Treatment of complex forms of cancer
New achievements of Russian scientists
According to WHO, one in five men and one in six women will get cancer sooner or later. Thanks to the research of scientists, it is now possible to treat even the most severe forms of this disease – cancer of the liver, stomach, brain. Scientists of the National Nuclear Research University "MEPhI" (NRU MEPhI) told about their unique developments in this field.
Photodynamic therapy (PDT) is one of the most effective and safe methods of cancer treatment, according to experts of the MEPhI Research Institute. It is widely used to fight malignant tumors of the skin, oropharynx, liver, lungs, brain, bladder, gastrointestinal tract organs.
The principle of PDT is based on the use of photosensitizers – substances that increase the photosensitivity of biological tissues. At the preparatory stage of therapy, the photosensitizer accumulates in the tumor tissue. Laser exposure to accumulation foci triggers the production of reactive oxygen species in tumor cells, resulting in their necrosis, apoptosis, or cell cycle stoppage, followed by the launch in a "healthy" mode.
First of all – accuracy
One of the main problems of PDT cancer treatment is the difficulty of accurately determining the boundaries of the tumor. The consequence of a possible inaccuracy is incomplete treatment of cancer cells, leading to a relapse of the disease.
To solve this problem, MEPhI scientists have created a unique endoscopic video fluorescence system that allows visualizing foci of photosensitizer accumulation in hard-to-reach areas with head and neck cancer.
The uniqueness of the system is that it allows you to clearly define the boundaries of neoplasms in which the photosensitizer is accumulated directly during the operation, as well as to quantify its concentration in tissues, scientists say.
"Accurate determination of tumor boundaries is a crucial factor in effective treatment. Intraoperative fluorescent diagnostics makes it possible to achieve this, which increases the efficiency of PDT and increases the median survival of patients with head and neck cancer," explained the head of the Department of Laser Micro-, Nano- and Biotechnologies of the Engineering Physics Institute of Biomedicine (IFIB) NRU MEPhI, Professor Viktor Loshenov.
Fluorescence is excited by this method using a red laser. In the red range of the spectrum, as explained by the specialists of the MEPhI Research Institute, the absorption and scattering of light in biological tissues is minimal, which increases the depth of penetration and the accuracy of the analysis.
How to save the liver?
One of the most difficult organs for PDT treatment is the liver. It is through it, as the scientists of the MEPhI Research Institute explained, that most photosensitizers are removed from the body, so in any case, a huge amount of these substances is contained in the patient's liver. This greatly complicates the correct detection of pathological cells.
Having analyzed the spectral-fluorescent properties of the tissues of the hepatobiliary system of wild boar, the optical properties of which are close to human, the specialists of MEPhI have developed a new method for quantifying the concentration of photosensitizer in the tissues of the bile ducts.
"By investigating our own fluorescence of liver tissues, we have improved the methods of spectral and video fluorescence diagnostics of malignant tumors arising in this organ. This made it possible to develop an optimal approach to the treatment of liver cancer by PDT methods," said Kanamat Efendiev, a graduate student of the IFIB of the National Research Institute of MEPhI.
Taking care of the stomach
Another direction being developed at the MEPhI Research Institute is spectral and video fluorescence diagnostics for PDT of stomach cancer. As the scientists emphasized, the use of PDT in this area is especially promising due to the high complexity of surgical intervention.
Spectroscopic examination of the gastric mucosa using a new technique made it possible to determine the tumor at a depth of three to four millimeters, which, according to scientists of the MEPhI Research Institute, is twice as high as analogues. The key elements of the technique are a unique endoscopic video fluorescence system and a 5-ALA photosensitizer.
"The study showed that spectral and video fluorescence analysis using 5-ALA can be recommended as a method of rapid diagnosis, including early diagnosis of the stomach, as well as for assessing the spread of tumors and detecting carcinomatous foci during laparoscopy," said Artem Shiryaev, surgeon, oncologist at the Levshin Institute of Cluster Oncology at Sechenov University.
Clinical studies of new techniques were conducted at the Levshin Institute of Cluster Oncology on the basis of the University Clinical Hospital No. 1 of Sechenov University. The methods and equipment developed at the MEPhI Research Institute for PDT and fluorescence diagnostics are already being actively introduced into many clinics in Russia, as the creators noted.
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