Tomothérapie hélicoïdale : aspects techniques et applications cliniques

Helical tomotherapy is an innovative device combining with the same linac on board-imaging and IMRT facilities. The first national French evaluations, supported by National Institut of Cancer (INCa) are presented. Dosimetric characteristics as quality of homogeneity, cut-off outside target volumes allow IMRT treatments for large andcomplex volumes and a good organ at risk sparing. First comparative dosimetric studies are discussed.     

Indications potentielles de la tomothérapie hélicoïdale dans les cancers du sein

PurposeTo evaluate the dosimetric gain obtained in either the planning target volume or organs at risk coverage by the use of intensity-modulated radiation therapy in some particular postoperative breast cancers.Patients and methodProspective dosimetric comparison between monoisocentric conformal radiotherapy and intensity-modulated radiation therapy in nine patient files.ResultsUsing intensity-modulated radiation therapy was shown to improve in each case, at least one conformity, homogeneity, and coverage index either for planning target volumes or for organs at risk. Intensity-modulated radiation therapy was therefore always chosen rather than conformal monoisocentric radiotherapy.ConclusionsIndications to retain intensity-modulated radiation therapy would consist of bilateral lesions, pectus excavatum, past thoracic irradiation (Hodgkin's disease) and complex volumes in obese or overweight patients.     

Adénocarcinomes du bas œsophage et du cardia: quelle chimiothérapie ou chimioradiothérapie dans le traitement des récidives et des métastases?

Adenocarcinomas of esophagus and cardia represent in France approximately 20 to 40% of the esophagus cancers. They have a high risk to develop lymph nodes metastases and liver metastases. Currently, only 50 to 70% of patients may benefit from surgical curative resection at diagnosis, but more than 50% of them will recur. The standard of treatment of these metastatic adenocarcinomas is chemotherapy. Three large randomized comparative studies, between chemotherapy and supportive care, showed that chemotherapy significantly extends the median of survival (from 3–4 months to 10–12 months) and improves the quality of life. Currently, the combination of epirubicin-cisplatin-continuous 5FU (ECF) is the most effective regimen but it is difficult to administer and tolerate because of the long continuous 5FU infusion. In France, the most commonly used combination regimen still associates 5FU and cisplatin. New drugs (such as docetaxel, CPT11, oxaliplatin) used alone or in combination, especially with 5U, are very promising. Radio-chemotherapy is the preferred treatment for locoregional recurrences, because it improves dyphagia and enables to obtain complete tumor responses. Current results from concomitant radio-chemotherapy studies for esophagus cancer, based on 5FU alone, 5FU-cisplatin or 5FU-mitomycin, given as preoperative treatment or as exclusive treatment, support to use radio-chemotherapy for the treatment of loco-regional recurrences after surgical resection. Nevertheless, the optimal radio-chemotherapy schedule still remain to be defined (dose, duration, splitting of radiotherapy, choice of anticancer drugs).     

Résultats préliminaires d’une tomothérapie hélicoïdale adjuvante avec boost intégré dans le cadre d’un traitement conservateur d’un cancer du sein

PurposeTo evaluate the dosimetry and acute toxicity of helical tomotherapy for locoregional irradiation of patients after breast-conserving surgery.Patients and methodsTwenty breast cancer patients with breast-conserving surgery treated by helical tomotherapy have been studied. The median age was 49 (min: 25, max: 69). The whole breast, tumour bed and lymph nodes were prescribed 52.2 Gy, 63.8 Gy and 50.4 Gy, all in 29 fractions. The dose per fraction was 2.2 Gy to the boost, 1.8 Gy to the breast and 1.74 Gy to the lymph node volumes. The reproducibility was analysed by recording the daily shifts in x, y and z directions and roll rotation. All toxicities were described using the Common Terminology Criteria for Adverse Effects v3.0.ResultsTwenty-two tumours were irradiated. Six-eight percent were located in the inner quadrant. In 90 % of patients supraclavicular and internal mammary nodes were treated. The coverage of planning target volumes (PTV) was as follows: PTV boost: V₁₀₇ = 0.3 % ± 0.5 SD, V₉₅ = 98.4 % ± 1.9 SD; PTV breast: −V₁₀₇ = 7.8 % ± 17.3 SD, V₉₅ = 96.8 % ± 2.2 SD; PTV LN: V₁₀₇ = 2.5 % ± 4.2 SD, V₉₅ = 92.7 % ± 13.2 SD. The mean V20 of the homolateral lung was 18.9 % ± 3.5 SD. For left side lesion, the mean V30 of the heart was 0.9 % ± 0.8 SD. The mean V5 was: V5 homolateral lung: 73.1 % ± 11.8 ET, controlateral lung: 38.9 % ± 21, heart (left side breast): 57.3 % ± 21, controlateral breast: 15.5 % ± 9.6. Median shifts were as follow: x-axis –0.04 mm (IC 95: –0.4 +0.38), y-axis –0.37 mm ± 5.51 (IC 95: –0.88 +0.14), z-axis 2.90 mm ± 5.42 (IC 95: + 2.4 + 3.4) and roll rotation 0.22 ± 1.10 (IC 95: –0.1 + 0.32). The treatment tolerance was acceptable with 1 definitive interruption couple of fractions before the end and 3 temporal interruptions for skin toxicity. No grade 3 or 4 toxicity. Ninety-five percent of patients experienced skin toxicity: 45 % grade 2. There were 3 cases of oesophagitis. The median follow-up of presented series is 9.7 months and all of the patients are free of disease without any residual early or late toxicity.ConclusionsHelical tomotherapy can achieve full target coverage while protected to the heart and ipsilateral lung. This treatment was well tolerated and reproducible. However, the low doses to normal tissue volumes need to be reduced in future studies.     

Techniques d’irradiation mammaire complexe : radiothérapie conformationelle tridimensionnelle mono-isocentrique et nomothérapie hélicoïdale

Purpose

To evaluate the dosimetric contribution of helical tomotherapy for breast cancers compared with conformal radiotherapy in mono-isocentric technique.

Radiothérapie stéréotaxique et radiofréquence dans le traitement du cancer bronchopulmonaire

Surgery is the standard treatment of early-stage non-small cell lung cancer (NSCLC). However, all patients do not undergo radical resection because of the very frequent co-morbidities occurring in smokers. Recently, new therapeutic options have emerged for limited-size (less than 4 cm) NSCLC tumors. Stereotactic radiotherapy consists of the use of multiple radiation micro-beams, allowing high doses of radiation to be delivered to the tumor in a small number of fractions. Radiofrequency ablation delivers high frequency electromagnetic waves through a needle-like probe, that produces ionic agitation, increase of the temperature in the tumor tissue, and ultimately leads to coagulation necrosis of the tumor. Several studies have been reported, that show the efficacy of these treatment modalities to control stage I/II NSCLC in medically inoperable patients. Local control rates are consistently reported to be above 90 %. Stereotactic radiation therapy and radiofrequency ablation are now being evaluated prospectively; namely, stereotactic radiotherapy is being compared to surgery in operable patients in several randomized trials. Overall, from a technical concept to the availability of specific treatment devices and the publication of clinical results, stereotactic radiotherapy and radiofrequency ablation are paradigms of implementation in thoracic oncology.     

Bénéfices de la radiothérapie avec asservissement respiratoire dans le traitement du cancer du sein

PurposeThe purpose of this study was to compare free-breathing radiotherapy, end-expiration gating and end-inspiration gating for left breast cancer, with respect to the target volume coverage and dose to organs at risk.Patients and methodsSixteen patients underwent 3D and 4D simulation CT. For each patient, five dosimetric plans were compared: free breathing, end-inspiration gating, end-expiration gating, and two optimised plans with a 3 mm reduction of the posterior field edge to create optimised end-inspiration and end-expiration plans. Dose–volume parameters, including planning target volume coverage and dose to lung, heart and left anterior descending coronary artery were analysed.ResultsPlanning target volume coverage was adequate and similar in the five dosimetric plans (P = 0.49). Significant advantage was found for end-inspiration gating in sparing the ipsilateral lung, heart and left anterior descending coronary artery compared to free-breathing 3D radiotherapy. Optimised end-inspiration was even more favourable than end-inspiration gating (P < 0.05), with less dose delivered to the ipsilateral lung, heart and left anterior descending coronary artery. When compared to end-expiration gating, end-inspiration gating dosimetric outcomes were similar regarding lung and left anterior descending coronary artery doses, but the heart dose was inferior on the end-inspiration gating compared to end-expiration gating.ConclusionBreathing-adapted radiation therapy allowed for dose reduction to organs at risk (left lung, heart and left anterior descending coronary artery), while keeping the same planning target volume coverage. Therefore it can be considered as an interesting option for left breast cancer radiation treatment.     

Irradiation pelvienne et toxicité hématopoïétique : revue de la littérature

Pelvic bone marrow is the site of nearly 50% of total hematopoiesis. Radiation therapy of pelvic lymph node areas, and cancers located near the bony structures of the pelvis, exposes to hematological toxicity in the range of 30 to 70%. This toxicity depends on many factors, including the presence or absence of concomitant chemotherapy and its type, the volume of irradiated bone, the received doses, or the initial hematopoietic reserve. Intensity modulated radiation therapy allows the optimisation of dose deposit on at risk organs while providing optimal coverage of target volumes. However, this suggests that dose constraints should be known precisely to limit the incidence of radiation side effects. This literature review focuses firstly on pelvic lymph node areas and bony volumes nearby, then on the effects of irradiation on bone marrow and the current dosimetric constraints resulting from it, and finally on hematological toxicities by carcinologic location and progress in reducing these toxicities.     

Séquelles esthétiques de la radiothérapie adjuvante dans le traitement conservateur du cancer du sein localisé

Radiotherapy after breast-conserving therapy for early breast cancer is reported to adversely affect the cosmetic outcome. The incidence of radiation-induced fibroatrophy is around 10% at 5 years. A better knowledge of its pathophysiology has revealed the essential role of activated fibroblasts and reactive oxygen species, mediated by TGF beta 1, allowing the development of antioxidant in the management of the established radiation-induced fibroatrophy. Cosmetic sequelae are evaluated with standardized scales, such as the LENT-SOMA and must be monitored during at least 5 years. The main factors determining the occurrence of sequelae are a large breast volume, dose heterogeneity and the use of tumour bed boost after whole-breast radiation therapy. Intensity modulated radiotherapy and partial breast irradiation position themselves as a good alternatives to reduce the incidence of late skin side effects. The use of predictive tests of intrinsic radiosensitivity might fit into the therapeutic strategy.     

TEP et radiothérapie stéréotaxique pulmonaire : rôles dans la préparation du traitement et le suivi de la maladie

Stereotactic body radiation therapy is the standard treatment for inoperable patients with early-stage lung cancer. Local control rates range from 80 to 90 % 2 years after treatment. The role of positron emission tomography in patient selection is well known, but its use for target definition or therapeutic response evaluation is less clear. We reviewed the literature in order to assess the current state of knowledge in this area.     

Apport de la RCMI rotationnelle et de la tomothérapie hélicoïdale dans les cancers pelviens : étude dosimétrique prospective sur 51 patients

PurposeTo compare the dosimetric results of different techniques of dynamic intensity modulated radiation therapy (IMRT) in patients treated for a pelvic cancer with nodal irradiation.Patients and methodsData of 51 patients included prospectively in the Artpelvis study were analyzed. Thirty-six patients were treated for a high-risk prostate cancer (13 with helical tomotherapy, and 23 with Rapid’Arc^®) and 15 patients were treated for a localized anal cancer (nine with helical tomotherapy and six with Rapid’Arc^®). Plan quality was assessed according to several different dosimetric indexes of coverage of planning target volume and sparing of organs at risk.ResultsAlthough some dosimetric differences were statistically significant, helical tomotherapy and Rapid’Arc provided very similar and highly conformal plans. Regarding organs at risk, Rapid’Arc^® provided better pelvic bone sparing with a lower non-tumoral integral dose.ConclusionIn pelvis cancer with nodal irradiation, Rapid’Arc and helical tomotherapy provided very similar plans. The clinical evaluation of Artpelvis study will verify this equivalence hypothesis.     

Étude prospective monocentrique de la toxicité et de l’efficacité du trastuzumab concomitant à la radiothérapie

PurposeProspective monocentric study of the toxicities related to concurrent administration of trastuzumab to breast radiotherapy.Patients and methodsOne hundred and seventy-three patients were treated between June 2003 and March 2009 by concurrent trastuzumab with normofractionated radiotherapy. Trastuzumab was delivered every 3 weeks (8 mg/kg in the first infusion then 6 mg/kg) during a median time of 12 months (2–62). Left ventricular ejection fraction was assessed by echocardiography or cardiac scintigraphy at baseline, before and after radiotherapy, every 3 months for 1 year and annually. A left ventricular ejection fraction strictly lower than 55% was considered as altered. All toxicities were evaluated using Common Terminology Criteria for Adverse Effects version 3.0.ResultsMedian follow-up was 52 months (17–88). Median age was 52 years (25–83). One hundred and thirty-four patients (77.5%) received radiotherapy to the internal mammary chain. Acute grade 1, 2 and 3 epithelitis was described in 132 (76.3%), 32 (18.5%) and six patients (3.4%), respectively. At 23 months, grade 1 and 2 fibrosis was observed in 31 and eight patients, respectively (18.8 and 4.6%). Left ventricular ejection fraction remained normal for 159 patients (91.9%) before radiotherapy. Among them, 18 (11.3%) experienced a left ventricular ejection fraction alteration, eight (5.0%) at the completion of radiotherapy. Congestive heart failure occurred in one patient (0.6%).ConclusionsToxicities related to the association of trastuzumab to breast radiotherapy were mild. Further follow-up is warranted.