[Predictive assays for responses of tumors and normal tissues in radiation oncology]. / Outils pour la prédiction de la réponse tumorale et des tissus sains en oncologie radiothérapie.

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the target volume. Tumor sensitivity to radiotherapy may be particularly inconstant depending on location, histology, somatic genetic parameters and the capacity of the immune system to infiltrate the tumor. In addition, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. In a same population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists, namely in terms of late side effects that are in principle non-reversible. This review details the different radiobiological approaches that have been developed to better predict the tumor response but also the radiation-induced late effects.

[Individual modification of the dose, volume and fractionation of breast radiotherapy]. / Personnalisation de la dose, du volume et du fractionnement de la radiothérapie du sein.

Randomized trials demonstrated similar overall survival between mastectomy and breast-conservative surgery followed by adjuvant radiation therapy. Breast-conservative surgery, with adjuvant radiation therapy, with or without neoadjuvant systemic therapy has become the standard of care for women with early or locally advanced breast cancer. Nevertheless, certain cardiac, lung or cutaneous toxicities may alter the long-term body image and the quality of life of a limited number of patients who consider having had "overtreatment" or treatment outside the best knowledge of science. In case of low-risk breast cancer, several trials have evaluated the carcinologic outcome in absence of radiation therapy after breast-conservative surgery. Local recurrences increased in case of breast-conservative surgery alone but without impact on overall survival. Multiple debates have emerged in order to select the most appropriate evaluation criteria. Finally, a large consensus has considered that reducing local recurrences is important but with modern technologies and after identifying patients of individual radiosensitivity. Indeed, in case of a low absolute risk of local recurrence, radiation therapy techniques have been developed to allow a focal treatment especially for patients with high risk of developing late effects. This kind of compromise takes into account the reduction risk of local recurrences but also the probability of developing radiation-induced cutaneous sequelae. In the same way, for patients considered at high risk of recurrence, the huge volumes need specific techniques to better cover the targets while protecting the surrounding critic organs such as heart and lung. Intensity-modulated radiation therapy and the local high boost may help to decrease local recurrences of these more extended and aggressive diseases while considering the individual radiosensitivity that paves the way of long-term sequelae. In this article, we detail a personalized approach of breast radiation therapy considering the absolute risk of local recurrences and the probability of radiation-induced toxicity appearance.

Early MRI predictors of disease-free survival in locally advanced rectal cancer from the GRECCAR 4 trial.

BACKGROUND: Tailored neoadjuvant treatment of locally advanced rectal cancer (LARC) may improve outcomes. The aim of this study was to determine early MRI prognostic parameters with which to stratify neoadjuvant treatment in patients with LARC. METHODS: All patients from a prospective, phase II, multicentre randomized study (GRECCAR4; NCT01333709) were included, and underwent rectal MRI before treatment, 4 weeks after induction chemotherapy and after completion of chemoradiotherapy (CRT). Tumour volumetry, MRI tumour regression grade (mrTRG), T and N categories, circumferential resection margin (CRM) status and extramural vascular invasion identified by MRI (mrEMVI) were evaluated. RESULTS: A total of 133 randomized patients were analysed. Median follow-up was 41·4 (95 per cent c.i. 36·6 to 45·2) months. Thirty-one patients (23·3 per cent) developed tumour recurrence. In univariable analysis, mrEMVI at baseline was the only prognostic factor associated with poorer outcome (P = 0·015). After induction chemotherapy, a larger tumour volume on MRI (P = 0·019), tumour volume regression of 60 per cent or less (P = 0·002), involvement of the CRM (P = 0·037), mrEMVI (P = 0·026) and a poor mrTRG (P = 0·023) were associated with poor outcome. After completion of CRT, the absence of complete response on MRI (P = 0·004), mrEMVI (P = 0·038) and a poor mrTRG (P = 0·005) were associated with shorter disease-free survival. A final multivariable model including all significant variables (baseline, after induction, after CRT) revealed that Eastern Cooperative Oncology Group performance status (P = 0·011), sphincter involvement (P = 0·009), mrEMVI at baseline (P = 0·002) and early tumour volume regression of 60 per cent or less after induction (P = 0·007) were associated with relapse. CONCLUSION: Baseline and early post-treatment MRI parameters are associated with prognosis in LARC. Future preoperative treatment should stratify treatment according to baseline mrEMVI status and early tumour volume regression.

ANTECEDENTES: El tratamiento neoadyuvante personalizado del cáncer de recto localmente avanzado (locally advanced rectal cancer, LARC) puede mejorar los resultados. El objetivo de este estudio fue determinar factores pronósticos precoces mediante RMN para estratificar el tratamiento neoadyuvante en pacientes con LARC. MÉTODOS: Todos los pacientes de un eensayo prospectivo de fase II, multicéntrico y aleatorizado (GRECCAR4-NCT01333709) se incluyeron en este estudio y se les realizó una RMN antes del tratamiento, 4 semanas después de la quimioterapia de inducción y después de completar la quimiorradioterapia (chemoradiation, CRT). Se evaluó la volumetría tumoral, el grado de regresión tumoral mediante RMN (MRI Tumor Regression Grade, mrTRG), la estadificación T, la estadificación N, el estado del margen de resección circunferencial (circumferential resection margin, CRM) y la presencia de invasión extramural vascular en la RMN (extramural vascular invasion, mrEMVI). RESULTADOS: Se analizaron 133 pacientes aleatorizados. La mediana de seguimiento fue de 41,4 meses (i.c. del 95%: 36,6-45,2). En 31 pacientes (23%) se diagnosticó una recidiva. En el análisis univariado de la situación basal, mrEMVI fue el único factor pronóstico asociado con un peor resultado (P = 0,0152). Después de la quimioterapia de inducción, un volumen tumoral más alto en la RMN (P = 0,019), una regresión del volumen tumoral ≤ 60% (P = 0,002), la afectación del CRM (P = 0,037), mrEMVI (P = 0,026) y un grado escaso mrTRG (P = 0,023) se asociaron con un mal resultado. Después de completar la CRT, la ausencia de respuesta completa en la RMN (P = 0,004), la presencia de mrEMVI (P = 0,04) y una insuficiente mrTRG (P = 0,005) se asociaron con una supervivencia libre de enfermedad más corta. En el modelo multivariable final en el que se incluyeron todas las variables significativas (basales, postinducción, post-CRT), el estado de ECOG (P = 0,011), la afectación esfinteriana (P = 0,009), la presencia de EMVI al inicio (P = 0,002) y una regresión precoz del volumen tumoral ≤ 60% después de la inducción (P = 0,007) se asociaron con una recidiva. CONCLUSIÓN: Los parámetros basales y post-tratamiento precoces de la RMN se asocian con el pronóstico en el LARC. La estrategia terapéutica preoperatoria futura deberá estratificar el tratamiento de acuerdo con la presencia de EMVI al inicio y la regresión precoz del volumen tumoral.

Prospective medical analysis of radiation therapist image repositioning during image-guided radiotherapy.

PURPOSE: Radiation oncologists are responsible for deciding which day-to-day variations are acceptable or not in the treatment setup. However, properly qualified and trained radiation therapists might be capable to perform image registration. We evaluated in our centre the capability and accuracy of radiation therapists to validate positioning images in a prospective study. METHODS AND PATIENTS: A total of 84 patients treated for prostate, head and neck, lung or breast cancer was prospectively and randomly included from July 2011 to July 2013 in radiotherapy unit of our institution. For each patient, three positioning images were randomly analysed. Two radiation oncologists analysed all positioning images and shifts decided by the radiation therapists in an independent and blinded way. The radiation oncologists had to decide whether to validate or not this shift and give a corresponding additional shift, if any. A theoretical disagreement rate less than 5% between radiation therapists and radiation oncologists was planned. RESULTS: A total of 240 images were analysed (head and neck: 15.0%; prostate: 14.2%; breast: 55.0%; lung: 15.8%). The global disagreement between radiation oncologists and radiation therapists for all the images analysed was 2.5% 95% confidence interval (95% CI) [1.0-5.0], corresponding to six images out of 240. A 100% agreement was reached for prostate and lung images, a 97.2% agreement for head and neck images and a 96.2% agreement for breast images. CONCLUSIONS: The radiation therapist validation for repositioning images seemed accurate for image-guided radiotherapy in our institution. Periodic evaluation and in-house training are warranted when routine delegation of image registration to radiation therapists is considered.