[Radiation induced brachial plexopathy: Diagnosis, risk factors, principles of care]. / La plexite radique : épidémiologie, diagnostic, facteurs de risque et prise en charge.

Radiation plexitis, also known as radiation-induced brachial neuropathy is a rare toxicity following axillary, breast, cervical or thoracic radiotherapy, first described in 1966 by Stoll and Andrew. Although improvements in radiotherapy techniques have greatly reduced its risk over the past seventy years, its severe form remains a dreaded complication that is difficult to manage in patients with increased life expectancy. This article summarizes the epidemiological elements, risk factors, diagnostic methods, doses and constraints to be respected in radiotherapy and the treatment strategies of radiation plexitis.

[Low dose radiotherapy for COVID-19 pneumopathy: Biological rationale and literature review]. / Radiothérapie de faible dose pour la pneumopathie covid-19 : rationnel biologique et revue de la littérature.

The world has now been facing the coronavirus disease 2019 (COVID-19) pandemic due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) since over a year. If most of clinical presentations are benign, fragile patients are at greater risk of developing severe or fatal lung disease. Many therapies have been explored with very low impact on mortality. In this context, Kirkby et Mackenzie have published in April 2020 a report reminding the anti-inflammatory properties of low-dose radiotherapy (delivering less than 1Gy) and its use in the treatment of viral and bacterial pneumopathies before antibiotics era. Large in vivo and in vitro data have demonstrated the biological rationale and anti-inflammatory activity of low-dose radiotherapy in many pathologies. Over the past year, three phase I/II clinical trials have been published, as well as one randomized controlled trial, reporting the feasibility and the clinical and biological improvement of a 0.5 to 1Gy treatment dose to the entire lung. 13 other studies, including a randomized phase III trial, are currently ongoing worldwide. These studies may provide data in the effect of low-dose radiotherapy in the treatment of SARS-CoV-2 pneumonia. This article explains biological rationale of low-dose radiotherapy, and reports already published or ongoing studies on low-dose radiotherapy for SARS-CoV-2 pneumonia.

[Interobserver variability study for daily cone beam computed tomography registration of prostate volumetric modulated arc therapy]. / Tomographie conique quotidienne pour les traitements pelviens et prostatiques: étude interobservateurs.

PURPOSE: This work evaluated the interobserver variability in cone beam computed tomography (CBCT) registration for prostate cancers treated with intensity-modulated radiotherapy. MATERIAL AND METHODS: Twelve technologists realized 286 CBCT/CT registrations (bone registration followed by prostate to prostate registration). The registration results were compared to those obtained by two radiation oncologists (reference). Each technologist reported the shifts calculated by the software in all three axes. A statistical analysis allowed us to calculate the minimum threshold under which 95% of the observers found similar values. A variance analysis followed by the post hoc test were used to find differences in interobserver registration variability and determine whether any individual users performed registrations which differed significantly from those of the other users. RESULTS: The registration differences compared to the reference in the three directions in terms of 95th percentile are: 2.1mm left-right, 3.5mm target-gun, 7.3mm anterior-posterior. In the posterior direction, 4% of the observers have found differences superior to 8mm, margin used in routine without the use of a daily CBCT. The variance test revealed a P-value <0.05 only for target-gun and for all observers there was no significant difference compared to the reference. CONCLUSION: This study confirmed the interest of a 3D tissue registration for prostate treatments. The registration study showed a good interobserver reproducibility. This showed the importance of a daily CBCT/CT registration in prostate treatment with the possibility of a planning target volume margin reduction in the three directions. An evaluation of a partial delegation of registration to technologists should be done by the radiation oncologists.

Differential expression of growth factors in irradiated mouse testes.

PURPOSE: By using as an experimental model the male mouse gonad, which contains both radiosensitive (germ) and radioresistant (somatic) cells, we have studied the growth factor (and/or receptor) expression of transforming growth factor-beta receptor (TGFbeta RI), stem cell factor (SCF), c-kit, Fas-L, Fas, tumor necrosis factor receptor (TNF R55), and leukemia inhibiting factor receptor (LIF-R) after local irradiation. METHODS AND MATERIALS: Adult male mice were locally irradiated on the testes. Induction of apoptosis in the different testicular cell types following X-ray radiation was identified by the TdT-mediated dUTP Nick End Labeling (TUNEL) approach. Growth factor expression was evidenced by semiquantitative RT-PCR and Western blot analyses. RESULTS: Apoptosis, identified through the TUNEL approach, occurred in radiosensitive testicular (premeotic) germ cells with the following kinetics: the number of apoptotic cells increased after 24 h (p < 0.001) and was maximal 48 h after a 2-Gy ionizing radiation (p < 0.001). Apoptotic cells were no longer observed 72 h after a 2-Gy irradiation. The number of apoptotic cells increased with the dose of irradiation (1-4 Gy). In the seminiferous tubules, the growth factor expression in premeiotic radiosensitive germ cells was modulated by irradiation. Indeed Fas, c-kit, and LIF-R expression, which occurs in (radiosensitive) germ cells, decreased 24 h after a 2-Gy irradiation, and the maximal decrease was observed with a 4-Gy irradiation. The decrease in Stra8 expression occurred earlier, at 4 h after a 2-Gy irradiation. In addition, a significant (p < 0.03) decrease in Stra8 mRNA levels was observed at the lowest dose used (0.5 Gy, 48 h). Moreover, concerning a growth factor receptor, such as TGFbeta RI, which is expressed both in radiosensitive and radioresistant cells, we observed a differential expression depending on the cell radiosensitivity after irradiation. Indeed, TGFbeta RI expression was increased after irradiation in interstitial radioresistant testicular cells in a dose- and time-dependent manner, while it decreased in seminiferous radiosensitive (germ cells) testicular cells. Such a differential expression between radioresistant and radiosensitive cells in TGFbeta RI levels was observed in terms of both mRNA and protein. In contrast, the growth factors specifically expressed in the somatic radioresistant (Sertoli) cells in the seminiferous tubules (SCF, Fas-L, TNF R55) were not affected by ionizing radiation (up to 4 Gy, 72 h). CONCLUSION: Growth factor expression decreased in the radiosensitive testicular cells after irradiation. Such a decrease occurred before the detection of apoptosis using the TUNEL approach. TGFbeta RI mRNA levels decreased in the radiosensitive cells, whereas it increased in the radioresistant cells, suggesting that TGFbeta RI may represent a biomarker of the intrinsic radiosensitivity of cells.

Three-dimensional conformal radiotherapy for paranasal sinus carcinoma: clinical results for 25 patients.

PURPOSE: To assess local control, survival, and clinical and dosimetric prognostic factors in 25 patients with locally advanced maxillary or ethmoid sinus carcinoma treated by three-dimensional conformal radiotherapy (RT). MATERIALS AND METHODS: Surgery was performed in 22 patients and was macroscopically complete in 16. Seven patients received chemotherapy (concomitant with RT in four). The following quality indexes were defined for the 95% and 90% isodoses: tumor conformity index, normal tissue conformity index, and global conformity index. RESULTS: The median radiation dose to the planned treatment volume was 63 Gy, with a minimal dose of 60 Gy, except in 2 patients whose cancer progressed during RT. The maximal doses tolerated by the structures involved in vision were respected, except for tumors that involved the optic nerve. After a median follow-up of 25 months, 14 local tumor recurrences developed. The major prognostic factors were central nervous system involvement by disease and the presence of nonresectable tumors. The radiation dose and tumor conformity index value were not significant prognostic indicators. Two patients died of acute infectious toxicity, and two developed late ipsilateral ocular toxicity. CONCLUSIONS: Improving local control remains the main challenge in RT for paranasal tumors.

[Cancer of the testis: role of radiotherapy in 2003]. / Cancer du testicule: place de la radiothérapie en 2003.

Germ-cell tumors of the testis are rare tumors of the young adult. Half of them are seminoma. The majority of patients have disease limited to the testis. Radiotherapy still remains the standard treatment of these patients. Almost all patients are cured by orchidectomy and radiotherapy on the lomboaortic area extended to homolateral iliac area. The dose is 24 to 30 Gy in a standard fractionation. Different studies are ongoing to reduce the irradiation field (omission of the pelvic irradiation), to decrease irradiation dose (to 20 Gy). Other treatment options are strict surveillance and adjuvant carboplatin based chemotherapy. None of these options are standard treatments. A strict attention must be directed on controlateral germ-cell tumors and second cancers.

[Respiration-gated radiotherapy: current techniques and potential benefits]. / La radiothérapie asservie à la respiration: techniques actuelles et bénéfices attendus.

Respiration-gated radiotherapy offers a significant potential for improvement in the irradiation of tumor sites affected by respiratory motion such as lung, breast and liver tumors. An increased conformality of irradiation fields leading to decreased complications rates of organs at risk (lung, heart...) is expected. Respiratory gating is in line with the need for improved precision required by radiotherapy techniques such as 3D conformal radiotherapy or intensity modulated radiotherapy. Reduction of respiratory motion can be achieved by using either breath hold techniques or respiration synchronized gating techniques. Breathhold techniques can be achieved with active, in which airflow of the patient is temporarily blocked by a valve, or passive techniques, in which the patient voluntarily breath-hold. Synchronized gating techniques use external devices to predict the phase of the respiration cycle while the patient breaths freely. These techniques presently investigated in several medical centers worldwide. Although promising, the first results obtained in lung and liver cancer patients require confirmation. Physical, technical and physiological questions still remain to be answered. This paper describes the most frequently used gated techniques and the main published clinical reports on the use of respiration-gated radiotherapy in order to evaluate the impact of these techniques.

Curative external beam radiotherapy for prostate carcinoma: results in 231 patients treated in Lyon.

BACKGROUND: Radical prostatectomy and external beam radiation therapy (EBRT) are the mainstays of treatment of prostate cancer with curative intent. The possible development of radiation proctitis and rectal bleeding are major concerns when using EBRT. Recently, conformal radiotherapy has been introduced in an attempt to improve the results of EBRT. This paper presents an overview of the Lyon experience using standard EBRT with doses of 68 Gy, and reports the preliminary results of a study of conformal radiotherapy with dose escalation. METHODS: From 1981 to 1995, EBRT was used to treat 231 patients with localized adenocarcinomas of the prostate. The dose of EBRT was 68 Gy/34 fractions/7 weeks using a four-field box technique with 18-MeV photons. A feasibility study of conformal radiotherapy was commenced in 1996. To date, 145 patients have been treated with doses escalating from 68 to 80 Gy. RESULTS: In the EBRT group of 231 patients, the 5-year overall survival was 80.3%. Anorectal function was scored as excellent in 90% of patients. Rectal bleeding was seen in 14.3% of patients and required local treatment in only seven. In the group treated with conformal radiotherapy, the preliminary results indicate good early tolerance. CONCLUSION: The curative treatment of patients with prostate cancer using EBRT gives good long-term survival with low rectal toxicity. Conformal radiotherapy appears to be an interesting approach to improve local control and perhaps survival.