Incidence and Factors Associated With the Development of Calvarial Osteoradionecrosis in Patients Treated for Cutaneous Malignancies.

Study design: Retrospective cohort study.

Objective: Calvarial osteoradionecrosis (ORN) is a rare but devastating complication of radiotherapy. The aim of this study was to describe the cumulative incidence of Calvarial ORN in patients in patients treated for cutaneous malignancy of the scalp.

Methods: Data was compiled from patient records of a large tertiary hospital Plastic Surgery department and radiotherapy records of an affiliated cancer Center. We included all patients that were treated for cutaneous malignancies of the scalp that received radiotherapy. Patient demographics, cancer stage, treatment modalities, intraoperative details, and patient outcome data were recorded. Patients with incomplete radiotherapy data were excluded.

Results: We analyzed 105 radiotherapy treatments to the scalp administered to 84 patients and recorded 7 cases of calvarial ORN resulting in a gross incidence of 6.67% per radiotherapy treatment. The parietal bone was the most frequently targeted site of radiotherapy and accordingly the most common site of ORN (85.7%). Median time from radiotherapy dose to the development of ORN was 846 days. Higher number of radiotherapy fractionation (P = .038), cumulative radiotherapy dose (P = .035), prolonged radiotherapy duration (P = .022) and skin grafting (P = .003) were associated with the development of ORN.

Conclusions: Our findings suggest radiotherapy variables, such as prolonged radiotherapy duration, increased cumulative dose and higher radiotherapy fractions were strongly associated with the development of ORN. In addition, skin grafting following surgical resection was associated with the development of ORN. Further studies with larger sample sizes are required to further explore this relationship.