The next question concerns completeness of resection. In the present study, cases undergoing R0 resection were shown to have better survival compared with R1/R2 resection. In resection of pleural lesions, it is sometimes difficult to discriminate R0 resection from R1 resection and to predict whether R0 resection can be obtained before surgery. I would like to know whether even R1 resection shows a significant difference compared with R2 resection or not.