Is Osteoradionecrosis Evolving with Improved Radiotherapy Delivery System?

Osteoradionecrosis¹(ORN) is a complication following radiotherapy and can often be difficult to manage. There remains no guaranteed cure once present and hence concerted efforts are made pre-radiotherapy through intervention such as prophylactic dental extraction to reduce the risk of its occurrence. This practice was largely based upon identifying induced causes, such as dental extraction² as the major cause. Furthermore with improved radiotherapy delivery systems through intensity modulated radiation treatment (IMRT) the incidence of ORN was hypothesised to significantly reduce, but remains to be seen.

At Guy's and St Thomas (GSTT) Hospital, both the department of Oral Surgery and Head & Neck manage ORN. Pooled databases of both departments allowed for retrospective analysis of data between the period of 2008-2015. This range was ideal as it covered an era of external beam therapy (EBRT) (2008 – 2011) as well as IMRT only (2011 – 2015) for institutionally treated patients.  Not all ORN patients were originally treated at GSTT for their oncology diagnosis. Data collection included patient demographics, oncology diagnosis, site, associated treatment and cause of ORN. Data was collected through a computer database and required basic data analysis to show breakdown of cohorts.

A total of 125 patients had presented with ORN within this 7-year period. Males dominated the cohort (92 patients, 73.6%) and the mean age was 64.3 years (range 33-86 years). The oropharyngeal (46.4 %, 58 patients) tumour group was the most common. From the cohort, 65 (52%) patients had received EBRT, and 60 (48%) IMRT only. For those that had received EBRT, 27 (41.5%) patients had additional chemotherapy while in the IMRT only group this was higher at 60% (36 patients).

Table 1 shows the various presentations of ORN via radiotherapy delivery and with or without additional chemotherapy. Spontaneous occurrence of ORN was vastly superior in comparison to induced ORN. Analysis of the tumour groups within the spontaneous cohort found oropharynx to be the most common at 45.4% (40 patients). Of these 40 patients, 75.0% (30 patients) were treated with both chemotherapy and radiotherapy.

 

	EBT only	EBT + Chemo	IMRT only	IMRTonly + Chemo	Total
Spontaneous	26	17	17	28	88  (70%)
Induced	12	10	7	8	37 (30%)
Total	38	27	24	36	125

Table 1: Occurrence of ORN from radiotherapy and chemotherapy

ORN has been a long-standing complication of radiotherapy. Clinically this condition has been difficult to manage and prevent and could be associated with  the evolving management of head and neck cancer. It appears that pre-radiotherapy intervention such as prophylactic dental extraction is not adequate enough to avoid ORN and the condition can now occur spontaneously especially in the oro-pharyngeal group identified at a heightened risk. This remains a concern as this group of cancers are on the rise and occurring in a younger population with increasing survival rates. The hypothesis of decreasing ORN following IMRT only is yet to be seen. On the contrary it appears ORN has just amended to the changing circumstances.

References

1. Syed Nabil, Nabil Samman. Risk factors for osteoradionecrosis after head and neck radiation: a systematic review. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012; 113:54-69)

2. M Burke, M Fenlon. Osteoradionecrosis – a review of prevention and management. Journal of Disability and Oral Health (2010)