rid of it.

On the prospects of using PDT

Currently, photodynamic therapy is widely used in the treatment of cancer. There is evidence of successful disposal of Barrett's disease using PDT. The method is applicable in the treatment of obstructive processes of the esophagus and biliary tract (in combination with laser therapy).

Research is being carried out on the use of photodynamic therapy for the treatment of malignant neoplasms of the gastrointestinal tract, breast, skin and soft tissues, and the abdominal cavity.

PDT gives excellent results in combination with other methods of therapeutic effects on the body, for example, with biotherapy, chemotherapy, hyperthermia, hyperglycemia.

PDT can be used as a method that improves the quality of life of palliative patients, patients with inoperable tumors, with multiple lesions of the body with metastases.

Scientists are constantly creating new photosensitizers and means of delivering light rays to the deep structures of the body.

The author of the article: Lapikova Valentina Vladimirovna | Gynecologist, reproductologist

Education: Diploma in Obstetrics and Gynecology received at the Russian State Medical University of the Federal Agency for Healthcare and Social Development (2010). In 2013 completed postgraduate studies at N. N. N. I. Pirogova.