Photodynamic diagnosis is an early diagnosis of bladder cancer.
There are a large number of different technologies for diagnosing bladder diseases. However, many diseases are diagnosed already in an advanced state, when the therapeutic measures taken are ineffective. A common problem with bladder cancer, in addition to early diagnosis, is the high rate of recurrence. Thus, after transurethral resection, the relapse rate in the first few months alone can increase to 60%. And if we look at data for five years, then up to 90%. In this case, relapses may be a manifestation of another type of tumor, have a different differentiation, in addition, it can penetrate deeper into the tissue. This worsens the prognosis and the effects of treatment. The main source of relapse in this case is the original tumor and cells that were not removed. They could not be diagnosed in time and, as a result, they were not resected. To exclude this type of relapse, specialists usually perform a random biopsy, in addition, cytology of urine and rinsing water is performed during surgery or cystoscopy. However, these methods have low sensitivity and specificity.
In Munich, at the Grosshadern Hospital of the Ludwig Maximilian University, a method for photodynamic diagnosis of tumors was first developed. After the methodology was approved, it began to be used and improved all over the world. The success of photodynamic diagnostics led to the fact that random biopsies were stopped. This led to a decrease in postoperative bleeding, incontinence and other complications. In addition, the relapse rate was reduced by three to four times.
Photodynamic diagnostics is aimed at detecting bladder cancer in the early stages. The method is based on a physical process, fluorescence. When a certain substance, 5-aminolevulinic acid, is introduced into a tumor cell, as a result of a cascade of reactions, protoporphyrin 9 is formed, which has the necessary properties for fluorescence.
This mechanism makes it possible to diagnose bladder cancer in the early stages, and during surgery, a specialist can visually observe tumor cells and remove the entire tumor mass. In addition, in addition to diagnosis, this approach can be used in the treatment of bladder cancer. Given the chemical reactions that occur, radicals are formed as a result, which, interacting with tumor cells, kill them. However, this area is still developing and requires many clinical studies. Initially, photodynamic diagnostics was used in the diagnosis and treatment of skin diseases.
A photodynamic study does not require a large amount of equipment. The main requirement is the presence of a light source that has high power to initiate fluorescence, as well as an endoscope. Typically the light source used is D-Light, Karl Storz. If videocystoscopy is performed, the specialist must have a special video camera. Before cystoscopy, a special drug containing 5-aminolevulinic acid is injected into the patient’s empty bladder. It is advisable that the bladder is not emptied before the operation. On average, this time is about 2-3 hours. If, due to any disorders, it is impossible to retain urine, various antispasmodics are prescribed along with the drug. After administration of the drug, the patient must move for some time so that the drug is evenly distributed in the bladder. The procedure is usually performed under local anesthesia. In this case, during cystoscopy, transurethral electroresection or Nd-YAG laser coagulation is simultaneously performed.
In most operations, special Karl Storz optics are used. The resectoscope has a long-wave filter that transmits red fluorescent light. Cancer cells appear as red, healthy cells remain blue. Depending on the type of oncology, the color will be different during examination. So, with inflammation and leukoplakia, red fluorescence will be detected. In this case, the contours will be uneven. Papillary cancer will show bright red fluorescence. Technological developments allow simultaneous diagnosis of the presence of cancer cells and their excision.
There are practically no side effects from the procedure. Usually, frequent urination or temporary incontinence may occur, but these side effects are most likely related to the cystoscopy itself rather than the effect of the drug. Allergic reactions to the drug have never been reported.
Thus, photodynamic diagnosis of bladder cancer has significant advantages over other diagnostic methods, increasing the effectiveness of therapy and the chances of cure.
But, to carry out successful photodynamic diagnostics, a highly qualified specialist is required. Our specialized urological clinic and the urological departments of other clinics employ leading urologists whose qualifications allow them to make an accurate diagnosis and carry out effective treatment.