The impact of intensity-modulated radiation treatment on dento-alveolar microvasculature in pharyngeal cancer implant patients

Peri-implant health after microvascular head and neck reconstruction-A retrospective analysis

INTRODUCTION

Prosthodontic rehabilitation after reconstruction with microvascular revascularized free flaps following ablative tumor surgery is challenging due to the altered anatomical and functional conditions. The aim of this retrospective study was to determine whether the type of graft and the type of peri-implant tissue have an effect on peri-implant inflammatory parameters and implant survival.

MATERIALS AND METHODS

Patients who received a free flap reconstruction with subsequent implant-prosthetic rehabilitation between 2010 and 2022 were retrospectively included. The primary outcome variable was the probing depth (PPD) at a minimum of 1 year after completion of prosthetic restoration. Predictive variables were type of free flap, emergence profile, and history of radiation.

RESULTS

Seventy-one patients after free flap reconstruction were included in the analysis. At a minimum of 24 months after implant insertion the primary outcome, PPD showed no clinically relevant differences between the types of free flaps used. The emergence profile through a skin island resulted in an increase in BOP compared to native mucosa in the descriptive analysis (p-value > .05). The analysis showed a 5-year implant survival of 96.2% (95% CI: 0.929-0.996) in cases without irradiation and 87.6% (95% CI: 0.810-0.948) with irradiation of the region evaluated (p-value .034).

CONCLUSION

Flap and associated soft tissue type had no significant effect on 5-year implant survival or peri-implant inflammatory parameters. However, the large heterogeneity of the patient population indicates that further prolonged studies are required for a more differentiated assessment of the long-term success.

The use of liquid formulation pentoxifylline and vitamin E in both established and as a prophylaxis for dental extractions "at risk" of osteoradionecrosis

BACKGROUND

Osteoradionecrosis (ORN) of the jaws remains one of the most debilitating complications of radiotherapy (RT) in patients with head and neck cancer (HNC). Liquid pentoxifylline and vitamin E (PVe) presents an alternative formulation to tablets for patients with dysphagia or enteric feeding.

OBJECTIVE

This study aimed to assess the clinical outcomes of using a liquid formulation of PVe for both established ORN and as a prophylaxis to avoid its occurrence after dental extractions. A secondary objective was to determine patient-reported side effects in relation to the liquid formulation of PVe.

STUDY DESIGN

The clinical records of 111 patients with HNC who were prescribed liquid PVe were reviewed retrospectively (66 with established ORN and 45 as prophylaxis before an invasive dental procedure).

RESULTS

In established ORN, 44% healed, and 41% were stable. In the prophylaxis group, 96% of surgical sites healed completely, with 4% (n = 2) developing ORN. Most patients (89%) were able to tolerate liquid PVe. Of the 11% (n = 12) who could not tolerate this regime, the most commonly reported side effect was gastric irritation (n = 5/12), whereas no more than 1 patient reported dizziness, malaise, and bleeding.

CONCLUSIONS

This retrospective review suggests that liquid PVe is efficacious for both established ORN and as a prophylaxis. Side effects reported were similar to those recognized for the tablet formulation.

The extent of unnecessary tooth loss due to extractions prior to radiotherapy based on radiation field and dose in patients with head and neck cancer

BACKGROUND AND PURPOSE

Prior to radiotherapy (RT), teeth with poor prognosis that pose a risk for post-RT osteoradionecrosis (ORN) are removed. To allow enough time for adequate wound healing prior to RT, decisions are made based on the estimated radiation dose. This study aimed to gain insight into (1) the overall number of teeth extracted and (2) the patient and tumor characteristics associated with the number of redundantly extracted teeth.

MATERIALS AND METHODS

Patients with head and neck cancer (HNC), treated with RT between 2015 and 2019, were included in this cross-sectional study. For each extracted tooth the radiation dose was calculated retrospectively. The cut-off point for valid extraction was set at ≥ 40 Gy in accordance with the national protocol. Potential factors for doses ≥ 40 Gy were identified, including age, sex, tumor location, tumor (T) and nodal stage (N), overall tumor stage and number of teeth extracted.

RESULTS

A total of 1759 teeth were removed from 358 patients. Of these 1759 teeth, 1274 (74%) appeared to have been removed redundantly, based on the mean dose (Dmean) of < 40 Gy. Using the maximum dose (Dmax) of < 40 Gy, 1080 teeth (61%) appeared to have been removed redundantly. Tumor location and N-classification emerged as the most important associative variables in the multivariable regression analysis.

CONCLUSION

To our knowledge this is the first study to provide insight into the amount of teeth redundantly extracted prior to RT and represents a step forward in de-escalating the damage to the masticatory system prior to RT.

The clinical effect of radiotherapy on pulpal microvasculature: a systematic review

Introduction/objectives Radiotherapy (RT) has a detrimental effect on the histomorphology of oral tissues. Patients undergoing RT are at risk of developing macrovascular and microvascular changes, which can lead to significant clinical consequences. Despite advances in RT delivery systems, radiation injury remains a modern-day clinical problem. The aim of this systematic review is to investigate the available evidence regarding the impact of RT to the dental pulp and the clinical manifestations of these effects.Data and sources A multi-database search (PubMed, Medline, Embase and CINAHL) was performed to identify related papers published from inception until November 2021. An additional manual search was performed to identify further articles. The data extracted from relevant papers were analysed according to the outcomes selected in this review.Study selection The search generated seven articles eligible for analysis with a total of 2,709 teeth included. RT dose exposure ranged from 30-71.2 Gray with a common finding that RT decreases the number of teeth responding to pulp sensibility testing.Conclusions Knowledge related to the impact of RT on dental pulp is limited and based on weak evidence and a low-level quality of studies. Future studies should incorporate exact RT doses to the teeth and use replicable pulpal testing methods. Understanding the pulpal status post-RT remains an important consideration as dental extractions should be avoided in this cohort due to the risk of osteoradionecrosis.

Osteonecrosis of the jaw in primary dental care: Recognition and referral

Osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ) are uncommon conditions, however when present they have a significant impact on a patient's quality of life and are notoriously difficult to treat. With medical advances resulting in improved survival rates and increased life expectancy, it is likely that general dental practitioners (GDPs) will more frequently be involved in the oral health management of patients at risk of both ORN and MRONJ. Though management of both diseases is beyond the scope of primary care dentistry, the GDP still has a key role in the patient's overall care. It is therefore important to have a good understanding of these conditions and their consequences for dental treatment in order to provide adequate patient support. Management requires a multidisciplinary approach to treatment and as part of this GDPs are integral in prevention, early recognition and maintenance of oral health following diagnosis. This article aims to refresh the reader's knowledge regarding MRONJ and ORN and support the GDP in managing this patient group.

Survival rates of dental implants in patients with head and neck pathologies: 12-year single-operator study

OBJECTIVE

To evaluate the survival rates of dental implants placed in patients with head and neck pathologies treated with resective surgery with or without free flap reconstruction, radiotherapy alone, and/or chemotherapy.

STUDY DESIGN

In this study, we retrospectively analyzed the survival of intraoral dental implants placed by the same surgeon over a 12-year period from 2007 to 2019. These implants were followed up clinically and radiographically for a period of 36 months postoperatively and throughout the restorative phase.

RESULTS

A total of 190 patients with a total of 739 dental implants, comprising both intraoral and zygomatic implants, were included in this study. Overall, the dental implant survival rate was 95%, with a similar rate for dental implants placed in irradiated and nonirradiated bone (90% vs 93%). A lower implant survival rate was noted in implants placed in transplanted bone (79%). In cases of implant failure (n = 17), 35% (n = 6) of protheses survived and remained functional.

CONCLUSIONS

Our findings support the placement of dental implants in patients with benign and malignant pathologies of the head and neck to improve their quality of life. However, we highlight the need for careful surgical planning and placement by experienced clinicians.

Genetic variants associated with mandibular osteoradionecrosis following radiotherapy for head and neck malignancy

BACKGROUND/AIM

Utilising radiotherapy in the management of head and neck cancer (HNC) often results in long term toxicities. Mandibular osteoradionecrosis (ORN) represents a late toxicity associated with significant morbidity. We aim to identify a panel of common genetic variants which can predict ORN to aid development of personalised radiotherapy protocols.

METHOD

Single nucleotide polymorphism (SNP) arrays were applied to DNA samples from patients who had prior HNC radiotherapy and minimum two years follow-up. A case cohort of mandibular ORN was compared to a control group of participants recruited to CRUK HOPON clinical trial. Relevant clinical parameters influencing ORN risk (e.g. smoking/alcohol) were collected. Significant associations from array data were internally validated using polymerase chain reaction (PCR) and pyrosequencing.

RESULTS

Following inclusion of 141 patients in the analysis (52 cases, 89 controls), a model predictive for ORN was developed; after controlling for alcohol consumption, smoking, and age, 4053 SNPs were identified as significant. This was reduced to a representative model of 18 SNPs achieving 92% accuracy. Following internal technical validation, a six SNP model (rs34798038, rs6011731, rs2348569, rs530752, rs7477958, rs1415848) was retained within multivariate regression analysis (ROC AUC 0.859). Of these, four SNPs (rs34798038 (A/G) (p 0.006), rs6011731 (C/T) (p 0.018), rs530752 (A/G) (p 0.046) and rs2348569 (G/G) (p 0.005)) were significantly associated with the absence of ORN.

CONCLUSION

This is the first genome wide association study in HNC using ORN as the endpoint and offers new insight into ORN pathogenesis. Subject to validation, these variants may guide patient selection for personalised radiotherapy strategies.

Should the HPV positive oropharyngeal cancer patient be considered for a two-stage dental assessment for their radiation treatment?

Patients due to commence head and neck radiation treatment are expected to undergo a dental assessment and be deemed 'dentally fit'. Though this intervention is welcomed by the dental fraternity it is not without its challenges especially in human papilloma virus (HPV) related oropharyngeal cancer (OPC) which has seen a phenomenal rise over the past decade. This perspective piece presents these challenges and proposes a potential adaption of the dental assessment for HPV OPC patients though not necessarily exclusive to this tumour sub-site.

Prophylactic pentoxifylline and vitamin E use for dental extractions in irradiated patients with head and neck cancer

OBJECTIVE

Osteoradionecrosis (ORN) of the jaw is preceded by dental extractions in up to 10% of cases. We present a case series of post-radiotherapy patients undergoing dental extractions who have received the prophylactic antifibrotic agents pentoxifylline and vitamin E (PVe) to prevent ORN.

STUDY DESIGN

A retrospective review was conducted of 219 patients with head and neck cancer (HNC) undergoing 1079 dental extractions between 2009 and 2020. Data regarding oncological treatment, prophylactic drug regimen, dental history, and clinical outcome was collected.

RESULTS

Twelve patients developed ORN at 17 extraction sites (ORN rates, 1.6% and 5.5% at tooth level and patient level, respectively). PVe regimen compliance significantly decreased ORN rates at the patient level (3.4% vs 11.5%; P < .03) and the tooth level (1.0% vs 3.5%; P < .01) compared with no PVe. Regimen compliance significantly reduced ORN rates in patients with oropharyngeal cancer (P < .01); in those with mandibular (P < .005) molar (P < .003), and flapless extractions (P < .04); in patients with radiation regions >40 Gy (P < .0009); and in those who underwent primary closure (P < .03). Machine learning analysis identified almost all these factors as influential at a tooth level for ORN.

CONCLUSIONS

PVe regimen compliance decreased dental extraction ORN rates more than the literature base rates of 7% at the patient level and 2% at the tooth level. Given its success in managing existing ORN, PVe could be extended prophylactically for dental extractions in irradiated patients with head and neck cancer.

Dentoalveolar radiation dose following IMRT in oropharyngeal cancer-An observational study

OBJECTIVES

This observational study aims to determine individual dental doses in oropharyngeal cancer (OPC) patients managed by intensity modulated radiation treatment (IMRT).

MATERIALS AND METHODS

OPC patients treated with IMRT had each tooth individually contoured on post-IMRT CT scans. The mean, maximum and minimum doses were calculated per tooth-based upon patient and tumor demographics (tumor size and nodal status).

RESULTS

A total of 160 patients were included in this study. Escalating tumor size and nodal status led to an observed increase in Dmean doses to the dentition on the contralateral tumor side. A significant region in both jaws received >30 Gy in this tumor group.

CONCLUSION

Tumor demographics were observed to influence RT doses to the dentition and need to be considered when providing a pre-RT dental assessment. The observed dose of >30 Gy in large spans of the dentition and jaws highlights future risk of dental deterioration and ORN with long term survival.

The use of pentoxifylline, tocopherol and clodronate in the management of osteoradionecrosis of the jaws

AIMS

Medical management of osteoradionecrosis (ORN) via pentoxifylline, tocopherol (PENTO) and clodronate (PENTOCLO) has shown both promise and early positive outcomes. We aimed to determine clinical outcomes for patients with established ORN managed solely via PENTO or PENTOCLO.

METHODS

The study retrospectively reviewed and collected data from the medical records of 169 patients diagnosed with ORN and treated via medical management. Patients that received any additional interventions such as surgery or hyperbaric oxygen were not included.

RESULTS

Medical management led to healed ORN in 54.4% (n = 92/169) of patients after an average of 12.9 months. Outcome comparison between PENTO and PENTOCLO identified the former regime to be significantly superior (p = 0.0001). There is an inverse relationship with increasing ORN severity and healing with medical management (p < 0.0001) with oropharyngeal cancer (p = 0.0347) patients responding favourably via this approach. Infection had a critical role in the final outcome with those healing requiring 1.3 antibiotic prescriptions, while those that had disease progression requiring 4.3 prescriptions.

CONCLUSION

Medical management is a viable treatment option for ORN. It appears to be most effective in Notani I and non-infected ORN. When healing was not achieved the regime was able to stabilise the condition.