[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.

Recommendations for stereotactic body radiation therapy for spine and non-spine bone metastases. A GETUG (French society of urological radiation oncolgists) consensus using a national two-round modified Delphi survey

Background and purpose

The relevance of metastasis-directed stereotactic body radiation therapy (SBRT) remains to be demonstrated through phase III trials. Multiple SBRT procedures have been published potentially resulting in a disparity of practices. Therefore, the french society of urological radiation oncolgists (GETUG) recognized the need for joint expert consensus guidelines for metastasis-directed SBRT in order to standardize practice in trials carried out by the group.

Materials and methods

After a comprehensive literature review, 97 recommendation statements were created regarding planning and delivery of spine bone (SBM) and non-spine bone metastases (NSBM) SBRT. These statements were then submitted to a national online two-round modified Delphi survey among main GETUG investigators. Consensus was achieved if a statement received ≥ 75 % agreements, a trend to consensus being defined as 65-74 % agreements. Any statement without consensus at round one was re-submitted in round two.

Results

Twenty-one out of 29 (72.4%) surveyed experts responded to both rounds. Seventy-five statements achieved consensus at round one leaving 22 statements needing a revote of which 16 achieved consensus and 5 a trend to consensus. The final rate of consensus was 91/97 (93.8%). Statements with no consensus concerned patient selection (3/19), dose and fractionation (1/11), prescription and dose objectives (1/9) and organs at risk delineation (1/15). The voting resulted in the writing of step-by-step consensus guidelines.

Conclusion

Consensus guidelines for SBM and NSBM SBRT were agreed upon using a validated modified Delphi approach. These guidelines will be used as per-protocole recommendations in ongoing and further GETUG clinical trials.

[Ultra-hypofractionated radiotherapy for the treatment of localized prostate cancer: Results, limits and prospects]

Still an emerging approach a few years ago, stereotactic body radiation therapy (SBRT) has ranked as a valid option for the treatment of localized prostate cancer. Inherent properties of prostatic adenocarcinoma (low α/β) make it the perfect candidate. We propose a critical review of the literature trying to put results into perspective to identify their strengths, limits and axes of development. Technically sophisticated, the stereotactic irradiation of the prostate is well tolerated. Despite the fact that median follow-up of published data is still limited, ultra-hypofractionated radiotherapy seems very efficient for the treatment of low and intermediate risk prostate cancers. Data seem satisfying for high-risk cancers as well. New developments are being studied with a main interest in treatment intensification for unfavorable intermediate risk and high-risk cancers. Advantage is taken of the sharp dose gradient of stereotactic radiotherapy to offer safe reirradiation to patients with local recurrence in a previously irradiated area.

Histosurgical mapping of endoscopic endonasal surgery of sinonasal tumours to improve radiotherapy guidance

PURPOSE

Endoscopic endonasal surgery (EES) is becoming a standard for most malignant sinonasal tumours. Margin analysis after piecemeal resection is complex and optimally relies on accurate histosurgical mapping. Postoperative radiotherapy may be adapted based on margin assessment mapping to reduce the dose to some sinonasal subvolumes. We assessed the use of histosurgical mapping by radiation oncologists (RO).

MATERIAL AND METHODS

A French practice survey was performed across 29 ENT expert RO (2 did not answer) regarding integration of information on EES, as well as quality of operative and pathology reportsto refine radiotherapy planning after EES. This was assessed through an electronic questionnaire.

RESULTS

EES was ubiquitously performed in France. Operative and pathology reports yielded accurate description of EES samples according to 66.7% of interviewed RO. Accuracy of margin assessment was however insufficient according to more than 40.0% of RO. Additional margins/biopsies of the operative bed were available in 55.2% (16/29) of the centres. In the absence of additional margins, quality of resection after EES was considered as microscopically incomplete in 48.3% or dubious in 48.3% of RO. As performed, histosurgical mapping allowed radiotherapy dose and volumes adaptation according to 26.3% of RO only.

CONCLUSIONS

Standardized histosurgical mapping with margin and additional margin analysis could be more systematic. Advantages of accurate EES reporting could be dose painting radiotherapy to further decrease morbidity in sinonasal tumours.

[Proposal for the delineation of postoperative primary clinical target volumes in ethmoid cancers]

It is proposed to delineate the anatomo-clinical target volumes of primary tumor (CTV-P) in ethmoid cancers treated with post-operative radiotherapy. This concept is based on the use of radioanatomy and the natural history of cancer. It is supported by the repositioning of the planning scanner with preoperative imaging for the replacement of the initial GTV and the creation of margins around it extended to the microscopic risk zones according to the anatomical concept. This article does not discuss the indications of external radiotherapy but specifies the volumes to be delineated if radiotherapy is considered.

[Post-treatment follow-up of head and neck cancer patients]

Post-therapeutic follow-up of patients with head and neck cancer involves numerous professionals. The radiation oncologist should play an active role in this process. His oncological knowledge and technical expertise position him as a cornerstone for the detection of recurrences from the treated tumor, the research of second primary cancers and the screening of potential side-effects induced by the different treatments administered. To improve the benefits/costs ratio and allow good patient-compliance, follow-up programs should be built through close collaboration between the different contributors and planned according to a feasible schedule. Paraclinical exams must be arranged to respond to accurate objectives. Patient-education is essential to ensure the patient's full understanding and active participation. Finally, the transfer of the long-term follow-up of cancer survivors from specialists to primary care physicians is relevant but would require a prospective evaluation of its efficiency for this specific population.

[Individualization of dose and fractionation of radiotherapy for head and neck cancers]

Head and neck cancers comprise a variety of tumours depending on the sub-site, for which target volumes and the prescribed doses need to be individualized according to each patient's history and presentation. This article aims at describing the main factors involved in decision-making regarding dose and volume, as well as ongoing research. Contouring and treatment guidelines, use of altered fractionation, major prognostic factors, the role of Human papillomavirus and of functional imaging will be presented and discussed.

Protein profiles of nasal lavage fluid from individuals with work-related upper airway symptoms associated with moldy and damp buildings

Upper airway irritation is common among individuals working in moldy and damp buildings. The aim of this study was to investigate effects on the protein composition of the nasal lining fluid. The prevalence of symptoms in relation to work environment was examined in 37 individuals working in two damp buildings. Microbial growth was confirmed in one of the buildings. Nasal lavage fluid was collected from 29 of the exposed subjects and 13 controls, not working in a damp building. Protein profiles were investigated with a proteomic approach and evaluated by multivariate statistical models. Subjects from both workplaces reported upper airway and ocular symptoms. Based on protein profiles, symptomatic subjects in the two workplaces were discriminated from each other and separated from healthy controls. The groups differed in proteins involved in inflammation and host defense. Measurements of innate immunity proteins showed a significant increase in protein S100-A8 and decrease in SPLUNC1 in subjects from one workplace, while alpha-1-antitrypsin was elevated in subjects from the other workplace, compared with healthy controls. The results show that protein profiles in nasal lavage fluid can be used to monitor airway mucosal effects in personnel working in damp buildings and indicate that the profile may be separated when the dampness is associated with the presence of molds.

[Postoperative external beam radiotherapy for medullary thyroid carcinoma with high risk of locoregional relapse]

PURPOSE

To assess the outcome of locally advanced medullary thyroid carcinoma treated with surgery and adjuvant external beam radiotherapy.

PATIENTS AND METHODS

Twenty-nine consecutive patients with non-metastatic medullary thyroid carcinoma treated in our institution between January 1995 and December 2012 were retrospectively evaluated. All underwent curative-intended optimal surgery, followed by external beam radiotherapy because of high risk of locoregional relapse. Twelve patients were stage III, 16 IVa and 1 IVb. Positive surgical margins were present in 11 cases (10 R1 and 1 R2). Median and average preradiotherapy serum calcitonin were 141pg/mL and 699pg/mL, respectively. Fourteen patients received 3D-conformal radiotherapy and 15 received intensity-modulated radiotherapy. Median prescribed dose was 63Gy to the high-risk volumes and 54Gy to the low-risk volumes. Treatment was delivered in 30 fractions. The median gap between surgery and radiotherapy was 1.9months. Median follow-up was 76.4months.

RESULTS

Kaplan-Meier estimates of 5-year locoregional relapse-free survival and overall survival were 79 and 96 %, respectively. Among the five locoregional relapses, two were related to a macroscopic metastatic cervical lymph node that was unfortunately not removed during the lymphadenectomy. Eight of ten patients with microscopic positive margins (R1) were controlled regarding the thyroidectomy bed. Eight patients had normal serum calcitonin after external beam radiotherapy, of whom only one developed a locoregional relapse during follow-up. Regarding the 21 patients with persistent positive serum calcitonin after treatment, only ten developed a macroscopic locoregional or distant relapse. One grade III and no grade IV acute morbidity were reported. Fifteen patients reported grade II chronic morbidity and no grade III/IV.

CONCLUSION

Maximal surgery followed by adjuvant external beam radiotherapy as a treatment for locally advanced medullary thyroid carcinoma provides a high rate of long-term locoregional control and overall survival with limited toxicity. Postoperative external beam radiotherapy should be considered when patients present features indicating a high risk of locoregional relapse.

BAYESIAN ANALYSIS OF COSMIC RAY PROPAGATION: EVIDENCE AGAINST HOMOGENEOUS DIFFUSION

We present the results of the most complete scan of the parameter space for cosmic ray (CR) injection and propagation. We perform a Bayesian search of the main GALPROP parameters, using the MultiNest nested sampling algorithm, augmented by the BAMBI neural network machine-learning package. This is the first study to separate out low-mass isotopes (p, p ¯ , and He) from the usual light elements (Be, B, C, N, and O). We find that the propagation parameters that best-fit p, p ¯ , and He data are significantly different from those that fit light elements, including the B/C and 10Be/9Be secondary-to-primary ratios normally used to calibrate propagation parameters. This suggests that each set of species is probing a very different interstellar medium, and that the standard approach of calibrating propagation parameters using B/C can lead to incorrect results. We present posterior distributions and best-fit parameters for propagation of both sets of nuclei, as well as for the injection abundances of elements from H to Si. The input GALDEF files with these new parameters will be included in an upcoming public GALPROP update.

[Intensity modulated radiotherapy for head and neck cancers: ethics and patients selection]

PURPOSE

Intensity modulated radiotherapy (IMRT) allows a better coverage of the target volume and a better saving of organs at risk with a decrease of toxicity in head and neck cancers. It requires more human labor and materials compared to conformational radiotherapy. If they are insufficient, a selection of the patients receiving IMRT may be necessary, raising an ethical problem.

MATERIAL AND METHODS

We collected the motives guiding the choice of the technique of radiotherapy for head and neck cancers during a month of physicists' shortage.

RESULTS

Nineteen patients received IMRT and eight conformational radiotherapy. Conformational irradiation was chosen in palliative and postsurgery treatments, to reduce delay, in laryngeal tumors and re-irradiation. IMRT was preferred for complex target volumes and the localizations at risk of important xerostomia following conformational radiotherapy. These choices were confronted with the bioethics criteria of Beauchamp and Childress. The beneficence justified the use of IMRT or conformational radiotherapy depending on the circumstances. The non-maleficence attempted to decrease the toxicity with IMRT. Justice was questioned by the selection. The autonomy of patients was not totally respected in the choice.

CONCLUSION

To help in the choice of the patients receiving an IMRT in a crisis situation, we proposed a hierarchical organization of selection criteria: complex volumes close to critical organs at risk, localization with high risk of xerostomia, long life expectancy and postoperative delay constraints.

[Functional modeling for risk analysis in radiotherapy]

PURPOSE

This document presents a systematic and structured approach for functional modeling for risk analysis in radiotherapy, aiming to reconcile the need, on one hand, for a method that can be applied generally and, on the other hand, for a method that provides a highly precise model.

MATERIALS AND METHODS

The approach relies on new functional structuring patterns and flux analysis, derived from system engineering and knowledge engineering.

RESULTS

The method affords strong support for the development of detailed models of the patient's process through a department of radiotherapy. Lack of structure of the actual process in a particular department may be easily identified leading to the development of specific procedures for the improvement of security.

CONCLUSION

Modeling approach derived from engineering may be used for functional modeling for risk analysis in radiotherapy.

Management of patients with head and neck tumours presenting at diagnosis with a synchronous second cancer at another anatomic site

AIMS

To understand management strategies and outcomes of patients diagnosed with a head and neck tumour and a synchronous second cancer developed at another anatomic site.

MATERIALS AND METHODS

Retrospective analysis of all patients diagnosed with a head and neck carcinoma and a synchronous cancer and engaged in curative-intent treatments. To evaluate therapeutic strategies, each patient's treatment process was divided into sequential therapeutic modalities and corresponding targets (head and neck and/or synchronous tumour) were identified. Patient outcome was analysed with an intent-to-treat approach.

RESULTS

Forty-three patients were entered into the study (mean age=57.4 years). Synchronous tumours concerned the lung (57.8%), oesophagus (31.1%) or other sites (11.1%). Treatments were complex, including one to four consecutive modalities, with a mean duration of 4.6 months. When both tumours were advanced, treatments were frequently initiated with dual-spectrum chemotherapy (66.7%). In other situations, a locoregional treatment was often (81.1%) proposed immediately. When both tumours were in early stages, this initial locoregional treatment could be extended to target both tumours together (30.0%). For patients whose tumours differed in severity, this locoregional treatment targeted only one tumour (85%); priority was given to the most advanced one (76.5%). Nine patients had definitive treatment interruption. Associated risk factors were a low body mass index (P=0.03) and advanced-stage tumours (P=0.01). Thirty-one patients died (72.1%) with a median time to death of 7.7 months. The median follow-up for survivors was 46.2 months. Three-year overall survival was 33.9%. Low body mass index (P=0.001), advanced-stage synchronous tumours (P=0.03) and oesophageal primaries (P=0.03) altered the overall survival. Three-year locoregional and metastatic progression-free survival was 40.8 and 62.5%, respectively. Low body mass index (P=0.01) and advanced-stage synchronous tumours (P=0.01) increased the risk of disease failure.

CONCLUSIONS

Head and neck tumours diagnosed with a synchronous cancer are a complex challenge. Despite a severe prognosis, patients who are not underweight, presenting with lower-stage tumours (especially the synchronous tumour) and without oesophageal involvement could most benefit from aggressive treatments.

[Neck dissection following chemoradiation for node positive head and neck carcinomas]

The optimal timing and extent of neck dissection in the context of chemoradiation for head and neck cancer remains controversial. For some institutions, it is uncertain whether neck dissection should still be performed upfront especially for cystic nodes. For others, neck dissection can be performed after chemoradiation and can be omitted for N1 disease as long as a complete response to chemoradiation is obtained. The question is debated for N2 and N3 disease even after a complete response as the correlation between radiological and clinical assessment and pathology may not be reliable. Response rates are greater than or equal to 60% and isolated neck failures are less than or equal to 10% with current chemoradiation protocols. Some therefore consider that systematic upfront or planned neck dissection would lead to greater than or equal to 50% unnecessary neck dissections for N2-N3 disease. Positron-emission tomography (PET) scanning to assess treatment response and have shown a very high negative predictive value of greater than or equal to 95% when using a standard uptake value of 3 for patients with a negative PET at four months after the completion of therapy. These data may support the practice of observing PET-negative necks. More evidence-based data are awaited to assess the need for neck dissection on PET. Selective neck dissection based on radiological assessment and peroperative findings and not exclusively on initial nodal stage may help to limit morbidity and to improve the quality of life without increasing the risk of neck failure. Adjuvant regional radiation boosts might be discussed on an individual basis for aggressive residual nodal disease with extracapsular spread and uncertain margins but evidence is missing. Medical treatments aiming at reducing the metastatic risk especially for N3 disease are to be evaluated.

CT assessment of woodworkers' nasal adenocarcinomas confirms the origin in the olfactory cleft

BACKGROUND AND PURPOSE

Endoscopic endonasal surgery let us observe that woodworkers' nasal adenocarcinomas originate in the olfactory cleft. Our aim was the identification of CT imaging features that corroborate the olfactory cleft as the site of origin for woodworkers' adenocarcinoma.

MATERIALS AND METHODS

We designed a retrospective study to compare CT scans of 27 unilateral olfactory cleft adenocarcinomas with 30 cases of nasosinusal polyposis (NSP) and 33 healthy sinus controls. Enlargement of the olfactory cleft, lateralization of the ethmoidal turbinate wall, and contralateral bulging of the nasal septum were measured on coronal scans passing through crista galli and posterior half of both ocular globes. Comparisons have been performed by using analysis of variance and the Bonferroni procedure.

RESULTS

The nasal septum was significantly bulging across the midline in adenocarcinoma (4.6 +/- 3 mm; range, -0.1-13.7 mm) compared with NSP (0.7 +/- 1 mm; range, -2.1-2.3 mm) or healthy sinus controls (0.5 +/- 1 mm; range, -1.2-2 mm) (P < .001). The olfactory cleft was significantly wider in adenocarcinoma (15.1 +/- 4.5 mm; range, 8.6-25.7 mm) than in NSP (3.6 +/- 0.4 mm; range, 2.8-4.6 mm) or healthy sinus controls (3.3 +/- 0.7 mm; range, 1.4-4.6 mm). The ethmoidal labyrinth width was significantly smaller on the pathologic side in adenocarcinoma (7.2 +/- 2.7 mm; range, 3.2-14.2 mm) than in the control groups (P < .001). Whereas the angle between the conchal lamina and vertical midline was close to zero degrees in NSP (0.03 +/- 2.25 degrees ; range, -5 degrees -3 degrees ) and healthy sinus controls (0.45 +/- 2.13 degrees , range, -5 degrees -5 degrees ), it reached 39.76 +/- 13.83 degrees (P < .001) in adenocarcinoma.

CONCLUSIONS

Radiologists should suspect nasal adenocarcinoma on sinus CT scans showing a unilateral expanding opacity of the olfactory cavity.

[Microsurgical reconstruction and full management of patients with head and neck cancer: importance of a quality approach and a patient care team]

MAIN OF STUDY: Management and surgical reconstruction of head and neck cancers remain a challenge. From the first consultation to surgery and radiotherapy it is necessary to gain time to ensure optimum treatment and better survival rates.

OBJECTIVE

To establish a kind of quality approach to the management of patients with head and neck cancers. 54 patients who received microsurgical reconstruction after head and neck cancer were included in this study between 1997 and 2006.

RESULTS

Multiple data were considered: body mass index (BMI), ASA stage, age, existence of a pre-or postoperative radiotherapy, the surgeon's experience and the number of drainage veins. The success rate is superior when more than one draining vein is sutured to the flap for patients with a BMI >20. Radiotherapy does not seem to affect the survival of the flap.

CONCLUSION

According to current literature, the survival rate of these patients is better when the overall time care is less than 100 days. That period is possible with a perfect organization of the medical and paramedical team. Therefore, we propose to include these patients in a circuit protocolisation care, which saves time, to better inform patients and improve survival rates.

Endoscopic surgery reveals that woodworkers' adenocarcinomas originate in the olfactory cleft

The olfactory cleft is a narrow chamber located under the cribriform plate and between the turbinate wall of the ethmoidal labyrinth and the corresponding nasal septum. Nasal adenocarcinomas are mostly described as originating in the ethmoid sinus and operated via external approaches. We designed a prospective study on twenty consecutive woodworkers' adenocarcinomas without intracranial extension to determine the precise site of origin of the tumour. All patients were operated under endoscopic endonasal control according to a methodical surgical procedure as follows: 1) debulking of the tumour and identification of the middle turbinate or conchal lamina, 2) exenteration of the ethmoidal labyrinth according to the nasalisation procedure, and 3) exenteration of the olfactory cleft. Endoscopic endonasal surgery showed that woodworkers' adenocarcinomas constantly originated in the olfactory cleft, appearing as polyp-like neoplasms with well-defined bodies. Over a long period of time, they do not invade, but just displace and push out the surrounding structures, i.e. the nasal septum and the turbinate wall. More than the volume of the tumour, the precise location of the pedicle and especially its connection to the cribriform plate could be of major prognosis value.

Proposition de sélection et délimitation des volumes cibles microscopiques péritumoraux dans les cancers de la cavité buccale et de l'oropharynx (aires ganglionnaires exclues)

This article reviews the concept of selectivity in peritumoral microscopic disease to be included in the Clinical Target Volume (CTV) for elective treatment for oral cavity and oropharyngeal squamous cell carcinoma, using the local tumoral spread. The objective of the present article is to present a procedure for the delineation of the target volumes, required for an appropriate application of 3-DCRT and IMRT for head and neck cancers. These propositions are for the delineation of microscopic peritumoral target volumes when external beam irradiation is required. CTVs are illustrated on CT sections.

Counteraction of pRb-dependent protection after extreme hypoxia by elevated ribonucleotide reductase

We have studied hypoxia-induced cell cycle arrest in human cells where the retinoblastoma tumour suppressor protein (pRb) is either functional (T-47D and T-47DHU-res cells) or abrogated by expression of the HPV18 E7 oncoprotein (NHIK 3025 cells). We have previously found that pRb is dephosphorylated and rebound in the nucleus in T-47D cells arrested in S-phase during hypoxia and that this binding is protracted even following re-oxygenation. In the present study, however, we show that the long-lasting arrest following re-oxygenation induced by pRb-binding in the cell nuclei may be overruled by an elevated level of ribonucleotide reductase (RNR). This seems to create a forced DNA-synthesis, uncoordinated with cell division, which induces endoreduplication of the DNA. The data indicate that the cells initiating endoreduplication continue DNA-synthesis until all DNA is replicated once and then may start cycling and cell division with a doubled DNA-content. Corresponding data on the pRb-incompetent NHIK 3025-cells show similar endoreduplication in these. Thus, the data indicate that endoreduplication of DNA following re-oxygenation may come, either as a result of hypoxic arrest of DNA-synthesis when pRb-function is absent in the cells, or if it is overruled by increased RNR. The present study further shows that pRb not only protects the culture by arresting most of the cells that are exposed to extreme hypoxia in S-phase, but also increases cell survival by means of increased clonogenic ability of these cells. Interestingly, however, cells having an elevated level of RNR have equally high survival as wild-type cells following 20 h extreme hypoxia. If RNR-overruling of pRb-mediated arrest following re-oxygenation results in an unstable genome, this may therefore represent a danger of oncogenic selection as the protective effect of pRb on cell survival seems to be maintained.

Radiothérapie conformationnelle avec modulation d'intensité des cancers des voies aérodigestives supérieures avec irradiation bilatérale du cou : résultats préliminaires

PURPOSE

To report preliminary results of a prospective study of intensity-modulated radiotherapy (IMRT) for head and neck squamous cell carcinoma (HNC) with bilateral irradiation of the neck.

PATIENTS AND METHODS

At the Alexis Vautrin Cancer Center, 23 patients have been treated with IMRT for HNC since January 2002-August 2003. The first 10 patients with a minimum follow-up of 3 months were analyzed. All tumors were oropharyngeal. There were four females and six males, with a mean age of 50 years (range 39-66). Stages were I-II in eight and III-IV in two. CTV1 was microscopic disease and N0 neck (prescribed dose : 50 Gy) and CTV2 was macroscopic disease and the volume at risk (prescribed dose: 66-70 Gy). PTV were CTV + 5 mm. Patient's immobilization consisted of a five-point head neck shoulder thermoplastic mask. Set-up verifications were done by semi-automatically matching portal images and digitized reconstructed radiographs. IMRT used dynamic multileaf collimation. Five patients (group A) received 50 Gy IMRT (two post-operative and three with a brachytherapy boost with a mean dose: 27.5 Gy), and five patients (group B) received 66-70 Gy IMRT (four post-operative). Acute and late normal tissue effects were graded according to the RTOG-EORTC radiation morbidity scoring criteria.

RESULTS

With a median follow-up of 7.4 months (range 3-18.5), no patient died or had loco-regional relapse. The displacements were <4 mm in 98% cases. CTV1 and 2 received 95% of the prescribed dose in 100% of the volume. On average the mean dose to the contralateral parotid was 25.5 Gy for group A vs. 31 Gy for group B (P = 0.09). Mean doses <26 Gy were obtained in three of five patients in group A vs. zero of five patients in group B (P = 0.04). Acute skin toxicities were grade 1 in five patients, grade 2 in four and grade 3 in one. Acute mucositis cases were grade 1 in three patients, grade 2 in five and localized grade 3 in two. At 3 months, 50% of the patients had a grade 0-1 late xerostomia.

CONCLUSION

The 26 Gy dose limit constraint to the contralateral parotid was easier to satisfy when IMRT was prescribed at a maximum dose of 50 Gy. Acute toxicity is low. The displacements in the mask indicate that it is possible to define the PTV as CTV + 4 mm. This reduction should decrease the mean dose to the parotids. At 3 months, a 50% rate of grade 0-1 late xerostomia encourages the hope of a very low rate at 2 years.