Proton versus photon radiotherapy for primary hepatocellular carcinoma: a propensity-matched analysis

• Published in: Radiation oncology (London, England) England), 2020-06, Vol.15 (1), p.159-10, Article 159
• Main Authors: Cheng, Jen-Yu, Liu, Chieh-Min, Wang, Yu-Ming, Hsu, Hsuan-Chih, Huang, Eng-Yen, Huang, Tzu-Ting, Lee, Ching-Hsin, Hung, Sheng-Ping, Huang, Bing-Shen
• Format: Article
• Language: English
• Subjects: Aged; Bias; Biological effects; Carcinoma, Hepatocellular - mortality; Carcinoma, Hepatocellular - radiotherapy; Clinical outcomes; Cohort Studies; Comparative analysis; Drug therapy; Female; Hepatitis B; Hepatitis C; Hepatocellular carcinoma; Humans; Liver - radiation effects; Liver cancer; Liver diseases; Liver Neoplasms - mortality; Liver Neoplasms - radiotherapy; Male; Medical research; Middle Aged; Patient outcomes; Patients; Photon; Photons; Photons - adverse effects; Photons - therapeutic use; Propensity Score; Proton; Proton Therapy - adverse effects; Protons; Radiation; Radiation dosage; Radiation effects; Radiation Injuries - epidemiology; Radiation therapy; Radiotherapy; Radiotherapy Dosage; Regression analysis; Relative biological effectiveness (RBE); Risk analysis; Risk factors; Studies; Survival; Tumors
• ISSN: 1748-717X; 1748-717X
• DOI: 10.1186/s13014-020-01605-4

Proton radiotherapy has a dosimetric advantage over photon radiotherapy. Many retrospective studies have shown promising results with proton radiotherapy in treating hepatocellular carcinoma (HCC). However, clinical evidence demonstrating the benefit of protons over photons is still limited. We therefore compared the clinical outcomes of the two modalities using medical research databases from our medical foundation. We conducted a propensity score-matched cohort study based on our multi-institution medical organization research database. From January 2007 to January 2018, a total of 413 patients (photon: 349; proton: 64) who were diagnosed with HCC and primarily treated with radiotherapy with curative intent were enrolled. Overall survival (OS) and radiation-induced liver disease (RILD) were assessed. Stratified analysis was also performed to evaluate the heterogeneous effects of the two arms. A total of 110 patients (photon: 55; proton: 55) were analyzed in the propensity-matched series. The matched groups were balanced for baseline tumor risk factors. Cox regression analysis revealed a significant survival benefit in the proton group (p = 0.032, HR 0.56, 95% CI 0.33-0.96). The median overall survival in the proton group was not reached and that in the photon group was 17.4 months. The biological equivalent dose of radiotherapy was significantly higher in the proton group than in the photon group (median, 96.56 Gray [relative biological effectiveness] vs. 62.5 Gray, p