Abstract 308P
Background
Despite rapid advances in targeted therapies for renal cell car-cinoma (RCC), bone metastases remain a major problem that significantly increases morbidity and reduces patients’ quality of life. Conventional fractionated radiotherapy (CF-RT) is known to be an important local treatment option for bone metastases; however, bone metastases from RCC have traditionally been considered resistant to CF-RT. We aimed to investigate the effectiveness of CF-RT for symptomatic bone metastasis from RCC and identify the predictive factors associated with treatment outcomes in the targeted therapy era.
Methods
Between January 2011 and December 2023, 62 lesions in 41 patients treated with a palliative course of CF-RT for symptomatic bone metastasis from RCC were included in this study. Forty-five lesions (72.6%) were treated using targeted therapy during CF-RT. The most common radiation dose fractionations were 30 gray (Gy) in 10 fractions (50%) and 39 Gy in 13 fractions (16.1%).
Results
Pain relief was experienced in 51 of 62 lesions (82.3%), and the 12-month local control (LC) rate was 61.2%. Notably, 72.6% of the treatment course in this study was combined with targeted therapy. The 12-month LC rate was 74.8% in patients who received targeted therapy, and only 10.9% in patients without targeted therapy (p < 0.001). Favorable Eastern Cooperative Oncology Group performance status (p = 0.026) and pain response (p < 0.001) were independent predictors of improved LC. Radiation dose escalation improved the LC in radiosensitive patients. A consistent treatment response was confirmed in patients with multiple treatment courses.
Conclusions
CF-RT enhances pain relief and LC when combined with targeted therapy. Patients who responded well to initial treatment generally showed consistent responses to subsequent CF-RT for additional painful bone lesions. CF-RT could therefore be an excellent complementary local treatment modality for targeted therapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The author.
Funding
Has not received any funding.
Disclosure
The author has declared no conflicts of interest.