Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group

Background To investigate the frequency of temporal lobe necrosis (TLN) soon after radiotherapy (RT) and identify differences among patients with various types of head and neck cancer (HNC) and between different RT methods. Methods We retrospectively reviewed 483 patients with HNC who had completed RT in our hospital after January, 2015. These patients were followed-up at the radio-oncology department and received contrast-enhanced magnetic resonance imaging (MRI) or computed tomography (CT) to identify metastases or recurrence of cancer at regular intervals. Meanwhile, the occurrence of TLN, graded according to the Common Terminology Criteria for Adverse Events V5.0, was recorded. We categorized the patients into nasopharyngeal carcinoma (NPC) and non-NPC groups and compared the cumulative occurrence of TLN between the groups using Kaplan–Meier and Cox regression analyses. We further compared the cumulative occurrence of TLN between proton beam therapy (PBT) and volumetric modulated arc therapy (VMAT) in patients with any HNC, NPC, and non-NPC HNC. Results Compared with the non-NPC group, the NPC group had a higher frequency of TLN (5.6% vs. 0.4%, p < 0.01) and were more commonly associated with TLN in the Kaplan–Meier analysis (p < 0.01) and the Cox regression model after covariates were adjusted for (adjusted hazard ratio: 13.35, 95% confidence interval: 1.37–130.61) during the follow-up period. Furthermore, the frequency of TLN was similar between patients receiving PBT and those receiving VMAT (PBT vs. VMAT: 4.7% vs. 6.3%, p = 0.76). Kaplan–Meier analysis revealed that the accumulated risks of TLN were similar between PBT and VMAT in patients with any HNC (p = 0.44), NPC (p = 0.84), and non-NPC HNC (p = 0.70). Conclusion Our study demonstrated that patients with NPC are susceptible to TLN during the early period after RT. In addition, PBT may be associated with an equivalent risk of TLN when compared with VMAT in patients with NPC or other HNCs.

Section: Introductionmentioning

confidence: 69%

Risk of temporal lobe necrosis between proton beam and volumetric modulated arc therapies in patients with different head and neck cancers

Liu,

Lin,

Huang

et al. 2023

“…Discussions about the optimal treatment strategy for techniques, prescription dosing, and segmentation are based on the need to prioritize curing the tumor while maintaining an acceptable risk of complications. Pediatric brain and head and neck malignancies requiring dose escalation, as well as adult skull base malignancies, are internationally recognized indications for proton therapy, exhibiting good local control, survival, and acceptable toxicity rates [ 46 , 47 ]. Due to the lack of robust prediction models of photons and protons for this toxicity, it is impossible to predict the risk of hearing loss based on the patient's disease and treatment characteristics.…”

Section: Discussionmentioning

confidence: 99%

The relevance of ototoxicity induced by radiotherapy

Huang

Zhou

An³

et al. 2023

Background The risk of ototoxicity, characterized by hearing impairment, tinnitus, or middle ear inflammation, is elevated in both child and adult cancer survivors who have undergone head-neck or brain radiation, or a combination of the two. To provide optimal care for these cancer survivors and minimize subsequent complications, it is crucial to comprehend the relationship between radiotherapy and ototoxicity. Methods A comprehensive search of databases, including the Cochrane Library, PubMed, Embase, and Web of Science, was conducted from the inception of the knowledge base up until January 2023. The metafor-package was employed to compare ototoxicity rates in individuals receiving radiotherapy. Two independent assessors extracted data and analyzed targets using a random-effects model. Results Out of the 28 randomized controlled trials (RCTs) included in the analysis, 25 were prospective RCTs. Subgroup analysis revealed that mean cochlear radiation dose, primary tumor location, radiotherapy modality, and patient age significantly influenced total hearing impairment. Intensity-modulated radiotherapy was associated with less ototoxicity than 2D conventional radiotherapy (OR, 0.53; 95% CI, 0.47–0.60; P = 0.73; I2 = 0%). Stereotactic radiotherapy appeared to be a superior option for hearing preservation compared to radiosurgery (OR, 1.44; 95% CI, 1.00–2.07; P = 0.69; I2 = 0%). Children demonstrated a higher risk of hearing impairment than adults. More than 50% of patients with vestibular neuroadenoma experienced hearing impairment following radiation therapy. A strong association was observed between the average cochlear radiation dose and hearing impairment. Increased cochlear radiation doses may result in a heightened risk of hearing impairment. Conclusion Several risk factors for radiation-induced hearing impairment were identified in this study. High cochlear radiation doses were found to exacerbate the risk of hearing impairment resulting from radiation therapy.

“…In recent years, other alternatives for treating neuroblastoma have been proposed [ 29 , 30 ]. Especially, proton beam therapy has been increasingly recommended for pediatric patients with neuroblastoma, even though this irradiation type can suffer dosimetric degradation from gastrointestinal air and tumor location and still requires large cohort studies to prove oncological benefit compared to state-of-the art photon therapy [ 31 , 32 ].…”

Section: Discussionmentioning

confidence: 99%

MRI-based inter- and intrafraction motion analysis of the pancreatic tail and spleen as preparation for adaptive MRI-guided radiotherapy in neuroblastoma

Van Ommen,

le Quellenec,

Willemsen-Bosman

et al. 2023

Background In pediatric radiotherapy treatment planning of abdominal tumors, dose constraints to the pancreatic tail/spleen are applied to reduce late toxicity. In this study, an analysis of inter- and intrafraction motion of the pancreatic tail/spleen is performed to estimate the potential benefits of online MRI-guided radiotherapy (MRgRT). Materials and methods Ten randomly selected neuroblastoma patients (median age: 3.4 years), irradiated with intensity-modulated arc therapy at our department (prescription dose: 21.6/1.8 Gy), were retrospectively evaluated for inter- and intrafraction motion of the pancreatic tail/spleen. Three follow-up MRIs (T2- and T1-weighted ± gadolinium) were rigidly registered to a planning CT (pCT), on the vertebrae around the target volume. The pancreatic tail/spleen were delineated on all MRIs and pCT. Interfraction motion was defined as a center of gravity change between pCT and T2-weighted images in left-right (LR), anterior-posterior (AP) and cranial-caudal (CC) direction. For intrafraction motion analysis, organ position on T1-weighted ± gadolinium was compared to T2-weighted. The clinical radiation plan was used to estimate the dose received by the pancreatic tail/spleen for each position. Results The median (IQR) interfraction motion was minimal in LR/AP, and largest in CC direction; pancreatic tail 2.5 mm (8.9), and spleen 0.9 mm (3.9). Intrafraction motion was smaller, but showed a similar motion pattern (pancreatic tail, CC: 0.4 mm (1.6); spleen, CC: 0.9 mm (2.8)). The differences of Dmean associated with inter- and intrafraction motions ranged from − 3.5 to 5.8 Gy for the pancreatic tail and − 1.2 to 3.0 Gy for the spleen. In 6 out of 10 patients, movements of the pancreatic tail and spleen were highlighted as potentially clinically significant because of ≥ 1 Gy dose constraint violation. Conclusion Inter- and intrafraction organ motion results into unexpected constrain violations in 60% of a randomly selected neuroblastoma cohort, supporting further prospective exploration of MRgRT.