A lot of noise from a moderately positive result

A new way to treat prostate cancer interested journalists more than experts

Anna Stavina, XX2 century

A new approach to the treatment of low-risk prostate cancer has demonstrated good results during phase III clinical trials. Therapy based on the injection of a photosensitive drug with subsequent activation with a laser led to the achievement of complete remission in half of the study participants who received such treatment.

Micrograph of invasive prostate adenocarcinoma.

"This is great news for men who have localized prostate cancer. Now they can be offered a treatment that destroys the tumor without removing the prostate gland," says study leader Mark Emberton, a member of the United Kingdom Academy of Medical Sciences, dean of the Faculty of Medical Sciences and a consultant urologist at University College London. He was a leading proponent of using high-intensity directional ultrasound waves to cut off part of the prostate instead of removing the entire gland.

A new approach to the treatment of prostate cancer has been called "targeted vascular photodynamic therapy" (vascular-targeted photodynamic therapy).

The results of a study on this treatment method (Azzouzi et al., Padeliporfin vascular-targeted photodynamic therapy versus active surveillance in men with low-risk prostate cancer (CLIN1001 PCM301): an open-label, phase 3, randomized controlled trial) were published in the Lancet Oncology on December 19, and have already become the reason for the appearance in the press of reports about a "truly revolutionary" approach to the treatment of prostate cancer. 

However, journalists ignored the expert's much less enthusiastic comment on the article in Lancet Oncology. "Targeted vascular photodynamic therapy is an interesting new approach to the treatment of prostate cancer, characterized by limited tumor control and moderate short–term side effects," writes the editor of the publication, Dr. Stephen Freedland from Cedars-Sinai Medical Center in Los Angeles, California. He also warns that the results of the study do not confirm the possibility of using photodynamic therapy as a treatment method for all men with low-risk prostate cancer.

The study covered 413 men from 10 European countries. The volunteers were randomly assigned to two groups. The participants of the first group were recommended active observation, the members of the second group underwent a course of targeted vascular photodynamic therapy.

Scientists, including the first author of the work, Dr. Abdel-Ramin Azzouzi (Abdel-Rahmene Azzouzi) from the Angers University Hospital (fr. Centre Hospitalier Universitaire d'Angers), described the study participants as having "low-risk" (but not "very low-risk") prostate cancer. All patients were diagnosed with localized prostate cancer, the diagnosis was confirmed by biopsy. The study included only patients who met a number of criteria, for example, those at the clinical stage of the disease T2a or higher. The tumor size should not exceed 5 mm, and the concentration of prostate-specific antigen (PSA) in the blood should be 10 ng/ml.

The participants included in the active observation group underwent a prostate biopsy once a year. Their PSA levels were measured every three months.

The volunteers in the experimental group were injected with padeliporfin at a dosage of 4 mg/kg at 10-minute intervals. Light guides were inserted into the tumor area, activating the drug with the help of laser radiation. In this group, the subjects also underwent a biopsy – 12 months after the procedure, and 24 months later, at the end point of the study.

After analyzing the data, it turned out that the probability of disease progression in the treated group was 66% lower than in the control group. 49% and 13.5% of participants achieved complete remission, respectively.

Also, in the experimental group, the need for radiotherapy or surgery was significantly lower – it was only 6%, while in the control group, such treatment was required by 29% of participants.

However, in an editorial accompanying the publication, Dr. Friedland noted that "any treatment after which a cancerous tumor persists in more than half of the participants (as happened in this study) cannot be considered ideal. In addition, more than a quarter of the subjects showed progress of the disease over 2 years, which also indicates the imperfection of the approach."

However, Dr. Friedland suggested that the new approach may precede more aggressive treatment (for example, radiotherapy) in some patients. "Groups of patients for whom photodynamic therapy will be optimal will certainly be found, but they are not yet obvious," the expert concluded.

Prostate cancer is one of the most common malignant neoplasms in men. More than 400,000 cases of prostate cancer are detected annually in the world; in a number of countries, it occupies the 2nd or 3rd place in the structure of oncological diseases after lung cancer and stomach cancer.
In Russian men over 60 years of age, prostate cancer is the most common malignant neoplasm. A feature of prostate cancer in Russia and other CIS countries is late diagnosis, when the tumor is diagnosed at stage III–IV. In the period from 1999 to 2009, the incidence of prostate cancer in Russia increased 2.8 times.

Risk factors that increase the chances of getting prostate cancer include:

• old age (more than 75% of prostate cancer cases are diagnosed in men over 65 years of age, and men under 60 years of age account for only 7% of cases);
• age-related hormonal disorders;
• nutrition features (in men who eat fatty foods, the risk of prostate cancer increases by 2 times, since the abundance of animal fats in food leads to a deterioration in the absorption of vitamin A and, as a consequence, beta-carotene – a protection factor against the occurrence of some malignant tumors;
• hereditary predisposition;
• environmental factors (for example, exposure to ultraviolet rays);
• viral infections (in particular, the hypothesis of the XMRV virus from the retrovirus family as a risk factor for prostate cancer is discussed);
• harmful working conditions (working with cadmium, in the rubber industry).

Portal "Eternal youth" http://vechnayamolodost.ru  22.12.2016