[Radiotherapy and spinal toxicity: News and perspectives]. / Radiothérapie et toxicité médullaire : actualités et perspectives.

Radiation-induced myelopathy is a devastating late effect of radiotherapy. Fortunately, this late effect is exceptional. The clinical presentation of radiation myelopathy is aspecific, typically occurring between 6 to 24 months after radiotherapy, and radiation-induced myelopathy remains a diagnosis of exclusion. Magnetic resonance imaging is the most commonly used imaging tool. Radiation oncologists must be extremely cautious to the spinal cord dose, particularly in stereotactic radiotherapy and reirradiation. Conventionally, a maximum dose of 50Gy is tolerated in normofractionated radiotherapy (1.8 to 2Gy per fraction). Repeat radiotherapies lead to consider cumulative doses above this recommendation to offer individualized reirradiation. Several factors increase the risk of radiation-induced myelopathy, such as concomitant or neurotoxic chemotherapy. The development of predictive algorithms to prevent the risk of radiation-induced myelopathy is promising. However, radiotherapy prescription should be cautious, regarding to ALARA principle (as low as reasonably achievable). As the advent of immunotherapy has improved patient survival data and the concept of oligometastatic cancer is increasing in daily practice, stereotactic treatments and reirradiations will be increasingly frequent indications. Predict the risk of radiation-induced myelopathy is therefore a major issue in the following years, and remains a daily challenge for radiation oncologists.

Brachytherapy boost (BT-boost) or stereotactic body radiation therapy boost (SBRT-boost) for high-risk prostate cancer (HR-PCa).

Systematic review for the treatment of high-risk prostate cancer (HR-PCa, D'Amico classification risk system) with external body radiation therapy (EBRT)+brachytherapy-boost (BT-boost) or with EBRT+stereotactic body RT-boost (SBRT-boost). In March 2020, 391 English citations on PubMed matched with search terms "high risk prostate cancer boost". Respectively 9 and 48 prospective and retrospective studies were on BT-boost and 7 retrospective studies were on SBRT-boost. Two SBRT-boost trials were prospective. Only one study (ASCENDE-RT) directly compared the gold standard treatment [dose-escalation (DE)-EBRT+androgen deprivation treatment (ADT)] versus EBRT+ADT+BT-boost. Biochemical control rates at 9 years were 83% in the experimental arm versus 63% in the standard arm. Cumulative incidence of late grade 3 urinary toxicity in the experimental arm and in the standard arm was respectively 18% and 5%. Two recent studies with HR-PCa (National Cancer Database) demonstrated better overall survival with BT-boost (low dose rate LDR or high dose rate HDR) compared with DE-EBRT. These recent findings demonstrate the superiority of EBRT+BT-boost+ADT versus DE-EBRT+ADT for HR-PCa. It seems that EBRT+BT-boost+ADT could now be considered as a gold standard treatment for HR-PCa. HDR or LDR are options. SBRT-boost represents an attractive alternative, but the absence of randomised trials does not allow us to conclude for HR-PCa. Prospective randomised international phase III trials or meta-analyses could improve the level of evidence of SBRT-boost for HR-PCa.

[Prognosis factors after lung stereotactic body radiotherapy for non-small cell lung carcinoma]. / Facteurs de récidive après radiothérapie stéréotaxique des cancers bronchiques non à petites cellules.

Lung cancer is the fourth most common cancer in France with a prevalence of 30,000 new cases per year. Lobectomy surgery with dissection is the gold standard treatment for T1-T2 localized non-small cell lung carcinoma. A segmentectomy may be proposed to operable patients but fragile from a respiratory point of view. For inoperable patients or patients with unsatisfactory pulmonary function tests, local treatment with stereotactic radiotherapy may be proposed to achieve local control rates ranging from 85 to 95% at 3-5 years. Several studies have examined prognostic factors after stereotaxic pulmonary radiotherapy. We conducted a general review of the literature to identify factors affecting local control.

[Treatment of primary disease with irradiation in case of de novo metastatic breast cancer]. / Irradiation de la tumeur primitive en cas de cancer du sein métastatique synchrone.

Synchronous metastatic breast cancer accounts for 5 to 6% of all breast cancers in Western countries, which corresponds to nearly 2500 new cases per year in France. Irradiation of the primary tumour in cases of metastatic disease at diagnosis was historically reserved for palliative indications. However, progress in systemic treatments, a better understanding of the biological basis of metastatic dissemination, the genesis of the concept of oligometastatic disease and ablative treatments directed towards metastases are revolutionizing the management of patients with de novo stage IV breast cancer. Survival of these patients has improved markedly over the years, and several studies have investigated the carcinological benefit of local treatment of the breast tumour in patients with advanced diseases at diagnosis. This article provides an update on the role of irradiation of the primary tumour in breast cancer with synchronous metastases, and discusses its interest through published or ongoing trials.

[Interest of image-guided radiotherapy for brain tumors and positioning control]. / Apport du guidage par l'image pour le repositionnement au cours de la radiothérapie des tumeurs encéphaliques.

A narrow therapeutic index and more and more patients with long survival characterize primary and second brain tumors. Image-guided radiotherapy can increase accuracy of the patient's position during a course of intracranial irradiation thanks to a direct or indirect visualization of targets volumes. Treatment reproducibility and organ at risk-sparing are the primary issues, particularly with the development of stereotactic radiotherapy and protontherapy. Regarding intracranial treatments, image-guided radiotherapy seems to be a repetitive task based on skeletal structures registration. And yet, this innovation makes possible to assess the dosimetric impact of daily positioning variations avoiding invasive immobilizations. Image-guided radiotherapy offers automated tools to limit time consumption and furthers adaptive radiotherapy opportunities. Nevertheless, medical evaluation is still necessary and image processing should be strictly defined (frequency, use, performance). The purpose of this article is to describe image-guidance in brain irradiation, as repositioning tool and to focus on its recent prospects.

[Doses to organs at risk for conformational and stereotactic radiotherapy: Bladder]. / Doses dans les organes à risque en radiothérapie conformationnelle et en radiothérapie en conditions stéréotaxiques : la vessie.

Bladder dose constraints in case of conformational radiotherapy/intensity-modulated radiotherapy and stereotactic radiotherapy are reported from the literature, in particular from the French radiotherapy society RECORAD recommendations, according to the treated pelvic tumor sites. The dose-volume effect on urinary toxicity is not clearly demonstrated, making difficult to establish absolute dose constraints for the bladder. In case of high-dose prostate cancer radiotherapy, the bladder dose constraints are: V60Gy<50% and maximum dose<80Gy for standard fractionation and V60Gy<5%, V48Gy<25% and V41Gy<50% for moderate hypofractionation (20 fractions of 3Gy). In case of prostate stereotactic radiotherapy (five fractions of 7.25Gy), the most frequent dose constraints in the literature are V37Gy<10cm3 and V18Gy<40%. In case of conformational radiotherapy of cervix cancer, postoperative endometrium, anal canal and rectum, the recommendations are V40Gy<40% and D2% lower than the prescribed dose.

[Toxicity and quality of life comparison of iodine 125 brachytherapy and stereotactic radiotherapy for prostate cancers]. / Toxicité et qualité de vie comparées après curiethérapie par iode 125 et radiothérapie stéréotaxique des cancers prostatiques.

Quality of life is a major issue for good prognostic prostate cancer, for which brachytherapy is one of the reference treatments. Stereotactic Body Radiotherapy (SBRT) is a recent alternative however not yet validated as a standard treatment. This review of the literature reports and compares the toxicities and the quality of life, either after exclusive brachytherapy with iodine 125 or after SBRT. The comparison is made with the limitations of the absence of randomized trial comparing the two treatment techniques. Acute toxicity appears to be lower after SBRT compared to brachytherapy (from 10 to 40 % versus 30 to 40 %, respectively). Conversely, acute and late gastrointestinal toxicity (from 0 to 21 % and from 0 to 10 % of grade 2, respectively) appears more frequent with SBRT. Late urinary toxicity seems identical between both techniques (from 20 to 30 % of grade 2), with a possible urinary flare syndrome. Both treatments have an impact on erectile dysfunction, although it is not possible to conclude that a technique is superior because of the limited data on SBRT. SBRT has better bowel and urinary (irritation or obstruction) quality of life scores than brachytherapy; while sexual and urinary incontinence remain the same. The absence of randomized trial comparing SBRT with brachytherapy for prostate cancers does not allow to conclude on the superiority of one technique over another, thus justifying a phase III medicoeconomic evaluation.

[Intensity-modulated radiotherapy for head and neck cancer. Dose constraint for salivary gland and mandible]. / Radiothérapie conformationnelle avec modulation d'intensité des cancers des voies aérodigestives supérieures. Dose de tolérance des tissus sains : glandes salivaires et mandibule.

Intensity-modulated radiation therapy (IMRT) is the gold standard for head and neck irradiation. It allows better protection to the organs at risk such as salivary glands and mandible, and can reduce the frequency of xerostomia, trismus and osteoradionecrosis. At the time of treatment planning, the mean dose to a single parotid gland should be kept below 26Gy, the mean dose to a single submandibular gland below 39Gy, the mean dose to the mandible below 60 to 65Gy and the D2% to a single temporomandibular joint below 65Gy. These dose constraints could be further improved with data extracted from cohorts of patients receiving IMRT exclusively. The dose administered to the target volumes should not be lessened to spare the salivary glands or mandible.