I have pleural mass in left lung 5cm I did the biopsy needle but the result was insufficient. How can make sure that mass is cancer or not?

Repeat biopsy. The way to make sure is with an adequate tissue specimen (from a biopsy). It is unfortunate that you had one, and it was insufficient. If you are willing to try it again, that may be your best choice. I'm assuming the biopsy was done with CT guidance. If it was not, then a biopsy with CT guidance may be helpful in confirming needle placement.