Survey of Stereotactic Body Radiation Therapy in Japan

Abstract

This study evaluated the updated Japanese status of stereotactic body radiation therapy (SBRT) by 2018 compared with that by 2016, 2014, 2010, 2008 and 2005. The numbers of institutions, cases, techniques and complications were evaluated. To recognize the current status of SBRT in Japan, a nation-wide survey was conducted by the Japan High-precision External Beam Radiotherapy Group. The questionnaire was sent by e-mail and mail to 841 institutions in 2019. Four-hundred and seventy institutions (56 %) responded by 20th of February 2020. Two-hundred and eighty-eight institutions had started SBRT by 2018, one-hundred and ninety-six institutions by 2016, one-hundred and thirty-seven institutions by 2014, one-hundred and thirty-two institutions by 2010, seventy-six by 2008 and fifty-three by 2005. 25,355 cases with lung tumor had been treated with SBRT by 2018. Among these patients, 7,256 were T1N0M0 and 2,732 were T2N0M0 non-small cell lung cancer. Metastatic lung cancer was 6,161, clinically diagnosed lung cancer was 6,993 and small cell lung cancer was 253. Primary liver cancer was 3,288 and metastatic liver cancer was 1,311. Eight-hundred and sixty cases of prostate cancer was treated by SBRT. The most frequent schedule used for primary T1N0M0 peripherally located lung cancer was 48Gy in 4 fractions at 134 institutions followed by 50Gy in 4 fractions at 35 institutions and 42Gy in 4 fractions at 27 institutions. In cases of 48Gy in 4 fractions, 47 institutions (35%) prescribed at isocenter, 32 institutions (24%) at PTV D95% and 30 institutions (22%) at PTV marginal dose. T1N0M0 centrally located lung cancer was treated most frequently by 60Gy in 8 fractions at 99 institutions and followed by 60Gy in 10 fractions at 28 institutions. Forty Gy in 5 fractions was the most frequent schedule for primary liver cancer at 32 institutions and metastatic liver cancer at 48 institutions. 3D-CRT was still the most popular irradiation technique at 221 institutions (48%) followed by VMAT at 125 intuitions (27%). The most frequent used IGRT technique for SBRT was 3D image registration device by on-board CT or in-room CT at 262 institutions (49%) followed by 160 institutions (30%) with 2D x-ray image registration. There were 63 (0.2% of 31,583 cases) Grade 5 complications with 43 cases of radiation pneumonitis, 7 cases of liver failure, 5 cases of hemoptysis, 3 cases of GI bleeding and five other causes. The current status of SBRT as of 2018 in Japan was surveyed. Continuous increase in the number of institutions and cases was confirmed.