Aims: Osteoradionecrosis (ORN) is a serious toxicity of head and neck radiotherapy. It predominantly affects the mandible. Extra-mandibular ORN is rare. The aim of this study was to report the incidence and outcomes of extra-mandibular ORNs from a large institutional database. Materials and methods: In total, 2303 head and neck cancer patients were treated with radical or adjuvant radiotherapy. Of these, extra-mandibular ORN developed in 13 patients (0.5%). Results: Maxillary ORNs (n 1/4 8) were a consequence of the treatment of various primaries (oropharynx 1/4 3, sinonasal 1/4 2, maxilla 1/4 2, parotid 1/4 1). The median interval from the end of radiotherapy to the development of ORN was 7.5 months (range 3-42 months). The median radiotherapy dose in the centre of the ORN was 48.5 Gy (range 22-66.5 Gy). Four patients (50%) healed in 7, 14, 20 and 41 months. All temporal bone ORNs (n 1/4 5) developed after treatment to the parotid gland (of a total of 115 patients who received radiotherapy for parotid gland malignancy). The median interval from the end of radiotherapy to the development of ORN was 41 months (range 20-68 months). The median total dose in the centre of the ORN was 63.5 Gy (range 60.2-65.3 Gy). ORN healed in only one patient after 32 months of treatment with repeated debridement and topical betamethasone cream. Conclusion: Extra-mandibular ORN is a rare late toxicity and this current study provides useful information on its incidence and outcome. The risk of temporal bone ORN should be considered in the treatment of parotid malignancies and patients should be counselled. More research is required to determine the optimal management of extra-mandibular ORN, particularly on the role of the PENTOCLO regimen. (c) 2023 Published by Elsevier Ltd on behalf of The Royal College of Radiologists.

In head and neck cancer (HNC), osteoradionecrosis (ORN) is one of the most significant complications of radiotherapy (RT). With an absence of effective non-surgical treatment, prevention of the development of ORN is the best approach. The purpose of this study was to identify the risk factors for the development of ORN in HNC. Records of 1,118 patients with HNC treated with radical RT (≥55Gy) from January 2010 to December 2019 were reviewed. After applying the exclusion criteria, 935 patients were included in the final analysis. In patients with confirmed ORN, exact RT doses were mapped. In total, 91 patients were found (9.7%) with a median (range) time of eight (3-89) months to the development of ORN. Smoking, having a primary site in the oropharynx, bone surgery before adjuvant RT, the addition of concurrent chemotherapy, the presence of xerostomia, dental extraction pre-RT, the time ≤20 days between dental extraction and start of RT, and receiving >55Gy RT dose were significant factors for its development. This comprehensive analysis including the precise RT dose mapping has shown the risk factors for the development of ORN. In practice, every effort should be made to avoid these risk factors without compromising the oncology treatment. The findings of this analysis may provide a basis for future prospective research on this topic.

Abstract Introduction: Following radiotherapy for head and neck cancer, a proportion of patients present with mandibular osteoradionecrosis (ORN). Reported incidence and presentation of ORN vary widely, although often initiated by trauma with radiotherapy being the biggest risk factor. Evolved disease requires surgery, mandibular resection and reconstruction. As ORN is a progressive disease, it can manifest beyond resected volumes, compromising surgery. To minimise surgical failures, we present incorporating radiotherapy dose into the surgical design and decision processes—dose guided surgery (DGS). Method: Five mandibular ORN patients, referred for resection and reconstruction, underwent DGS—mandible visualised on diagnostic CT, propagated to radiotherapy planning CT, radiotherapy dose displayed on the mandible, high-risk mandible converted to stl files and incorporated in the surgical design. Results: DGS ensures high-dose, high-risk ORN mandible is resected, and fixation devices are located in low-dose, low-risk areas. Conclusions: DGS represents a potential new standard of care for patients presenting with mandibular ORN post-radiotherapy. Formal follow-up of this small cohort is ongoing although DSG is anticipated to increase the success rate of this high cost, high burden procedure compared to surgery designed on clinical and radiological assessments alone.

The aim of this single center, retrospective, observational clinical study was to determine the incidence and causative risk factors of osteoradionecrosis (ORN) in head and neck cancer (HNC) patients treated with radiotherapy (RT). In our analysis, there was a particular emphasis on impact of pre-RT dental intervention on the occurrence of ORN. Data on all 936 consecutive HNC patients from Newcastle catchment area, treated with radical RT (definitive and adjuvant) from January 2010 to December 2019 were collected. Median follow-up was 34 months. Average age of patient cohort was 61 years. The dose fractionation was as follows; 55Gy in 20 fractions (f) (n = 58), 60-65Gy in 30f (n = 878). 92 patients were found to have ORN. Authors reconstructed all the RT treatment plans and analyzed the dose distribution in all 92 patients with ORN. Bearing in mind the location of ORN, exact RT dose mapping was performed in order to explore the possible relationship of RT dose distribution and occurrence of ORN. ORN developed in 92 patients (9.8%) with a median time of 17.2 months, the incidence was higher in patients who underwent dental extraction pre-RT (12.1% vs 7.2%; p = 0.008). Mean number of teeth extracted were 6.02 (95% CI 4.72 – 7.32). Primary site oral cavity (p<0.01), bone resection before adjuvant RT (p = 0.03), addition of concurrent chemotherapy (p = 0.01), presence of xerostomia (p = 0.004) were also significant factors for ORN development. ORN was most common in mandible (n = 85) than in maxilla (n = 7). Gender (p = 0.18) smoking (p = 0.425) and IMRT vs 3D CRT (p = 0.7), intent of RT radical vs adjuvant (p = 0.171) were insignificant factors. Interestingly, being edentulous pre-RT (p = 0.002) was a protective factor for ORN development. Radiotherapy dose >55Gy was associated with a steep increase in risk of ORN development. Out of 505 patients with dental extraction before RT, ORN developed in 61 patients but only in 51 in the location of extracted teeth. In 79 patients in whom the extraction has been performed in between 0-15 days from commencement of RT, ORN developed in 10 patients (12.7%). In 273 patients with extraction performed in 16-30 days from commencement of RT, ORN developed in 33 patients (12.1%); however, in 153 patients with extraction performed in more than 31 days, ORN developed in 8 patients (5.2%). To the best of author's knowledge, this is first report of exact radiotherapy dose in the center of origin of ORN. Dental extraction prior to commencement of RT, RT dose and addition of chemotherapy are the most significant variables influencing the development of ORN. Authors recommend avoiding teeth extraction before RT, if possible. In patients with extracted teeth, every effort should be made outline the sockets after extraction as areas at risk in order to minimize the RT dose without compromising the target coverage.Abstract 1092; TableDose of RT (Gy)No of patients with ORNPercent (%)< = 40.088.740.1 – 45.055.445.1 – 50.055.450.1 – 55.055.455.1 – 60.01516.360.1 – 65.05458.7Total92100.0 Open table in a new tab

To compare the treatment outcome and toxicity between patients with stage IVA (TNM 7th edition) squamous cell carcinoma of the tonsil treated with either primary (chemo)radiation therapy or surgery followed by adjuvant (chemo)radiation therapy. Between March 2009 to February 2013, 52 consecutive patients with a biopsy-proven squamous cell carcinoma of the tonsil, stage IVA (TNM 7th edition), were analyzed retrospectively. Group CRT (primary radiation therapy ± chemotherapy, n=37) was compared against group S+CRT (surgery followed by adjuvant radiation therapy ± chemotherapy, n=15). The two groups were well-matched in terms of patient’s age (median age 57 years in group CRT vs 60 in group S+CRT), HPV status (54% vs 60% positive, 16% vs 20% negative, and 30% vs 20% not available). However, the number of patients with T1/2 was higher in group S+CRT (80% vs 54%) and more patients received concurrent chemotherapy in group CRT (89% vs 60%). The radiation therapy regime was 63- 65 Gy in 30 daily fractions ± weekly cisplatin (40mg/m2) chemotherapy or cetuximab (loading dose 400mg/m2 followed by weekly 250mg/m2) biotherapy. In group CRT, complete response (CR) was achieved in 97% patients (in 1 patient, CR was not achieved). Out of 36 patients with response, 2 patients (6%) developed locoregional recurrences (LRR) and 3 patients (8%) developed distant metastases (DM). This was comparable to group S+CRT (7% LRR and 7% DM). With a median follow-up of 51 months, 29 patients in CRT group were alive (5 out of the total of 8 deaths were disease related). In S+CRT group, 14 patients were alive and 1 died of disease. Five-year disease specific survival (DSS) was 88% in CRT group versus 93% in S+CRT group (HR 0.60; 95% CI 0.09-4.0). The difference in overall survival was not statistically significant. Addition of chemo(bio)therapy influenced the outcome (P=.02). HPV status (P=.83), age (P=.41) and number of cycles of chemotherapy received (P=.16) were not significant variables. There was a trend of less acute toxicities (grade 3 mucositis was 27% vs 54%, P=.068), and hospital admission rate (27% vs 49%, P=.21) in group S+CRT, but it was not statistically significant. There was no statistically significant difference in incidence of late effects in two groups (we assessed esophageal, soft tissue, bone, salivary gland and laryngeal toxicity). This retrospective analysis has not confirmed any significant difference in the outcome of definitive (chemo)radiation therapy versus combined modality treatment in patients with locoregionally advanced carcinoma of the tonsil. Although the TNM 8th edition has been updated based on HPV status, our analysis did not show HPV status as a significant variable.

Objective: To compare the dosimetric consequences of volumetric modulated arc therapy (VMAT) for high-dose palliative thoracic radiotherapy through comparison with conventionally used isocentric parallel opposed pair (POP) of fields. Methods: 20 consecutive patients with non - small cell lung cancer who received 36 Gy in 12 fractions using a POP technique were re-planned using a single VMAT arc. Salient dosimetric parameters were compared between the plans using a paired t-test. Results: VMAT demonstrated dosimetric superiority; all PTV dose parameters were significantly improved and importantly the volume of normal lung receiving a high dose was also significantly reduced (mean volume of normal lung receiving 36 Gy was 12.9% in POP vs 1.8% in VMAT, p < 0.005). Conclusion: The standard POP technique does not take into account tissue densities which results in higher doses to the normal tissue outside the target volume and reduced conformity to the PTV. Advances in knowledge: With the help of modern VMAT techniques, it is possible to effectively achieve highly conformal dose delivery which may provide an opportunity to escalate the dose to the tumour in this group of patients.

Introduction: Breast conserving surgery (BCS) is increasingly becoming the choice of local treatment in breast cancer, which in up to 10% of cases can be bilateral. There are very limited data on the dose distribution, safety and feasibility of adjuvant bilateral breast radiotherapy, which we are assessing here along with clinically identified pneumonitis, cardiac toxicity and patient outcome.