A digital rectal examination is carried out to look for any lumps and any roughness and thickness in
the anal
mucosa. If
the doctor finds any change in anal
mucosa either visually or by feeling it by a DRE, or feels a lump, then a biopsy is taken from that region to look for cancer cells.
So, yes, if you have had so many examinations, cancer is probably ruled out. If there was a suspicious region then the health care provides would have notified the specialist.