Facial deformation following treatment for pediatric head and neck rhabdomyosarcoma; the difference between treatment modalities. Results of a trans-Atlantic,multicenter cross-sectional cohort study

Background

The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities.

Methods

Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age–sex–ethnicity-matched controls. Additionally, we computed individual facial asymmetry.

Findings

A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007).

Interpretation

When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians’ bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options.     

La protonthérapie : bases,indications et nouvelles technologies

With over 70,000 patients treated worldwide, protontherapy has an evolution on their clinical applications and technological developments. The ballistic advantage of the Bragg peak gives the possibility of getting a high conformation of the dose distribution to the target volume. Protontherapy has accumulated a considerable experience in the management of selected rare malignancies such as uveal melanomas and base of the skull chordomas and chondrosarcomas. The growing interest for exploring new and more common conditions, such as prostate, lung, liver, ENT, breast carcinomas, as well as the implementation of large pediatric programs advocated by many experts has been challenged up to now by the limited access to operational proton facilities, and by the relatively slow pace of technical developments in terms of ion production, beam shaping and modelling, on-line verification etc. One challenge today is to deliver dynamic techniques with intensity modulation in clinical facilities as a standard treatment. We concentrate in this paper on the evolution of clinical indications as well as the potentialities of new technological concepts on ion production, such as dielectric walls and laser-plasma interactions. While these concepts could sooner or later translate into prototypes of highly compact equipments that would make easier the implantation of cost-effective hospital-based facilities, the feasibility of their clinical use must still be proved.     

Histoire de l'évolution des techniques de radiothérapie

Since the discovery of X-rays, the goal of radiotherapy has been to deliver an optimal dose in the target volume and the lowest possible dose in the normal tissues. The history of radiotherapy can be divided in three periods. The Kilovoltage era (1900–1939) where only superficial and radiosensitive tumours could be controlled, the Megavoltage era (1950–1995) where Telecobalt and linear accelerators could deliver high doses in all parts of the body. Radiotherapy has since been playing an important curative and conservative role for most cancers. The Computer-Assisted Radiotherapy era (1995–2010) now provides the capacity to optimise the dose distribution in three dimensions. Dose is better conformed to the target volume and organ at risk are better preserved. intensity modulated radio-therapy (IMRT) allows to “shape” concave isodoses and to spare the parotids when irradiating oropharyngeal tumours. Moving targets (lung, liver etc.) are efficiently irradiated using “on-line tracking” and “image-guided radiotherapy”. Stereotactic irradiation, first initiated for brain lesions, is now performed for extra-cranial tumours and due to its millimetric precision opens the way back to hypo-fractionated treatments. The next period, already ongoing, is Hadrontherapy with protons and soon helium or carbon ions techniques. In a multidisciplinary strategy, progress in radiotherapy is based on a global approach of the patient and tailored/personalized well targeted treatment of the tumour.     

儿童颅咽管瘤质子和光子治疗的剂量学比较

目的：对3例儿童颅咽管瘤进行剂量学比较，以探讨质子在儿童颅咽管瘤放疗中的潜在优越性。方法：靶区肿瘤照射剂量为55Cy。每例患者分别作单纯光子、光子和质子混合射线以及单纯质子的治疗计划，治疗方法均为三维适形治疗；应用适形指数以量化地比较3种治疗计划对靶区的剂量覆盖和正常组织的照射容积和剂量。结果：3种治疗计划均达到满意的靶区剂量覆盖，92％～100％的PTV在处方剂量95％的范围内。质子治疗的运用使得正常脑组织、脑干、大脑颞叶和内耳的剂量显著下降。当肿瘤与视交叉有少许间隙时，质子治疗可以降低视交叉的平均剂量和最低剂量。单纯质子体现出较混合射线更强的优越性。单纯光子、混合射线和单纯质子的适形指数分别为O．631、O．784和O．848，即质子治疗提供的高剂量区曲线分布更符合PTV的形状。结论：在保证靶区剂量的基础上，质子的应用普遍减少了颅内正常组织的照射，并在部分患者中提供了剂量提升的可能性。     

New radiation techniques in paediatric cancers

Despite the risk of long-term side effects, external radiation therapy remains a cornerstone of the treatment for many cancers in childhood, in particular for brain tumours and head and neck cancers. Conformal radiation has been the standard of care since several decades. However, new techniques, including stereotactic radiation, intensity-modulated radiation therapy, or protontherapy have proven many advantages in adults, and are more and more discussed in pediatric management due to a favourable cost/benefit rate in some situations. The aim of this article is to point out the potential indications as well as the limits of these new techniques in childhood.