[Preoperative radiotherapy in hypoxia in the complex treatment of the rectal carcinoma--long term results].

Introduction: The aim of this study was to evaluate long term results of patients with rectal carcinoma which were irradiated in hypoxic conditions.

Patients And Methods: Of all patients which were irradiated in hypoxic conditions in Masaryk Memorial institute, 93 patients were followed up longer time than five year.

Results: The most common surgical procedure was resection in 60%, overall five year survival was 73.

[Preoperative radiotherapy in hypoxia in the complex treatment of the rectal carcinoma--complications].

Introduction: Preoperative radiotherapy is considered to be the standard approach in the treatment of the rectal carcinoma. Acute hypoxia decreases partial pressure of oxygen in healthy tissues immediately, but in the tumor after 30 min of duration. There is a higher radioresistance of healthy tissues in this interval because of lower oxygenation compared with normooxic status and the tumor is still relatively good oxygenated.

Hypoxic versus normoxic external-beam irradiation of cervical carcinoma combined with californium-252 neutron brachytherapy. Comparative treatment results of a 5-year randomized study.

Purpose: The article focuses on the treatment and protective effects of hypoxyradiotherapy during external-beam irradiation of cervical carcinoma, including paraaortic lymph nodes, combining radiotherapy with californium-252 ((252)Cf) neutron brachytherapy. An analysis of treatment results, early and late side effects and complications is presented.

Patients And Methods: From January 1989 to May 1997, 307 women with stage IIb and IIIb cervical carcinoma, treated with (252)Cf neutron brachytherapy, were randomly divided into two groups and treated with external-beam irradiation to the paraaortic lymph nodes as follows: 155 patients (59 with stage IIb, 96 with stage IIIb) were treated by external-beam irradiation administered as a 60-Gy dose applied under conditions of acute hypoxia; 77 patients (30 with stage IIb and 47 with stage IIIb) received extended-field irradiation up to L4 and 78 patients (29 with stage IIb and 49 with stage IIIb) up to T12.

Californium-252 (252Cf) versus conventional gamma radiation in the brachytherapy of advanced cervical carcinoma long-term treatment results of a randomized study.

Background: When photon radiotherapy is applied to cervical carcinoma, it has been observed that, despite important progress in radiotherapy technique and quality assurance, no significant increase in curative rates has resulted. Among the reasons for this is the varying radiosensitivity of different tumor subpopulations. Treatment with californium-252 ((252)Cf), as a source of gamma/neutron radiation in brachytherapy, provides properties and new treatment modalities that help to overcome this factor.

Remote afterloading for neutron brachytherapy using californium-252.

Background: Despite a pronounced technical process attained in radiotherapy of malignant neoplasms, no remarkable improvement in the treatment results has been achieved. The reason for this stagnation is the interaction between tumor cell and photon radiation. Tumor resistance against photon bombardment can be broken down by applying high linear energy transfer (LET) radiation-based treatment.

Preoperative hypoxyradiotherapy of colorectal carcinoma.

Aim: The article focuses on the radioprotective effect of acute hypoxia on healthy tissues during preoperative accelerated hypoxyradiotherapy of colorectal carcinoma performed as locoregional irradiation including the common iliac lymph nodes. Analysis of early and late side effects and complications.

Patients And Methods: In this prospective study, early and late complications were assessed in 50 patients as a function of hypoxyradiotherapeutic dose increase.

Modulation of radioprotective effects of respiratory hypoxia by changing the duration of hypoxia before irradiation and by combining hypoxia and administration of hemopoiesis-stimulating agents.

Aim: Analysis of radioprotective effect of respiratory hypoxia on hemopoietic tissue and enhancement of this effect by hemopoietic activation.

Material And Methods: In mice breathing hypoxic gas mixture during total body gamma irradiation the recovery of pluripotent and committed granulocyte-macrophage progenitor cells and animal lethality were determined.

Results: In mice forced to breathe 10% O2 and 8% O2 during irradiation, the oxygen tension in the spleen decreased to 40% and 20%, respectively, of control values.

Early changes in flow cytometric DNA profiles induced by californium-252 neutron brachytherapy in squamocellular carcinomas of the uterine cervix.

Ninety-five squamocellular carcinomas of the uterine cervix, clinical Stages II and III, were treated by either four schedules combining 252-californium neutron-gamma-radiotherapy with different proportions of a neutron component (9, 6 and 3 Gy) or gamma-irradiation alone. Flow cytometric DNA profiles were obtainable in 72 cases before treatment and 56 cases were monitored for DNA content by flow cytometry (FCM) in weekly intervals by analysis of sequential microbiopsies for one month during and after radiotherapy. DNA aneuploidy was reduced from 40% (25/63) to 19% (9/47) one week within therapy in neutron-treated groups, but not after initial gamma-radiotherapy alone.

[Hypoxic radiotherapy. The radioprotective effect of acute hypoxia in the radiotherapy of tumors in the abdominal area].

Aim: We tested, whether inhalation a of gas mixture containing 8.0 to 8.5% O2 reduces the radiosensitivity of healthy tissue in order to deliver higher tumor doses without increasing the side effects of radiation therapy.

A contribution to the comparison of the efficacy of radiotherapeutic procedures in cervical carcinoma.

This paper presents a new method in which the regression velocity of cervical carcinoma is measured by computer tomography and the results evaluated by two statistical methods: non-linear regression analysis and survival analysis. By means of this approach it was possible to compare the early effect of therapy in patients treated with intracavitary application of 226Ra plus external radiotherapy with those treated with 252Cf, 226Ra and extended radiotherapy. In the latter group a higher efficacy of the therapy was demonstrated by both statistical methods.

Hypoxyradiotherapy of uterine cervix cancer to decrease of acute side-effects and treatment complications.

The authors have reported on preliminary results of hypoxyradiotherapy in the course of external irradiation in patients with uterine cervix cancer from a view-point of the occurrence of acute reactions and treatment complications. A mixture of nitrogen and oxygen containing 8.0 to 8.

Tumor response and treatment complications in radiotherapy of localized prostate cancer.

The response of primary tumor to definitive radiation therapy and treatment related morbidity has been analysed in a group of 35 patients. All of them were treated with 20 MeV photon beam to a total dose of 67 to 71 Gy to the prostate. The effect of radiotherapy to a primary tumor were evaluated by means of repeated CT examination of the tumor volume.

Complications of radiotherapy of uterine cervix carcinoma.

The retrospective analysis of 242 patients treated for uterine cervix cancer at VUKEO Brno within 1977-1982 has been realized. The patients being only treated with radiotherapy alone using the external 42 MeV X-ray betatron beam irradiation of the pelvis, and the vaginal and intrauterine application of 226Ra, were included in this study. The complications of therapy were evaluated in accordance with the grade of severity, location and time of their source.

Calculation of radiation doses in critical organs compared with in vivo dosimetry during brachytherapy of carcinoma of the uterine cervix.

In a group of 38 patients with carcinoma of the uterine cervix, radiation doses were measured by thermoluminiscent dosimeters (TLDs) placed in catheters introduced into the urinary bladder and rectum during a 24 h uterovaginal application of 226Ra. The values of radiation doses registered by the TLDs were compared to those calculated from roentgenograms made after 24 h. To calculate the radiation doses, we used the program Brachy 9.

Effect of small doses of 252Cf on the tumour regression in cervix uteri during combined radiotherapy.

The results of a randomized study on the regression rate of the cervix uteri tumour for a group of 56 patients, investigated during and after radiotherapy with 2 Gy dose of the 252Cf neutron component applied by means of intracavitary therapy at the beginning of the therapeutic cure are presented and compared with the conventional 226Ra therapy. It was found that the tumour regression curve after 252Cf irradiation is significantly steeper than the curve of the control group. The quantitative evaluation of the results regarding the time required for a 50% regression of the original tumour shows that a group of patients treated by 252Cf needs a 27 days' cure in comparison with 40 days' cure for patients treated only by gamma radiation.

Variations in dose distributions by the use of independent asymmetric jaws. A new technique for irradiation of localized carcinoma of the prostate.

The use of independent jaws set asymmetrically in the moving field technique with bilateral arcs allows the entirely new dose distributions be obtained. The basic principle of this technique is that, with the use of moving field technique with bilateral arcs, the independent jaw more proximate to the central ray (axis) of beam must always be on the side of the critical organ. In this area the characteristic deformation of isodoses and the formation of very steep dose slope occur.

[Regression of cervix uteri neoplasms in combined radiotherapy using low dose gamma-neutron irradiation].

The authors compared the results in the regression of uterus cervix tumour after intracavital therapy with gamma-neutron irradiation by 252cf and conventional sources of radiation gamma 226Ra in the course of a combined radiotherapy procedure. On the basis of a randomized study in 20 patients for a group it became obvious that due to the irradiation of the tumour in the initial phase of therapeutic cycle by physical dose 2 Gy of neutron component of 252Cf in the point A there was an increased regression of the tumour process causing in the 6th week since the beginning of the therapy a significant difference in the size of the tumours in both groups of patients. The time period required for 50% tumour reduction from the beginning of the therapy proved to be 23 days in patients treated with the 252Cf nuclide as compared with 48 days in the group of patients after conventional therapy.

[Manual afterloading applicators for intracavitary brachytherapy].

A technical description of uterovaginal and rectal applicator system of manual afterloading is described. A simple solution while using domestic materials covering the requirements of present-day brachytherapy. The applicators proved to be suitable for gamma radiation sources as well as for gamma-neutron radiation of 252Cf sources.

[Reoxygenation of tumors of the uterine cervix during combined radiotherapy using low dose gamma-neutron irradiation with californium-252].

A polarographic method was used to follow the changes in oxygenation of a tumour of uterus cervix after intracavital irradiation by 252Cf by a physical dose of 2 Gy, applied at the beginning of a therapeutic cycle of combined radiotherapy. The results reached are compared with the results of tumour oxygenation in the course of a conventional therapeutic procedure. It has become apparent that even after the irradiation of a tumour of uterus cervix by a small dose of gamma-neutron radiation with 252Cf there is, beginning with 2nd week of therapy, a significant reoxygenation of the tumour population.

[Radiotherapy of carcinoma of the prostate--5 years' experience].

Forty three patients were treated for cancer of prostate by irradiation at the Radiotherapeutic Ward of the Research Institute of Clinical and Experimental Oncology in the years 1976 to 1981. The five-year period of survival in patients with a localized tumorous disease was 45%. The authors analyzed causes of unsuccessful therapy and evaluated complications of the therapy, the latter being mostly early postirradiation reactions.

A technical equipment for workroom with californium-252 used for the gamma-neutron brachytherapy.

A proposal for the 252Cf intracavitary brachytherapeutic workroom with the description of the technical equipment for the radioactive source storage and manipulation and the personal protection against the gamma-neutron radiation is provided.