E. Briot

RADIOTHERAPY AFTER OVARIAN TRANSPOSITION: OVARIAN FUNCTION AND FERTILITY PRESERVATION

The outcome of ovarian function preservation and fertility after ovarian transposition was examined in women treated for cancer. Of 134 patients, 126 were treated with radiotherapy and 72 with chemotherapy. In a multivariate analysis, three factors appeared to be prognostic of ovarian castration: the age over 25, MOPP chemotherapy and a total dose to the ovaries higher than 5 Gy. The incidence of birth was lower in the general population but no abnormality was observed.

High-dose-rate brachytherapy as sole modality for early-stage endobronchial carcinoma

PURPOSE To evaluate exclusive high-dose-rate brachytherapy for localized early-stage non-small-cell bronchial carcinoma; to develop new insights in treatment-catheter positioning and tumor-volume assessment by computed tomography (CT) scan. METHODS AND MATERIALS Between 1992 and 1996, 34 patients with non-small-cell bronchial carcinoma were treated by brachytherapy alone. All patients were medically inoperable and had contraindications for external beam irradiation. The treatment protocol was six sessions of 5 Gy over 6 weeks. The treatment catheter was placed under fiberoscopy and was positioned with the help of spacer catheters or with a surrounding plastic tube; CT scan was performed in 50% of the cases to measure the spacing between the applicator and the bronchial wall. Dose prescription was individually based on clinical and radiologic evaluation of tumor volume. RESULTS Local disease failure occurred in 5 patients (15%). With a median follow-up of 2 years, the local control rate was 85% and the survival rate 78%. No acute toxicity was found, except one pneumothorax. CONCLUSION Brachytherapy alone can give an optimal therapeutic ratio in small endobronchial carcinomas without radiation-induced morbidity. Such results are achieved after careful tumor volume evaluation and individualized treatment catheter positioning.

Single dose versus hyperfractionated total body irradiation before allogeneic bone marrow transplantation: a non-randomized comparative study of 54 patients at the Institut Gustave-Roussy

At the Institut Gustave-Roussy (IGR), from January 1982 to December 1986, 54 patients received total body irradiation (TBI) as a part of the conditioning regimen before allogeneic bone marrow transplantation. The patients were non-randomly assigned to either single dose TBI (STBI) (31 patients receiving 10 Gy at a 4.5 cGy/min dose rate, 8 Gy to the lungs) or to a hyperfractionated scheme (HTBI) (23 patients receiving 13.2 Gy in 11 fractions, 3 fractions per day, 9 Gy to the lungs). Relapse rate and overall survival were not significantly different in the two STBI and HTBI groups, in spite of a larger number of 2nd and 3rd remission patients in the HTBI subset. The incidence of interstitial pneumonitis (IP) was significantly reduced in the HTBI group (13%, versus 45% after STBI, p = 0.02). Lethality by IP was also lower after HTBI (4%, versus 26% after STBI, p = 0.08). There was no case of veno-occlusive disease of the liver in the HTBI group, whereas three cases were observed after STBI. Based on these results, the IGR activated, in January 1987, a randomized trial comparing the single dose 10 Gy TBI (8 Gy to the lung) to a new hyperfractionated schedule (11 fractions of 1.35 Gy, 3 fractions per day, 9 Gy to the lungs).

Prospective Randomized Comparison of Single-Dose Versus Hyperfractionated Total-Body Irradiation in Patients With Hematologic Malignancies

PURPOSE Fractionated total-body irradiation (HTBI) is considered to induce less toxicity to normal tissues and probably has the same efficacy as single-dose total-body irradiation (STBI) in patients with acute myeloid leukemia. We decided to determine whether this concept can be applied to a large number of patients with various hematologic malignancies using two dissimilar fractionation schedules. PATIENTS AND METHODS Between December 1986 and October 1994, 160 patients with various hematologic malignancies were randomized to receive either a 10-Gy dose of STBI or 14.85-Gy dose of HTBI. RESULTS One hundred forty-seven patients were assessable. The 8-year overall survival rate and cause-specific survival rate in the STBI group was 38% and 63.5%, respectively. Overall survival rate and cause-specific survival rate in the HTBI group was 45% and 77%, respectively. The incidence of interstitial pneumonitis was similar in both groups. However, the incidence of veno-occlusive disease (VOD) of the liver was significantly higher in the STBI group. In the multivariate analysis with overall survival as the end point, the female sex was an independent favorable prognostic factor. On the other hand, when cause-specific survival was considered as the end point, the multivariate analysis demonstrated that sex and TBI were independent prognostic factors. CONCLUSION The efficacy of HTBI is probably higher than that of STBI. Both regimens induce similar toxicity with the exception of VOD of the liver, the incidence of which is significantly more pronounced in the STBI group.

Consequences of two different doses to the lungs during a single dose of total body irradiation: Results of a randomized study on 85 patients

PURPOSE To evaluate the incidence of lung complications and leukemia recurrences after two different doses to the lungs during total body irradiation. METHODS AND MATERIALS Seventy-nine patients with acute leukemia (AML or ALL) in first complete remission or chronic myeloid leukemia in the chronic phase, five patients with high grade lymphoma, and one with chronic lymphocytic leukemia were entered in the study. They were given a single dose of total body irradiation (10 Gy over 4 h) with two different doses to the lungs (6 Gy or 8 Gy) prior to bone marrow transplantation. The median dose rate was 0.04 Gy/min. The median follow-up for both groups of patients was 24 months. RESULTS The actuarial 5-year overall survival rate was similar in both groups, 59% and 43% for patients given 8 Gy and 6 Gy to the lungs, respectively. The lung complication rate was similar in the two groups (28% vs. 22% for the 8 Gy and 6 Gy group, respectively). The actuarial leukemia recurrence rate was significantly higher in the group of patients given 6 Gy to the lungs (25%) vs. 0% in the 8 Gy group. Interestingly, all recurrences occurred in the group of patients who were given 6 Gy to the lungs, who had acute leukemia, and no chronic graft vs. host disease (GVHD). CONCLUSIONS Although the number of patients was not very large and the follow-up relatively short, these findings suggest that a lower dose to the lungs could lead to an increased incidence of leukemia recurrences due to a lower dose to the thoracic wall or to lower incidence of chronic GVHD.

The source-skin distance measuring bridge: a method to avoid radiation teleangiectasia in the skin after interstitial therapy for breast cancer

Inappropriate positioning of interstitial Iridium 192 implants, used as booster dose in the breast conserving treatment of mammary cancer, may cause disturbing teleangiectasia of the breast skin, when high radiation doses are delivered on the dermal blood vessels. Based on the localization of the vascular plexuses in human breast skin, and on the dose distribution around different types of interstitial implants, a method is described to avoid overlap between the high dose area of the implant and the blood vessels in the skin. The latter are demonstrated to run within the first 5 mm under the epiderm. For source lengths varying from 5 to 8 cm, simple mathematical relations exist between the maximal security margin (MSM) and intersource distance (E) for single plane implants (MSM = 0.4 (E + 1)), double plane square implants (MSM = 0.4 E) and double plane triangular implants (MSM = 0.4 (E - 1)). We developed a device to measure precisely the distance between the radioactive wires and the overlying skin, along the whole source trajectory. Using this method, the occurrence of teleangiectasia in the breast skin after interstitial implants with Ir 192 may be significantly reduced.

Dosimetric comparison of an integrated multileaf-collimator versus a conventional collimator

The dosimetric characteristics of both a conventional GE collimator (CC) and a GE multileaf collimator (MLC) are compared for different photon beam energies. The integrated GE MLC consists of 32 pairs of tungsten leaves, replacing the lower pair of jaws of the conventional collimator. Measurements were performed with the conventional collimator before this collimator was replaced by the MLC. All parts of the accelerator except the collimator remained the same. Leakage and transmission measurements show good agreement with the manufacturers specification, stating a leakage between leaves of less than 1% for all energies and a transmission through leaves of less than 0.5%. The dosimetric characteristics of both collimators are very similar for square and rectangular fields. No significant change in beam quality, beam attenuation and depth of maximum dose could be detected within the measurement accuracy. The MLC output ratio variation is smaller than the one measured with the CC. The penumbra difference in the Y direction is less than 0.5 mm at a depth of 5 cm in phantom; in the X direction the penumbra is 1 mm larger for the MLC due to the rounded leaf fronts. As the two leaf banks replace the lower pair of collimator jaws the distance from the collimator end to the isocentre is similar for the two collimators, therefore the MLC does not reduce the flexibility of the treatment unit. For symmetrical and regular collimator settings the MLC can be treated as the CC.

Endoluminal High-Dose-Rate Brachytherapy with a Palliative aim in Esophageal Cancer: Preliminary Results at the Institut Gustave Roussy

Ten patients with advanced esophageal carcinoma were treated with endoluminal high-dose-rate brachytherapy at the Institut Gustave Roussy. Eight of them had recurrences after external beam radiotherapy. They were treated with a high-dose rate iridium-192 source. Five patients received 6 sessions of 4 Gy, 4 patients 3 sessions of 4 Gy, and 1 patient received 3 sessions of 8 Gy. The interval time between each session was 1 week. Seventy percent of patients improved their dysphagia, with 80% endoscopic tumor response. The Karnofsky index was improved in most of the patients. The mean survival was 4 months, and dysphagiafree survival was 2.5 months. Two patients had treatment toxicity but only a transitory WHO G1 esophagitis. Endoesophageal high-dose-rate curietherapy seems an effective technique in palliative treatments. We found low toxicity and an excellent tolerance to treatment in previously irradiated patients. The efficacy of the treatment is highly dependent on a precise tumor volume evaluation.

Principles of total body irradiation

Total body irradiation delivered prior to bone marrow transplantation remains an important component of the conditioning regimen. Proper engraftment of autologous or allogeneic bone marrow is possible because of the multifarious effects of high doses of ionizing radiation on tumor cells and the host immune system. We will broadly outline the techniques used to deliver total body irradiation, and the effects of ionizing radiation on normal and tumor cells from a biological and molecular point of view. Finally we will report the results of randomized c1inical trials that have been conducted in our institution during the last ten years.

Optimisation en curiethérapie

Advances in technology have initiated a process of redefinition of planning and evaluation of brachytherapy. The new approach involves conformal positioning of a source configuration for which the treatment isodose contour is adapted to the shape of the target volume which is defined by 3D dimensional imaging. A good implant aims for a balance between good coverage of the target volume, a high dose uniformity inside the target volume and a steep dose fall-off outside the target volume. Computer hardware and software is now available to obtain a high level of sophistication, for instance in treatment planning. In addition, new after loading equipment became available allowing a large variety in source placement in the catheters. To facilitate optimisation procedures, new parameters for the judgement of the quality of the implant have been suggested.