Short course palliative radiotherapy in advanced solid tumors: a pooled analysis (the SHARON project)

Previous trials showed the tolerability and efficacy of a palliative radiotherapy (RT) regimen (SHARON) based on the 4 fractions delivered in 2 days in different oncological settings. In order to identify possible predictors of symptomatic response, the purpose of this study is to perform a pooled analysis of previous trials. We analyzed the impact on symptomatic response of the following parameters: tumor site, histological type, performance status (ECOG), dominant symptom, and RT dose using the Chi-square test and Fisher's exact test. One-hundred-eighty patients were analyzed. Median RT dose was 20 Gy (range: 14-20 Gy). The overall response rate was 88.8% (95% CI 83.3-92.7%) while pre- and post-treatment mean VAS was 5.3 (+/- 7.7) and 2.2 (+/- 2.2), respectively (p < 0.001). The overall response rate of pain, dyspnea, bleeding, dysphagia, and other symptoms was 86.2%, 90.9%, 100%, 87.5%, and 100%, respectively. Comparing the symptomatic effect based on the analyzed parameters no significant differences were recorded. However, patients with locally advanced disease showed a higher rate of symptomatic responses than metastatic ones (97.3% vs 83.0%; p = 0.021). Finally, the complete pain response rate was more than double in patients with mild to moderate (VAS: 4-7) compared to those with severe (VAS > 7) pain (36.0% vs 14.3%; p = 0.028). This pooled analysis showed high efficacy of the SHARON regimen in the relief of several cancer-related symptoms. The markedly and significantly higher complete pain response rate, in patients with mild-moderate pain, suggests early referral to palliative RT for patients with cancer-related pain.