[Proposal for the delineation of postoperative primary clinical target volumes in maxillary sinus and nasal cavity cancers]

In this article, we propose a consensus delineation of postoperative clinical target volumes for the primary tumour in maxillary sinus and nasal cavity cancers. These guidelines are developed based on radioanatomy and the natural history of those cancers. They require the fusion of the planning CT with preoperative imaging for accurate positioning of the initial GTV and the combined use of the geometric and anatomical concepts for the delineation of clinical target volume for the primary tumour. This article does not discuss the indications of external radiotherapy (nor concurrent systemic treatment) but focuses on target volumes when there is an indication for radiotherapy.

Radiotherapy for laryngeal cancers

We present the update of the recommendations of the French society of oncological radiotherapy on radiotherapy of laryngeal cancers. Intensity modulated radiotherapy is the standard of care radiotherapy for the management of laryngeal cancers. Early stage T1 or T2 tumours can be treated either by radiotherapy or conservative surgery. For tumours requiring total laryngectomy (T2 or T3), an organ preservation strategy by either induction chemotherapy followed by radiotherapy or chemoradiotherapy with cisplatin is recommended. For T4 tumours, a total laryngectomy followed by radiotherapy is recommended when feasible. Dose regimens for definitive and postoperative radiotherapy are detailed in this article, as well as the selection and delineation of tumour and lymph node target volumes.

Radiotherapy for hypopharynx cancers

We present the update of the recommendations of the French society of oncological radiotherapy on radiotherapy for hypopharynx. Intensity-modulated radiotherapy is the gold standard treatment for hypopharynx cancers. Early T1 and T2 tumors could be treated by exclusive radiotherapy or surgery followed by postoperative radiotherapy in case of high recurrence risk. For locally advanced tumours requiring total pharyngolaryngectomy (T2 or T3) or with significant lymph nodes involvement, induction chemotherapy followed by exclusive radiotherapy or concurrent chemoradiotherapy were possible. For T4 tumour, surgery must be proposed. The treatment of lymph nodes is based on initial primary tumour treatment. In non-surgical procedure, for 35 fractions, curative dose is 70Gy (2Gy per fraction) and prophylactic dose are 50 to 56Gy (2Gy per fraction in case of sequential radiotherapy or 1.6Gy in case of integrated simultaneous boost) radiotherapy; for 33 fractions, curative dose is 69.96Gy (2.12Gy per fraction) and prophylactic dose is 52.8Gy (1.6Gy per fraction in integrated simultaneous boost radiotherapy or 54Gy in 1.64Gy per fraction); for 30 fractions, curative dose is 66Gy (2.2Gy per fraction) and prophylactic dose is 54Gy (1.8Gy per fraction in integrated simultaneous boost radiotherapy). Doses over 2Gy per fraction could be done when chemotherapy is not used regarding potential larynx toxicity. Postoperatively, radiotherapy is used in locally advanced cancer with dose levels based on pathologic criteria, 60 to 66Gy for R1 resection and 54 to 60Gy for complete resection in bed tumour; 50 to 66Gy in lymph nodes areas regarding extracapsular spread. Volume delineation were based on guidelines cited in this article.

Delineation of organs at risk

The delineation of organs at risk is the basis of radiotherapy oncologists' work. Indeed, the knowledge of this delineation enables to better identify the target volumes and to optimize dose distribution, involving the prognosis of the patients but also their future. The learning of this delineation must continue throughout the clinician's career. Some contour changes have appeared with better imaging, some volumes are now required due to development of knowledge of side effects. In addition, the increasing survival time of patients requires to be more systematic and precise in the delineations, both to avoid complications until now exceptional but also because re-irradiations are becoming more and more frequent. We present the update of the recommendations of the French Society for Radiation Oncology (SFRO) on new findings or adaptations to volumes at risk.

Evaluation of a software for automatic delineation of the mammary gland and organs at risk in patients treated for breast cancer in lateral position

PURPOSE OF THE STUDY

The purpose of this study was to assess the potential for improvement of routine breast and organs at risk contouring in patients treated in the lateral decubitus position using Workflow Box™ (Mirada Medical™, UK) automatic contouring software.

MATERIALS AND METHODS

Automatic contouring of the breast by this software is currently based on an atlas created from isodoses representing 95% of the prescribed dose in a population of patients previously treated at institut Curie. Forty cases of breast cancer (20 right breasts and 20 left breasts) were contoured by three radiation oncologists specialized in breast cancer, allowing the creation of a new atlas in the automatic contouring software. This study assessed the quality of contouring in 20 patients (ten right breasts and ten left breasts) by comparing manual contouring performed by the expert radiation oncologists (reference) with those generated by the old and new atlases developed at Institut Curie. The accuracy of contouring was assessed by overlap volume and the associated standard deviations.

RESULTS

Breast contouring based on the new atlas and by radiation oncologists presented a mean overlap of 0.80±0.09 for the right breast and 0.81±0.06 for the left breast. By comparing volumes of interest contoured by radiation oncologists and those obtained from the old atlas, mean overlap volumes were 0.75±0.08 and 0.74±0.13 for the right and left breasts, respectively. Twenty cases (ten right breasts and ten left breasts) used to create the new atlas were also reprocessed by this same atlas in order to assess the quality of automatic contouring of the breast when the case was already known to the software. The mean overlap volume in this case was 0.84±0.08 for the right breast and 0.83±0.06 for the left breast. Finally, after automatic contouring of organs at risk by means of the new atlas, the mean overlap volume was 0.87±0.04 for the heart and 0.93 for each lung (±0.05 for the right lung and±0.04 for the left lung).

CONCLUSION

Workflow Box™ automatic contouring software, based on our new atlas provides reliable and clinically relevant organs at risk and breast contouring. The contours proposed by the software from the new atlas were better than those obtained with the previous atlas based on 95% isodoses obtained from old treatment plans. This software has therefore become more efficient, justifying its use in routine clinical practice for breast cancer contouring in patients treated in the lateral decubitus position. Investigations are currently underway to develop a fully automated process to ensure reliable, robust and operator-independent contouring and breast cancer treatment dosimetry in the lateral decubitus position. Promising preliminary results have already been obtained.

Institut Curie guidelines on breast target volume delineation for patients treated in lateral position

PURPOSE

To develop guidelines for and describe the delineation of breast for patients treated in lateral position and to transform this three-dimensional technique based on the virtual simulation to volume-based modern intensity-modulated irradiation technique.

MATERIAL AND METHODS

In our department, during the daily delineation, radiation oncologists specialized in breast cancer treatment sought consensus on the delineation of clinical treatment volume of the breast through dialogue based on cases. A radiation oncologist delineated clinical treatment volumes on CT scans of five to 20 patients, followed by a discussion and adaptation of the delineation between all radiation oncologists of the team. The consensus established between clinicians was discussed, corrected and improved. All patients were delineated in treatment position; skin markers were used to visualize the breast tissue after careful palpation.

RESULTS

Breast clinical treatment volume was situated and delineated between pectoral muscle and 5mm below the skin (dosimetric considerations), within the space outlined by skin markers, that showed the limits of the palpable breast tissue. In lateral position some vessels were very useful to define the limits as rami mammarii (from thoracica interna) for the internal one and thoracica lateralis for the external. This is the first atlas proposed for the delineation of the breast clinical treatment volumes for breast cancer using alternative technique of breast irradiation (lateral).

CONCLUSION

This atlas will be helpful for the volume definition in our daily practice of breast irradiation in lateral position and can open perspectives to develop also atlases for other alternative techniques as treatment in prone position.

[Impact of reconstructive or minimal invasive surgery on the assessment of current definitions of postoperative clinical target volume for head and neck cancers]

Advances in the reconstructive surgery and minimally invasive endonasal endoscopic surgery of head and neck is poorly evaluated in terms of their impact on radiotherapy planning and outcomes. These surgical advances have resulted in reduced morbidity with equivalent or better tumor control. In the absence of a recommendation on how to delineate target volumes in patients with flaps or to consider margins after endoscopic endonasal surgery, radiotherapy practices are inevitably heterogeneous. Efforts are needed to increase the therapeutic index of postoperative radiotherapy in these situations. We analysed the rare existing literature and outlined a preliminary basis for a recommendation. Strengthening of multidisciplinarity to accurately define target volumes in these complex and relatively new situations, and "delineation concertation meetings" between radiologists, surgeons and radiation oncologists could probably contribute to improved outcomes.

[Proposal for the selection and delineation of clinical target volumes for the radiotherapy of submandibular gland tumours]

This article provides a proposal for the selection and delineation of clinical target volumes for the treatment with radiation of submandibular glands tumours. This article does not deal with external radiotherapy indications but specifies the volumes to be treated if radiotherapy is chosen. High-risk and low-risk peritumoral clinical target volumes are described based on the probability of local tumoral spread. High-risk and low-risk clinical target volumes are illustrated on CT-scan slices. A proposal for the selection of nodal clinical target volumeis also proposed.

[Delineation of the primary tumour clinical target volumes and neck node levels selection of parotid cancers]

Salivary glands tumours are uncommon tumours showing a large diversity of histological types. This article presents a synthesis of patterns and paths of invasion of parotid glands tumours in order to propose an approach of the delineation of primary tumour clinical target volumes and of the selection of lymph nodes target volumes. This article does not discuss treatment indications but defines clinical target volumes to treat if radiotherapy is indicated. Postoperative situation being the most frequent, the delineation of primary tumour clinical target volume is based on an anatomical approach.

Harmonization of practices between radiotherapy centres in the Nord and Pas-de-Calais regions (France): A three-year evaluation

PURPOSE

The delineation of volumes of interest can be a source of significant interobserver variability. The purpose of this study was to improve the homogeneity of delineation between oncologist-radiotherapists in the territorial departments of Nord and Pas-de-Calais (France) through discussions of clinical cases and the adoption of common published reference documents.

MATERIALS AND METHODS

All eleven radiotherapy centres in the Nord and Pas-de-Calais departments of France participated. The localizations assessed to date included prostate, head and neck, breast and brain cancers. For each localization, the junior or senior physician(s) in charge of pathology delineated the volumes of interest according to their usual practices. Validated indices, including the Dice similarity coefficient, were used to quantify the delineation differences. The anonymized results were presented at two to three annual meetings. A second delineation of the clinical cases was then carried out to quantify homogenization. An evaluation of dosimetry practices was also conducted for prostate cancer. Wilcoxon assay matched data were used.

RESULTS

Our work showed either satisfactory delineation concordance after the initial assessment or improved delineation concordance. For prostate cancer, the Dice similarity coefficient values were greater than 0.6 initially in two of the three clinical cases. For head and neck cancers, a statistically significant improvement was observed for only one of the clinical target volumes. More than half of the Dice similarity coefficient values were greater than 0.6 in the first comparison. The study of clinical cases of breast cancer allowed a homogenization of the delineation of five of the six lymph node clinical target volumes. The dosimetry study of prostate cancer allowed for a homogenization of practices.

CONCLUSION

This work makes it possible to harmonize the delineation practices around validated standards. An extension to the entire Hauts-de-France region is planned.

[Siriade 2.0: An e-learning platform for radiation oncology contouring]

PURPOSE

In 2008, the French national society of radiation oncology (SFRO) and the association for radiation oncology continued education (AFCOR) created Siriade, an e-learning website dedicated to contouring.

MATERIAL AND METHODS

Between 2015 and 2017, this platform was updated using the latest digital online tools available. Two main sections were needed: a theoretical part and another section of online workshops.

RESULTS

Teaching courses are available as online commented videos, available on demand. The practical section of the website is an online contouring workshop that automatically generates a report quantifying the quality of the user's delineation compared with the experts'.

CONCLUSION

Siriade 2.0 is an innovating digital tool for radiation oncology initial and continuous education.

Contouring workload in adjuvant breast cancer radiotherapy

PURPOSE

To measure the impact of contouring on worktime in the adjuvant radiation treatment of breast cancer, and to identify factors that might affect the measurements.

MATERIAL AND METHODS

The dates and times of contouring clinical target volumes and organs at risk were recorded by a senior and by two junior radiation oncologists. Outcome measurements were contour times and the time from start to approval. The factors evaluated were patient age, type of surgery, radiation targets and setup, operator, planning station, part of the day and day of the week on which the contouring started. The Welch test was used to comparatively assess the measurements.

RESULTS

Two hundred and three cases were included in the analysis. The mean contour time per patient was 34minutes for a mean of 4.72 structures, with a mean of 7.1minutes per structure. The clinical target volume and organs at risk times did not differ significantly. The mean time from start to approval per patient was 29.4hours. Factors significantly associated with longer contour times were breast-conserving surgery (P=0.026), prone setup (P=0.002), junior operator (P<0.0001), Pinnacle planning station (P=0.026), contouring start in the morning (P=0.001), and contouring start by the end of the week (P<0.0001). Factors significantly associated with time from start to approval were age (P=0.038), junior operator (P<0.0001), planning station (P=0.016), and contouring start by the end of the week (P=0.004).

CONCLUSION

Contouring is a time-consuming process. Each delineated structure influences worktime, and many factors may be targeted for optimization of the workflow. These preliminary data will serve as basis for future prospective studies to determine how to establish a cost-effective solution.

[Anal canal cancer: In the era of intensity-modulated radiotherapy, outstanding issues]

Intensity-modulated radiotherapy makes possible to optimize the irradiation and spare normal tissues. The toxicity remains important with concomitant chemotherapy often associated. The improvement of MRI and PET-CT define more precisely the target volumes, which need a higher dose, but necessitates to respect the rules of contouring. The treatment is uniform whatever the stage but should be individualized based on clinical stage and tumor response. New paradigms concern biology, staging, volumes and doses, fractionation and combined treatments.

[Delineation of the surgical bed of operated brain metastases treated with adjuvant stereotactic irradiation: A review]

Stereotactic radiotherapy of the surgical bed of brain metastases is a technique that comes supplant indications of adjuvant whole brain radiotherapy after surgery. After a growing number of retrospective studies, a phase III trial has been presented and validated this indication. However, several criteria such as the dose, the fractionation, the use of a margin and definition of volumes remain to be defined. Our study consisted in making a literature review in order to provide a guideline of delineation of surgical beds of brain metastases, as well as the different modalities of their implementation process.

[Consequences of prosthesis on quality of the radiation therapy]

Dose prescription, delineation and dose calculation are clearly complicated when a patient have been operated on with insertion of prosthesis. Knowledge of the physical and material characteristics is needed to decrease incertitude of calculations. Recommendations for each step of treatments are proposed in this article allowing to optimization of the treatment safety.

[Prophylactic axillary radiotherapy for breast cancer]

Adjuvant radiotherapy, after breast conserving surgery or mastectomy for breast cancer, improves overall survival while decreasing the risk of recurrence. However, prophylactic postoperative radiotherapy of locoregional lymph nodes for breast cancer, particularly of the axillary region, is still controversial since the benefits and the risks due to axillary irradiation have not been well defined. To begin with, when performing conformal radiotherapy, volume definition is crucial for the analysis of the risk-benefit balance of any radiation treatment. Definition and contouring of the axillary lymph node region is discussed in this work, as per the recommendations of the European Society for Radiotherapy and Oncology (ESTRO). Axillary recurrences are rare, and the recent trend leads toward less aggressive surgery with regard to the axilla. In this literature review we present the data that lead us to avoid adjuvant axillary radiotherapy in pN0, pN0i+ and pN1mi patients even without axillary clearance and to perform it in some other situations. Finally, we propose an update about the potential toxicity of adjuvant axillary irradiation, which is essential for therapeutic decision-making based on current evidence, and to guide us in the evolution of our techniques and indications of axillary radiotherapy.

Interobserver variability of clinical target volume delineation in soft-tissue sarcomas

PURPOSE

The present observational study reports the results of a multi-institutional dummy-run designed to estimate the consistency of interobserver variability in clinical target volume delineation in two different cases of soft-tissue sarcomas in which postoperative and preoperative radiotherapy were prescribed, respectively. The purpose of this work was to quantify interobserver variability in routine clinical practice.

PATIENTS AND METHODS

Two different cases of soft-tissues sarcomas were chosen: a case of postoperative and a case of preoperative radiation therapy. Participating centres were requested to delineate clinical target volumes according to their experience in both cases. Descriptive statistic was calculated for each variable (volume, diameters) separately for two cases. Box-whiskers plots were used for presentation of clinical target volume. A Shapiro-Wilk's test was performed to evaluate the departures from normality distribution for each variable. The comparison between relative variations of diameters was evaluated using the Student's t test.

RESULTS

Several variations affecting both volumes and diameters were observed. Main variations were observed in the craniocaudal and laterolateral diameters. Each case showed similar dispersion, indicating a lack of reproducibility in volumes definition.

CONCLUSIONS

This observational study highlighted that, in the absence of specific instructions or guidelines, the interobserver variability can be significant both in postoperative and preoperative radiotherapy of soft-tissue sarcomas.

[Positron emission tomography for volume delineation of pelvic nodal involvement]

Radiotherapy planification has recently known important developments, with the rise of new technologies, such as conformational radiation therapy, intensity-modulated radiation therapy (IMRT) or stereotaxic radiation therapy. Delineation of target volumes has become primordial. Hybrid imaging by positron emission tomography associated to computed tomography scanner (PET-CT) gives an access to functional and morphological information. Radiotherapist and nuclear physicians working closely have the potential to allow a more optimal delineation, and a better preservation of organs at risk. During the past few years, this has been explored by many articles, and we propose a literature review organized by localization, about the use of PET-CT for pelvic nodes delineation.

[Guidelines for the delineation of the lymph nodes areas in gynecological malignancies]

Gynecological cancers are lymphophilic cancers, which require the systematic inclusion of nodal areas in the clinical target volume when irradiation is planned in the therapeutic strategy for these cancers. Radiotherapy with intensity modulation that achieves better saving of healthy tissue is more often used. However, the very steep dose gradients generated by this technique can lead to poorer coverage of target volumes if they are not defined very precisely by taking into account their anatomical location. This is particularly true for lymph node target volumes, so the purpose of this article is to present recommendations from a literature review focused on this issue, in terms of selection and delineation of lymph node in irradiation of cervix and endometrial cancers.