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Biomedical subjects

V I Lebedev

Publications and source records attributed to V I Lebedev.

At least 19 recordsLinked to original sources
PubMed2002

[Radiotherapy in multiple modality treatment of children with nephroblastoma].

The role of radiotherapy in multiple modality treatment of Wilms' tumor is evaluated in 225 children aged 3 months to 11.5 years (mean age 3.5 years) with stage III-IV. 184 (81.8%) patients presented with stage III, 93.7% with typical nephroblastoma. Intervention was combined with drug and radiotherapy in 99.6% patients. Exposure of the abdominal cavity in total focal doses of 10.5-50.2 Gy (mean dose 28 Gy) was carried out in 219 (97.3%) of 225 patients. Special attention is paid to the incidence of relapses, remote metastases, and survival of patients in relation to prognostic factors (sex, age, stage of tumor process, terms of exposure, and total focal doses). All patients were followed up for 2-203 months (median 32 months). During this period relapses and/or metastases were observed in 34.2% patients; 30.2% died because of disease progress. 35.1% children live without signs of disease for more than 5 years, 14.7% for more than 10 years. Relapses were more incident during the first year of treatment (in 65% children) and outside the exposed field (72.5% cases). 33.2% patients with stage III developed metastases after 1-49 months; the lungs were involved most often. Prolongation of the period between surgery and exposure of the abdominal cavity led to increase in the incidence of relapses in the abdominal cavity from 6.7% (up to 2 weeks) to 21.9% (more than 1 month), p = 0.02. Relapses were the most frequent in children aged over 4 years. This parameter virtually did not depend on the total focal dose. The absence of relationship between the incidence of local relapses and life span after exposure to a total focal dose of up to 21.6 Gy in comparison with higher doses recommends reduced doses for therapy without notable deterioration of the survival of patients with nephroblastoma.

Child↗
PubMed2001

[Modern prospects for polychemotherapy of solid neoplasms in children].

To improve life quality and to increase survival in children with solid tumors, emphasis is placed on chemotherapeutical treatments along with other existing ones (surgery, radiation). By taking into account the fact that most malignant tumors in children are highly responsive to chemotherapy, programme treatment in children with neoplasms included the new drugs iphosphamide, vepeside, cisplatin, carboplatin, melfalan, bleomycin. The results of therapy with these drugs alone or in combination with well-known effective anthracycline antibiotics and plant preparations are presented. Whether more rigid modified schemes for administration and increment of dosage can be used is shown. This investigation opens new vistas for treating patients with not only localized, but disseminated forms of tumors, such as nephroblastomas, germinogenic tumors, soft tissue tumors, tumors of the bone, head, and neck. Regular assessment of the existing programmes in order to amend them, the use of new drugs, the increase of dosage and administration regimens enhance promises in treating malignant tumors in children.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

[Clinical manifestations and diagnosis of childhood mediastinal tumors].

Mediastinal tumors make up as high as 7% of the malignant neoplasms in children and are encountered in all age groups, slightly more commonly in preschool children. Three main groups of common symptoms that are typical of mediastinal tumors are identified. These include 1) symptoms associated with tumor compression of thoracic organs; 2) neurological disorders associated with compression or destruction of ganglionary nodes; 3) general symptoms. Posterior mediastinal tumors are diagnosed by X-ray in 85% of cases. X-ray computed tomography makes it possible to judge of the initial site of a neoplasm, the presence of inclusions, the status of adjacent organs and tissues, the density of a pathological focus. Gallium-67 citrate radionuclide study allows one to make an early differential diagnosis between a solid formation and lymph proliferative disease. The lack of morphological verification of a diagnosis requires the use of transthoracic aspiration biopsy whose diagnostic value enhances when it is made under guidance of ultrasound or X-ray computed tomography.

Biopsy, Needle↗
PubMed2000

[Tyrosine metabolism, antioxidative system and free radical lipid oxidative processes in children with pigmented nevus and melanoma].

The plasma levels of tyrosine and the lipid peroxidation intermediate malonic dialdehyde (MDA) were measured in children with pigmental nevus and melanoma. They were found to have antioxidative protective failure. The presence of pigmental nevus predetermines the high incidence of tyrosine metabolic abnormalities. In children with pigmental nevus and melanoma, there was an impairment in the correlation of the parameters of tyrosine metabolism, the rate of free radical lipid peroxidation processes, and the status of the antioxidative system. The findings suggest that children with pigmental nevus may be referred to as a high cancer risk group and monitoring of these parameters should be recommended at follow-up of pigmental nevi.

Antioxidants↗
PubMed2000

[Metastatic lung tumors in children (clinical course, diagnosis, prognosis)].

According to data available at the Institute (1985-1999, approx. 1,200 patients), the lung is the most frequent site of cancer dissemination (up to 75%). Such most frequent pediatric children tumors as Wilms' tumor, neuroblastoma, rhabdosarcoma, osteogenic sarcoma and that of Ewing disseminate to lung in 85%, particularly, at advanced stages.

Child↗
PubMed1996

[Experience in treating Nephroblastomas].

The treatment of nephroblastomas which accounts for 72% of all malignant neoplasms in children is one of the topical problems of pediatric oncology. To detect the tumor at early stages of a tumorous process is one of the main conditions of successful treatment for nephroblastomas. The histological types of nephroblastoma, its international classifications and present-day treatment policy are given. A role of radiation treatment is shown at pre- and postoperative therapeutical stages. Drugs, their combinations, and the efficiency of polychemotherapy regimens in use are outlined. The importance of comprehensive examination of the patient to determine the extent of malignancy and to choose adequate antitumor treatment regimens is emphasized.

Child, Preschool↗
PubMed1991

[Evolution of drug treatment of rhabdomyosarcoma in children].

Rhabdomyosarcoma is the most frequently occurring type of malignant solid tumors in children. The tumor site, aggressive growth, proneness to recurrence, metastatic spreading, and high neglect predetermine the negligible share of the surgical method in multimodality treatment of rhabdomyosarcomas. Of importance are the development and the use of different types and schemes of drug therapy which can be employed in combination with radiotherapy. Drug therapy of rhabdomyosarcomas has large practical potentialities which rise from year to year.

Antineoplastic Agents↗
PubMed1991

[Significance of therapeutic pathomorphosis in the treatment and prognosis of osteogenic sarcoma in children].

To decide the problem of adequacy of preoperative treatment and postoperative special therapy, it is necessary to determine the degree of therapeutic pathomorphosis of primary osteogenic sarcoma. According to the materials of the children's clinic of the All-Union Cancer Research Center, USSR AMS, the degree of impairment is dependent on the size of the neoplasm, nature of the treatment and the x-ray-morphological variant. In a group of patients given preoperative chemoradiation treatment for degrees III and IV of therapeutic pathomorphosis, the 5-year survival amounted to 37.9 and 67.2% of cases, respectively. In a weak degree of tumor lesion (I-II), only 7% of the patients survive the 5-year period without metastases. The degree of therapeutic pathomorphosis is of great importance for correcting postoperative therapy as well as for predicting the course of osteogenic sarcoma in children.

Antineoplastic Agents↗
PubMed1988

[Adjuvant chemotherapy in the combined modality therapy of nephroblastoma in children].

The paper discusses the end results of complex treatment of 31 children comprising preoperative therapy, nephrectomy and adjuvant chemotherapy. Two-year survival was 64.5% and two-year recurrence-free survival--48.4%. Adjuvant chemotherapy (vincristine, dactinomycin and adriamycin) was given to 25 cases. Complete treatment consisting of 4 courses of adjuvant chemotherapy was carried out in 12 patients only, tumor progression and toxic hepatitis being the most frequent causes of adjuvant treatment suspension. Survival was shown to depend on such prognostic factors as the efficacy of preoperative chemotherapy, stage and morphological pattern of tumor rather than adjuvant chemotherapy duration. Therefore, a short course of adjuvant chemotherapy may be recommended for localized nephroblastoma in pediatric patients.

Adolescent↗
PubMed1984

[Clear-cell variant of nephroblastoma (clinico-morphological characteristics of 9 cases)].

Nine post-mortem cases included 5 boys and 4 girls at the age from 1 1/2 to 13 years. The ratio right/left kidney was 6 to 3; average tumour weight 780 g, higher than in typical nephroblastoma. Bone metastases were found in 6 cases, the therapy was inefficient. Light-microscopic examination revealed structural polymorphism (typical for nephroblastoma areas, fibroses, hyalinosis, myxomatosis), smooth muscles in 2 cases. Electron microscopy of clear cells revealed fibrillar component developed at a various degree, vacuoles, pynocytosis vesicles, large nuclei with fine structure of chromatin. The results indicate the clear-cell variant of nephroblastoma is a sarcomatoid tumour with characteristic structure and uncommon clinical behaviour which makes necessary a special diagnostic and therapeutical approach.

Adenocarcinoma↗