transrectal biopsy transrectal biopsy transrectal biopsy is a biopsy procedure in which a sample of tissue is removed from the prostate using a thin needle that is inserted through the rectum and into the prostate. transrectal ultrasound (trus) is usually used to guide the needle. the sample is examined under a microscope to see if it contains cancer. transrectal biopsyicd-9-cm60.11