Oropharyngeal cancer and osteoradionecrosis in a novel radiation era: a single institution analysis

Abstract

Aim: This study investigates the incidence of osteoradionecrosis (ORN) in patients with oropharyngeal cancer (OPC) since the use of intensitymodulating radiation therapy (IMRT). Materials and methods: The multi-disciplinary log for head and neck cancer (HNC) at Guys & St Thomas' NHS Foundation Trust was used to identify and collect data on all patients with OPC and treated with a curative intent. Basic and oncology-related demographic data were collected retrospectively. The presence and absence of ORN along with the causative factor was recorded. Results: A total of 361 patients were available for analysis 1-year post-IMRT with the number decreasing to 129 patients at ≥5 years post-IMRT. Thirty-eight cases of ORN were identified from which 29 patients had necrotic areas in the region of pre-RT dental extractions. The occurrence of spontaneous ORN was most evident within the first 2 years following RT while induced causes appear a steady lifelong threat particularly in the human papilloma virus (HPV)-positive OPC group. Conclusions: The introduction of novel targeted IMRT has not seen a significant reduction in the incidence of ORN with the condition of concern particularly evident in the HPV-positive OPC group. These patients present with a relatively intact dentition receiving RT doses above the threshold for development of ORN. Additionally, the favourable long-term survival of the HPV-positve OPC population is likely to be contributory to the rise of cases seen which provides a clinical challenge the dental sector will have to proactively manage. Clinical Relevance Scientific rationale for studyThe use of the intensity-modulating radiation therapy in the treatment of oropharyngeal cancer (OPC) has not seen a significant decline in osteoradionecrosis (ORN) rates with their heightened risk, superior dental status and increasing incidence; ORN disease pattern in this group needs to be further understood. Principal findingsThe mean yearly incidence of ORN in OPC patients is 2.66%. Worryingly, the disease pattern shows a heightened risk in early years post-RT especially among the HPV-positive cohort in association with pre-RT dental extractions. Practical implicationsSuperior dental status of HPV-positive OPC patients coupled with increased survivorship poses a clinical Oral Surgery 14 (2021) 113--121.

Normal Tissue Complication Probability (NTCP) Prediction Model for Osteoradionecrosis of the Mandible in Patients With Head and Neck Cancer After Radiation Therapy: Large-Scale Observational Cohort

“…5 With the rising incidence of human papillomavirus (HPV) associated subtypes of HNC, 6 survival rates have improved, as HPV-associated tumors are more sensitive to radiation therapy (RT) than HPV-negative tumors and exhibit improved tumor control. [7][8][9] Moreover, because patients with HPV-positive tumors are typically younger and healthier, 10 the longer life-years expectancy postradiation and expected chronic compromise to bone healing for these patients result in a higher cumulative lifetime risk for ORN development, 11 highlighting the importance of dedicated strategies aimed to prevent ORN in modern practice.…”

Risk factors associated with osteoradionecrosis

“…Beyond this early-phase ORN in OPC, they also experience a lifelong risk of ORN of steady risk with the need for extractions in the future. 26,27,45 The current study identified 32 patients (16.2%) with maxillary ORN, highlighting it occurrence is a real entity and requires appropriate recognition. Many definitions still in place for ORN are historic and refer explicitly to only mandibular ORN.…”

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

“…This aspiration has not been achieved with the suspicion that rates of ORN may have increased especially in the OPC group. 18,19 It is argued that with IMRT all areas of the mouth become a target for some degree of exposure which explains the late effects not often seen previously. 20,21 Traditionally ORN has been associated maximum RT doses >60 to 75 Gy 6,15 ; however, it is now conceded that doses exceeding in the range of 30-40 Gy place patients at "at risk" of ORN.…”

“…24 The sensitivity of OPC to radiation produces improved long term survival but with it an opportunity to develop ORN with a compromised but heavily restored mouth and may explain the increase of this complication in OPC patients. 12,19 It has always been appreciated that the molar teeth were at risk following RT and extraction carried a threat of ushering in ORN. This remains the case, but the data presented shows that attention should be paid to the whole dentition.…”

“…29 The importance of laterality with respect to the dose of radiation to individual teeth shows clear differences (Table 4) and highlight the need to re-evaluate the practice of prophylactic molar extraction of sound teeth, particularly on the contralateral side of the jaw. Ironically, prophylactic extraction is not necessarily protective against the complication 19,[30][31][32] and leads to reduced oral and dental function. This study found that on the ipsilateral side, regardless of tumor and nodal status, mandibular third molars and second molars receive on average >60 Gy.…”