Impact of a dedicated palliative radiation oncology service on the use of single fraction and hypofractionated radiation therapy among patients with bone metastases.

BACKGROUND

Radiation therapy (RT) is frequently used to palliate symptomatic bone metastases. While high quality literature has shown that for uncomplicated bone metastases, shorter radiotherapy courses are just as effective as longer courses for the treatment of pain, shorter courses remain under-utilized. We aimed to assess the impact of a dedicated palliative radiation oncology service on the frequency of single fraction RT (SF-RT) and hypofractionated radiation (hypo-RT) (≤5 fractions) among patients with bone metastases.

METHODS

We identified 2,086 instances of palliative radiation (RT) for complicated and uncomplicated bone metastases between April 10, 2008 and September 17, 2014. We used multivariable logistic regression analysis (MVA) to estimate the association of the Supportive and Palliative Radiation Oncology (SPRO) service with the likelihood of receiving SF-RT or hypo-RT after controlling for age, sex, tumor type, and treatment site.

RESULTS

Prior to SPRO's implementation on July 1, 2011, the proportion of SF-RT and hypo-RT for bone metastases was 6.4% and 27.6% respectively. After SPRO's implementation, the proportion of SF-RT and hypo-RT increased to 22.3% (P<0.001) and 53.5% (P<0.001) respectively. In MVA, patients were more likely to receive SF-RT [odds ratio (OR) =3.3, 95% confidence interval (CI) =2.4-4.7, P<0.001], and hypo-RT (OR =2.5, 95% CI =2.0-3.1, P<0.001) after SPRO's implementation. Compared to sites without a dedicated palliative service, patients receiving care at the SPRO affiliated department were more likely to receive SF-RT (OR =1.9, 95% CI =1.1-3.2, P=0.02) and hypo-RT (OR =1.5, 95% CI =1.1-2.0, P=0.004) for bone metastases. After SPRO's implementation, the average number of RT courses delivered for bone metastases increased from 17.4 to 25.6 per month, (+8.3, 95% CI =4.99-11.55, P<0.001). Despite greater SF-RT and hypo-RT, the average total fractions per month of palliative RT for bone metastases increased from 163.5 pre-SPRO to 166.8 post-SPRO, though not significantly (+3.22, P=NS).

CONCLUSIONS

Implementation of a dedicated palliative radiation oncology service was associated with increased use of SF and hypo-RT and with greater courses of RT delivered for bone metastases.